Carolina Blues Special

[tubenit]

Still one of my favorite amps!  Sort of like a clean/more headroom version of 5E3, IMO.

I built this for a close friend some years ago and every few years have "borrowed" it to give it a check up. I'll have to say that I feel like I
"got it right" on this amp yrs ago.  It has some unique features with a Dano tone stack and the one tube reverb with a concertina phase invertor.  This time I changed the master volume to be a LarMar PPIMV. 

It sounds really really great to me!  Just a very fun amp to play.  The cab is pretty small. It's the one on the left in the photo. It sports a
Emminence Ragin Cajun speaker.  The reverb works fine for me and I like it set on somewhere between "3-5" on this amp.  Subtle, but you can sure hear it. 

With respect, Tubenit

EDIT:  I recommend using a PPIMV master volume instead of a crossline master volume.  Look in ARCHIVES under master volumes for examples of a PPIMV  (post phase invertor master volume.

[angelodp]

Hi I realize this is an old topic. This pertains specifically to the CBS Bax layout.


1. Are the volume pot connections incorrect? Nothing at the wiper?


2. On the reverb pot is that input wire meant to land on the rd line?


3. Is the dwell pot 10k or 25k? Ok I see 1M


4. Between the schematic and the layout, is RV the same as RD?


Thanks for clarification

[mresistor]

Follow V3-A pin two back to the board and you'll also see that the 10K grid stopper is also missing and the wire from there to the wiper of the volume pot is missing. 
So sketch it in on your own.   I don't know if Tubenit is aware or not.


According to the schematic the right side terminal of the reverb pot should aslo attach to V3-A Pin two.


About RV and RD and the schematic and layout showing them., you'll have to ask Tubenit. 

[angelodp]

Ok I gave it a shot. Should be good to build now...? 


Just one more question right now - the green dot with a question mark, should that not be to ground?


I'll update with a layout of mine and include PPIMV


Thanks

[angelodp]

I suppose there is a question about insertion point for the reverb circuit. Here on this version there is a different insertion point. if you built one of these can you comment on a preference here.

[tubenit]

Anytime you see a discrepancy between a schematic and layout I've posted ............... go with the schematic.


Regarding reverb insertion points with a Carolina Blues Special.  The insertion point prior to the 2nd gain stage around the volume/tone connection gives more reverb.  However, as one adjusts the volume, they may need to adjust the reverb also.


The CBS with the reverb insertion point after the 2nd gain stage prior to the phase invertor has less reverb.  However, when one adjusts the volume/tone pots ............ the reverb is not impacted and one doesn't need to readjust the reverb pot also after adjusting the volume pot.


With respect, Tubenit

[angelodp]

Very good sir, I can see that the later insertion may be more suited to what I am after. I will adjust my layout accordingly.


Best Ange

[angelodp]

Here is my modifications to the layout to match the schematic (CBS - Gene's 10/20/14).


Now I will also create a layout that fits into the existing Bogen, once stripped mostly down.