Back in the summer of 1997 I did an internship in the museum collection of the Wisconsin Historical Society in Madison, WI. I found one of these amps and a matching Gibson lap steel in the collection one day while doing inventory. Being a curious guitarist I had to plug it in and try it. It powered up and made a horrible loud buzzing sound and passed no guitar signal. Quickly turned it off, put it back where I found it and went about my business. 😂
I went to see Tommy Emmanuel in Anaheim, CA a year ago, John Jorgensen opened for him with a Jazz lineup. Because it was local gig (for John) he brought his Charlie Christian setup including an amp that looked very much like that one as well as an es1?? With CC pickup. So cool to see the insides! Thanks!
I have one of these, 1936 EH-150 and it’s all original. It’s a very cool little amp, the mic channel rocks. It is a boxy sounding amp, small 10’ speaker and closed back cab. But it is a very usable amp. My speaker is an Admiral, I think my grand parents had an Admiral refrigerator. I also have an EH-185, rebuilt, another sleeper/secret/weapon.
Very cool. Amazing its even still around and in tbis condition. Made during Martins golden era. Dont even think about amplifiers being around pre war Martins.
Was fortunate enough to work on one this year. Wires break if you squint at them 😂. ST tubes so close they touch. But a real screamer with a PAF at the bridge. Great video!
I couldn't help myself, I looked up what these things are fetching. WOW! I wonder is its worth as a piece of history more than for the actual sound, am guessing so. Having said that, if money was not a problem, would I want one? Hell yeah. ;))
LOVE the old amps. Looking forward to the next video and giving it the once over. Yeah, HATE the old caps like that 10nF. Had a bunch of them from old tv and radio shops. They are junk and ended up throwing them all away. If they didn't outright drift 50-100% out of tolerance, they dry up and short!! I know some people want to original and original components, but really you don't! The caps and resistors are not to the quality they are now-a-day. The iron on the other hand...that stuff must have followed Bosch's cliche and "built for life" because they last forever!!
The metal can 6n7 may be the better choose over the glass 6n7gt . Not totally sure without testing both in that amp . A bit of a different sound to each in this application testing both is the only way to know for sure.
Very cool to see such a piece of history like that, and how often do you see any electrical or mechanic device predating World War II still in operation? Also, that thing has so many transformers in it there should be a logo on the front saying 'More than meets the eye'.
An old Electric Hawaiian amp. If those EH amps were kept closed up when not in use and weren't water damaged, they tend to stay really really clean inside that suitcase cab. I had an EH150 set come in a few years back. An EH150 lap steel and the complimenting EH 150 amplifier set. 6F5 pentode in from the mic jack? These did have a field coil and a choke, which is rather odd, as the filed coil kind of becomes a de facto choke.
Early electric guitar pickups used huge magnets and massive coils because amp technology was so primitive.Rickenbacker used a giant horse shoe magnet that surrounded the strings..The first Charlie Christian pickups had large bar magnets bolted to the inside of the guitar that must have weighed 2 or 3 pounds and really put out.Possibly the low gain instrument channel is correct and impedance matched.
So many 1920s and 30s amps had multiple transformers. I keep thinking it must have been easier to make a very accurate transformer than a very accurate cap, and certainly good caps were MUCH more expensive to make back then than they are today.
I haven't watched the whole video yet but I'll take a guess that one of the Transformers is an interstage transformer that functions as a phase inverter between the driver tube and the output tubes. This was a very common design in radios and amplifiers of the 1930s and early 40s'. A transformer used as a phase inverter has the advantage of never drifting in the way that a tube and capacitor phase inverter circuit might, and never leaking DC to the grids of the output tubes to cause the bias to go haywire.
Interestingly, I have a 70s solid state Aussie made 'Audio Telex' PA amp which uses interstage transformers! (& an output TX for 100v distribution). All that iron makes it heavy though.
Always wondered what those amps sounded like. Lyle or anyone heard or played Vintage Sound amps? Got one for sale my way Vintage 22sc. AB763 circuit in Princton size combo. WGS G12C/S Price is low…
The two additional transformers are a small filter choke (in addition to the field coil) and an interstage phase inverter transformer. Glad to hear that the amp's working well, too. Good original iron always a plus. The work inside looks pretty good imho, fwiw, the speaker cone looks like a replacement. Thanks for sharing this old beauty. Was any cabinet work done to make the glass 6N6 tubes fit? Most of these I've seen use the smaller version (metal) 6N6 as they're just barely able to fit. Looking forward to more details, nice way to start the week! (:
I agree with you so much I said the same things in the video. ;) Cab seems all original but I’ll double check re: tube clearance. I haven’t checked to see if the speaker is original to the amp. The wires to/from the speaker don’t look like 1936. And there are a few other things we’ll look at in the next video.
