Resurrected Peavey Triumph 60

[Racing]

True and agreed.

Took it upon myself to rip the Triumph 60 of mine apart today. Did an inventory of what i had laying around and at least came up with the lytes for the pre-amp filtering and cathodes. So..said n done.
That done i handled the EQ and diode mod. All good.(Honestly i found the gain channels to sound just bloody awful before removal of the diodes)

Have ordered the 100mF caps needed for main filtering as the ones in there look like Hindenburg and those are supposed to show up come tuesday.
Checked the infamous voltages for heating and iīm a bit off too. Will wait n see what fresh caps brings there too.
The ones in there...have passed their best before to say the least.



I mainly use semis. Either HB or P90-and their derivates-when i play. So. Said n done i hooked her up and let her rip. IMO the clean channel is really good. Textbook good even.
Mine being a 60 sports Svetlanas for pre-amp,a local vendor AT7 for reverb driver and an Electro-Harmonics AX for PI.
Powers are a pair of Svetlana 5881s.

The OEM speaker...is IMO very very harsh and "in your face". I tried it through an old 412 cab with 1974 blackbacks in it...and that icepick treble went away and that put ME in control over the EQ pots.
Then through another 412 with a setup of just the "wrong side" of Rola greenbacks. As expected the tone went more mid and nasal. I am however a fan of the somewhat wider blackies..so the teleplug went that way once more and stayed there for like an hr or so.

Seing that i still havenīt gotten around to swap the main filter electrolytes out i really shouldnīt pass judgment,but i will none the less as i think some mods iīm going to at least consider are rather obvious.
Clean channel i believe iīll let be. It sounds good and carries ample headroom as well as warmth-with less peaky speakers than the OEM one at least.
The 150k anodes of the clean kind of tells the story to an extent.

As i removed the CR1 and CR2 i believe it was,the diodes that are supposed to works as sort of a noisegate i presume,the amp also settled down a bit as far as gain. Donīt get me wrong thereīs still ample amounts there,but they certainly got more managable.

Crunch channel however lacks a bit of bite IMO. It lacks that "engine roar" kind of attitude i look for on lower side strings upstrokes.

From what i gather in turn the crunch and ultra channels share and share alike and the only real difference is the pots used for respective channel. All good i guess,but that in turn dims up the possibilitys a little IMO.
If i look at the schematics for it the gain tubes run very "peavey" in as much that anode and cathode resistor values are basicaly within range all of them. This leaves out the possibility of using various wave harmonics and my idea is that iīll look into some more contemporary designs for ideas.
Point being that to salvage those harmonics in for instance crunch mode doesnīt for a sec mean itīll will work when you switch to ultra.

All in all though i have to say that i find the Triumph a diamond in the rough. Well built and sturdy. That it needs service after odd 20yrs is to be friggin expected. Having worked previously on Peaveys ranging from old VT Artists to Prowlers to Valvekings as well as later 5150s and 6505s...iīd without a doubt rate the build of the Triumph right up there with the early 5150s.
Sure. Tone is different,but the main thing is that someone put this piece together with some afterthought-altho being a child of its time.

Step up to for instance a Prowler is IMO more a step down. But hey..thatīs just me.

[Racing]

Finished the remains of the resolder job. Spent especial attention soldering the Molex pins of all cards,and as such all and any residual noise went out the door.

Hope for the fresh 100/400 caps to show up tomorrow.

Then played around a little with C13. Tried various cap sizes but have to conclude that Peavey made a rather close and reasonable assumption from the onset with them 1000p seing how the pre-amp is set up. Tried all the way up to 6800 but lower midrange just got undefined and mushy bigtime. Settled for a 1500 Mica.

The gain channels surely cuts all over the place though and i had a hard time balancing out the crispness/highs of the clean with what happend for the remaining two.(Yes the relay activated filter is out of the equation already) So i made short work of C17 which helped IMO. In crunch mode with C17 removed some crispness seems to be recaptured. In crunch mode the amp simply opened up a bit when run through a 412 cab with blackbacks.
Axe used was an old Daion Headhunter with SD Phatcats.

Got a Q for those more in the loop on Peaveys though. Why are the 3rd and 4th gainstages of the gain channels driven the way they are over the anodes? What made Peavey arrive on that solution? To me that just points to someone aiming for a relentless compression of the signal,but the Q in my case is to which avail?(Inc the vastly higher current draw then normal)
Point being from a practical POW that the post anoderesistor swing is limited to say the least and indeed in crunch or ultra i surely lack some dynamic capacity. One rarely see that design these days so hence why iīm asking. Cascade of the 4th being the more interesting.Basicaly to compress without driving the amplitude up the wall i presume.?
Then again. The Triumph being a child of its time and in the early 80s,and onwards for quite a while,all hi-gain music was compressed out the fabled so i guess that kind of answers my own question to a degree.

