WARNING: Dangerous Levels of GAIN! ...EPIC Guitar Amp Conversion!
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- Опубликовано: 15 авг 2018
- In this vid, we'll convert a vintage Precision Electronics Grommes 50PG-3 PA amplifier into a high gain guitar amp with a Fender Princeton tone stack and 6V6 output. I left a lot in this one, so pull up a comfy chair and grab some popcorn. (Schematic used in this vid is for a model 55PG.)
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Man this is one of the best sounding amps you've done. Nice job dude.
I find watching Brad's videos very meditative, even if I only can follow 1/4 of the tech stuff. Great sounding amp!
Another nice one Brad.
I rather sit here for an hour and half and learn something than watching a stupid TVshow or movie.
Sounds great.
best answer ever! go build your own stuff, even if it won´t work first place, keep on doing it, and you end up with a unit that just will perform maximum right for you.
i agree
I spend hours and hours learning on you tube. I even learned to play guitar.
Amp sounds killer man! Thanks for your slow burning videos. Don't change a thing! It's nice to just sit back and observe your thought process. Also, it's a nice change of pace in the rush of every day life. Keep on truckin'!
That's probably one of the best sounding amps I've ever heard.
Ever hear a hovercraft?
@@johnymartin5411 lol every hear of a mace?
@@Buhhhhhh-xi4ju nope , but hovercraft are some pretty awesome amps
Yes!!
Peavey Festival 200w head biased so hot you're changing tubes between songs. Take that to the bank.
One of the nicest sounding amps in a while! Thanks, Brad!
What a fantastic sounding amp, qudos to you Brad, you know how to make these circuits sing!
Standing ovation man. Great job. Always. fascinating to see where you end up and to watch a masters mind work. Thanks pal
Thanks for the Vid. I went to school for electronics, a vocation I never used. Watching your vids is ringing a bell. I might just get back into it.
Wow what a conversion, that thing sounds fantastic. Absolutely fantastic.
Wow! That PRS and little amp sounds epic together and definitely some beautiful Fender tones without being too clean!!! Great job Brad and great playing!!! Bob in Germany
Your best video yet. I've watched this three times, great amp Brad. Thanks.
Had to come back and watch this again.Genius conversion ma man,sounds awesome!
Loved this video !! It's awesome to hear the reason for changes and see the changes! Playing later AWESOM !!! Loved hearing you play !!!
love your videos! I just found your channel last week and I've been geeking out ever since! I subbed 10 minutes into the very 1st vid! Thanks for your knowledge,humor and ability to explain in a very entertaining and interesting manner!
Welcome aboard, Mike! Buckle your seatbelt.
can't watch it enough. your playing is just the best ever, at least I think so. and the amp sounds out of this world.
Stayed long enough to hear "I'm Broken" Dime lick. Appreciate the references you throw into the demo. Thx Brad!!!
Love the closeups at 25 minutes in!
I’ve made point to point connections that were all rosin too. You’ve got an experienced eye!
Waow Brad! Cudos & hail to the Guitologist!!! Awsome conversion
this amp sounds fantastic. can't believe you played Pantera with this thing. Awesome job man
Beautiful point to point beast! Isolate and protect leads on this kind of circuit is laborious, but always needed.
Yeah! Pantera from the little amp!! Awesome video as always, these are the videos I love watching from you. Don't ever think that your videos are too long, most RUclips videos are too short love this style of vid. Keep up the great work
yeah, most of his videos seem to long till you get past the 2 or 3 minute mark and than you're like 'wait, I just sat here for an hour watching this shit?'
and than you look for another one :)))
Agreed .
Excellent work Brad ! How could any one not be happy with that Amp !
Brad, that is the most killer amp I've heard come through your shop. Fantastic. Well done!
Great video. Loved the clean up of the innards and the end result. So fun to listen to. Good stuff.
Dude, your amp skill are amazing. That thing sounds awesome. Nice chops too! Thank you!
From 34:00 to 39:00 I love when you tell the effects of each part on the sound. I learned a ton!
Great job on this one. It sounds great all around, but it's really the clean sounds that are gorgeous on this one. I'm sure the owner was blown away by the end result.
You play surprisingly well. Impressed with your soldering skills too.
This channel is so relaxing to watch!
A long one, but as always, informative - Keep 'em coming. Thoroughly enjoyed.
Brilliant video. What a great in-depth look and you have turned it into an amazing amp.
i do believe what the client meant by "smooth" was the transition from clean to overdrive on the gain pot. A smoother transition from clean to distorted...
Kept my attention the whole time Brad. I'm digging the cut aways, if that's what they're called. Amp sounds like what your client wanted.👍
What a beautiful sounding amp. Incredible!
I love what you did for the tone over all.
Great vid! Badass sounding amp, sounded like it had a sort of cocked-wah kind of tone at one point, I dig it! Hope the owner was happy, you put a lot of work into that!