It could be a replaced speaker or perhaps a reconed (and rewired?) speaker, although the speaker itself looks about right, an old 10" Utah/Rola FC, a tough one to scrounge. 😜 The field coils usually measure b/t 700-1000ohms DCR, 8 ohm VC. A shallower basket might also explain the space allowing for the glass 6N6s. Thanks for the reply and I'll try to watch more carefully next time! 🙄🤓👍🏽
Hi Lyle - no, I haven't. I've worked on a few of these early ones and several of the slightly later versions and not seen any caps across the grids of the 6N7s or like-functioning tubes. Btw, I misspoke above about the field coil DCR, the last one like this I had on my bench read 2500ohms DCR and 8ohm VC, it was a factory 10" Utah w/the Gibson round badge on the speaker bell. Please lmk if I can be of any informational assistance, happy to offer whatever I'm able to provide. Thanks again for sharing. (:
I remember a couple years ago studying the schematic of the 6N6 version with the interstage transformer and for some reason wondering if this amp runs in class B, actually above my pay grade so I never figured it out, any idea? I also briefly entertained the idea of building one with equivalent or close enough novals just for poops and giggles, looking back at my notes I figured it would work out pretty nifty with 2 tubes: 12DW7 and 6CG7. The 12AX7 half of the 12DW7 for the 6F5, 6CG7 for the 6N7 twin triode, and the 12AU7 side of the 12DW7 for the 6C5/6J5, 2X 5881 for the output with a smallish non-interleaved OT, something like the 5K Hammond 1750S, modernized power supply with a 5V4 or 5U4, 500-1K dropping resistor for proper sag instead of field coil choke, and upping the filtering but not too much, 16-16-8-8, the voltages and operating point of the 5881s would need to be figured out. No idea about the proper interstage, also above my pay grade, but AES has P-T156 and Mercury offers a pricier repo. The tone if IIRC was done through a cap and a toggle switch, a rotary switch with several caps could be used for more choice. If anyone wants to go with it I pass the baton.
That sounds cool; do you figure cathode-biased Class AB for the 5881s, to put out something like 25 or 30 watts? A cathode-biased, single-ended 5881 could also be cool, but a pair in parallel Class A is also interesting.
My intent was to duplicate the original as much as possible avoiding octal pre's which except maybe hifi are nothing special and are mostly microphonic leftovers these days, but they were always too microphonic for guitar amps due to the large internal structures, same for ST power tubes, been there done that, just not worth the effort in a new build. It would be nice to have a voltage map and knowing the correct impedance of the OT to try and figure out the operating point for 5881, preamp tube operating points too. There's not much on the forums. Maybe our host could provide.
Hello, you mention to have a scope in your stuffs but I wonder why you don't use it to check the circuit. When I have to fix an old amp I always used to replace the speaker by a Hi-power resistor, and after a check of the voltages (anodes cathodes) I put a LF generator in the input and look with a scope at the signal after each stage till the "speaker".
I have a Gibson BR9 amp all original and needs help I played a few chords and stopped playing it because at the time I didnt have a variac or current limiter,it was made in 1948 and very basic this amp being 12 years younger is well worth being serviced ,I will service mine when I have the time but they do have great tones ,Its a wonder why Gibson didnt try to follow thier only Electric competitor in those days but Leo got it right almost immediately so theres that
I thought the Neutrik Silent plug should only be plugged into the guitar. Is there something about the wiring of some amps that makes this a non-issue?
Lyle, Been subbed since your channel was quite a bit smaller, and for the record, I respect the hell out of your work. I'm not ever trying to troll, even if I do try to crack dumba** jokes in the comments sometimes. Here's my serious philosophical question for you: If an amp makes it this long, to the point where only the iron, chassis, and cabinet are "original" (the physical components themselves, not that the values aren't the same), doesn't this mean the amp isn't original anymore? How does this differ from taking an old Bassman and rewiring the preamp as an SLO dirty channel for example? People seem to get really mad at the thought of modding old amps, but how is that really much different than this jewel? To me, it just shows that someone cared enough about this old thing to put in the effort to try and make it fit for their purpose. I mean, amps are just tools anyway, right? So what's wrong with modding something to suit the player? Thanks. Love your channel and wish you the best.
