1937 Gibson EH-150 Amp Restoration.....Part 2: Completed, Tested, and Utterly Unique
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- Опубликовано: 27 авг 2013
- This is the second of two videos depicting the restoration of a 1937 Gibson EH-150 amplifier. All repairs are discussed, as well as the very unusual nature of the circuit and the skillful modifications, probably done in the late 1930's, to create a second, high gain (and tone), channel. It should be noted that no existing schematics come close to describing the unique circuit in this amplifier, even before the early modifications were performed. Therefore, it may well be either an interim design or a one-of-a-kind unit, possibly custom built for the musician whose name is hand-lettered on the front of the cabinet.
Of the hundreds of amplifiers I have owned and worked on, this one is, by far, the most interesting and unique.
If you enjoy videos such as this one, featuring classic vintage jukeboxes, guitar amplifiers, and hand-made electronic gear, then please subscribe to my channel. You will gain access to over 50 similar videos, and you will be notified each time a new video is posted.
Thanks for watching !!! 
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Radial Twin-City ABY Amp Switcher Pedal has a 'drag' control that changes the input impedance and works great on single coil pickups. I find it amazing that that circuit was around 70+ years ago.
Thanks for sharing, CA :)
This is in reference to all your videos, not just this one, but I believe that your channel is the single best thing I've seen on RUclips, period. Your deductive reasoning skills, knowledge, thoroughness, curiosity, train of thought, delivery and teaching methods are top notch! Thank you!!! (And give Rusty and scratch behind the ears for me 😂)
#worldsbestteacher
Wow.....high praise indeed, Johnny. Thanks so much from all of us. We really appreciate it (especially Rusty) !!!
W.L. Dickerson was a guitar and amp,icier company from that era in the Chicago area. Apparently they produced product for a variety of “name” brands such as Fan Electro and Magnatone and apparently Gibson as well. This was a high end “Hawaiian” steel guitar amp originally back in those days and it looks like it may have been modified by the W.L. Dickerson company for the “new” Spanish style electrics that were coming out at the time.
This was an amazing find! Nice presentation, respectfully restored!
Thanks so much, Richard.
@@UncleDoug Unfortunately for this theory, there was no such company as 'W L Dickerson'. The Dickerson amplifiers were produced by Dickerson Musical Instrument Company from 1938. (Possibly renamed to 'Dickerson Brothers' or 'Dickerson Brothers Musical Instrument Company' by 1941. This site is a useful source of information: www.magnatoneamps.com/dickerson.html ) The Dickerson logo was just the word 'Dickerson'. The Dickerson brothers were named Delbert and Carl, respectively.
On balance, I believe that your 'W L Dickerson' was probably an unrelated individual. There are several persons identifiable through Google named W. L., William or Walter Dickerson, all now deceased, who would have been of an age to have purchased this amplifier close to the date of its production. Without more information, it's impossible to establish which, if any of them was the owner.
Incidentally, the output labelled 'Echo', which as you correctly surmised is in fact a socket for an extension cabinet, was originally promoted as a way of producing an echo effect. “Its use presents many new possibilities. The true Echo effect is obtained by placing the E-150 speaker and amplifier near the player and the Echo Speaker at an approximate 35-foot distance, preferably further from the audience and to either side. The slight soundwave lag time…creates a new and beautiful effect.” www.vintageguitar.com/1757/gibson-eh-150/
I believe that the large capacitor bank is also an addition. You can see a near-pristine model here: www.folkwaymusic.com/museum/amplifiers-/1938-gibson-eh150-0913/ The capacitor bank is nowhere to be seen.
I've been renovating two rooms and two walk-in closets in my house, with new hardwood floors, painting, new molding, shelving, etc. for the past 3 weeks, so I haven't had any time for a new project or video. I'm almost finished, however, and a new video should be posted this week.
An astonishing bit of kit. With a good few mysteries, to boot. Charlie Christian probably smoked... Top class, respectful restoration, as ever. 10/10.
Thanks so much, Bill :)
Great work and great video Doug, many thanks!
thank you for the amp repair videos im 62 and had repaired a lot of tube amps when i was a lot younger,i recently started up again,my father in law taught me about circuits and function on tube circuits,i just finished a hiwatt i have owned for decades and a early gibson falcon thanks for all your information this is a great resource ,mark
You're welcome, Mark. You were lucky to have such a helpful and well-informed father-in-law. I was never so fortunate :)
That is an incredible find. Another gem of a speaker! And Wow...1937.
Thanks, JL. Of all my pawnshop finds, this one is probably my favorite (and best).
