# Traynor YBA-2B question for wild wild Bill!



## Kapo_Polenton

Bill, 

Thought you might have some insight into what mods or tweaks can be done to a YBA-2B combo for guitar. I decided to pull the trigger on this amp based on reviews and my desire to own an old Traynor. I'd be very interested in what can be done to it to make it into a rockin guitar machine. Some people say this thing already rocks your socks off and breaks up early on the high channel, other people say it needs a cap job or a few values changed before it really smooths out. I was interested in your take on this and what you would point out in the preamp part of the circuit or value wise anywhere else.

Thanks!:rockon2:


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## Wild Bill

Kapo_Polenton said:


> Bill,
> 
> Thought you might have some insight into what mods or tweaks can be done to a YBA-2B combo for guitar. I decided to pull the trigger on this amp based on reviews and my desire to own an old Traynor. I'd be very interested in what can be done to it to make it into a rockin guitar machine. Some people say this thing already rocks your socks off and breaks up early on the high channel, other people say it needs a cap job or a few values changed before it really smooths out. I was interested in your take on this and what you would point out in the preamp part of the circuit or value wise anywhere else.
> 
> Thanks!:rockon2:


Hey KP! This is going to be fun!

First off, there were FIVE different versions of the BassMate! I've never found a schematic that says exactly "YBA-2B". So we need to know a few things, like does your amp use 6V6's or EL84/6BQ5 tubes in the output? Do you have two 12AX7's or just one 12AU7 before the output tubes?

The plate resistors on the phase inverter 12AX7 that drives the output tubes, are they both 100k or is one of them the traditional blackface 82k?

I need to know specifically what we have to work with. Some models only used half of the 1st 12AX7, which means it's still there for us to hook up.

If you go to http://www.schematicheaven.com and find the file for YBA-2BUsersmanual it contains 3 of the schematics. The file "YBA-2x" has the rest. We need to compare them to yours and find out which is a match. There may still be a couple of minor differences. Pete often changed things faster than someone could update the schematics.

Whatever, I would lean towards the YGM-2 GuitarMate circuit. Is yours the one with fixed bias instead of using a bigass cathode resistor? A switch on the back to toggle between the 2 modes would be fun!

Tell me what we need to know so that we are working from the same page and let's get started! There are notes to play and apartment leases to break!:rockon2:

:food-smiley-004:


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## Guest

Can beg you two to keep a running record of this conversation here on the board? This is fascinating. :smile:


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## Kapo_Polenton

Well, I will have to wait to get it but in the meantime I can ask the seller to look at the year it was issued and can compare based on the schematics (which I downloaded). I know it runs the EL84/6BQ5 tubes in the output stage and there are 2 12ax7 in preamp. I am pretty sure that with the combos, both halves of the first 12ax7 were used but again, we won't know till i crack it open and look at that as well as the other questions you have asked! I don't mind documenting it for everyone this forum either. It looks to be a fairly simple layout with a ton of room to work in. (unlike that damn weber which had no room to work in - sounds great though). I'm still a beginner builder but the stuff you asked made sense to me so there is hope after all for me to become an amp guru one day


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## Kapo_Polenton

Ok back for the attack.. got the mp in hand and its inners are in good shape as well as its exterior cosmetics... When i cranked it, it had a bit of raspy distortion... broke up, but nowhere as full as I would like. So with that, here I am with the answers to your post Wild Bill: 

2 (EL84)/6BQ5 tubes in the output. There are 2 two 12AX7's in the preamp stage, both halves of the preamp stages seem to be used as there are wires going to every pin. 

long tail pair - 3 to one resistors in the PI are 3 470K resistors.Where would the plate resistors be here?I have tried researching but it is a confusing subject and visually i don't get it. Building an amp was easy, just followed the schema and layout but knowing what is what by name is hard for me.In theory should it not run off one of the pins of the 2nd 12ax7? 

Looks to be fixed bias with no trimpot anywhere. There is also a diode in place here like the YBA-1A has.

Sorry I cannot be more specific , I am rusty!


