Traynor Bass Mate YBA-2B: Added a LarMar PPIMV and Cut Control

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by slicktone, May 12, 2015.

  1. slicktone

    slicktone Member

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    Last night and today I added a LarMar PPIMV and a High Cut control to my EL84 Traynor Bass Mate. They are both working great, and I'm liking the new tones and drive sounds that these additions have added.

    Many times, when amps are cranked up to overdriving...I feel...that even though the overall sound is good...the highs become a bit too pronounced...the cut control really helps with this.

    From what I can tell, the stock circuit for this amp is darn close to a Matchless Spitfire...with the addition of the MV and Cut, I'm now pretty tempted to add an EF86 channel with the rotary tone switch and a volume...then it would be kinda like a 15 watt DC30.

    Any thoughts? Just curious if any other Traynor fans have had similar ideas...or done other cool things.

    I was hesitant to do any mods...I love the amp as it was, but the cab isn't in great shape, the face and rear plates aren't pristine, and I"m going to keep it, so I thought I might as well see how these mods work!
     
  2. JDW3

    JDW3 Member

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    Make sure the bias isn't too hot. My tech installed a bias pot, as it was running hot from the factory. I've read they have been known for that.

    I decreased my slope resistor down to 33K. A lot more mids. Takes away the appearance of ice pick highs. As does lowering the bias.
     
  3. Silent Sound

    Silent Sound Member

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    I would avoid the EF86. They're expensive and prone to microphonics. Good tubes if you can find a good one, but not worth the time, money, or hassle, imho. If you want the sound, but not the cost or the issues, I'd look at building a 6AU6 preamp, which is also a pentode preamp, in a 7 pin format. Some 6AU6's can be microphonic too, but they make more rugged version of this tube, like the 6136 and a few others. They're great sounding tubes and should be cheaper to find a good NOS version than a shoddy new production EF86.
     
  4. axpro

    axpro Member

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    I spent the last year or so messing with EF86's. Badcat Judah, A 15 watt DC30 type clone i got off the forums, a DR.Z based build... My end result is that i don't want to mess with them anymore. Sometimes they sound good, but they are SO noisy and microphonic. Tried 4-5 different mid/upper grade tubes. None of them made me happy. Ended up buying some super high heat silicone and made little blanket sleeves for the ones i liked, using a pipe clamp to hold it on. Took care of the rattle and microphonics, but I just found myself no longer loving them.

    I MUCH prefer the 12ax7 side of my DC30 based amp. so much that I have been trying to find a Matchless Brave schematic.... none yet. WOuld LOVE that channel with a 35 watt EL34 power amp.

    On the BassMate subject, I just got the gremlins worked out of mine! It had lots of noise (2 prong plug/old filter caps) and when the treble was turned under half it would just get weird distortion. Put on a new plug, installed new filter caps, replaced the long signal runs with shielded cable, replaced the caps in the tone stack and it sounds WAY better. Have a Legend 1518 speaker to replace the Peavey Black widow someone put in there years ago... And I am LOVING the sounds of the stock circuit with a 12ay7 in the preamp slot!
     
  5. slicktone

    slicktone Member

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    Thanks JDW3, I had thought about the bias...actually was worried it may end up too low...the LarMar is supposed to end up keeping a dual 220K in place of the two bias resistors you remove from the board...the Bass Mate has dual 100K, so if anything I would imagine it biased it a bit "cooler". I'd be interested to try some different values for the slope resistor...would that be the 100K coming off the bass pot?

    Cool suggestions on the EF86 preamp vs. other options Silent Sound and axpro! EF86's always seem to draw controversy when discussed on forums...I figure there's got to be a reason Matchless, Dr. Z and others use them, and even tout them as a selling point.

    My reasons for wanting to try it:

    1: The "darn close" to a DC30 vibe.
    2: I really like the throaty drive that those amps have on the EF86 channel with a MV and Cut.
    3: The Bass Mate's really only have 2 gain stages before the PI, and there's a fair amount of insertion loss in the tone stack...so for a higher drive I'm diming the V, B, and T controls then adjusting the MV and Cut to how I like it. Now the 12ax7 is getting close to that EF86 sound I like...but seems like just a bit more might be nice, and maybe open up the tone stack to be used with out losing so much gain. That said, that lower drive sounds are just sweet.

    The idea of a 6AU6 preamp is interesting, I'll look into that too....I also thought about adding another 12ax7 before the PI as well...may be easier and less hassle to deal with then the EF86. Maybe screening all those tubes is part of what drives that Matchless' up in price!

    I really love the stock sound of mine with an Amperex 12AT7 in the first spot as well axpro! Awesome cleanish sound, and a great base for pedals.
     
  6. JDW3

    JDW3 Member

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    I decreased the cathode resistors in V1. You have to be careful there, as it will start squealing. Also the slope was either 100K or 220K, can't remember. But 33k removes all the excess bass frequencies you're probably not going to use anyway.

    All this increasing the gain into the power stage. With the bias hot from the factory, mine was blowing fuses and tubes.

    I had a tech put it on a scope, and he noticed the bias extremely high. Installed a bias pot and new tubes and it sounds great. Try the slope resistor, it's very easy.

    I was also told the power stage wasn't designed for too much gain, B+ voltage too low possibly? It's been a few years. I think the amp is a great platform for a few mods.
     

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