just wondering what value resistors and caps to use with the ken fischer prefered PPI MV on a plexi/fenderbassman (plexified traynor YBA-1 in my case)
here is the traynor schmatic unchanged, i'm just going to be ordering the parts i need to make it a hot rodded plexi which isnt many.
http://www.lynx.bc.ca/~jc/661021_YBA1.gif
Master volume
Moderators: pompeiisneaks, Colossal
Re: Master volume
Not to discourage you from installing the master volume, but I've just finished installing one of Dana's (UR12) VVR 2 (variable voltage regulator) boards in my 68' Traynor YBA-1. I'm still tweaking it, but I gotta tell you it's the bomb. I'm regulating the voltage to the whole amp. You can also use it with a PPI master volume and just scale the output tubes.
Do you know what year your YBA-1 is? That schematic you referenced is from a earlier model with 7027 output tubes. Just curious.
These things sound great with just swapping the volume controls out for 1M, and removing the bright cap from the pot and installing it over the mixer resistor for the bright channel. IMHO, of course! Give it a try before you hot rod it. You may love it!
Mark
Do you know what year your YBA-1 is? That schematic you referenced is from a earlier model with 7027 output tubes. Just curious.
These things sound great with just swapping the volume controls out for 1M, and removing the bright cap from the pot and installing it over the mixer resistor for the bright channel. IMHO, of course! Give it a try before you hot rod it. You may love it!
Mark
"- Yeah, can we have everything louder than everything else? Right!"- Ian Gillan
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strummer_83
- Posts: 5
- Joined: Sun Oct 05, 2008 8:13 pm
Re: Master volume
maybe, the main issue is how loud the thing is. I don't really use the amp at all because of the volume, most venues I play don't need a 50 watt amp. I'll look into that or maybe building an 18 watt. thanks a lot.
Re: Master volume
You have a rough schematic? I've got a 71-73ish YBA-1 that's been PPIV modded. Seem to always keep the master on 10 all the time tho, lol. VVR2 sounds like a great idea.Blindog wrote:Not to discourage you from installing the master volume, but I've just finished installing one of Dana's (UR12) VVR 2 (variable voltage regulator) boards in my 68' Traynor YBA-1. I'm still tweaking it, but I gotta tell you it's the bomb. I'm regulating the voltage to the whole amp.
Mark
Re: Master volume
Gearhead, here is a link to the VVR schematic: https://tubeamparchive.com/download/file.php?id=6178
The later YBA-1 models really pushed the the voltage up to get around 90 watts, so I don't think this version of VVR will work for you. It's good for 50 watts with additional heatsinking for the mosfet. PM Dana (he is UR12 here) and he can get you pricing on a complete board or a kit. He has fixed bias and cathode bias versions.
I have mine out of the circuit for now. I'm replacing the bias supply electrolytics and modifying the B+ dropping string and filtering to Marshall 1987 specs before I finalize it. It's a little wild right now (it is over 40 years old after all!)
strummer_83, Ken Fischer talks about 4 different types of MV circuits. Are you talking about type 2 in the"Trainwreck Pages"? If so, you don't need to change any components, just add a dual gang pot.
Mark
The later YBA-1 models really pushed the the voltage up to get around 90 watts, so I don't think this version of VVR will work for you. It's good for 50 watts with additional heatsinking for the mosfet. PM Dana (he is UR12 here) and he can get you pricing on a complete board or a kit. He has fixed bias and cathode bias versions.
I have mine out of the circuit for now. I'm replacing the bias supply electrolytics and modifying the B+ dropping string and filtering to Marshall 1987 specs before I finalize it. It's a little wild right now (it is over 40 years old after all!)
strummer_83, Ken Fischer talks about 4 different types of MV circuits. Are you talking about type 2 in the"Trainwreck Pages"? If so, you don't need to change any components, just add a dual gang pot.
Mark
Last edited by Blindog on Wed Oct 15, 2008 11:32 pm, edited 1 time in total.
"- Yeah, can we have everything louder than everything else? Right!"- Ian Gillan
Re: Master volume
I've been watching this thread carefully as I have a YBA-1 that I don't know what to do with. I installed a traditional MV, but something still ain't right.
If you try VVR2 in one, do let us know how it turns out - that might be my next experiment.
Another option I considered is plain-'ol VVR, after switching to cathode bias. Have you considered that?
BTW, is the tone stack in yours plate or cathode loaded? I've seen a few variations of each.
W
If you try VVR2 in one, do let us know how it turns out - that might be my next experiment.
Another option I considered is plain-'ol VVR, after switching to cathode bias. Have you considered that?
BTW, is the tone stack in yours plate or cathode loaded? I've seen a few variations of each.
W