I just started watching your vid's a couple months ago Unc.Doug. I've been a gigging guitarist for over 50 years...and what you're doing is priceless. Hats off sir
+Mesa Vella Thanks so much, MV. I'm really glad to hear that you appreciate and enjoy the videos :)
I really enjoy watching these videos sir some times I believe I grew up in the wrong generation but I have found all of your videos very informative and have even strengthened my little understanding of electricity I'm a diesel mechanic in san Bernardino and play guitar in our band at church on the weekends and have been hoping to find a project that I can get into on a budget and have a nice sounding amp and you have really given me the inspiration to do so and thank you for time you take doing the videos dont count all us young guys out yet lol
Thanks so much, Tony, for your interesting comment and kind words. I'm quite pleased to hear that the videos are informative, and I will endeavor to maintain your interest with new videos in the future. Please stay tuned !! :) ^. .^
Thanks Doug and Rusty for another fine series on a fine amp. Interesting story about Dickerson too. Take care and looking forward to more videos.
You're welcome, Colin. Thanks for watching and commenting :)
Great video. Nice amp. Thank you for the time you put into both.
Rd B Thanks, RB. Glad you liked it :)
wow. can hear the richness even on youtube. astounding. thankyou
Thanks, Scott.....glad you liked it.
Thank you for another very interesting video.
+RODALCO2007 You're welcome. Thanks for watching :)
The demo guitar is actually a late 70's solid (ash) body Matsumoku Vantage VS-695 Performer Model guitar with (hot) MMK-45 humbucker pickups. It's an inexpensive guitar (that puts out a good, strong signal), so I don't mind exposing it to the hazards of the work shop. In the 1970's, when CBS and Norlin were busily destroying Fender and Gibson, the Japanese produced some very fine guitars that many collectors now appreciate for their reasonable prices and very high quality.
My Strat was made in Japan, has humbucker at the bridge, the bridge is a Floyd Rose type floating, but it has fender moulded into the tail piece, the hammy bar gets pushed into the bridge and only swivels 120º plus on the end it has a Allen wrench and the other end has a screwed off end with a smaller Allen wrench, pretty cool and the fine tuners are on the bridge with a locking nut. I think it was made in the 70’s I’ll have to look at the serial number. one of the old owners took a small box cutter knife and carved he or her initials right on the front of the head stock. 1/8th x 1/8th not big but still sucks. when I was in Maui at the Hard Rock Cafe there, a another one was hanging on the wall, but I dont remember who it was owned by. the cord gets inserted the same as a les paul in the edge of the body. it has the noisy volume pot, thats ive been questioning you about cleaning them. 8^)
Good suggestions, Cat. I will check into them. Thanks !!!!
Thanks for looking, Gary. Let's hope something turns up.
That has got to be one of the most beautiful amps ever
I agree, Brandon. I found it in a local pawn shop. They knew what they had, and kept it safely behind the counter with a big price tag. I almost fainted when I saw it, never expecting anything of this age and quality to be available locally. It took a lot of talking, begging, bargaining, and bucks.....but it finally found a good home.
I did some research and found the same Dickerson Hawaiian steel guitar company, which later morphed into Magnatone. Neither of the original brothers who started the company have "W.L" as their initials (which is likely William Larry or something), but perhaps this amp you have is an early Dickerson conversion, when one of the brothers was tinkering in the garage, and this amp was modified for a family member who shared the family passion for Hawaiian music.
In any case, most of these early amps pay homage to Western Electric (AT&T), and were usually licensed by AT&T. Even early Gibson amps of this period are AT&T circuits, and it's possible it wasn't even made in Kalamazoo, MI!
You will see a lot of different amps of this vintage with different names, many with no brand names at all, porting the same black textured chassis material and the same thin wood construction. I have one right now in my collection:
ruclips.net/video/X-nxK39fy3Q/видео.html
Wow....what a great little amp, Brad !! I LOVE these ancient, primitive mini-amps.....and they never fail to sound a whole lot better than anyone might expect, as does yours. Thanks for the link to this excellent video. I am now an officially-subscribed fan :)
Yeah, the one I have had been completely serviced before I got it, and I'm pretty sure all the tubes are original Ken-Rad glass bottle. (The 6L6G dates back to, I think 1936 along with the metal tube version.) The Type 80 rectifier with the 4-pin base is a common sight on these old boys, according to my research. Some will actually have an AT&T license sticker on the inside of the cabinet.
Mine sounds phenomenally good. Just an excellent, very musical breakup on the notes when pushed. Nice and gritty with lots of interesting harmonic content. I have gut shots and more research on mine if you ever need it.
Feel free to post photos on my FaceBook page if you wish: Uncle Doug's Vintage Amps.
I'll like your page and keep up there too. I'm "The Guitologist" on Facebook.
what a find ! Thanks for sharing.
You'r welcome, Jason:)
I was a negative 10, when this amp was made. But I have a '53 or '54 Gibson GA-20, and it sounds incredible!!