More importantly though has anyone tried to alter that setup along the lines of something more contemporary? If so,what was done and what was the results?

B+ of this amp is reasonably high. Checked vs the OEM schematics and iīm basicaly a tad high all over the place. Not beyond realms though,mine being an export/240V model.

[Racing]

Got some time with the Triumph today.

First thingīs first tho. On the schematics iīve downloaded the anode resistor for the 3d gainstage of the lead channels is marked as 10k. This is wrong. It is referenced as R21 and it is 100k.

Second of all look out with the anode resistor for the last stage,post loop. This is resistor R39 and by schematics is set to 220k. When i started to fool around with the pre-amp i soon discovered that this 1W referenced resistor has gone to hot making it drift to in my case approx 400k. As it is post loop it will affect the sound of the entire amp. I replaced with a regular 2W metal film.

That said.
I tried to get some sense out of the serial setup of anode resistors of the 4th gain stage of the lead channels. As i tossed the values around to hearts content it soon became evident what was going on but the fact,IMO,remains that a LOT of this amps "flatness" resides right there in lead mode.

First thingīs first tho.
It turned out that someone at Peavey,i presume cause the amp hasnīt been modded as far as i can see previous me,had mistaken the cathode decoupling cap for the intitial gain stage at V1b. What is supposed to be a 22mF one was in reality a 0,47 one-which is used for other gainstages.
That corrected the clean channel wasnīt all that clean anymore. So,i replaced C9 with a more "guitarish" 0,022mF one. Way better but still way to much. As can be seen on the schematics neither the 2nd stage for the clean or the lead carries any gridstopper. So,i installed one for the clean 2nd stage of 100k.

The amp now reacts more conventional in clean. Iīm a sucker for 150k anoderesistors for cleans..so they stayed. Might be that iīll fool around a little more with the stopper and whatīs more a filter across it aīla Marshall et al. Thinking along the lines of 120 or 220pF.

Lead channels then.
2nd stage first of all got a gridstopper too. 220k to be more exact. Second the cathode cap was changed from a 22mF to 1mF. This cleaned that stage up considerably. Iīm still uncertain if to play with the grid ground reference resistor. As is though it is still stock. That aside i also thought that the amp sounded "same same but different" and to adjust that i set the cathode resistor to 3.3k which worked very well in this case.

Third lead stage i didnīt really touch. Out of it though the fabled diodes marked CR1 and CR2 was removed since previously. The cap C17 too. I played around a bit with various ceramic disc caps in that postition but arrived on that the amp sounded its best without. It brought with it a briljance i lacked previously.

Then for the forth stage. ground reference resistor R27 was changed for 220k and in turn anode resistors R22 and R23 was set to share n share alike. Ie the anode resistance was divided per OEM but in this case it was set to 47k/47k and the output signal was still set between the two. This got rid of much of the "flat head" attitude of the amp. Now you can nuance what it is you do with the guitar in leadmode too.
I played around quite a bit with this ranging from connecting output right at the anode of the tube per normal,which as suspected ended in distortionville you wouldnīt believe,down to stock. Them 47/47 was kind of a happy medium.

For the sake of argument my amp also lacks R97 and R98 as well as C63. From what iīve read on the schematics layout this is as it should be for 60watt models?

As is the dubbed crunch channel IS a crunch channel,and a rather well sounding one at that. It has kept reasonable dynamics over the pot and the sound ranges from early rock to later 80s style iīd say.
The ultra channel though i presume needs some sort of treble bleed over the pot,which TBH can very well be due to a worn pot. No matter iīm going to install something rangingen between 120 to 330p to see what happens.

Further mods,apart from modding to adjustable bias and such more convenient mods,iīm thinking along the lines what goes on at and around the PI. Giving thought to putting "imbalance" at the anodes along the lines of the more "regular" 100k/82k. Whatīs more i see no reason what so ever for those 0,047 caps in and out of the PI. Those will receive an imbalance too.

Screen resistors in turn will be swapped for a set of 1k.

[nashvillebill]

The schematic that seems to be found most commonly on the 'net must've had a fold or something when it was scanned and so R21 shows as 10K on that scan. However, somewhere, I don't know where, I downloaded another schematic which does not have that fold in the paper and R21's value is plainly 100K on that schematic.

