Teeco 610D conversion

[angelodp]

you mean for DC leak?

[TUBEDUDE]

Leakage,short, value.

[angelodp]

Hello, ok well I finally got a schematic going for this amp. I have replaced all the old caps and some resistors. I recently added a voltage divider in the tone stack to get the amp into line with regard to gain. It sounds pretty good for a nice blues amp. I have a 10" speaker in a wine crate cab. I may up the cab later. My issue is still that the tone stack is somewhat lack luster in terms of range. With the NFB shut off and the bright cap on ( not shown but on the Volume pot ), the amp is fun and quite playable. Any sharp eyes out there that can suggest how to get this tonestack more responsive. I have tried quite a few alternate stacks to no success and therefor have re-installed this stack.

Just realized that I had a gapping error in the V1 power supply, now fixed.

Best Ange

[angelodp]

Here is the chassis as I have been modifying it. The cab is a wine crate job and for now will suffice.

Honestly its a good sounding amp even if I know very little about the deeper circuit. Voltages coming

[angelodp]

Layout - current

[martin manning]

Any sharp eyes out there that can suggest how to get this tonestack more responsive. I have tried quite a few alternate stacks to no success and therefor have re-installed this stack.

As drawn it doesn't look like it would be very effective. I think I would just start over and replace it with a Fender Blackface Treble-Bass ala Deluxe Reverb.

What type of sound are you after? The tone stack could be relocated between the gain stages, It'd probably be easy to experiment with that, but then you would not be driving the second stage hard like you are now.

[angelodp]

Hi Martin, well, Blackface tone is just fine. I love a Fender pushed a bit into breakup. Your suggestion is to position the standard Fender stack ala Deluxe Reverb between the two stages of the 6SC7. That the 6SC7 has a common cathode is not an issue here?

[martin manning]

That the 6SC7 has a common cathode is not an issue here?

I don't see a problem as long as the cathode resistor is bypassed.

[angelodp]

Hi MM, tried it, did not work, it was a noisy mess with almost no signal until the vol pot was wide open. Put the old tone stack in and it works fine except for the original issue of poor response on the Treble, Bass Pots. Not sure what to try next, maybe just live with it as is.

Anyway thanks for the support.

Given the tube compliment and all, do I have a shot and turning this into a Tweedle-D amp? Would the 6SC7 and 6SL7 work out?

[martin manning]

You have the two triodes cascaded now with a fixed high-pass filter in between, so I don't see why you can't put the TS there.

[angelodp]

MM, here is what I tried, but it was a mess. I must have made an error somewhere.

A

[angelodp]

Hi Martin, I was able to insert the Fender style Deluxe Reverb tone stack after V1 into V2 ( the cascaded input). Its working, but when I tried to go between the V1 and V2 I got nothing. Do I need to remove the grid leak resistors when inserting the stack between V1 & V2?

Ange

[martin manning]

You don't need a grid leak resistor after the tone stack, but I don't see how it would kill the signal. I'm not clear on what you are calling V1 and V2 after into and between. Are you saying it doesn't work as shown in the schematic above?

[angelodp]

You don't need a grid leak resistor after the tone stack, but I don't see how it would kill the signal. I'm not clear on what you are calling V1 and V2 after into and between. Are you saying it doesn't work as shown in the schematic above?

Yes it works as shown. Alternately, I did try to insert the tonestack between the two stages of the 6SC7 and that was not working, no signal passed. V1 is the top triode, V2 is the bottom triode. My path was 500pf into the Tone-stack+Vol and then back into the grid of V2 then from the Plate of V2 - .01uf coupling into the grid of 6SL7.
That method did not pass a signal, that I could hear.

[angelodp]

Here is the Tone-stack I have settled on. Its far better than the Hi-Fi configuration at the beginning for this thread. The NFB foot-switch is now functioning. My question is regarding the Treble response in the tone-stack,
which is subtle. What can I do to enhance the range of frequency response from the treble control.

I am on a Mac and cannot access the Duncan app to analyze the stack.