Awesome tone and video, love your tonal sense. Sounds awesome, great work.
Learned a lot in this one and man, that sounds fantastic. Great work.
I don't usually comment but I just have to say...Wow. This really cleared some mud for me. The amp sounds great. Big, bold, and honest. Much appreciate the inspiration you've given me for my own tube amp builds and conversions.
BTW... I sure wish that could get my right hand to do finger picking magic that you do so easily. A pleasure watching and listening as always Brad. Thanks for sharing your wisdom and talent.
That’s very kind of you to say. I did a video about fingerpicking tricks. You can search it out. Might help you.
Great job Brad. From watching many videos (mostly yours) I've converted all of the Grommes Little Jewl amps to guitar amps from the LJ2 to the LJ7 and they all sound great. I'm especially fond of the octal (6SL7) pre-amp tube sound in the early models.
Cheers.
RC
Wow, Brad! Great job cleaning that mess up. Sounds awesome, too.
Re: Loudness. Very common on Hi-Fi systems. It adds bass boost at lower volume settings so that the sound doesn't go "tinny" because of the way our ears work. Look up Fletcher-Munson or equal-loudness contours for the details on the "why". Seems like this might be a nice thing to have in a practice amp.
I recall the stereos systems of the '70's and they usually had a loudness button.
Thanks for another great amp presentation. I love your work.
This is another one I'll be watching multiple times. Really like this one!
You got that thing sounding creamy and smooth as hell when needed and plenty of snarl and groan when needed! I would absolutely love to own that amp. Fantastic job Brad, peace and respect from Ireland mo chara x.
Really enjoying watching you work on this stuff - I am an equipment nerd that's how I found your channel - Also you play very good with a nice feel and touch on the guitar. I am using a Carvin Legacy 3 head and Legacy 2x12 (vintage 30's) cab in Stereo with a recently purchased Line 6 DT50 212 / Bogner combo. Sounding really nice - Will continue watching keep on rockin Bro
Man, that's the sort of amp I want right there.
I really liked the riff you played when you tested the amps tone before beginning the modification......I thought it was a solid rhythm! The amp sounds great too.
Great job, Brad! Congrats!
Dude its like class is in session im really digging your video's this amp sounds killer on my studio speakers, i could only imagine how it sounds in person. Thanks for sharing your knowledge with us
This is a real good amp, for some old school grind! Good job Brad!
Nice playin Brad. Nice work on the amp !!!!
Aesthetically Reminds me of a Sears Silvertone, or a Magnatone style. Really cool conversion!
I'll bet that guy was pleased with that job. What a versatile amp that has turned out to be.
Great movie, and the tired eyes blues opener at the end was simply delightful. I'm Glad I caught it.
I see "dangerous levels of gain" I click.
Very cool video and I always learn a thing or two from your vids and it's fun going along through these circuits.
She sure did clean up from all the noise and man what killer gnarly gain.
It was awesome to hear you talk about the same changes as I did to my 5E3 clone the 220k V1 plate load resistor and .022uF coupling cap.
I do though have the .022uF coupling caps on V2 and V1 normal Ch .005uF.
As you mentioned the 220k plate load resistor did drive the second preamp stage harder and with a lower coupling caps and man she cooks.
Holy shit that thing sounds fantastic for rock and roll. and the clean sounds really nice as well.
Hell of a job you did here, friend.
Such a GREAT little Tone MONSTER..!! Super job Brad..!!
I want to see you in your thinking cap, love the company having you on the tube, here at work
That is definitely one of the best amps you’ve done over. You really should design and sell your own brand, even if it’s limited runs. I would also love to hear these amps in a small rig with a right matching cab and some comp and delay with a tube screamer to really get the amp pushing.
Awesome to watch this. I restored a similar vintage mono 6V6 amp by Bell and also found the hum to be too large. I will definitely try relocating the center tap location.
Amp customized by the Guitologist! Sounds pretty nice. Looks like a sleeper. Well designed tube amps are awesome.
Brad, you are very kind, generous, and diplomatic when it comes to the other guy's work! I have a few adjectives I might use....none of them complimentary. Bless your patient manner.
BTW, if you're forced, by design and space, to live with an output transformer adjacent to a power transformer, simply turning one 90 degrees (so that the cores are perpendicular to one another) will cut down *some* of your mutual inductance problems. I suspect you knew that....but you didn't mention it, so..... :-)
Also, where those gain adjustments send the amp into oscillation - try adjusting the pot(s) to just below osc. then measure the pot resistance...then insert a like-valued resistor in the wiper circuit so that that circuit can never fall below a minimum resistance...and get rid of the possibility of driving it into osc.....or just switch to a 12 AT7, 12 AU7, etc....but sacrifice gain.
