Traynor YGM-3 Tweak & mod Part 1 repair maintenance

[wade7163]

Question for you:  have your tried these mods with the YGM-3 reissue? The reissue sounds great at low volume but is lacking (or has too much of something) at high volume. Would clipping C11 and reducing C1 fix the high volume sound but still leave the amazing low volume sound? I'd like to improve the sound while doing as few mods as possible, and there seems to be a large number of mods for these amps floating around the internet. Speaker is the Jensen P12Q (stock speaker).

[patfurlan]

@wade7163 yes I have a reissue and it has the same mods ... its the amp you hear most often in the Band videos... FWIW I am not a fan of the Jensen in the re-issue it is similar to the old Marsland and possibly less appealing.

[wade7163]

@patfurlan So the mods don't affect the low volume, they are a total improvement? Sorry to ask but your band videos are high volume, they do sound great but I want to make sure the low volume performance isn't changed for the worst. thanks for the great videos

[patfurlan]

@wade7163 you can do the mods in steps... and back up if you feel they go to far. Changing the first coupling cap from .1 to .01 moved the low end from 8 hz up to 80 hz ... most people cannot hear this as anything other than rumble. Guitars don't go down to 8hz so you are cutting out noise & that helps improve the bass.

[wade7163]

@patfurlan Ok, one last question - you changed the presence from "10" (.1 cap) to "0" (no cap). If I wanted a compromise, presence at "5", would I replace C13 with a .047 cap or a .2 cap? or maybe the scale isn't linear? thanks so much.

[patfurlan]

@wade7163 you would put the .1 in series with a pot or resistor ... or you would hnge the 4.7k resistor under the cap to 2k or 3k but leave the cap off

[patfurlan]

@wade7163 if you used .02 or .047 it would still be full presence but at an even higher frequency ... fwiw my 2 favorite presence circuits are the marshall .68 cap from about 72 and the dumble 2.2mfd "accent" cap, a larger cap in this position adds mids to the presence ... both of those circuits use a 4.7k pot BTW

[wade7163]

@patfurlan Ok, I had it backward. So to get an adjustable presence like your examples I would solder a 4.7K pot in series with C11 cap. Thanks!

[patfurlan]

@wade7163 right ... you could do it temporary then measure the pot when you like the sound & use a fixed resistor ... the other way to do it is remove the cap and try replacing the 4.7k with 1.5k 2.2k or 3.3k I prefer 3.3k

[patfurlan]

@wade7163 presence works backward... the cap pulls frequencies out of the loop and grounds them ... since the loop is a negative control loop those removed frequencies do not control the power amp.. the 100k resistor and the 4.7 k resistor are a voltage divider network and about 4.7% of the signal is being fed back into the inverter ... the cap shunts all feedback above a certain frequency to ground making the amp run wide open above the cutoff value ... removing the cap makes the eq flat

[wade7163]

@patfurlan This amp (reissue) seems to have excessive hum when above 6-7 on the volume, as well as very annoying high freq noise. Is this characteristic of this amp because it is a vintage design?

[patfurlan]

@wade7163 how fresh are your power tubes El84's hum when they go bad especially SOVTEKS use JJ's in this amp ... if you have hi frequency noise you may have another problem

[patfurlan]

@wade7163 I've never had a noise problem with these, but I'm pretty meticulous in my regular service

[patfurlan]

@wade7163 I've never had a noise problem with these, but I'm pretty meticulous in my regular service

[rousejeremy]

The tremolo at 1:29 almost sounded like a univibe.

[patfurlan]

@rousejeremy because i am turning the speed knobby

[2Langdon]

Fantastic. Thank you so much for putting this up. You make it all really clear and easy to understand and inspire me to go do likewise! All the best, Langdon

[abcfuckind]

I wish I did know what you were talking about.

[pegasomarcelo]

See this

youtube.com/watch?v=YHfoON7ukS­c

[QuiltedPine]

Hi Patfurlan

I just got one these amplifiers today, and I love it so far. The only thing I don't really like about it is that I noticed the tremolo, at the lowest speed setting, is still quite fast (around 3Hz). IS that normal? The highest speed is quite unusable I think. Another thing is that there's only 1 6BQ5! I was quite surprised it worked, until I read that it was actually a class A amp, not Class AB. Is it at all dangerous to run these half-way with only 1 tube?

[patfurlan]

no harm in running a two tube amp with one tube, but it will not sound good ...

to slow down the tremolo locate the trmolo coupling caps and increase the value of one of them ... there are three in a chain (feedback loop) .01 +.01+ .01

chane one of them to .02

[patfurlan]

c 22 on the factory schematic .015 gets bumped up to .022 or .033

[QuiltedPine]

@patfurlan Hey thank you! The tremolo mod I figured that I should change either one or two (I'd say two) of the caps. Gonna have to get my Tektronix 543A scope running again, so I can repair my vintage amp with a vintage scope, wearing vintage clothes! lol

[74LesPaul]

Well explained and fascinating information. . thanks for posting. .