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## Wild Bill

Kapo_Polenton said:


> Ok back for the attack.. got the mp in hand and its inners are in good shape as well as its exterior cosmetics... When i cranked it, it had a bit of raspy distortion... broke up, but nowhere as full as I would like. So with that, here I am with the answers to your post Wild Bill:
> 
> 2 (EL84)/6BQ5 tubes in the output. There are 2 two 12AX7's in the preamp stage, both halves of the preamp stages seem to be used as there are wires going to every pin.
> 
> long tail pair - 3 to one resistors in the PI are 3 470K resistors.Where would the plate resistors be here?I have tried researching but it is a confusing subject and visually i don't get it. Building an amp was easy, just followed the schema and layout but knowing what is what by name is hard for me.In theory should it not run off one of the pins of the 2nd 12ax7?
> 
> Looks to be fixed bias with no trimpot anywhere. There is also a diode in place here like the YBA-1A has.
> 
> Sorry I cannot be more specific , I am rusty!


Hey KP! This is starting to help!

The plate resistors that are important are the ones used for the phase inverter, which would be the last 12AX7 in the string and the one that feeds the output tubes. They would be attached to pins 1 and 6. They might be 82k and 100k, or both 100k or even 47k.

Actually, if we can't absolutely indentify the model it really doesn't matter. You've got all the pieces to change the amp to a YGM 3 Guitar Mate! Just get the right schematic and make all the small part changes. 

In fact, your amp will likely then sound BETTER than a Guitar Mate! Pete would have used an output transformer beefy enough to handle those low bass notes. The lower the frequency limit in an OT the more iron and size it needs to do the job. That's just physics. So your converted Bass Mate will have a much better low end response than the standard Guitar Mate.

We're getting there!

:food-smiley-004:


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## Kapo_Polenton

From 1st pin of second 12AX7 - 100 K resistor which feeds into a .10 uf cap
From 6th pin of second 12AX7- 82 K resistor which feeds into the 100 K resistor and another .10 uf cap. 

So this is the phase inverter porion of the circuit eh? Interesting. 

so would you then suggest that i find the YBA-2B schematic that corresponds to this and A/B it with a guitar mate schema in this same section and do some swapping? 

:banana:


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## torndownunit

iaresee said:


> Can beg you two to keep a running record of this conversation here on the board? This is fascinating. :smile:


Ya I am interested as well.

I got my YBA-2A with plans on modding it. As soon as I plugged it in though, I realized I probably didn't need to. I like how it sounds stock better then I liked the YGM-3 I had....and it sounded great! 

The only thing I would like to change is the bass on it. It's got a fantastic bottom end, but I basically have to play with the bass dialed down to 1 on the knob. It would be nice to have a little more play there.


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## bRian

> So your converted Bass Mate will have a much better low end response than the standard Guitar Mate.


I can echo those sentiments as well. My YGM-3 had a nice clean sound but my Bass Master is closer to the sound I was looking for. 



> I got my YBA-2A with plans on modding it. As soon as I plugged it in though, I realized I probably didn't need to. I like how it sounds stock better then I liked the YGM-3 I had....and it sounded great!


Couldn't have said it better, my sentiments exactly. I plan on building a cab and going with a 12" Weber.


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## Kapo_Polenton

what type of pickups do you guys use? fairly hot? How about tubes? Mine doesn't seem to have the jam stock.


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## torndownunit

I mainly use my Tele, and my Reverend which has Filtertrons on it. The Reverend pickups are the closest I get to humbuckers. I have a feeling the tone of the amp might be a little muddy unmodded with humbuckers. It sounds great with single coils and the Filtertrons though.


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## bRian

I'm using Kinman Broadcasters; no pedals with Groove Tubes. I prefer JJ's but at the time GT's were all I could get. They actually sound pretty good. Btw, tdu, could you possibly post a pick of the back of your amp. I'd like to see the shape of the rear panel. Mine is missing and I'd like to make one. Thanks.


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## torndownunit

Brian, mine is the YBA-2A head. Are you looking for the back panel of a head or the combo?


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## bRian

Mine is the head also.


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## torndownunit

brian, my camera is at work right now. I will bring it home next week and snap some photos for you.

I saw your post about this in another thread, but I thought you had the combo version.


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## Kapo_Polenton

Bill, did you have a chance to see my last post on the YBA-2B and what mods I should proceed with? I was intersted in a bit more guidance and wondered what your thoughts might be. 

Thanks!


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## Wild Bill

Kapo_Polenton said:


> Bill, did you have a chance to see my last post on the YBA-2B and what mods I should proceed with? I was intersted in a bit more guidance and wondered what your thoughts might be.
> 
> Thanks!


Even simpler, KP! It sounds like your amp has everything you need to convert it to a Guitar Mate. I would get a GM schematic and change the entire preamp.

