Traynor YBA-1 Master Volume

[jrdamien]

Hey all. Relative had a YBA-1 sitting around and gave it to me. Man oh man. I have wanted one of these for a long time. It needs work but sounds plain amazing.

Someone had incorrectly installed a 3 prong cord so I redid that the same way I've done it dozens of times. It kept tripping the breaker. I swapped the wires around several different ways until it stopped tripping the breaker.

I installed a larmar same way as I have a dozen times on several amps - keeps tripping the breaker. Here's a pic of where I was at before I gave up for the night in frustration.



The red and white wires are going to a dual 100k pot with 220k resistors (100k pot and 220k in par. - 68k). The black lead between them is the pot ground connected to where the 68k resistors met (in a Marshall circuit these would be 220k - lower here per original schematic likely because of the higher voltages) and grounded through the bias ground.

I also removed the 1k5 resistors that joined the negative side of the .1 Caps and went to pin 5 of the output tubes. I tied these resistors to pin 6 and connected leads from here (the yellow wires) to the other set of wipers on the mv pot.



Everything is as it should be but I keep tripping the blankety blank blank circuit breaker. Any ideas?

A tech friend of mine said to try a straight Fisher MV using a 250k dual pot with no safety resistors. I did so but could immediately tell something was wrong.

[Dave Curtis, dB AudioTech]

"I swapped the wires around several different ways until it stopped tripping the breaker."

??? I think you might need to procure a clue...

"Everything is as it should be but I keep tripping the blankety blank blank circuit breaker. Any ideas?"

Yup, I was right. Here's a free clue: If every thing was as it should be, you wouldn't be tripping the breaker.

Take it back to stock (as it should be). You said it sounds amazing; why mess with amazing? Update the electrolytics; make sure the 3-wire cordset is done right, and forget the PPIMV for now. It will sound even more amazing. Try a standard MV, it's easier and IMHO sounds better. Oh, and it looks like your soldering skills could use some fine-tuning; don't use so much heat (you're burning the board), and there's quite a little mess under the 1K5 on the 8-pin socket on the right.

Here's one I did a few years ago:

[jrdamien]

??? I think you might need to procure a clue...

Helpful tip #1!

Yup, I was right. Here's a free clue: If every thing was as it should be, you wouldn't be tripping the breaker.

Helpful tip #2! See: tautology.

Take it back to stock (as it should be). You said it sounds amazing; why mess with amazing?

I said it needs some work but sounds amazing. Scratchy pots. Bad solder joints on a few jacks. Too loud. Needs a mv.

...forget the PPIMV for now.

No. But if you'd like to contribute to helping me install one that'd be cool.

Oh, and it looks like your soldering skills could use some fine-tuning; don't use so much heat (you're burning the board),

Wasn't me - someone previous worked on amp.

and there's quite a little mess under the 1K5 on the 8-pin socket on the right.

Wan't me - someone previous worked on amp. At which step of fixing stuff comes the cleaning up is not really germane to the question.

Here's one I did a few years ago:
[ATTACH=CONFIG]21086[/ATTACH][ATTACH=CONFIG]21087[/ATTACH]

Eh, your soldering skills could use a little work. Too much solder in some places (beware the cold solder joint!) and what's with all the flux? Oh, that's how it was when you got it? I maybe should have asked before accusing!

Sorry to get up your ass on this but wth? Why even reply if you're only contribution is to tell me I suck, you're amazing, and to not do what I'm asking for help with? Is this a video gaming forum? Do we next entirely neglect the topic and just start calling each other gay?

[jrdamien]

Try a standard MV, it's easier and IMHO sounds better.

How and why does it sound better? Is that what I'm looking at in the first pic, a cross line mv ala Matchless?

[Enzo]

Oh, everyone relax, geez.

The reason to forget adding the master volume FOR NOW is that it is always better to get an amp working before trying to also change things in it. You are blowing fuses or tripping breakers. Solve THAT before doing mods. Once the amp functions, THEN do all the mods you care to. MY personal analogy is going to the emergency room to have your appendix out. That is not the time to tell the doctor "Oh as long as you are already operating, please do my tummy tuck and nose job."

When an amp doesn;t work in the first place, we have no way to know if our modification process is working either.

These are sturdy, roomy amps and ideal for modifications, once working. I recommend Traynors for the purpose.

I swapped the wires around several different ways until it stopped tripping the breaker.

Seeing this line is a giant red flag to most techs, allow Dave his reaction. It scares me too. One should determine the proper wiring first. Just hooking it up various ways to see if they blow fuses is not very systematic. NO, I gues it is systematic, but it is not appropriate. It is in reaction to that statement that any assumptions about clue lacking are born.


It is unlikely that a master volume control is blowing your breakers. That is unless in doing the wiring you soldered something to ground that doesn't belong there. There may be more than one way to implement a MV, but changing from one way to another is not likely to solve the breaker issue.

Pull all the power tubes, does the amp still blow breakers?

Does the position of the standby switch matter?

Look up "light bulb limiter" and make one and use it. These are very simple to make, and effective.