Exactly the same with me, TT.......minus 10 :)
thanks for sharing..love these well considered vids.....
+chiba tae You're welcome, Chiba.....glad you like the videos :)
A beautiful find, with what looks like custom factory mods (and a power transformer to support them) plus personal signature on the front, perfect speaker & tubes condition... That's just insane :)
I'm 80% happy for you and 20% green with envy :)
Warm regards, Stan.
Thanks, Stan. I almost fainted when this jewel turned up in a local pawn shop. It was behind the counter, to prevent tampering, and I knew I was at their mercy the moment I laid eyes upon it. Naturally, they had already looked it up on the Internet and had come up with an astronomical price tag. It took a poker face, superhuman self-control, and more negotiation that a GM union contract to get it out the door.....:))
Its not unheard of for the original manufacturer to update their own gear back in the day. Everything points to this being the case, so I'd suggest that is the answer. Its a very interesting amp for sure. Those old oil-filled caps are HUGE too, OMG!!!! They're consistent with the period imo.
Agreed, HTH. Thanks for your input.
I first heard Charlie Christian when I was about 14, and I've had an EH-150 on my wish list since 1980 when "Guitar Player" magazine did a feature on him and told about this amp. It's one of the all time "Holy Grail" amplifiers. I hope I can find one some day. In Las Vegas you can score all kinds of cool old stuff because everybody here is so hip and trendy, they mostly want brand new shiny, flashy things, Not many people in these parts appreciate historic gear, and some are so dumb they'd sell the T.V. to pay the cable bill.
Thanks for an interesting video!
+NoName You're welcome, NN :)
Thanks, Travis. That's a very interesting theory. You can see why I don't think this was just thrown together in a garage by some guy with a soldering iron and a paintbrush. The technology and skill(s) required, especially back in 1937, were extraordinary. I really hope we can find out more about this amp and its original owner.
W.L. Dickerson , who ever he was, was a guy with an awesome amp, but badly in need of an ashtray.
No kidding, Frankie. I wonder if he died of lung cancer???
Very good video ! Enjoyed it !
I'm glad, Kal. Thanks !!!
Thanks for looking, Sparky. That would make him about 57 when he bought the amp new. It seems like most of the steel guitar players were older guys, so I guess that might make sense. Fannin County, TX is over 700 miles away, in the extreme NE part of the state......but things get moved around over the years.
Fascinating old amp. Never seen anything quite like it... more like looking inside an old radio than an instrument amp although the two do have some things in common.
The real early amps are my favorites. The circuitry and components are quaint and very interesting.
That's a awesome 😎 piece of Art
Thanks, Jean.
Very nice tone for a unit that is decades old.
+John Cunningham Thanks, John. It actually sounds much better in person :)
very interesting, thanks
You're welcome, Griff.
Uncle Doug:
Although I am not interested in guitar amplifiers, I find your presentations very informative and listen to them all the time. The only complaint I have is that it's unfortunate, for people like me, that your expertise is not directed to the repair of audio amplifiers. But great and thank you anyway.
+Edward Boghosian Thanks so much, Edward. I would think that about 90% of guitar tube amp technology would apply to audio amps. Other than the encouragement of distortion by one (guitar) as opposed to the absolute avoidance of distortion by the other (audio).....they tend to operate on similar principals :)
Thanks, Cat. That would make a lot of sense. The Dickerson family, due to their business, would have access to all sorts of technical expertise to modify the amp. You have to wonder why they modified a Gibson amp, rather than simply building one of their own from scratch, but the coincidence of the two names and the specific type of instrument is compelling.
They sure didn't skrimp out on materials back then. What a great find!
Quite so, Trebor. Thanks :)
Damn that is a gorgeous amp! Amazing! One point to make about that transformer phase inverter... when you do phase inversion with a tube, you will never achieve a perfect signal balance... and you can get much closer with the transformer method. This method is also smoother, but you do have some signal loss. Hammond still make inter-stage audio trannies. That's also pretty cool how they tied the two plates together on that 6n7 to effectively make it a great mixer for the mic and instrument inputs. That's a far better design then simply tying them all together to the same grid with a few resistors like most everyone else did in that era! And that "tone switch" that switches the 0.0007uf and the 0.013uf DC Blocking Coupling Capacitors in and out of the plate audio chain is an excellent tone control method! I use it all the time instead of a lossy tone stack. The small value works great for humbuckers and the larger value for single-coil pups. I am extremely impressed with the engineering and the build quality! archive.gibson.com/Files/schematics/EH-150%20Amp.pdf
Thanks, Mark. I agree with your very favorable review of the circuit. I really is a nicely designed and executed amp. As always, thanks for your very knowledgeable input.
Teamwork... this would be a great amp for Gibson to release an anniversary edition of.