[patfurlan]

For all you folks who don't want to do this work themselves ... go check out the Traynor Dark Horse ... it's everything good about the guitar mate ... updated and with far cooler switchable "mods"

[NoelGrassy]

Re: YGM-3 variants_

Mine doesn't have the offset 12AX7 but it had those nasty freqs when cranked. Your experience and helpful vids made correcting my amp a breeze. I always felt like 2 X EL84s should sound great cranked and now they do it righteously! Thanks man,

Noel Grassy.

[patfurlan]

Most excellent ...

[bjenkins1031]

I have the three input, no bright switch version of this amp.  Any idea what the difference in the circuit is?

[patfurlan]

just the switch ... and the jack

they will be the same amp

[bubblebobbledfgsfdhs]

Sick vid, thanks.

[calmistheway]

In that case I'm all set. Got a 50 watt speaker in there form a Mesa Boggie .50 cal amp. Vintage Black Shadow type vs-12. IMHO the amp sounds great right now. So i'm gonna get back to shredding instead of soldering... ;) Once I got the "shrill" off the reverb it became usable. Thanks again!!

[calmistheway]

Hey PAtfurlan great vids!! I have a 69' ygm3 with a reverb transformer. cant find a schematic with reverb transformer on it. Serial # 22126 real early one i think. I did the .1 to .01 cap mod and there is improvment. There seems to be no presence cap to remove. And no evidence that one was removed. I tamed the reverb by changing the 330K R to 1M R coming from the reverb knob. and using a 12au7.. lost vibrato. What other changes can be made to the inverter section??? More headroom? thanks!!

[patfurlan]

The Biggest improvement in headroom comes from a speaker upgrade look for high db @ 1 watt 1 meter ratings

Celestion Blue/gold/v30, Em Red fang, EVM12

all are at least 3db better than the Marsland

to do 3 db better you have to double amp power

[patfurlan]

Look at the YGM1 schematics I bet you'll

see one closer to your amp

[BigFishingShop]

Hi, I have one of these, now can't you snip the long leg and in line a potentiometer and be able to dial it from cut to original ??

[patfurlan]

yes you'd use a 25k pot, and if it was a vintage amp the polarity switch hole would make a good place to mount your "presence control"

[BigFishingShop]

Thanks, truly an excellent job showing all this and just amazing what a difference. So assuming I could do something like have several different resistors like you tried the few different ones and have them wired through a multi position dial switch and run through one or the other as well, it all seems so simple.

[patfurlan]

yes you can do all sorts of things, In fact you always have too many choices.

When I set up an amp I always do it on a day when I can play flat out and at a variety of volumes. I want the amp to sing, sustain and ring with rising harmonics. Sometimes its about removing ugly frequencies either in the bottom end or in the top (ie fizz)

The ugly frequencies tend to mask the musical note, and the amp opens up when you dial them out.

I can't play a boogie with 200 options...

[EdPolepsy]

Ha...I just bought a YGM-3 today, and after watching that vid, my first thought was "mount a pot between the cap and ground, put it in one of the unused jack holes." Scrolled down and saw I wasn't the first person to think that.

[patfurlan]

Bias voltage and plate voltage vary a little

some were B+ 395 others were 415

the 415 amps will be louder

you can also bring up the volume by adjusting the bias ...

[cbcvbv]

I bought a used one in about 1971. It had no drive and not very loud. It was checked out and was working perfectly. I ended up using an LPB1 continuously to make it rock.

[patfurlan]

Interesting, I now have 7 or 8, they are slightly different but all have too much gain.

Generally if they can sound weak they need service ...

The ygm 1 was a more "tame amp" so perhaps you had that one

[backthisway]

One of my 4 is much cleaner than the others .. made in 72 .. it is also the loudest though.

[backthisway]

I have 4 YGM 3s .. 1972, 73 75 and 75 ... all look almost indentical inside .. all transformers and caps the same .. 2 have bright swithc .. but they all sound differente .. very different .. all really good .. but different . and I have switched all the speakers and tubes to do a direct comparison .. still distinctly different .. best amps I have had since 1976 .. and I used to have lots of 60s and 70s marshalls, hiwatts and fenders. Hail Pete Traynor

[patfurlan]

I have lots of old marshalls and fenders too...

I always loved the sound of a small amp driving a closed back 4-12 cab ... and hate lugging around

old stacks ... one day I looked at one of these and went ... heck the perfect solution .. just need to tidy up the bottom end

[8mileshigher]

These videos are incredible ! Thanks for taking the time to make these ! If I can ever find one again, I'll surely try these mods. Let me know if you know of one for sale. Chris

[patfurlan]

This one even has its Phillips Mullard tubes. Yorkville/Traynor is reproducing most of the other parts in exact detail.

[NoelGrassy]

Great stuff man! I bought one of this vintage but m,any of the OEM parts are missing. I'm grateful to see the original guts.

I'll need to seek out "Part One" of this series.

Thanks!