Thanks. In general I’m not opposed to unobtrusive mods. But in the case of rare historical pieces they should be left to the original circuit (but if parts of that circuit fail, replace them to keep that circuit working as designed). If the player wants a different sound, get a different amp. As far as “if things are changed is it still vintage” the analogy is a vintage car with fresh oil, belts, and brake pads. Yes, it’s still vintage, just driveable.
It's so gruntling that this unit is still in service!
Back in the summer of 1997 I did an internship in the museum collection of the Wisconsin Historical Society in Madison, WI. I found one of these amps and a matching Gibson lap steel in the collection one day while doing inventory. Being a curious guitarist I had to plug it in and try it. It powered up and made a horrible loud buzzing sound and passed no guitar signal. Quickly turned it off, put it back where I found it and went about my business. 😂
Also in Wisconsin, had a BR9 Amp with matching lap steel.
Fun kit indeed 😎👍
Wow, that amp is in amazing condition for its age! Looks like somebody's been taking good care of it.
good golly, what a piece of history! that suitcase rear is a great idea, no messing with screws.
Absolutely!
That microphone channel had some beautiful sounding distortion. From a pre war amp. So cool!
Wow same year as the 1936 summer Olympics in berlin. That is definitely some kind of old amplifier.
The cranked microphone channel was a pleasant surprise. I would love to spend some time with that.
I went to see Tommy Emmanuel in Anaheim, CA a year ago, John Jorgensen opened for him with a Jazz lineup. Because it was local gig (for John) he brought his Charlie Christian setup including an amp that looked very much like that one as well as an es1?? With CC pickup. So cool to see the insides! Thanks!
A really nice old amp and I reckon that suitcase cabinet kept it really clean inside.
I have one of these, 1936 EH-150 and it’s all original. It’s a very cool little amp, the mic channel rocks. It is a boxy sounding amp, small 10’ speaker and closed back cab. But it is a very usable amp. My speaker is an Admiral, I think my grand parents had an Admiral refrigerator. I also have an EH-185, rebuilt, another sleeper/secret/weapon.
To hear a current guitarist in the Charlie Christian style using one of these check out Jonathan Stout, an amazing player.
Very cool. Amazing its even still around and in tbis condition. Made during Martins golden era. Dont even think about amplifiers being around pre war Martins.
Wow that is a beautiful piece of History.
The Supro Delta King amps are styled after this! Stripes and all. I love mine, great sounding amp.
Agreed, for its age this amp is in great condition.
I just get excited when I see BED resistors in stuff! It’s interesting to see how things were built back then.
Fantastic vid Lyle, always thankful for your wisdom and care in practice.
What an absolute gem of an amp!
Thanks Lyle!
Was fortunate enough to work on one this year. Wires break if you squint at them 😂. ST tubes so close they touch. But a real screamer with a PAF at the bridge. Great video!
Thank you for sharing this wonderful piece of history with us.
Wow! I've never seen one of these before. Thanks for sharing!
Thanks for sharing this gem 💎, happy holidays ☮️
I really like the "Suitcase" like cabinet.
Aloha Lyle! Another very interesting and historical amp. Looking forward to more. Mahalo
Very enjoyable
I couldn't help myself, I looked up what these things are fetching. WOW! I wonder is its worth as a piece of history more than for the actual sound, am guessing so. Having said that, if money was not a problem, would I want one? Hell yeah. ;))
Nice! I have a ‘38 which has round top corners.
She's a beauty!
Oh yeah, the focus........
Great condition. Wonder if there's a Harley knucklehead under a tarp in this persons barn...?😎✌👍❤🖖
LOVE the old amps. Looking forward to the next video and giving it the once over.
Yeah, HATE the old caps like that 10nF. Had a bunch of them from old tv and radio shops. They are junk and ended up throwing them all away. If they didn't outright drift 50-100% out of tolerance, they dry up and short!! I know some people want to original and original components, but really you don't! The caps and resistors are not to the quality they are now-a-day. The iron on the other hand...that stuff must have followed Bosch's cliche and "built for life" because they last forever!!