No kidding. I have seen a re-issue of the old Electar amp, with the beautiful grill cutout. They did a pretty nice job with it. The EH-150 would be a nice follow-up.
I love it!
Awesome😎👍🎵
Thanks, Janice :)
Hi Doug, I realize it's been a while since you posted this installment in your superb series of videos, but I could not refrain from doing some sleuthing about this model. I came across a page which gives considerable background on this amplifier at vintageguitar.com. Unfortunately I cannot paste the link for some reason, but I'm sure you will be able to locate the page. I would say that your model is a bit later than 1937, and possibly a custom job (cf. the missing stripes on the top). Note that the Echo was intended as exactly that: a speaker placed 35 feet away that would actually give the impression of an echo. Keep on truckin'
I googled WL Dickerson and there is a record in the 1940 Census. He Appeared to Live in San Augustine, Texas.
+Stephen Hinkle That's interesting, Stephen. I'm also in Texas, but at the extreme opposite side of the state from San Augustine......we're about 850 miles apart. If it was indeed his amp, perhaps he or a relative brought it to my area.
Had one of these as well and did not touch it. It worked and had that antique smell. Loved it. This one is sweet too! This is in much better shape as mine was used a lot more I fear. Sounded almost exact. There were some tags attached indicating it was worked on at some points over the years. It distorts but in those days they were lucky to have any amplification at all. I googled W.L. Dickerson and got hits for W. Logan Dickerson...... Maybe something there? Enjoy
Thanks, Dennis. It's difficult to believe that these EH-150's were almost 20 years old when Fender started making the early tweed amps.....and they still work today ! Quite a testament to the high quality of their construction.
Doug Great Job. I would love to find one at a yard sale.
+w7hrcgreg Thanks, Greg. So would I. Unfortunately, I had to "pay the price" for this one :(
The back panel has to be removed prior to using the amp, to allow access to the input jack(s) and controls, so the whole back of the cabinet is open to facilitate ventilation.
Strafed by the Lüftwaffa, hilarious
+kcrmson It's not impossible.....the German Air Force has a major presence at a local military base.....but hopefully, unlikely :) Glad you enjoyed it :))
+Uncle Doug Oy vey! Let's just hope it's the post war German Military or else my family will have to escape once more. I seriously had a good laugh over it, your commentary is always great. Your teaching experience definitely pays off, it's nice understanding new info the first time around instead of how most stuff is learned nowadays.
Thanks so much, KC. I appreciate your very kind appraisal.
I have read about the EH-160. It must be a heavy beast to lug around.... :)
Doug,the guitologist recommended your channel loving your videos greetings from wales u.k(new sub)
I appreciate the referral from Brad and welcome you, MtL. Thanks for subscribing :)
Doug
Another great job here Sir. I would say that W.L. Dickerson was a Gibson Employee.
I think that name was placed there in the factory.
Travis
1937. The last year of the first, and greatest decade of electronically recorded pop music. Typically known as the PRE-SWING ERA. Orchestral banjo and everything!
Good historical insights, Paul. Thanks.
Greetings, Cal. Is there any accessible source for schematics reflecting these upgrades? I have been unable to find a schematic that comes close to describing this circuit. Also, I thought Lyon & Healy made harps, not amps. This information comes as a complete surprise to me.....are there references describing their amp production?
Thanks, Sam. I understand that a man named Dickerson started the Magnatone amplifier company back in the late 30's (see post below), but I can't find anyone with that name and the initials W.L.
Wouldn’t it be nice to hear what a lap steel guitar would sound like through this amplifier? I have learned so much from your videos. Thanks from Portugal. ☮️🌎❤️🇵🇹
That's great to hear, Sandi. I share your curiosity about the sound of a well-played lap steel through the amp. Sadly I'm not up to the "well-played" part ;)
You are welcome. I saw a 57 Chevy with a factory 4 speed in the floor. The guy had factory docs to prove it real. This is a fact that anything can happen in the factory.
Travis in Ky.
Delbert J. Dickerson invented a horseshoe pickup in 1938 for the guitar. Gibson was involved with a man named Guy Hart who filed patents. It is possible that this amp was around during that time. You lucky dog, nice find!!
How many of these exist in working condition today? This belongs in a museum, on loan, of course.