My priorities in life have undergone major changes in the year or so since I started this thread, so I have not had a chance to experiment much more with this amp or even play it much. Still, though, I keep coming back to a major "what if".....what if Peavey had not packaged this amp in the small 1x12 chassis, but instead had gone to a full-size chassis like their Classic VTX (2x12). Then they could've kept the circuit boards down to 2 (like the Classsic VTX), with a power supply board and the preamp board, and they could've mounted the tube sockets on the chassis like the Classic VTX. The amp's reliability and serviceability would be immensely improved; and with a much cleaner signal path (no traces and jumpers going from board to board and back) I suspect it would be quieter too. (I'm not real happy with the noise floor on this amp, still too much "hiss" IMHO).

[Racing]

Yeah. Ill sign that last sentence too. Thatīs one of the culprits iīm going to look into down the road with this machine.

As for how distortion is built suffice it to say that it is done somewhat different these days. Close friend and fellow guitarist however told me that there are metalheads out there looking for Triumphs in an effort to get to the very compressed sound it is. Typical 80s if you wish.

Iīm gonna try a little something as that goes. Albeit the setup is half redesigned already as is on mine iīm going to try a different pre-amp approach completely. Ie; iīll make the second gainstage for the lead channels become a asymterical one with 100k anode and 10k cathode. Third stage in turn will be 100/2.7 and the last one will as such lose the serial/cascade anode setup and be run 100/1.5.
Of course iīll have to laborate with ground refs and stoppers,but i have a feeling that this might redesign the pre-amp in such a manner that the scoping and distortion will come out more contemporary.
From what iīve gathered fooling around with the post loop stage is rather easy in as much that you simple hook up the signal at the effects send point and return it at the pre-amp point and as such jump the last stage completely.
An easy way of getting a grip on how much that last stage colours the sound.

[Racing]

FWIW iīm going to try this instead of the OEM one.



Lets just say that iīm no fan of the Scorpion.

[alerich]

I just picked up a Peavey Triumph 120 in outstanding condition for a song. I've been reading around about folks modding them to try and clear up the gain channels (beyond the ubiquitous EQ and diode mods) and I found a discussion over on the Hoffman Amps forum from a year or two ago. The guy made a few mods to the tone stack (short this, clip that - nothing major) to clean up the response but he said the biggest thing he did to open the amp up was to lower the 1M resistor before the effects loop (and where the reverb mixes in) to 470K. He said this does dampen the reverb a bit but opens up the amp in a dramatic almost Marshall like fashion. It seems that this 1M resistor chokes off the signal starting with the highs first. You cannot bypass it entirely (and probably would like the tone, anyway) because it will kill the reverb. Would be very easy to make it switchable - just add another 1M across it. Maybe a pot even. It's very near the effects loop in the circuit. I am going to bench my Triumph tomorrow and try his mods.

Just thought I would share.

[tedmich]

My Ultra PAG 120 has Triumph boards, but I have never seen a Triumph with the 13 knobs like the Ultra (which came next) Is you Triumph 120 the little 10 knob head, or the bigger 13 knob head? For my money the head improves greatly by upping the 1nF coupling caps to 2.2nF/630vdc PP film and also upping the 0.47uF cathode bypass caps to 1uF film.

[nashvillebill]

I don't see how the 1M resistor R36 "chokes the highs" or how dropping it slightly would make that much difference, but I'm no expert.

[Enzo]

1M R36 and 33k R37 form a voltage divider to knock the signal down for the FX send. That is a pretty large reduction. 1M over 33k results in the signal at the FX send at .03 the original signal. Dropping R36 to 500k increases the signal level to .06 the original. The "original" meaning whatever signal voltage was coming into the left end of R36. SO all it does is make it a little louder, by about 6db, which your ear interprets as "better". A little louder pushes you up the Fletcher-Munson curves some, so your ear hears the highs a little more. Probably does the same thing to lows, but in a guitar amp like this, you don;t hear a lot of lows to begin with.

[alerich]

I don't see how the 1M resistor R36 "chokes the highs" or how dropping it slightly would make that much difference, but I'm no expert.

Change it and see what you think for yourself. I just subbed in a 470K with a 10pf across it (sorta ala the way Leo did it). Good. Lord. Have. Mercy. An entirely different amp. It completely opened up the gain channels to an almost Marshall-esque tone. Gone is the nasal Brian May tone. This is hands down the single best sounding Peavey amp I have ever heard, played or owned. I'm glad I have a buyer lined up next week for my 6505. Through the same cabinets this thing eats it for lunch.

