How to tame the top end of newer Traynor YBA-1?

[Tone_Terrific]

http://img216.imageshack.us/img216/9120/yba1latemodel78pt2.jpg (http://img216.imageshack.us/img216/9...model78pt2.jpg)
This is not the conventional tone stack arrangement common to so many other amps, including the early Bassmasters.

This amp is too bright, usable with the treble at minimum, so almost no adjustable range. I'll keep the bright cap on the one channel as an option.

Any suggestions for expanding the range of the treble control or maybe the presence could be knocked down a bit, too?

[doctorx]

linky no worky.

[Tone_Terrific]

linky no worky.
Tx. Me fixxy.

[SatelliteAmps]

Copy and paste the linky. Then it worky. Clicking it doesn't work.

The link is only half the schematic.

You can change C6 to a higher value. You could change the NFB. You could change the coupling caps in one of the stages to a higher value. Any of these would affect the overall treble and presence of the amplifier.

[Tone_Terrific]

Copy and paste the linky. Then it worky. Clicking it doesn't work.

The link is only half the schematic.

You can change C6 to a higher value. You could change the NFB. You could change the coupling caps in one of the stages to a higher value. Any of these would affect the overall treble and presence of the amplifier.

The schematic is a scan of the print on the lid, that's all that would fit on my scanner. The missing part is just the OP stage which is very ordinary.

Notice how the presence control is is after the 2nd stage, not tied to the NFB and how the middle control is in a similar configuration but after the 3rd stage with the other tone controls. I think upping c6 would only allow more mids to pass via the treble control and what I am looking for is a way to roll them off more or not have so much upper boost.

I suspect raising the values of c5 and c12 (? beside it both 150p) would help decrease high boost but there may be implications that I can't foresee.

Anybody recognize this type of tone circuit? Maybe a link to a how-it-works?

[SatelliteAmps]

The presence is not connected directly to the NFB, but if you change the value of the NFB, then the overall presence of the amp is going to change. Upping C6 would clip the high end a bit. Changing C5 & C12 would also make a small difference, as would changing any of the caps along that rail.

[Tone_Terrific]

After some experimentation I am just leaving it stock.
With some tube juggling, channel balancing, etc., I have it sounding very good but it just does not do mellow. It does rock, however!

[bolero]

sean kilback used to have a great site that talked about old traynors


http://www.kilback.net/traynortweaks2.htm

[Structo]

You could also experiment with the slope resistor C16.
Lowering it would lower the knee that the bass and treble control.

And remove or up the value of the bright cap on the volume pot.

[Tone_Terrific]

sean kilback used to have a great site that talked about old traynors


http://www.kilback.net/traynortweaks2.htm

That is a good one!

This YBA-1, however is not the same config for the tone section.
I suspect that there is a positive feedback emphasis, to the top end, happening around that inter-stage presence control cct but I don't have the skills to assess its operation properly.

The bright cap is absent from ch 1 (and it's still bright) but there is a channel interaction even without jumpering.

They may have tuned this model for use with the common, but deficient, standard Traynor issue speakers.

[rockon1]

Ive read lowering the input grid resistor works on 800's. Dont know if it works-just throwing it out there. Bob

[rockon1]

Ive read lowering the input grid resistor works on 800's. Dont know if it works-just throwing it out there. Bob

Ahhh. dont know why the Schematic Heaven mods suggests the above but I actually increased the input grid resistor from 68K to 470k in my Laney with good results to reduce high frequency fizziness in the od. Better yet it was a simple mod.Bob

[RedMan]

Traynor tonestacks take some getting used to. The bass control works much better than a Fender/Marshall/Vox and the treble control although voiced quite low works well too. Don't expect it to be what it isn't and you'll probably end up loving it. If anything I would say you may want to lower C6's value instead of raising it.

[donnyjaguar]

Its a bass amp, brutha. Don't expect it to be the same as a Fender Twin. :)