Traynor YCV40-Fender Tone Stack

[JustMike]

If I change values as shown (Super Reverb), will the amp sound more fendery? I'm sure the tube rectifier has a lot to do with the sound, but I'm not going there.

[sluckey]

I think it will sound like a slightly modified Traynor. 

[JustMike]

OK. So maybe getting a little philosophical here, but what then is the classic Fender sound?


Scooped mids- is this just a function of the tone stack?
Tube rectifier - voltage sag
I've heard there's some sag because of the smaller output xfmr (Deluxe).


 Is there such a thing as the Fender sound without the sag? That's what I'm after. A Fender clean pedal platform in a 1-12 40w combo. I was hoping I could get the Traynor to give me this sound kuz I'm cheap!

[shooter]

maybe getting a little philosophical

spend quality time with a pile of Fender amps, find what you're looking for then replicate, otherwise it's like asking what blue is the real blue for the sky 

[sluckey]

Is there such a thing as the Fender sound without the sag? That's what I'm after.

Sure. Twin Reverb.

[JustMike]

Yes, the Twin. But what a Beast! I'd really like a 1-12 combo I can move. This is a gigging amp for me.
 So the Twin doesn't have a tube rectifier but it has the same tone stack.
As far as the output section- I don't imagine the difference between 2x 6L6's vs 4x 6L6's comes into play much until we're really driving the volume? That ain't going to happen these days with a Twin but the deluxe I played thru wasn't quite enough. When I play thru it the sweet spot seems to be at about 4 on the volume, but it's not quite loud enough. That's why I'm thinking about a 40w.

[sluckey]

Build a TR with only two output tubes.

[pdf64]

If I change values as shown (Super Reverb), will the amp sound more fendery? I'm sure the tube rectifier has a lot to do with the sound, but I'm not going there.

At 47k, the current slope resistor R15 is half the BF Fender value; that will reduce the mid scoop.

[JustMike]

I traced the circuits and there appear to be very minimal differences between the Traynor and a Fender. The Fender values I got from the AB763. I learned in the process that the Super and the Twin are very similar.
 How critical are these values to the Fender sound and will I notice if I change the Traynor to these values? On the Super schematic it shows 465v at point A (+410v) and 465 at point B (+410v). I assume these voltages will affect the sound?

[JustMike]

 I changed out the slope resistor from a 47k to a 100k and I like the sound. Definitely scoops the mid out. Now I'd like to reduce the gain of the drive channel. I'm hitting the front end of the amp pretty hard with some stacked boost & drive pedals and the clean channel is about where I want it but it's a compressed mess when I switch to the drive channel. Unfortunately they're splitting the tubes between the channels so a simple tube swap is out.
 Basically, the input feeds V1a and before the signal gets to the tone stack, it's switched to the drive channel which starts with V1b then V2a. V2b follows the clean channel tone stack. I'm sure it's because of the PCB construction that they did it this way.
 Anyway, can I get some suggestions for reducing gain in the drive channel? I know about the volume knob, but anything past 1.5 on the drive gets mushy. I'd like to have some range to work with. Is it as simple as bypassing the 500k Drive pot with a resistor?


https://el34world.com/charts/Schematics/files/Traynor/Traynor_ycv40_sm.pdf

[shooter]

what's your magic number on the drive pot?
ie; 4 is as much as I want  5-10 are too much

eager to solder;
start with a 47k, solder one leg on the right side R114, solder other leg to pre-amp ground

use your "calibrated" drive pot to decide if R114A helped or hindered

(R114A can be gator-clipped and changed up for more fun) NOT WITH POWER ON 

[PRR]

Take out C1.

Increase R5.

[tubenit]

Remember there is a 12DW7 and a reverse 12DW7 where one of the triodes is essentially a 12AU7 gain and the other is 12Ax7 gain. You can consider that for V1.   

Can you change the LTPI tube to 12AT7?   

And you can change the cathode cap on the second gain stage to 5uf.

All of those will help you get a "clean pedal platform".

With respect, Tubenit

[jjasilli]

OK. So maybe getting a little philosophical here, but what then is the classic Fender sound?
"Classic Fender Sound" in common usage tends to refer to the Blackface era amps.  This tone is largely due to the tonestack, adopted (stolen & modified) by Marshall & Vox, leading to the term FMV Tonestack.  Even though different Models of Blackface era amps sound different from one another -- And even though the Tweed, Brown and SF era's are also "classic" in the sense of "vintage"; the term "Classic Fender Sound" connotes the BF era. The BF era has become the de facto benchmark standard for comparison of tone in guitar amps.

I suggest you download the Duncan tonestack calculator to analyze the different tonestack values.

Focusing on the TS:  The Traynor values seem to contribute to a dark tone.  N.B.: How the tonestack is driven -- by the plate or by the cathode of the driving stage -- is significant, especially in terms of the value of the slope resistor.  The driving stage is not included in the section of the schematic you posted.  In general: dark tone is enhanced by low values in the slope R, and in the T & B pots; and by hi values in the treble cap; M pot; and bypass cap to the vol pot.  "Hi/lo values" are by comparison to typical BF values.

[JustMike]

Focusing on the TS:  The driving stage is not included in the section of the schematic you posted. 

I posted a link of the schematic from the EL34 Library, but here it is again;


https://el34world.com/charts/Schematics/files/Traynor/Traynor_ycv40_sm.pdf

[jjasilli]

Ok, the amp is Fender topography & voltages.  Regular channel: Input stage > TS > Tone recovery Stage > PI.  The likely place for origin of overdrive is the PI (then, Power Tubes).  Gain channel has a cascading gain stage before its TS.  Hence, earlier OD in the preamp is available.

In either channel tone differs from Classic Fender due to the values of the TS components and the driving stage.  Driver is the plate of the driving stage (not cathode) through a .1uF cap.  By Fender standards this cap is optional, but could be, say, 1/10th the value of .01uF, to become a hi-pass filter.  For AC signal operation, the large stock value of this cap is pretty much a short circuit -- effectively, it's not there.    EDIT:  for treble.  In series with the .047uF bass & mid caps, it effectively reduces their combined values to about .03uF which is reasonably in the range of Classic Fender values.  (nF values screw me up)

A Fender plate driver expects to see a 100K slope resistor; lower values > darker tone.  Per my prior Reply, the Traynor's TS component values should contribute significantly to dark tone compared to Classic Fender.  EDIT:  also 1M vol. pot.  If you swap-in components with Fender values, you will have Fender tone.

EDIT:  In short, changing the value of the slope R to 100K (up to maybe 150K); the treble cap to 250pF (as you suggest), and the vol pot to 1M, as first steps, should show an increase in brightness of tone.

[JustMike]

Remember there is a 12DW7 and a reverse 12DW7 where one of the triodes is essentially a 12AU7 gain and the other is 12Ax7 gain. You can consider that for V1.   

Can you change the LTPI tube to 12AT7?   

And you can change the cathode cap on the second gain stage to 5uf.

All of those will help you get a "clean pedal platform".

With respect, Tubenit

These will change the gain of the whole amp. I like the clean channel. I just want the drive channel to be useable for my setup. I was talking on the phone with an amp tech friend of mine and he suggested removing the cathode bypass cap on V1B as well as splitting the plate load resistor and connecting C81 at the junction of the 2 (22k & 89k). This brought down the gain of the drive channel, but it sounds kind of lifeless now, I think.
Fun stuff BTW. Also, I'm half tempted to just gut it and Fender/Dumbleize it.