If pulling the tubes has no effect, then we need to look for something shorting the high voltage to ground, bad cap maybe? Or possible wiring issues with the power supply/transformer.

If pulling the power tubes stops the breaker blowing, then measuer the voltage on the pins of each socket. You need to see good B+ on both pins 3 and 4 of each, and also important that good bias voltage be on each pin 5.

[jrdamien]

Oh, everyone relax, geez.

The reason to forget adding the master volume FOR NOW is that it is always better to get an amp working before trying to also change things in it. You are blowing fuses or tripping breakers. Solve THAT before doing mods.

I concluded my rant/scolding with a smiley face! It does work. Now on to the mv.

Seeing this line is a giant red flag to most techs, allow Dave his reaction. It scares me too. One should determine the proper wiring first. Just hooking it up various ways to see if they blow fuses is not very systematic. NO, I gues it is systematic, but it is not appropriate. It is in reaction to that statement that any assumptions about clue lacking are born.

OK OK. Granted. Mea culpa. If you installed a power cord as it should be done and you turned the amp on and it blew the fuse, what would you do? You'd check your work. You'd check your joints. You'd correct anything that may be incorrect. In this case I removed the PT lead from the switch and moved it to the acces. plug. That's the whole of what was implied by that statement.

It is unlikely that a master volume control is blowing your breakers. That is unless in doing the wiring you soldered something to ground that doesn't belong there. There may be more than one way to implement a MV, but changing from one way to another is not likely to solve the breaker issue.

Pull all the power tubes, does the amp still blow breakers?

Does the position of the standby switch matter?

Look up "light bulb limiter" and make one and use it. These are very simple to make, and effective.

If pulling the tubes has no effect, then we need to look for something shorting the high voltage to ground, bad cap maybe? Or possible wiring issues with the power supply/transformer.

If pulling the power tubes stops the breaker blowing, then measuer the voltage on the pins of each socket. You need to see good B+ on both pins 3 and 4 of each, and also important that good bias voltage be on each pin 5.

Thank you. Don't you guys ever get into something and can't figure it out and then, once the frustration sets in, you need another set of eyes on it or a new perspective? I do all the time and use the forums for some help. Is this not a welcome use of the forum?

Whether you've been doing amps or guitars or what have you for years and years, nothing sucks worse than asking a question on a forum and being responded to as if you're a clueless idiot. It's a HUGE let down and discouragement. No reason to treat people that way.

[Enzo]

Um, look, whatever seems to be going on, I myself have no interest in shoving anything in anyone's face, nor do I sneer at anyone's level of experience. Part of my life's work is training technicians, I teach troubleshooting. That is all I am trying to do here. I don;t know you from Adam, so I cannot assume what you do or do not know. I didn't question your intelligence.

Maybe i am confused, you say the amp is working, but you also say it is blowing breakers. I find those two things incompatible. So I am trying to find out just what is going on. I suggested pulling the power tubes, in part because the preamp tubes pretty much have no way to blow fuses. Your MV is wired to the grids of the power tubes, so by pulling them and looking for p[resence of bias voltage at pins 5, we find out if your wiring has killed the bias.

[jrdamien]

Um, look, whatever seems to be going on, I myself have no interest in shoving anything in anyone's face, nor do I sneer at anyone's level of experience. Part of my life's work is training technicians, I teach troubleshooting. That is all I am trying to do here. I don;t know you from Adam, so I cannot assume what you do or do not know. I didn't question your intelligence.

Maybe i am confused, you say the amp is working, but you also say it is blowing breakers. I find those two things incompatible. So I am trying to find out just what is going on. I suggested pulling the power tubes, in part because the preamp tubes pretty much have no way to blow fuses. Your MV is wired to the grids of the power tubes, so by pulling them and looking for p[resence of bias voltage at pins 5, we find out if your wiring has killed the bias.

I wasn't referring to you but to how the original tussle got started which is, ultimately, irrelevant. And I wildly appreciate your help.

The amp, wired as it was originally (power cord aside - power cord is fine and works/should never have mentioned it), works. Wired with a larmar ppimv using a 100k dual pot and 220k safety resistors, trips the breaker.

As soon as I am back at it I am going to pull the power tubes and see if my wiring is killing the voltage.

Like I said, I very seriously appreciate the step by step and will use it to get to the bottom of my problem.

[Dave Curtis, dB AudioTech]

To some it sounds better, and of course, your mileage may vary. Not wired like Matchless (which is Post Phase Inverter Master Volume, but with one pot), but like Marshall; pre phase inverter. The customer tried all three types and ultimately chose the Marshall style MV, saying it sounded tighter (and I concur).

I apologize for my post, but as Enzo said, your second paragraph did raise a red flag to me (and others, I'm sure). It made you seem as if you don't really know what your doing. Sorry for being a tad harsh, but please don't put words in my mouth; I didn't say you suck, did I? Nor did I say I was amazing..

So you're saying you didn't solder the red, white and black wires to the board? But you say you installed a larmar (whatever that is) master volume and safety resistors (whatever those are). I have no idea what MV circuit you're using without seeing a drawing of it; got links? There's a bunch of dual-pot PPIMV circuits floating around, and I don't know of any off-hand that would trip your OC device.

