Carolina Eclipse boost mod

[tubenit]

Given Charlotte, NC is in the 98% solar eclipse path within the next hour ......................  I decided to name it after the event.

I have had this Carolina Overdrive Special 5879 plus amp that original had a PAB (preamp boost).  I hardly ever used it and it made a BIG jump in volume and wasn't as smooth as I wanted. It had a little high end hash/grind that I wasn't fond of.  So, it was there unused for the most part.

I wondered what would happen if I used a cathode bypass cap, or cathode bypass cap with resistor paralled or simply a paralleled resistor with the 8.2k cathode resistor on the 3rd gain stage on the clean channel?   I spent two hours trying all kinds of combinations of caps, caps & resistors and resistors paralleling the 8.2k.  I tried a 220uf there, 1.5k there, 2.2uf with 3.9k  etc. etc. etc. ...............

I ended up liking a 10uf/100v cathode cap paralleled with the 8.2k resistor.  Never have used a cathode cap with such a large value resistor.  Typically you have a 100k/1.5k  plate/cathode ............... I've got a 120k/8.2k.

However,  I found I also liked a 10uf and 5.6k in series then paralleling the 8.2k.   So it's now called the Carolina Eclipse Boost mod.   

Ironically, I found the larger cathode resistor 8.2k with 10uf much smoother in tone and sweeter in harmonics then 1.8k with a 2.2uf to 10uf range cap.  I have no idea why but it just has more sweet harmonics, IMO.   I have NO idea if this idea would work well with other amps but I try to pass on "new ideas" with the hope someone might find it useful?

Nothing new about paralleling a switchable cathode bypass cap,  but I haven't seen that done with this large of a cathode resistor?  Nor have I seen a toggle switch option to send the 10uf directly to ground  (large boost) vs. 5.6k tail to ground (more modest boost)

Anyhow, I like it!  The toggle switch having the 10uf with 5.6k tail resistor to ground paralleling the 8.2k is very nice.  Using the 10uf directly to ground really gives a very pushed driven overdrive tone with some sustained feedback.

With respect, Tubenit

[Joel]

So 14 months on, I'm curious if you are still liking this Eclipse Boost mod? 

I'm currently playing around with DIYLC, learning the how to use it and laying out a CoS clone of my own (actual building will need to wait until after I've move interstate in the new year).

[tubenit]

Yes, I liked it a lot.  ……………………..

AND,  I needed the toggle switch for something different and so it's not in the amp right currently.  But yes, it was a nice boost & used it frequently.

With respect, Tubenit