You'll find that the output stage and power supply will need little or no modding.

As I had said, I think that a converted BassMate will sound BETTER!

:food-smiley-004:


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## bRian

> I will bring it home next week and snap some photos for you.


Merci, much appreciated


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## Kapo_Polenton

Thanks, I'll have a look. Is there a particular version of the guitarmate or model that I should look to? Is there as much variance with his guitar amps as there was with the bass amps? I suppose the best way would be to head on over to schematic heaven and have me a looksie.


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## sambonee

Howdy!

I just got one of these and would like to hear about KP's results. 

I am going to do ape mods as well. Paid $300 for mine. No logo. Thoughts?


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## parkhead

There are a couple of quick things to pay attention to on these amps. 
when looking at them for guitar or improved bass use.
The good news is that the power amp section runs without a feedback loop 
so its a pretty good sounding setup for guitar if we can get the 
front end dialed in ...

The Keys: 

How the pre amp gain is set up 

How the stages are coupled 

and how the tone stack works 

if you have a look at the available schematics you will probably see your amp 

http://www.schematicheaven.com/bargainbin/traynor_bassmate_yba2b_manual.pdf

Interstage coupling: 

if you follow the schematic through the first tube you will see 
that the audio signal exits the tube on pin 6 of the first pre amp tube 

at that point it meets a 100k plate load resistor and a .1 400volt coupling capacitor 

that .1 capacitor sets the bandwidth of the signal passing into the next 

stage. If we were to do the math .1 puts the amps bottom end well below 

guitar frequencies a more typical "guitar value" would be .02 mfd but lots of 

values between .047 and 500pf will work between the first and second 

stage. I used .02 on my bassmate. All capacitors should be 400volt 

The tone stack : 

The next thing you see in the schematic is a network of capacitors resistors 

and controls. Follow this along and see if you can figure out how this divides 

the signal and provides tone controls. With bass mates you should consider 

adjusting the slope resistor r5 in the second last schematic and r10 on the 

last schematic. The slope resistor adjusts the separation of treble and 

bass. On later bassmates they use 220k. Fender used 100k during their 

golden era, and marshall used 56k then 33k in their lead amps. There is more 

mid gain and growl with a lower value slope resistor, I think I used 33k on 

mine. 


These two changes alone should tighten up the bottom and boost the 

rich mids. 

More Gain: 

Finally once you have the amp eq'ed with a nice sweep of tonal range suiting 

your guitar and style you can look at tweaking the gain. 

I suggest you do this last because most people go crazy and choke up their 

amp with too much gain. 

Looking at that first 12ax7 look for pins 3 and 8. These are the cathodes of 

the 12ax7. In most guitar amps the typical value is 1.5k with a 25 mfd 

bypass cap. On some bass mates you see a 5.6k resistor with no bypass 

cap. This setup keeps the gain low and that gain stage very clean. 

If you have the final version of the bassmate with the double gain stage 

before the tone controls you can swap the pin 8 5.6k resistor in the first gain 

stage over to 1.5k and have all the gain you might want or need. 

If you have the 6v6 single gain stage type bass mate you probably want to 

drop the existing 1.5k resistor to 820 ohms and leave the 25mfd bypass 

cap. If you have the single stage bassmate and you need more gain you 

might want to raise the 100k plate load resistor to 220k r8 on that 

schematic. 

To sum up, these are great little amps and they require very little to sound 

amazing. Don't go to wild simply study the schematic tighten up the 

tone a little and bump the gain slightly if you want, the key is to drive that 

nice 20 watt open loop power amp hard! 

here's a guitar mate getting this kind of treatment 

http://www.youtube.com/watch?v=hLhGeU4wb2U 


Note: in the video the guitar mate power amp is modded to work more like the bassmate version
the bassmate power amp needs no such adjustment 


here's the bass mate almost done 










in the picture you can see the new yellow mallory 150 .02 400 volt 
that replaces the .1 mustard 

you can probably make out the "tropical fish" (orange and brown) 300pf treble cap with the new slope resistor 
replacing the 220k slope with 33k 

you can also see two unused eyelet holes I put a 1.5 k cathode resistor in those holes 
and since the 5.6k was located under the filter cap making swapping values to tune the amp a bear 

I went with 1.5k unbypassed 

In use "the wall of Traynor" 










p


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## sambonee

you see, Parkhead is the GURU of Traynor amps. I once gave him a 12 of Moosehead to mod a Bassmate about 15 yrs ago that was my main amp.

funny how things go, I was just visiting with him about this very mod and didn't know his "handle" on here!!

