Dedicated clean - design question

[mlp-mx6]

Folks - a quick question.

If you wanted an ODS "on one side" with a switchable dedicated clean, which would you do? Would you

1 - Share the first stage and have it feed 2 tone stacks
2 - Have the input completely switch between two preamps (both the input and the output)? IOW, have a dedicated 2-stage "clean" preamp, and a regular ODS clean-into-OD preamp and switch completely between the two.

Is it possible to relay-switch the input and not have big-time noise?

If you share the first stage, would you -
1 - just use a normal first stage to feed 2 tone stacks?
2 - parallel the two sides of a 12AX7 to feed 2 tone stacks?
3 - Normal stage into a cathode follower to feed 2 tone stacks?

Thanks,
Michael

[Structo]

I think the ODS style amp is very quiet if you build it right and use good technique.
A wise guy once said, An amplifier is the sum of it's parts.

Really, a good ODS has great cleans and great overdrive, what more could you want?
Add pedals if need be.

[mlp-mx6]

Oh, I know. I've built 3 so far, with a 4th (the Bluesmaster effort) already under way. But I have another chassis that has 5 preamp tubes, so I thought I'd do the channel optimized for clean and switch that w/ the regular ODS clean + OD structure.

[Structo]

I figured you had more experience than you were letting on just by your post count.

Several of the pro builders are modding amps with more than two channels.

Tom

[talbany]

Check this out...

Tony

[Tonegeek]

Check this out...

Tony

Tony,
What drawing software ru using? looks really good.
thanks

[mlp-mx6]

Thanks very much, Tony.

So, sending the input signal to two grids works as well as switching the input between the 2 grids? I guess the input impedance is high enough that it doesn't matter, eh? That would definitely address my concern about the click/pop I would likely incur by switching the input.

[talbany]

Tony,
What drawing software ru using? looks really good.

Wit
This great drawing was posted way back several years I believe Bob-I did this one so the kudos is on him.. Maybe he can tell you!!..

So, sending the input signal to two grids works as well as switching the input between the 2 grids? I guess the input impedance is high enough that it doesn't matter, eh? That would definitely address my concern about the click/pop I would likely incur by switching the input.

Yes that's why it's done this way.. I've never had any luck switching inputs can get poppy using the mechanical relays we use here..You could probably have better luck with the LDR's for input switching if you decide to go that route..
Hope this Helps!!

Tony

[jaysg]

If you wanted an ODS "on one side" with a switchable dedicated clean, which would you do?

I have a modified Fender that shares the grid resistors. One half of the 12ax7 drives a BF tone stack, the other half drives the Dumble tone stack. Separate plate and cathode components. All switching is after the tone stack recoveries.

https://tubeamparchive.com/viewtopic.ph ... ht=concert

[heisthl]

The Carr 2 channel stuff uses that method - share the input between 2 separate preamp tubes and then use relay to switch the outputs of the individual preamps ahead of the PI (or reverb stage). Works like a million bucks, and no tone sucking mixing resistors.

[Bob-I]

Check this out...

Tony

Tony,
What drawing software ru using? looks really good.
thanks

I use Visio. There's some built in symbols and a bunch floating around.

That 3 channel amp is ok, but doesn't knock my socks off. The Fender channel doesn't have as much headroom as I'd like, and the Dumble clean is almost a waste. I'd rather have a little grit on that. Someday I may re-design this one.

[JD0x0]

JMO I think you should try an ODS with an EF86 (or similar) clean channel with two outputs. One goes to a standard non-hrm/HRM OD the second output can either be used as a "clean out" or run it into the PI so even with OD engaged the clean signal is still being mixed in. You could then add a second control to control the "blend"

Just my 2cents

[ampdoc1]

Here is a design I'm in the process of building, that corresponds to a lot of your goals. Not counting the switchable EQs and dual boosts, it is a design I've built before. The combination of the TW front end and the Dumble OD section is great!

[Bob-I]

Here is a design I'm in the process of building, that corresponds to a lot of your goals. Not counting the switchable EQs and dual boosts, it is a design I've built before. The combination of the TW front end and the Dumble OD section is great!

Looks like a mistake in there. The first triode is 220k/1.5k, second 10k/3.3k. Seems like Rk is reversed and the bias will be off.

[ampdoc1]

Bob-I

I'm pretty sure this is correct as to what I built before. That's the only design (derivative) I've built that I went thru stage by stage trying different combinations of plate and cathode values.

a'doc