Now, it does impact the reverb and there's less of it for the same setting. My Ultra channel howls a little bit with the gain set high but I think I'm gonna swap out that 1M ultra gain pot for something a little smaller, anyway. The clean channel will overdrive a bit at higher volumes. I probably will make this mod switchable by putting the 1M back in place and setting a switch to jump in another 1M across it. I already have a front panel switch installed since the previous owner liked to switch the EQ mod in and out. I took it out entirely.

I'm not kidding. Try this. You are going to be amazed.

[alerich]

1M R36 and 33k R37 form a voltage divider to knock the signal down for the FX send. That is a pretty large reduction. 1M over 33k results in the signal at the FX send at .03 the original signal. Dropping R36 to 500k increases the signal level to .06 the original. The "original" meaning whatever signal voltage was coming into the left end of R36. SO all it does is make it a little louder, by about 6db, which your ear interprets as "better". A little louder pushes you up the Fletcher-Munson curves some, so your ear hears the highs a little more. Probably does the same thing to lows, but in a guitar amp like this, you don;t hear a lot of lows to begin with.

I understand the theory behind your post and how our ears react differently to different volume levels but the change I am hearing is so dramatic that I think there is more at play here. This just doesn't sound like a 6db increase of the same tone. I could achieve that by nudging up the post volume just a hair, couldn't I? That would give me the same tone just a bit louder. This resistor change yielded a profound change in the sound that the circuit is producing apart from the level. I don't know enough about tube theory to understand why it's happening.

[Enzo]

I could be totally off base, I offered that explanation as a place to start, take some of the mystery out of it. I find it valuable to look at a circuit in terms of function. It may wind up having nothing to do with your results, but a lot of people never would recognise that as a voltage divider, though it is - even if it doesn't wind up mattering.

[alerich]

I could be totally off base, I offered that explanation as a place to start, take some of the mystery out of it. I find it valuable to look at a circuit in terms of function. It may wind up having nothing to do with your results, but a lot of people never would recognize that as a voltage divider, though it is - even if it doesn't wind up mattering.

Your comments were spot on. Circuit theory is always an excellent place to start when dissecting a circuit. That's the pitfall of these guitar amplifier circuits. Sometimes they behave just like they should and sometimes they don't. Sometimes we bend the rules around standard design practice and it can either sound pretty ugly or yield some really sweet tone. I wish I had the tech chops to be able to analyze these circuits in the fashion that you and some of the others do.

You wouldn't think a small change like this would net such a huge tonal difference. I don't often gush about equipment but this is really remarkable. I have a Peavey 6506 that I like but that I don't love. Too over the top for me. I have a seller lined up next week (if he doesn't flake out on me). I had planned to invest those proceeds in a Jet City JCA50H head. I've heard good things about them and love all the video samples I have heard. Then I see this Peavey Triumph 120 combo on in almost mint condition with the original foot switch last week on Craigslist for $125 so I rolled the dice on it. Before this mod I was thinking "Well, I can probably flip it and get my money back" but now I've shelved the plans to buy the Jet City. A few more tweaks to the circuit and tone stack and I can see this becoming my "go to" amp. I have a friend with excellent woodworking skills. I can see this amp in a boutique style head cabinet in the near future.

I called Peavey today to order a few replacement pots for this amp. Their customer service is excellent. And thanks for your posts here, Enzo. I always enjoy reading them and they are always very helpful.

[alerich]

The more I investigate this amp the more I think the 10pf bypass cap I added on the 1M resistor (or whatever you sub in) is having the most effect on the tone I am hearing. I reinstalled the original 1M resistor and bypassed it with a 10pf and then added a second switchable 1M in parallel to drop it to 500K when I wish. Even with the second 1M switched out (yielding the original 1M with 10pf bypass) the tone is much improved over the stock nasal tone. Again, I don't have the tech chops to understand why such a small capacitor has this effect but Fender amps also have this 10pf bypass cap. Leo must have put it there for a reason. Maybe and even larger resistor would improve the reverb.

This amp is sounding better by the day. I am not finished with my mods yet. My PS choke should arrive in tomorrow's mail. Tomorrow I will mod the bias circuit for variable bias and suitable voltages and install 1 ohm sense resistors and bias it up properly. I just bet this thing is currently biased colder than a witch's thorax. When I finish up this work I'll come back and post a list of everything I added, removed or changed.