The metal can 6n7 may be the better choose over the glass 6n7gt . Not totally sure without testing both in that amp . A bit of a different sound to each in this application testing both is the only way to know for sure.
I like the ones with the rounded shoulders better.
That sounds amazing
Not yet it doesn’t…
@@PsionicAudio no…it has an amazing sound as is!
Very cool to see such a piece of history like that, and how often do you see any electrical or mechanic device predating World War II still in operation?
Also, that thing has so many transformers in it there should be a logo on the front saying 'More than meets the eye'.
Sure; back when the company was known as "Sibson"... I remember!
An old Electric Hawaiian amp. If those EH amps were kept closed up when not in use and weren't water damaged, they tend to stay really really clean inside that suitcase cab. I had an EH150 set come in a few years back. An EH150 lap steel and the complimenting EH 150 amplifier set. 6F5 pentode in from the mic jack? These did have a field coil and a choke, which is rather odd, as the filed coil kind of becomes a de facto choke.
I can just smell that old amp! They have a certain aroma to them...
Early electric guitar pickups used huge magnets and massive coils because amp technology was so primitive.Rickenbacker used a giant horse shoe magnet that surrounded the strings..The first Charlie Christian pickups had large bar magnets bolted to the inside of the guitar that must have weighed 2 or 3 pounds and really put out.Possibly the low gain instrument channel is correct and impedance matched.
It’s not, but spoilers.
So many 1920s and 30s amps had multiple transformers. I keep thinking it must have been easier to make a very accurate transformer than a very accurate cap, and certainly good caps were MUCH more expensive to make back then than they are today.
I haven't watched the whole video yet but I'll take a guess that one of the Transformers is an interstage transformer that functions as a phase inverter between the driver tube and the output tubes. This was a very common design in radios and amplifiers of the 1930s and early 40s'. A transformer used as a phase inverter has the advantage of never drifting in the way that a tube and capacitor phase inverter circuit might, and never leaking DC to the grids of the output tubes to cause the bias to go haywire.
Oooh, transformer phase inverter! Now there's a thing you don't see very often these days.
Interestingly, I have a 70s solid state Aussie made 'Audio Telex' PA amp which uses interstage transformers! (& an output TX for 100v distribution). All that iron makes it heavy though.
Always wondered what those amps sounded like.
Lyle or anyone heard or played Vintage Sound amps? Got one for sale my way Vintage 22sc. AB763 circuit in Princton size combo. WGS G12C/S Price is low…
😊
The two additional transformers are a small filter choke (in addition to the field coil) and an interstage phase inverter transformer. Glad to hear that the amp's working well, too. Good original iron always a plus. The work inside looks pretty good imho, fwiw, the speaker cone looks like a replacement. Thanks for sharing this old beauty. Was any cabinet work done to make the glass 6N6 tubes fit? Most of these I've seen use the smaller version (metal) 6N6 as they're just barely able to fit. Looking forward to more details, nice way to start the week! (:
I agree with you so much I said the same things in the video. ;)
Cab seems all original but I’ll double check re: tube clearance. I haven’t checked to see if the speaker is original to the amp. The wires to/from the speaker don’t look like 1936. And there are a few other things we’ll look at in the next video.
It could be a replaced speaker or perhaps a reconed (and rewired?) speaker, although the speaker itself looks about right, an old 10" Utah/Rola FC, a tough one to scrounge. 😜 The field coils usually measure b/t 700-1000ohms DCR, 8 ohm VC. A shallower basket might also explain the space allowing for the glass 6N6s. Thanks for the reply and I'll try to watch more carefully next time! 🙄🤓👍🏽
I appreciate the insights into this old fossil.
Larry - have you seen them with 1nFs across the grids of the 6N7s? This one came with one (non original to the amp) but no schematics seem to show it.