I'm not sure how many survived, Joe. There probably weren't all that many ever built in the first place. I must admit, it does look like a museum exhibit....but it still works perfectly :)
I have the 1939 (version 3) example of this amp, which is in most ways similar to your model two version, with the major difference being that all three inputs on mine are of the now conventional 'plug-in' variety as opposed to yours, which includes the now obsolete 'screw-on' type input for the microphone and one of the two instrument connections. This arrangement precluded you from testing the amp's microphone channel with your guitar. If you had been able to, I think you would have found a similar increase in gain (and an improved overall tonal richness) akin to what you found with the 'modded' input added to your amp (by either Gibson or an experienced tech). The volume is easily double that of the standard input channel. My understanding is that the 65F tube was dedicated exclusively to the microphone input. The other major difference is that all the filter capacitors are beneath the chassis on my later (version 3) model with the rest of the wiring, as opposed to being mounted on the top with the tubes. I agree that the tone switch in the bottom position is also quite useful in getting a great tone out of this amp. It was replaced in the final version of the amp (version 4) with a full sweep tone potentiometer that Gibson unveiled in 1940. Then it was off to war, with few advances in amp technology for the better part of a decade. This amp is really an incredible piece of equipment. It sounds as good or better than just about any amp I have played - modern or vintage. How many things built in the 1930s can you say that about?
rofred09 Thanks so much for your informative input, RF. I agree completely......the fact that these amps still function, and function quite well, is a testimony to the quality of their initial manufacture and design.
I have at least one question remaining on this amp you or one of your subscribers may be able to help me with: have you (or anyone out there in vintage amp land) ever hooked up a second speaker to the "Echo" output, and if so, what ohm rating did the speaker used have? I've wanted to try this, but didn't know what OHM load the output transformer would be looking for. In its original literature, Gibson recommended putting the second speaker 25' away from the EH-150 and slightly behind it to achieve the "spacious echo effect." I originally thought the amp included a second output transformer for driving the second speaker, but you disabused me of this notion by pointing out that what I thought was the second OT was actually a choke or unconventional (by today's standards) phase inverter. I'd really like to try and hear what they were going for with the 2nd speaker. If it works as advertised, it really would be the first "special effect" in an amp (predating tremolo by close to a decade). Please let me know if you're able to figure out what speaker load to safely connect to this jack (I've read there's an arcane formula for determining the ohm tap of an output transformer if it's not marked by counting the windings - shown on schematic - and then making some other calculations, but I don't have a complete schematic to even accomplish this, and besides, Rusty is probably better at math than me). Please let me know if you've preceded me here, and I'll do the same if I get there first. Thanks.
I have never connected an "echo" speaker, RF, and have not seen provisions for one on a schematic. I would assume, if such a feature were possible, that the "echo" speaker would be a permanent magnet speaker with the same voice coil impedance as the main electrodynamic speaker. Any difference in impedance would probably result in a significant volume difference between the speakers. I also suspect that the term "echo" is simply marketing puffery used to describe a remote speaker, making it seem more impressive than it really is.
Uncle Doug That it was simply 'puffery,' as you describe, it was my first thought too...but that's what I originally felt would be the case with the tone switch as well, and like you, I was pleasantly surprised by how well it actually worked.
I think "Tone" is a fairly basic necessity, early Fender Champ amps aside, but claiming that an auxiliary speaker is an "Echo" effect tends to get into the gray area of misrepresentation :) God bless those early marketing and ad men. They probably moved on to automobiles, with "Corinthian Leather" and "Cloud-like Suspension", etc.
Thanks for looking, WW. It makes you wonder why they named a street after him? Maybe he was the greatest pre-WW II steel guitar player in all of Montgomery, Alabama....:)
Perhaps it would be possible to check the Dickerson "family tree" to see if he had any close relatives with the initials W. L. Like you, I think the modifications were performed by a very skilled individual, and the Dickerson name on the front must be more than just a coincidence. Thanks again for your input, Sam.
I really enjoy watching your videos, please keep posting! For some time now I have been thinking about building a tube amp. I don't have much knowledge in electronics but plan on learning. I would love to tinker in a shop or in my basement on old equipment like you do, I also play guitar so that's where my interest was sparked. Any advise for someone just starting out with electronics? Thank you.
Greetings, Josh. I suggest that you pick out a fairly simple amplifier circuit, like a Fender 5F1 Champ, download the schematic, and start watching instructional videos (I have many posted) and accessing Internet sites for information, until you gain a working knowledge of basic amplifier circuits. Then you can either buy separate components (more challenging) or order a kit (simpler, and there are many available) and build your first amplifier. Best of luck !!
Deke Dickerson LEGONDARY Surf Guitarist in California. He play's through vintage Gibson Amps. Played on a Trashmen Disk. Ya know Surfin Burd. Maybe his dad or brother? or him?
Ps: Rusty's in Heaven helpen out the Big Guy's work shop. We loved him sooo much. We know you loved him even more.
Thanks, James.
The extra gain stage is for a microphone input. Check the schematic for the EH-185 -- it uses three SJ7s
You're probably correct, Gavin. Amps of this vintage (and several years newer) traditionally had a lower-impedance, higher output "Microphone" channel. The unusual characteristic of this amp, however, is that the extra gain stage appears to have been (skillfully) added to the amp after manufacture.
