solid state preamp WIP

[Steben]

Hi guys,

I'm switching to a more complex circuit now.

Circuit rev A with CFP



Circuit rev B with opamp stage.

[antonis]

Can't get the reason for adding another CFP for Tonestack drive..

10k GAIN pot is actually a "Sustain" one 'cause Q3/Q4 stage gain is solely set by R11 & R9..

Also, you could save a Tonestack by utilizing a DPDT switch for first "Select Channel" and wire Q4 Collector on it..

[Steben]

Can't get the reason for adding another CFP for Tonestack drive..

10k GAIN pot is actually a "Sustain" one 'cause Q3/Q4 stage gain is solely set by R11 & R9..

Also, you could save a Tonestack by utilizing a DPDT switch for first "Select Channel" and wire Q4 Collector on it..

Totally agree on the scrapping of the cfp. Already working on an opamp stage which is so design friendly but was hindered in completing.

The two stacks are likely to be kept... I like separate settings.

[antonis]

So, shall we procced to a new thread for the rest of the cicuit or we'll discuss here about C16/R13 HPF corner frequency..??

[Steben]

So, shall we procced to a new thread for the rest of the cicuit or we'll discuss here about C16/R13 HPF corner frequency..??

I´ll add rev B 😄

[Steben]

Added!
Stage is set to mimick just slightly a triode clipping.

[antonis]

Too many items..

Why not using a JFET in its ohmic region..??

P.S.
Don't ask me for an example 'cause I hate JFETs a lot..

[Steben]

Too many items..

Why not using a JFET in its ohmic region..??

P.S.
Don't ask me for an example 'cause I hate JFETs a lot..

Exactly.... jfets are guess and gamble

[FSFX]

Exactly.... jfets are guess and gamble

Only to some.

JFETs are measure and calculate rather than guess and gamble.

That is not too difficult to do if you have the basic tools and knowledge to use them.

[Steben]

Exactly.... jfets are guess and gamble

Only to some.

JFETs are measure and calculate rather than guess and gamble.

That is not too difficult to do if you have the basic tools and knowledge to use them.

I "did" some jFETs in the past. But I dislike the whole procedure. jFET's are like cats: cute yet eventually you have to accept their ways. Is this where English has provided us with the "I hate to love them" principle?
Let's say I've fallen for the things that made opamps come to live in the first place: opamps do what you want them to do. What they do not offer is a load of non linear spice.

Back on topic: the classic tonestack is perhaps not ideal for the drive channel...

[Steben]

Too many items..

really?