PS does anyone know if twinkle twinkle sounds good through these amps? I just bought one. 

A big thanks to PARKHEAD as it's people like him that allow the pesants to sound like the CREAM albums!
:banana:


AND

does anyone want one? I have an extra one for $450. it's the el84 version. LMK asap via response in this thread because I might have it gone by tomorrow.

thanks


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## parkhead

you know I'd take it but I have a mint guitar mate on the way !

I would snap for the earliest one volume one tone version though 

sorry kids no food, but you got a new amp this week 

p


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## JDW3

parkhead said:


> The Keys:
> 
> How the pre amp gain is set up
> 
> How the stages are coupled
> 
> and how the tone stack works
> 
> if you have a look at the available schematics you will probably see your amp
> 
> http://www.schematicheaven.com/bargainbin/traynor_bassmate_yba2b_manual.pdf
> 
> Interstage coupling:
> 
> if you follow the schematic through the first tube you will see
> that the audio signal exits the tube on pin 6 of the first pre amp tube
> 
> at that point it meets a 100k plate load resistor and a .1 400volt coupling capacitor
> 
> that .1 capacitor sets the bandwidth of the signal passing into the next
> 
> stage. I used .02 on my bassmate. All capacitors should be 400volt
> 
> The tone stack :
> 
> Looking at that first 12ax7 look for pins 3 and 8. These are the cathodes of
> 
> the 12ax7. In most guitar amps the typical value is 1.5k with a 25 mfd
> 
> bypass cap. On some bass mates you see a 5.6k resistor with no bypass
> 
> cap. This setup keeps the gain low and that gain stage very clean.
> 
> If you have the final version of the bassmate with the double gain stage
> 
> before the tone controls you can swap the pin 8 5.6k resistor in the first gain
> 
> stage over to 1.5k and have all the gain you might want or need.
> 
> here's the bass mate almost done
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> in the picture you can see the new yellow mallory 150 .02 400 volt
> that replaces the .1 mustard
> 
> you can probably make out the "tropical fish" (orange and brown) 300pf treble cap with the new slope resistor
> replacing the 220k slope with 33k
> 
> you can also see two unused eyelet holes I put a 1.5 k cathode resistor in those holes
> and since the 5.6k was located under the filter cap making swapping values to tune the amp a bear
> 
> I went with 1.5k unbypassed
> 
> In use "the wall of Traynor"
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> p




Hey Parkhead, I'm back with more questions. Oh boy...

I have a new Bass Mate head this time with el-84s. I swapped out the 1st coupling cap (.1uf) with an .02uf. I then swapped the next coupling cap from pin 6 to .022uf from .1uf. Mine looks opposite what you have in your pic. Older I think.

I noticed you left your .1uf in there. Was there a reason for this? I thought it might bring up the mids. Maybe I changed the wrong cap?

I also wondered if you thought about bypassing your 1.5K cathode resistor with a cap. I was thinking about it. I haven't changed the res out yet. I'd like to tune the amp up first with fresh caps.

This amp is much louder than the 6v6 version.

I put a 100K res in for the slope. It's a bit better. 

The preamp stage looks more different than I thought compared to the 6v6 version. So I'm trying to wrap my head around it. This one really has a lot more headroom.


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## JDW3

Thought I would bring this old thread up, with an update.

I recently re-evaluated my tone in the el-84 BassMate head. I ended up using a 33K slope, one cathode at 2.7K and one at 3.3K. The PI was altered slightly with 1M resistors on the grids. Probably not necessary.

But the most satisfying change was the 330pf cap, being changed to the biggest ceramic cap I had, which was 560pf. It really took the grainy harshness out of the signal, and the pick attack was much more intense. That cap, with the 33K slope made all the difference, possibly the most important.

Going any lower with the cathodes will get motorboating. I would use a shielded cable but grounding would be a hassle, and the amp really doesn't need to be driven that hard. 

I want to thank Parkhead again for all the points in the right direction.


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## chris9723

Hey all! I have this yba2.
Which is the slope resistor?
Thanks so much!
traynor yba2 - Google Search


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## PTWamps

The slope resistor is the 100k one (brown, black, yellow) that runs sideways in front of V1, 4th and 6th eyelets probably. 

To avoid dredging up nine year old threads, you should just start a new one.


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