Traynor Bass Master YBA-1 tube suggestions

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Major76

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Hey guys. New to the forum and I'd like to have some insight if anyone has some experience with Traynor YBA-1.

My amp was in a closet for nearly 15 years as it failed on me during a gig in the early 2000s and, since I had other amps, I did not feel the urge to fix it then. I just got it fixed and I am not sure on the sound.

It currently has a Sylvania 12AX7 in V1, a pair of Sovtek 12AX7WA in V2 and V3 and a pair of JJ EL34 in V4 and V5 (this is a 1968 model with solid state rectification so no rectifying tube)
V1 is split between channel 1 and 2. Then the signal hits V2.

The Sylvania was in V3 and I switched it to V1, it improved the tone some but I am not sold on the Sovtek tubes. Anyone has suggestions?

At home I do have a HIT RAY vintage 12AX7 (with the Hitachi logo). A Chinese 12AX7A (only labelled made in China) and a 12AX7 that has Mesa str written on it.

I intend to do some swapping and testing but if someone could give me informed advice I would really appreciate.

Thanks!
 
Has the amp had any plexi mods done to it, or is it the stock circuit?
If it's stock, it might be a tad dark sounding, and might benefit from a Tung Sol in v1. Not sure if the Soviet wa tubes have spiral filaments, but if they do, I would not run that tube in v2 which is the cathode follower. They won't hold up in that position. Put the Chinese in v2. The Mesa str might be cool in v1. If it's Chinese, it will be brighter. If it's a jj, it will be darker sounding
These are fantastic amps, and only a couple tweaks away from a killer plexi-style monster.
 
Looks like it's the Sovtek 12ax7LPS that has the spiral filaments. The wa should be OK in v2, but those aren't great sounding tubes. The LPS on the other hand is a killer phase inverter tube for v3.
So with just the tubes you already have, I'd probably start with the 2 sovteks in v2 and v3 as a baseline and find the best sounding tube for v1. Then go to v2 and v3 and swap ou the sovteks one at a time until you find the best combo.
 
Thanks fusedbrain. I will try some of that.

Any insight on the Hitachi made Raytheon 12ax7? I can post pics of the tubes later if that helps.
 
This is what I'm running in Plexi modded '71 YBA-1 and it absolutely kills.

V1 I63 Mullard 7025
V2 Sylvania long plate
V3 Sylvania long plate



I tried swapping out V2 with another Mullard and noticed a big drop in the amp's punch. Those long plate's kick like a mule and are great in those slots. I tried a long plate Tung-Sol in V1 and that was also very good but the Mullard had a tad more mid-range bite. I tried a Matsushita (Japanese Mullard, angled getter and even flashed on start up) in V1 and couldn't tell the difference between that and the IEC Mullard.



 
If I have a single Sylvania on hand, would it be better in V2 or V3?

I will get to try them tomorrow.
 
V3 should make the most difference after V1 but try both. V3 sends your signal to the power section and a good strong tube there effects the way the amp feels. My V3 is an ANOS tube so I didn't bother swapping that one for comparison once I put it in.
 
So here are the tubes I have. I will try the Sylvania in V3, The Hitachi in V2 and the Chinese in V1.

I will try to swap V2 and V3 and I might try the Mesa tube in V1. Sadly. It'll have to wait tomorrow, my cabs are not at home.

From left: Sylvania 12AX7A/7025A, Hit Ray 12AX7A, China 12AX7-A, Mesa STR 12AX7-A, Sovtek 12AX7WA
The Sovtek will likely retire
Pic of the tubes:https://goo.gl/photos/4vMzZxDSabTrXXDy5
 
Sounds like a good plan. Looks like you arranged the tubes in the pic from best to worst left to right. The Mesa str looks like a jj to me, so it will be on the dark side. Could be OK in v2 if your amp has been plexi-fied and is on the bright side.
Good luck with your testing!
 