Not sure if this has been covered already, but I think the 'Echo' socket will have been for a spring line reverb unit.
Standard practice on vintage gear was to feed it from the speaker output, possibly via a resistor as you wouldn't want the full whack on it. Its output was returned to the power amp input, or to a mic input. Using a mic input meant there was a risk of causing howl if you raised the master gain though, so a separate return circuit with its own level control was better.
From what I've heard the Hawaiian steel players were/are keen on reverb, which would figure.
Thanks for your input, IWR, but the actual nature of the "Echo" feature in early Gibson amps is well documented. It was merely an auxiliary speaker output. The (rather misleading) name is based on the fact that if the auxiliary speaker was placed fairly far away, it's sound would be like an echo.
I would love to hear what Gibson has to tell of the history of this!
***** So would I , Stephen. I think a lot of these old amps have histories that would be fascinating. Thanks for watching....and for your input :)
Personally I love the original handle.........it gives it originality!
But sort of like the wreckage of the Hindenburg, it seemed to lack the style and function of the original.
great doug. just ordered esr meter, very useful. what do you think of the craze about putting likke .1 , .05 caps have a right and wrong way to connect tnem
freak55beat Non-polar capacitors (i.e. they are not electrolytic, with + and - labeled leads) can be connected either way with no problems. Axial capacitors that use two layers of foil generally have the outer-layer lead marked with a band on the outside of the cap. If the cap is connected to ground (i.e. used as a bypass cap), then the outer foil lead (with the band) should be connected to ground to shield the inner foil (signal) lead, to reduce noise. Other than this, in my opinion, non-polar caps can be wired either way. With the ESR meter you can connect either clip to either lead of any cap and get a good reading. The meter is entirely non-polar.
The modifications are so well done. This is why I mentioned Delbert. He was a great tinkerer, from what I have read. He would not have cared about the Gibson logo if he thought it was progress on design. Possibly for a relative? Anyone's guess.
Awesome! I'm thinking of building one of these amps! I have Tino Zottola's book with a lot of info but I'd love some transformer recommendations and other suggestions if you have them. Thanks!
Aaron McCloskey The one component that would be hard to obtain would be an appropriate electrodynamic speaker.....perhaps on Ebay. Re the transformers, you'll have to calculate the voltage and current demands and then select one, perhaps from Triode Electronics. Best of luck.
Thank you for this series. I found it because I was looking for information on the ES-150 amps. I have a 1938 ES-150 guitar I inherited from my grandpa (he used to play with Charlie Pride), and I want to build the amp that goes with the guitar. I really appreciate that you shared this.
I don't suppose you happened to get any readings while you had it unbuttoned...?
I didn't record any of the voltage measurements, Jeremy. This would not be an easy amp to replicate. I wish you luck with your project.
Thanks, Henry. Maybe W. L. Dickerson was a pal of Charlie Christian.... :>)
Great video. I have an EH-150 question for you...I have an EH-150 and when you turn it on it blows the fuse in about 20 seconds and the rectifier tube gets very hot in that amount of time too. Any idea what might be causing the problem?
Thanks, Seth. There must be a partial short downstream from the rectifier tube that is drawing too much current. See if any of the filter caps get hot. They are where I would focus my attention.
Yes, they were meant to be used together. Perhaps the guitar is out there somewhere with the same beautifully-lettered name on it. I'll ask the people at the pawn shop where I got the amp if there are any other Dickerson items to be had.....maybe waving some cash while making the inquiry (it never hurts). They had to keep records of the name and address of the person who brought it to them. Who knows? Maybe they were related to him.
I built a huge home made guitar/bass cabinet out of a combination of plywood and pine boards and made it the same shape as that amplifier. I glued 2X4's together ,same depth as cabinet.and put them on both sides of the top....then t.took a draw knife and rounded them just like the top of that amp Art Deco! Could also use many layers of thick veneer ...next time...
That sounds like an interesting project, Chris. The rounded shoulders in this cabinet are rather thin and definitely not up to supporting the weight of the (very heavy) chassis. They would have been better off with 2 x 4's like you used. :))
wow ....yes most push/pull radios from the late 20's to the mid 30's used transformers for phase inverters.....very high quality but sometimes they open up after years and years and have to be rewound/replaced etc.
Jukeboxes from the 30's and 40's do also. I always wondered if that didn't contribute to their strong bass response.
Doug: if, along with this total enlightenment, you also have analytic content on what happened to JFK - then I am never leaving your channel
Thanks, Andrew. By coincidence, I have a video in the works explaining, in detail, exactly what happened in Dallas on that fateful day......:))
Honestly, at the risk of decreasing your loyal viewership, I must admit that I, like most schmoes, don't have a clue. I do however have witnesses that place me 650 miles away (in high school) at the time.....so I'm not on the list of suspects :))
Uncle Doug
This brings to mind the old Woody Allen joke about him being busy writing "a non-fiction version of the Warren Report" ;)
hi Doug. Really enjoy your videos though I am not so much into instrument amps, more a hifi guy myself but principals still apply.
