Objective:
I wanted to go with a full on multi-channel build that would have both a high gain channel and a standard Plexi / 2204 style channel. The solo boost is icing on the cake. This seems like the ideal design for a ‘do it all’ amp, without the need to plan on using outboard pedals to get enough dirt. Either way, i will definitely be voicing one channel as a plexi / 2204 channel, and I’ll want it to sound as ‘vintage correct’ as possible.ALL NOS in Preamp
Sound Test - King Kong 50:
1/25: Played the PRS CU22SH thru both channels. This amp sounds great! Very quiet too. Ch. 1 is very Plexi-like with a lot less gain than Ch. 2. It can get pretty crunchy, but even with the ERA switched to diode clipping, it’s not as nearly as saturated as Ch. 2. It has a very sweet clean channel, with maybe a hair too more bass than needed, but sweet mids & a nice chimey top end. It may be a bit too sweet. It’s all relative. The controls have a lot of range and it’s not harsh at all. I’m changing the slope resistor to knock a bit of bass out & eventually decide if not needs to be a bit hotter. Ch. 2 is a screamer! It’s super thick & can get super saturated like many ‘Jose’ style designs. It’s a flamethrower for sure! It’s voiced a lot like the Yeti, but it’s even a bit tighter & more punchy. I can think of lots of ways to tweak this amp, but it really doesn’t need it. It’s an awesome amp as is. Still, I am going to play it for at least a few days before making any changes. However, I’m going to go ahead & try a couple other clipper pairs & change the Slope R on Ch. 1.
1/26/22: I made a couple small changes… I swapped out the clipper circuits with higher rated (1.3w) 20v zeners, new MPSA06’s and a 2N5401/2N5400 in series for Asymmetrical on the Solo switch so I can A/B the two via the footswitch. The OD channel is super tight & punchy. Sounds great! More to come…
1/29/22: This thing rips! Beautiful cleans & killer ‘Jose’ style lead channel with Solo MV… great layout for sure! Very versatile. I think the clean channel could use a bit more gain. Still, the channels compliment each other very nicely as is. The Solo MV is a great touch to an already killer amp.
2/11/22: I think I’m going to see if I can give the clean channel a bit more gain & see how that does. It’s a really nice sounding channel, just maybe a bit more polite than I’d like. As for the lead channel, I’m going give it a bit more time.
2/18/22: I made a few changes to the clean channel. I took it to Cameron CCV specs. except for the clipping diodes in the modern mode. It’s not bad at all, but I think I’m going to change it more towards a Plexi style circuit.
2/19/22: Tested changes made to Clean Channel. I’m going to leave these changes, at least for a couple weeks as this could be the way she stays. I really like the couple minor changes I made on the clean channel. It has a very sweet, clean tone & can get a bit crunchy when pushed as well. It’s a very versatile amp overall for sure.
3/31/22: I’ve decided to parallel the currently unused ‘b’ half of V3, the input stage for the Clean channel. I expect this will give it bit more gain & thicken it up a bit. Also, I am going to exchange the transistor clippers for 12v/12v zener pairs. I like the 12v/12v pair a lot. Makes a great alternate to the 20v Zeners. There’s less volume drop too.
4/1/22: The few changes really made an already excellent amp. even better! Parallel triodes on the clean channel really do give it more character & body, as well as a bit more gain, and it still cleans up beautifully. I plan to wire the drive channel to Chupa Specs. at some point as I prefer the Chupa over the Yeti. This OD channel can be wired to either pretty easily. I may wait and leave the choice up to the buyer. Whichever they prefer. If I set it up as a Chupa, I’ll need to change the NFB a bit as well. It should be a bit looser, in keeping the Chupa vibe.
2/20/23: This amp sounds KILLER! I don’t think it needs any changes. I’m staying with the Yeti-like drive channel. I think the tightness is spot on for this amp.