That's what I thought for the order :)

The amp is stock. Besides the bright cap on channel two which is a bit too bright for my taste and the 4M volume pots, I like it stock. It sounds like it is going to kill something.
However, with a bit of tube tweaking, I might find out what it is going to kill
 
The Plexi mods are really simple and take an already great amp to another level. I like mine better then any Marshall I've ever owned.



Service related

A) Filter cap replacement, two 2 x 50uf /500V cans replaced the old 2 x 40uf dynamite sticks

Plexi mods

B) Replaced 470k volume controls with 1meg volume controls. Used pull switch pot on the bright channel which lowers the cathode resistor value and adds a bypass cap for a gain bump. For the switch I went with a 2.2k resistor and 25uf cap parallel the existing 1.5k resistor because that's what I had. Using a 1.8k and .68uf cap gets you to the actual Marshall specs but it sounds great so I'll leave what I used in.
C) Replaced 100k mixing resistors with 220k
D) Tone stack shift – replaced .01 & .1 caps with .022 caps
E) Tone stack shift – replace slope resistor with 33K & replace 320pf cap with 500pf silver mica cap
F) Re-purposed the old ground switch to switch the feedback resistor between the stock 100K and 33K which adds some sag. I actually like the stock position best because it has more punch in that position.

I snapped this picture before I added the cathode bypass cap which is installed parallel to the resistor coming off the top right corner of the board.



 
Major76":1t2bv84g said:
I will try the Sylvania in V3, The Hitachi in V2 and the Chinese in V1.

I will try to swap V2 and V3 and I might try the Mesa tube in V1. Sadly. It'll have to wait tomorrow, my cabs are not at home.
Click to expand...

I ended up with China in V1, Sylvania in V2 and Raytheon in V3. That's where the cream was at. The Mesa tube was close but sounded thin.

I will eventually try to find some more NOS tubes.

It sounds good when I play by myself but with a band everyone has to crank their amp so loud that it's borderline dangerous for our aging ears. Thus, I would like the amp to break up at lower volume would it be better to get a lower mu tube such as a 5751? Or perhaps try to find different output tubes? I have JJ standard EL34 (without suffixes)

In the meantime I like the sound I have with a clone TS808 or a Morley Distortion one (similar schematics to DOD250 or MXT Dist +) I will have to try with my Boss SD1 eventually.
 
Changing the output tubes won't enable the amp to break up earlier; ditto with changing the x7s with less-gainy tubes.

If you want earlier 'internal' breakup, talk to a tech about the following options:
- install a post PI master volume (like the so-called 'LarMar').
- re-wire the parallel inputs as cascaded gain stages, and add pre- or post- PI master
- add a diode-clipping circuit

Or, just hit the front end with a good pedal. Try a Barber Direct Drive or something from either Wampler or Suhr.
 
Yup, this amp with a plexi conversion and a lar / Mar master would take you right where you want to go. Guys in the know have been buying these amps up cheap and doing the conversion and getting themselves a killer plexi style amp for not a lot of cash. The transformers are massive Hammond built iron, and the amps are full of mustard caps. Total sleepers.
 
You can get a nice gain bump by lowering the resistor value on the V2B cathode and adding a cathode bypass cap. Replace your volume pots with 1 meg pots and use a switch type on channel 2 (bright channel). Wire the switch so it connects a 1.8k resistor and a 25uf cap in parallel to the existing 2.2k cathode resistor. That will drop the value down to 820 ohms which is the same value as Marshall uses in the Plexi. The 25 uf cap will add gain too. Lowering that cap value will make that channel brighter. Marshall uses .68uf which I was out of when I did mine but the 25uf sounded so good I left it alone. It's what fender used on the Bassman.
 
My channel 2 is already too bright as it is. Otherwise it sounds fabulous when I mix both.
Funny thing is I paid 30$ for that amp about 15 years ago.

I think I'll try an l pad on the output
 
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