You replaced the cathode bypass caps with considerably higher value parts ie. 47uF vs 10uF. Can you explain your reason for this. Does it not affect the tone/volume of the amp?
I usually experiment with component values in amps, Sharkey, trying to achieve the tone that I prefer. Increasing the value of CBC's generally increases gain and bass response, to varying degrees. Apparently, in this case , I felt that the change was beneficial.
Perhaps a tutorial on caps would be useful, if you haven't covered that already. Nice vids. And your (other) machinist skills and eye for detail are obvious. It's a pleasure to read the comments, which most of the time in other places are snarky if not just mean. I'll have to check out the tube video. Lately, I've been working with homeless and abused Hammond organs. Those tube amps are something. Lots isolated grounds so it's a "hairs nest" of wires. I have two small leslie (amazing sound) that were scrapped. The amps are good for general use too. Thanx.
It's sort of cool how whoever did the mod for the high gain, put the input jack right above Michigan. Especially over the micHIGAN part. Maybe it was accidental but, it still accommodated the mod, well!
Sort of like a built-in label for the "Hi-Ga(i)n" input. I salute your careful scrutiny of the video images, and I doubt that anyone else (myself included) would have noticed this :)
+Uncle Doug Probably just accidental. But you never know, I guess.
Ok, the EH150 model stands for ElectraHarp model 150. This was a steel guitar amp built when these Gibson steel guitars were manufactured up to... and still offered in their catalogue as late as 1960 at least.
These unique four and six pedal steel guitars had voicings and organ like effects. Gibson also made an accordion amp which
along with their steel guitars were popular with musicians for that period.
LoL! The cigarette burns..lap steel...makes sense now. This amp seems to have a bit of vintage patina as well.
The tone switch is somewhat a bit of a kludge..but considering it was made 76 years ago (from 2013)..it was probably
all that was required from the ElectraHarp players at the time which would be sidemen in country and western groups.
Gibson discontinued their 'mellow amps' because the guitar players preferred the raucous sound of the Fender amps,
but at least (unlike the Ford Edsel), there are still a few of the GA amps around.
SuperCarver2011 Thanks for your input, SC.
Just my 2 cents. I think from the video and all that you said and the way it was made that the mods were made at the Gibson Company. I think W.L. Dickerson is maybe not related to Delbert Dickerson. Just a guess, but I don't think if Gibson made the amp custom, they wouldn't be making it for a potential competitor. I also think that if you contacted Gibson, they might could find documentation on this really nice Amp and who they custom made it for, or maybe not!
You may be right, LM. A detailed geneological investigation of Delbert Dickerson's family tree revealed no relatives with the initials W. L. I have not checked with Gibson yet, but may do so.
Doug, you should move those new cathode bypass caps. You have them much too close to the resistors they're bypassing. Those things are rated at several watts for a reason: they get hot. If you leave the amp on long enough you will hear a boiling sound, and guess what that is: the electrolyte boiling in the cap. Mount them as far away as you can get.
Nice unit, in remarkable condition. I'm wondering whether the PTX is original: it looks too good to be true, and too clean visually for the 1930s.
The three parallel lines are a very common Art Deco motif.
QuadMaestro Good advice, QM. If I open it up to work on it in the future, I will definitely keep your suggestion in mind. I don't use the amp very often or for long periods, so it's probably OK, but safe is always better than sorry. I tend to believe that the PT is original.....recall that this unit has a rear cover that seals and protects the chassis.....but will take a close look the next time I am rooting around in the circuit.
i think thad the exstra channel is for harmonica!!
very interesting vid
roodbaard51 Thanks.....glad you liked it :)
i love old amps and radios gad a RV french amp 58 and a stevens from 65
that is a nice Mallory cathode bypass capacitor,...
Doug: I found a couple photographs of another "Dickerson" amp for you. Mike's Guitars has one for sale. According to them, Dickerson Company was the predecessor to the Magnatone Company out of the 1930's. Makes sense?
Greg
Greg Guitars LLC
GREG GUITARS LLC Yes, this is what I understand to be true. I will try to find the photo of the amp at Mike's guitars. Thanks for the input.
Hi Uncle Doug, I have a 1937 EH-100 amp, but the only thing that is there is the speaker with the speaker wire... haha It was basically a barn find but in a nice clean barn. So I have the cabinet and speaker. What do you think I should do with it? I know Ill probably never find the amplifier section for one. I thought about putting in a different amp that fits in the area(new or vintage). Or maybe it would it be something you might be interested in buying from me? If so let me know. I could get you some pictures.