Hi Lyle - no, I haven't. I've worked on a few of these early ones and several of the slightly later versions and not seen any caps across the grids of the 6N7s or like-functioning tubes. Btw, I misspoke above about the field coil DCR, the last one like this I had on my bench read 2500ohms DCR and 8ohm VC, it was a factory 10" Utah w/the Gibson round badge on the speaker bell. Please lmk if I can be of any informational assistance, happy to offer whatever I'm able to provide. Thanks again for sharing. (:
I remember a couple years ago studying the schematic of the 6N6 version with the interstage transformer and for some reason wondering if this amp runs in class B, actually above my pay grade so I never figured it out, any idea? I also briefly entertained the idea of building one with equivalent or close enough novals just for poops and giggles, looking back at my notes I figured it would work out pretty nifty with 2 tubes: 12DW7 and 6CG7. The 12AX7 half of the 12DW7 for the 6F5, 6CG7 for the 6N7 twin triode, and the 12AU7 side of the 12DW7 for the 6C5/6J5, 2X 5881 for the output with a smallish non-interleaved OT, something like the 5K Hammond 1750S, modernized power supply with a 5V4 or 5U4, 500-1K dropping resistor for proper sag instead of field coil choke, and upping the filtering but not too much, 16-16-8-8, the voltages and operating point of the 5881s would need to be figured out. No idea about the proper interstage, also above my pay grade, but AES has P-T156 and Mercury offers a pricier repo. The tone if IIRC was done through a cap and a toggle switch, a rotary switch with several caps could be used for more choice. If anyone wants to go with it I pass the baton.
That sounds cool; do you figure cathode-biased Class AB for the 5881s, to put out something like 25 or 30 watts? A cathode-biased, single-ended 5881 could also be cool, but a pair in parallel Class A is also interesting.
My intent was to duplicate the original as much as possible avoiding octal pre's which except maybe hifi are nothing special and are mostly microphonic leftovers these days, but they were always too microphonic for guitar amps due to the large internal structures, same for ST power tubes, been there done that, just not worth the effort in a new build. It would be nice to have a voltage map and knowing the correct impedance of the OT to try and figure out the operating point for 5881, preamp tube operating points too. There's not much on the forums. Maybe our host could provide.
Hello, you mention to have a scope in your stuffs but I wonder why you don't use it to check the circuit. When I have to fix an old amp I always used to replace the speaker by a Hi-power resistor, and after a check of the voltages (anodes cathodes) I put a LF generator in the input and look with a scope at the signal after each stage till the "speaker".
I do when necessary. Isn’t always necessary.
I have a Gibson BR9 amp all original and needs help I played a few chords and stopped playing it because at the time I didnt have a variac or current limiter,it was made in 1948 and very basic this amp being 12 years younger is well worth being serviced ,I will service mine when I have the time but they do have great tones ,Its a wonder why Gibson didnt try to follow thier only Electric competitor in those days but Leo got it right almost immediately so theres that
Restored '46 Gibson BR-4
ruclips.net/video/QS-fzD3NBHw/видео.html
@@PsionicAudio thanks Lyle its a real treat for me to see you craft and enjoy watching you do your magic
I thought the Neutrik Silent plug should only be plugged into the guitar. Is there something about the wiring of some amps that makes this a non-issue?
It’s a non-issue on any good quality jack. My cable here has silent plugs at each end, one straight, one right angle.
And I thought my 1963 was old.
Lyle,
Been subbed since your channel was quite a bit smaller, and for the record, I respect the hell out of your work. I'm not ever trying to troll, even if I do try to crack dumba** jokes in the comments sometimes.
Here's my serious philosophical question for you:
If an amp makes it this long, to the point where only the iron, chassis, and cabinet are "original" (the physical components themselves, not that the values aren't the same), doesn't this mean the amp isn't original anymore? How does this differ from taking an old Bassman and rewiring the preamp as an SLO dirty channel for example? People seem to get really mad at the thought of modding old amps, but how is that really much different than this jewel? To me, it just shows that someone cared enough about this old thing to put in the effort to try and make it fit for their purpose. I mean, amps are just tools anyway, right? So what's wrong with modding something to suit the player? Thanks. Love your channel and wish you the best.
Thanks. In general I’m not opposed to unobtrusive mods. But in the case of rare historical pieces they should be left to the original circuit (but if parts of that circuit fail, replace them to keep that circuit working as designed). If the player wants a different sound, get a different amp.
As far as “if things are changed is it still vintage” the analogy is a vintage car with fresh oil, belts, and brake pads. Yes, it’s still vintage, just driveable.
I hope you charge less since the back of the amp is so easy to remove! 😂
Hi, Ted sent me. I think I would really like this content, but - pardon me for being so blunt - the lighting sucks. Mr. Carlson spoiled me.