I can see the same stock rosin splatters on your board as the ones that were on the board of the '71 amp I was working on; those are from the original build (and all the other early Traynors I've worked on). I was talking about the overheated eyelets that you (or "someone previous") soldered those wires to. You also said you worked on the 1K5 resistors on the sockets, which is why I mentioned the solder; now you say that was "someone previous". If someone previously left a mess of solder, I clean it up.

The "housekeeping" stuff mentioned are things you want to tend to, as some of what was mentioned could possibly contribute to overcurrent, if not now, then later (excess solder floating in the amp, etc

"At which step of fixing stuff comes the cleaning up is not really germane to the question."

Huh? Hows that go?

Actually, You really should get the thing working like it was intended before modding it. Clean the pots, sockets, jacks and any other contacts. Replace your electrolytics (you're keeping it, right? how old are they?) and any badly out-of-spec resistors/signal caps. On an amp like this that's what I normally do before anything else; just because.

[Jazz P Bass]

A bit of info that I came across on the MV mod.
Are these close to what you have in mind?
Link: Lar/Mar PPI-MV - MetroAmp Wiki
Link: PPIV Master Volume Kit [PPIVMVKIT] - $15.00 : Granger Amplification Custom Shop, Your source for awesome tone!

[jrdamien]

To some it sounds better, and of course, your mileage may vary. Not wired like Matchless (which is Post Phase Inverter Master Volume, but with one pot), but like Marshall; pre phase inverter. The customer tried all three types and ultimately chose the Marshall style MV, saying it sounded tighter (and I concur).

I apologize for my post, but as Enzo said, your second paragraph did raise a red flag to me (and others, I'm sure). It made you seem as if you don't really know what your doing. Sorry for being a tad harsh, but please don't put words in my mouth; I didn't say you suck, did I? Nor did I say I was amazing..

In the interest of all things I will humbly repeat, Mea Culpa. Perhaps I overreacted...perhaps.

My issue with the pre-pi master (on the amps I've used them on/heard them on) is that their primary benefit is to dial in more highs. What I really need for this amp (all I need) is to shave off some volume for live use/smaller clubs. Having had one (or do you still have it) you can appreciate how loud this "50 watt" amp is.

So you're saying you didn't solder the red, white and black wires to the board? But you say you installed a larmar (whatever that is) master volume and safety resistors (whatever those are). I have no idea what MV circuit you're using without seeing a drawing of it; got links? There's a bunch of dual-pot PPIMV circuits floating around, and I don't know of any off-hand that would trip your OC device.

No, the red and white's were mine. I had a larmar 'harness' already wired up and just swapped it in. There was work done previous to mine or anything seen in pics.

I can see the same stock rosin splatters on your board as the ones that were on the board of the '71 amp I was working on; those are from the original build (and all the other early Traynors I've worked on). I was talking about the overheated eyelets that you (or "someone previous") soldered those wires to. You also said you worked on the 1K5 resistors on the sockets, which is why I mentioned the solder; now you say that was "someone previous". If someone previously left a mess of solder, I clean it up.

Oh man, I was just bustin' b**ls. Not enough smiley faces to add the necessary levity. My bad, again.

The "housekeeping" stuff mentioned are things you want to tend to, as some of what was mentioned could possibly contribute to overcurrent, if not now, then later (excess solder floating in the amp, etc

Certainly.

Actually, You really should get the thing working like it was intended before modding it. Clean the pots, sockets, jacks and any other contacts. Replace your electrolytics (you're keeping it, right? how old are they?) and any badly out-of-spec resistors/signal caps. On an amp like this that's what I normally do before anything else; just because.

This was all done before the master volume mods were attempted with the exception of the electrolytics. I know I will likely be shunned for saying so, but even in classic amps, I don't replace the caps unless there is an audible or obvious problem. If it sounds good I leave it good until it has to be fixed.

I am keeping it. I can't imagine getting a better sounding amp.

I ended up with a Rich Mod MV. I could not get the Larmar dialed in (see link in JPB's post below for details on the Larmar). I suspect it is messing with the bias (or NFB) in some way that I don't have the time to diagnose right now (I have 2 gigs tomorrow and need the amp working and sounding good). And what I would consider to be the best way to do it would be to install a bias pot. But I have no 25/50k pots so...

I tried a cross line myself because it's easy. Terrible. I tried a resistorless version of the Larmar. Same problem. I finally went with this:



Works perfect. Sounds the same as the Larmar but with less loss of tone controls as the master is turned down. It goes to bedroom volume and still sounds great. Most importantly, I can turn it down to tolerable levels and it sounds no different than it did before.

[Dave Curtis, dB AudioTech]

I'm glad you're up & running, and again apologize for being a snit.

The one I had here was a customer's, and yes 50W is quite loud. Hell, I have a 5W build (Marshally-Champ type thing) that has no problem with loud drums & bass in the jam-room; just don't ask it to do clean tones at that volume.

Good luck with your gigs, J. Knock 'em dead.