Running dual coupling caps off of V1a ?

[joesatch]

Supposedly to add a clean out i see an additional 22nf running off of v1a to a 1M volume pot, this is switched to the PI for a clean raw channel. Yay or Nay? Will is effect the stock circuit that is running from the first coupling cap?

[SILVERGUN]

The spot where your schematic is supposed to be looks like this 

[joesatch]

standard 2204 circuit. An additional coupling cap is added to the plate of V1A and sent to a 1M pot with wiper that is switched to PI input.

[acheld]

That picture means nothing to me.

Could you post a schematic please?   It is really helpful, and you've been around long enough to know that is the language we speak.

[sluckey]

standard 2204 circuit. An additional coupling cap is added to the plate of V1A and sent to a 1M pot with wiper that is switched to PI input.

You can do that. Probably won't be happy. Not enough signal to drive the PI very loud. But it will be clean.

[joesatch]

how then ? should i add a zero loss effects loop and use the return for clean in ?

[sluckey]

What are you trying to accomplish? Be specific and give lots of details.

[joesatch]

My plan is to take the 2204 circuit and make a switchable (with relays) path to the power amp from the input jack. I was thinking to split the first gain stage with 2 coupling caps  so i can select between just a MV to PI (bypassing the TS and cascading gain stages)and the standard circuit. This is to facilitate some pedal preamps I'd like to use with the amp. Really didnt want to put an effects loop in this.

[tubeswell]

My plan is to take the 2204 circuit and make a switchable (with relays) path to the power amp from the input jack. I was thinking to split the first gain stage with 2 coupling caps  so i can select between just a MV to PI (bypassing the TS and cascading gain stages)and the standard circuit. This is to facilitate some pedal preamps I'd like to use with the amp. Really didnt want to put an effects loop in this.

So how do you envisage 'splitting the first stage with 2 coupling caps'? Schematic please.

[HotBluePlates]

My plan is to take the 2204 circuit and ... bypassing the TS and cascading gain stages ... This is to facilitate some pedal preamps I'd like to use with the amp. Really didnt want to put an effects loop in this.

What you describe is a perfect Use Case for a passive effects loop of Send and Return jacks, where the Return jack has a switched contact and "normals" a connection from Send to Return when nothing is plugged in to the Return jack.

The only drawback (besides not being a great, full-featured loop) is that every decade or so, you will need to clean that switched contact to ensure it doesn't become an intermittent connection.


The Silver Jubilee has such a Passive Effects Loop with normaling at the Return jack.


You might say, "Yeah, but I want to be able to switch between using the Pedal Preamp and the amp's preamp."

The slick guys don't do the complicated switching inside the amp, they use some kind of pedalboard switching system to handle that chore.  The Amp Input, Send and Return are all connected at the switcher, with loops setup to use the Amp Preamp, Pedal Preamp, pedals, and any combination thereof.

The really good (but expensive) ones like G3 incorporate buffering & level adjusting (as needed) to help solve relative-level issues.

[Williamblake]

I tried that once (for reverb) and there was unwanted interaction through the coupling caps. I felt very smart putting two resistors in series as the plate load to have the right gain levels and less interaction, too but never got anywhere with that, i chose a voltage divider that was driven by that gain stage and that worked very well and is easily adjustable. Would require an additional gain stage in your case either way i guess. My point being you will probably need to adress the mixing.

[joesatch]

I tried that once (for reverb) and there was unwanted interaction through the coupling caps. I felt very smart putting two resistors in series as the plate load to have the right gain levels and less interaction, too but never got anywhere with that, i chose a voltage divider that was driven by that gain stage and that worked very well and is easily adjustable. Would require an additional gain stage in your case either way i guess. My point being you will probably need to adress the mixing.

You have to mute the unused circuit with the relay to ground. I have tried this before but just not with two coupling caps and no TS with direct to PI