Wow, it really sounds amazing by the time you are done with it! Sounds like it would cut through the mix, too.
You're a fkn badass, dude! This is the coolest thing i've seen in a LONG time.
Fantastic work on this amp !
Nice playing, f'n GREAT tone, and a OUTSTANDING tutorial video of tweaking a tube amp.......I don't care how old the vid is.......THANK YOU for this!
You sir have the coolest job in the world!!!!👍😊🤘
Excellent content!!!
That thing produces distortion extremely well. Man you do great work.
Best Video yet, an Hour and a half of entertainment
Yes! A switchable NFB is my favorite mod. Tonally subtle but the amount of gain it frees up is crazy. It’s like an old school treble booster.
This amp, with the Princeton tone stack, is far more Boogie Mk1 than Marshall. The bottom end and clean is great! No fizzy bullshit either!
I was just picking my brain on what amp has that killer of tone.
You're spot-on with the NFB analogy imo. If more people looked at it as an built-in treble boost pedal, they wouldn't be so apprehensive about them.
Wow killer job, Brad!
Always interesting to see how other techs approach a problem such as no output (this isn’t a criticism of you at all, just an observation of how we all do things differently). Your approach of the signal trace is one that I had not done before, but will do in the future as I’m sure it will help me at some point. I on the other hand always do things from the output working back, checking plate volts and lack of volts on the grids starting from output tubes working back toward V1, and use the audible “pop” as my leads hit the grids as my indicator that the stage is working. But there has been a time or 2 with PCB faults where my method had me scratching my head, but if I had used the signal trace like you did it would have saved me time (just as I’m sure if you used my method it could have saved you time at one point or another).
In any case, always enjoy your videos as I always seem to learn something new (not always an easy task for someone my age! Lol).
.
P.s. Friends don’t let other friends ever use 220k plate resistors! Lol
Holy crap! I bet that customer was very happy with that tone! Great job!
This is my new favorite channel
every time I watch your videos... at first I wanna pick up my soldering iron... then at the demo part I wanna pick up guitar... :D great videos and great playing..
tnx alot...
Just finishing some work on a couple Marshall JCM 900 combo amps (4502 & 4102), came across your videos. Great stuff!
That is massive gain!
WOW! That little sh*t has some serious punch when you cranked in the drive!! Well done Brad.. between the Princeton tone stack and moving your main volume to just before the phase inverter really livened it up, and even though the transformers are still too close together, I'm really impressed you got it so quiet with a little other internal magic to alleviate the power hum. You're right about the theory of possibly driving the finals to the point of *just under* oscillation to get some cool effects that you could only hope to achieve on a transistor amp with a bunch of pedals. I know you were getting that just by fiddling with the gain and main vol. and going straight in with your guitar! Even on your 'shop' speaker it sounds pretty badass, so I can imagine what it will be like in a cabinet with a 12" Black Widow or similar. Nice work man, really enjoy watching the process from beginning to end!😍🎸 🤘😎🤘 Rock on!!
That’s one sweet ride 👍👍
Nicely done ✅ !!!
What a badass amp thanks to you!! And also hats off to your chops.....definitely smokin !!
What a straight up little beast that thing is.
Hey Brad Just watched this and I couldn't help thinking that this wee beastie in full rip mode on the edge of oscillation sounds not unlike one of the hi-gain stages in John Petrucci's latest Mesa Boogie Amp Head that he demonstrated on Rob Anderton's RUclips channel not too long ago. It is super vicious and dirty - I like it!
Great job man, what an analysis and modification process you went through there - Hat's off to you big time - So Cool!
All the best from Alex the K in Scotland
show off!! sounds great. been checking you out since the knight km15 amp
good shit man. subbed immediately. loved your demo at the end.
Very nice. I didn't expect versatility.
Wow when you hit the distortion I didn't expect that at all Cool little amp 👍✌️
Dad was Army Air Corps radio repairman, 1945-46 Guam , I find your old amp fixes fascinating.
Good job Brad!
You turned that thing into a rock beast. Love it.
Great video ! Nice playing too!
This is pretty funny. When I first started learning to play guitar this January, I tried watching some of your vids, Brad, and just, couldn't do it. Here I am 10 months later binging Guitologist vids 😆❤️👍🎸
I guess because I much more clearly understand what you're saying and what I'm looking at.
I know nothing about what you are doing but love watching your vids lol. That amp sounds awesome!
"know nothing about what you are doing"
I'm in the same boat I just won't admit it.
oh, nice art at the beginning. . Hey Brad.... Enjoyed this vid. Looks like a bad boy conversion. Thanks.
Awesome job could watch you for hours learn a lot thank you very much
That thing sounds fantastic! I bet it would sound great with a Tele running into it.
Wow. that thing really sings with some gain, so warm and clear but its got some bite. Nice.
Man, that thing sounds amazing!