Anyhow, I love your videos, so interesting!
I appreciate the offer, SJ, but am not really in need at the moment. If you are unable to find or construct a replacement amp for the cabinet, you might consider offering it on Ebay. No doubt there will be some interest.
I know this is a late comment but here goes: I think the early musicians did not have the luxury of stage monitors so they would rely on the open backed cabinets so they could hear their work. I also believe that Gibson made this amp as an upscale one for pros. They put the removable back on to protect the innards while being transported and made it easily removable because they knew what the musicians wanted - to hear themselves. That explains also why the cigarette burns don't extend onto the back. The amp was regularly played without its back.
Good observations, Willy.....and I agree with you. These amps were not cheap back in the late 30's, and it's doubtful that many young, amateur guitarists could or would afford one. Removing the back also provides access to the controls and allows for cooling of the tubes.
What was the usual output of pick ups back then? Would that make difference between then and now?
Steel guitar pickups had a rather high output, I believe, James. The pickups added on to acoustic instruments had a rather low output.
All the signs (extra gain stages, impedance pot on the 'instrument' input, etc) suggest that the amp was modified to take multiple vocal inputs, for use as a PA.
The work definitely seems to have been done at the factory. (I have two first series EH-185s open about five feet from the computer). Keep in mind that these pre-war Gibson amps were built under contract by Lyon and Healy in Chicago.
This coincides with my guess that the amp was either a "special order" unit with added gain stage or was returned to the factory for modification. There is a Dickerson located in Las Cruces, NM who is an auctioneer. Perhaps this amp was used by his father or grandfather for that purpose.
Uncle Doug Wow, here's some interesting coincidences. I live in Las Cruces, and have connections to the Dickerson family. I also have owned a 1946 Gibson BR-1 amp for almost 30 years. Bought it for $20 in PA. I just took it to a local amp expert to have some work done. The Jensen field coil speaker is on its way to Weber right now to be reconed.
Greetings, Wes, and good luck with your amp restoration. I was aware that Charlie Dickerson was an auctioneer in Las Cruces and was wondering if "W. L. Dickerson" might not be a relative. If so, did he use the amp as an auction loudspeaker......or perhaps for music?
OH MY GOOOSH ... I WISH I COULD MY HANDS ON ONE OF THOSE ... GGGGRRRRR !!!!
I felt the same way when I walked into the pawn shop and saw it behind the counter :)
They don't make 'em like this anymore. Did you happen to draw a schematic when you were working on it? I'd be interested in the additional gain stage. Wonderful video!
Agreed, Tim. Thanks !! No, I didn't......sadly ;(
Well it explains the lack of cigarette burns on the back!What type of hollow body guitar do you use for the demos?Gretsch or Gibson?
Is there a chance that Gibson would have record of the modifications made for W. L. Dickerson in their archives? Or maybe his purchase of this unit?
Kevin Colt I have no idea, Kevin. Do they still have sales or service records from this era ??
Did you ever get to the bottom of the name? There was the Dickerson Brothers who made lap steels back in the 30's. As well as being in the LA music scene then and I think in 38-39 they started selling their own amps. Might be the same family.
I tend to think it was owned by an auctioneer who worked in southern New Mexico back in the old days.
Would that amp be a good one to build if the schematics were available? With nine tube its a beast and maybe not worth the effort.
As much as I love this amp, Geoff, I would not recommend it for a build. The tubes, transformers, and speaker would be tough to get, and the overall cost would be prohibitive. If you're looking for a great early amp to copy, check out the Fender Model 26 Deluxe. See my video and updated schematic.
you should always replace the filter caps, it will filter out any noise and also save the tubes in the future, because they leak DC through them and will damage the rectifier circuit
Thanks for your input, TD :)
JUST IMAGINE THE TALES IT COULD TELL IF IT COULD TALK
I feel the same about all vintage equipment, Fred, including the jukeboxes I restored.....it would be fascinating.
has anyone come up with a schematic for a fender 5d7 bandmaster?i have yet to find one
Is the circuit all that different from the 5E7? Whenever I can't find a specific schematic, one that is from a closely related model will generally do.
Why aren't filter chokes more common in valve amplifiers? They seem pretty handy, so why aren't the majority of them equipped with one?
I think because simple, much less expensive, resistors work rather well, Liz. It's just cheaper and easier to go with them instead of chokes.
wondering if this amp was moded by Dickerson Amplifiers for lap steel in the late 30's?
Viewers have been speculating for several years, Nathan.
It's funny how you touched the hot leads on the 20uF can cap. Zzzzzap!
Got the 1937 EH160 ACDC Il has got 12 valves and can run on a car battery