Traynor YBA-1 thoughts

[toneseeker74]

When I play my YBA-1 it reminds me of a mix of Laney lower midrange grind and Hiwatt punch. Lots of people mod these to spec out closer to early Marshall circuits. I thought I would go that route, but now I'm reconsidering. Right now I want to lessen the low-end response in the "bass channel" to make it tighter and less round, and also decrease the gain. Then I want to tame the ultra brightness in the "treble channel" while increasing the gain. The idea is to have one channel be a little more clean & full while the other a bit in the raunchy side. What do you think?

 

[BrianS.]

Re: Traynor YBA-1 thoughts

If you remove the .001 mfd cap from across the "treble" side volume control, both "channels" will be exactly the same.

That's all I got for ya.

 

[beaubrummels]

Re: Traynor YBA-1 thoughts

I'm keeping mine as is, though I can't play it past 3 or I have to practically leave the room. It's painful. Louder than a Hiwatt 100.

 

[zzmoore]

Re: Traynor YBA-1 thoughts

You are going to have to try some things.
1. V1 has a shared cathode...you need to split that. The possibilities of values are endless.
2. For the Bass Channel. Try a 0.68uF and a 1k5 resistor.
3. On the other channel...try a 4.7uF cap with a 820-1k2 resistor. Try knocking down that bright cap across the volume pot to 50pF-220pF. try a different plate resistor 150-220k.
Try it one at a time of course. That amp is Real Nice to work on. You should not have any problems.
The tone stack is shared...probably leave well enough alone for now.
The PI coupling caps are BIG...they all seemed to be "back then".
You can try reducing those by half or more.
As always, maintenance should be done first. Make sure it is functioning properly and safe. Make sure it has a 3 wire cord and that all the caps are somewhat new.
good luck

 

[toneseeker74]

Re: Traynor YBA-1 thoughts

Thanks, zz! I already put a grounded cord on. I have new filter caps and bias cap, I just need to install them then bring the amp up slowly on my variac. Then check the bias. I'm running some old made in Holland RCA power tubes right now. Who knows how much life they have left? After I play it a while then I'll dive into the step by step mods. Should be a fun project.

 

[toneseeker74]

Re: Traynor YBA-1 thoughts

I'm keeping mine as is, though I can't play it past 3 or I have to practically leave the room. It's painful. Louder than a Hiwatt 100.

The past two weeks I have played the Traynor at 1, 3, 5, 7, and 10 on the volume...through each input, but never jumpered. Yeah, it gets loud. But nothing that ever made me cringe. Of course, I only do this for a few licks to compare overdrive, tone, tightness and punch characteristics. As it is, I find that there is a big jump in volume and overdrive from 1 to 3. From 3 to 5 the overdrive and volume both increases a little bit more, but still noticeable. From 5 onward I don't get any more overdrive, and the amp doesn't get any louder. It does, however, get a little fuller. But at 8.5 or 9 it just starts to get too fat and mushy.

 

[zzmoore]

Re: Traynor YBA-1 thoughts

Thanks, zz! I already put a grounded cord on. I have new filter caps and bias cap, I just need to install them then bring the amp up slowly on my variac. Then check the bias. I'm running some old made in Holland RCA power tubes right now. Who knows how much life they have left? After I play it a while then I'll dive into the step by step mods. Should be a fun project.

Sounds like you have things well under control.
I will just add:
1. Make sure you removed the "death cap"...I am sure you already did.
2. The bias caps are Positive Ground.
3. Would be Real Nice to make the Negative Bias... adjustable. In round numbers...replace R30 with a 15k resistor, and put a 50k pot between it and the junction of C15/R28.
It is weird...I have never really looked at this shem I guess. At the reservoir cap, for the power tube plates...Do they really use a single 80 mic cap with a dual 40 mic can.?
For a dollar...I would just go ahead and replace those "Totem-Pole" (2x 100k) resistors on that cap configuration. They will help the caps split the voltage evenly...thus improving cap life and amp reliability.
I would spend another 50 cents and install new screen resistors as well. That is what Really Kills the 34's. They can probably, easily, handle 600-800 VDC on the plates...but the screens do not dig a lot of current or Voltage. But that is just me.
These are really good amps. Pete Traynor was ahead of his time in some ways... he just made good quality amps that were easy to work on. Imagine That.....
Congrats My Friend :beerchug:

 

[toneseeker74]

Re: Traynor YBA-1 thoughts

Death cap removed. I have a small 50k pot to use as a bias pot; thanks for the directions on where to add it!