More 'life' to high plate cleans

[Charlie Wilson]

10thTx and anybody else that is interested. The 2nd Gen Hybrid layout was posted by Jborders several years ago. I am pretty sure it was to replicate the Bludotone 70s voicing as the components in the layout match the one in the photo of the Bludotone. I for one would like to build that circuit and I know a few guys have done it already including Barryw (see attached photo). I think there are some things that do need to be sorted out on the layout such as the relays and a tail on the bass pot. Maybe it would be a good idea to start a new thread discussing the circuit so as to easier to reference it in the future and see if some of the builders who have built it could chime in.

CW

[JD0x0]

Finally got around to doing some changes to this amp. Dropped in a 'preferred series' 7025 into V1, step in the right direction, but still wasn't completely there. Changed V1a plate from a measured 221K to 181K and that seemed to do the trick. Didn't seem to affect the OD too much. Maybe a tad more dynamic, otherwise no real tonal change to the OD that I'm noticing at this point. I'm going to do more testing tomorrow. I'm still considering dropping the V1a grid resistor from 23.5K (CC) to a 10K (RN65D) but I'd like to get more testing in first.

[Structo]

Dropping V1a grid stopper value can change response as well as affect the ability to block RF at the input grid.
I personally wouldn't go below 22K but hey, see if you like it.

The only way to learn and hear the differences is to try things.
Just try to make one change at a time and listen to the change at different volume levels.

[telentubes]

I got inspired by this thread to rebuild the 3rd generation 50 Watt I built a few years back. It never really did it for me. The inability to make both channels sound good at the same time was a big part of the frustration.

Fast forward to this discussion, which led me to break out the soldering iron again, and so far I am really digging the amp. Better cleans than the Small Special.

Clean channel is #124, with 10uf bypass caps and a 33k V1a grid stopper.

OD has #102 values, except that I left the .02uf coupling cap for V2a (#102 has a .01uf cap). Plates are 220K and 150K (#102 values). No snubbers so far. Not sure I'll need them.

Everything down stream from there, into the PI etc., is 3rd Generation 50Watt with a few exceptions.
I added the OD and PI trimmers, and a Ratio pot for the OD. I also upped the first stage filters from 100uf to 220uf. It has a toggle switch for "Presence" ala 3rd Gen. and the NFB value is 3rd Gen. as well. The first dropping resistor was upped to 4K7.

Cleans are rich. Still dialing in the OD trimmer/ratio/level relationship, but the OD channel sounds like an extension of the clean channel now. Haven't found the singing overdrive/bloom thing yet, but I'm still tweaking. Maybe I just need to turn up more!

V1 and V2 are around 190V. V3 280V. V4 and V5 plates are 450V. Bias 34mV.
I'm running it through a single EV12L.
It is now a pretty fun amp. Thanks so much to all once again!!!

[M Fowler]

I have a Bludotone chassis I should build something into it.

Mark

[telentubes]

I imagine you will Mark.
Forgot to mention that the only relay is for OD channel switching.