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previous: Trace Steve;I've goofed a... -- 9/28/2000 1:44 PM

Re: Trace, please post your results.

9/28/2000 3:02 PM
Peter S	Re: Trace, please post your results. Trace, "think Ken might have based it on a plexi with a cleaner (Vox-ish PI) and a few twists but that's my gut feeling talking (not fact)" I posted a couple days ago about my experience(so far) with attempting to build one of these amps. If you read my post you can easily see that I resorted to my old standby....when all else fails, I always resort to a 5F6A derivative.......seems like you can't screw these amps up no matter how hard you try. Anyway....I had some extra time(and parts)...so I went back in and made the following changes: 1) I installed a Super Reverb PT with a 5y3 recto which brought the plate voltage up to 390 volts. 2) I changed out the OT for a BIG JUICY interleaved/paper 6.6K:16r OT. 3) Installed a Naylor SD 50 12" speaker 4) removed the negative feedback loop and changed the design of the PI to a Vox AC30 style. 5) cheanged the design of the tone stack to a Vox AC30 design. Now the amp sounds incredible! Still not anything like the express clone schematics, but..... Beautiful sweet clear clean tone...Dynamics out the yang.....really cool output tube distortion. Amazing sustain for such a low volume/low gain amp. Now that I've got this thing sounding AWESOME, I'm stoked to play with it some more. I think I'm going to try the following tonight: 1) remove the paralleled preamps and just use 1/2 of v1 for the preamp. 2) insert a gain stage between the tone stack and PI. I'm going to leave the tone stack cathode driven, because I've always found that my amps always sound better with a cathode follower somewhere in the circuit. I'll post whether or not this is a dismal failure or a step in the right direction. I'm miles away from a wreck express, but I don't have access to the inside of one anyway, so I'm just going on gut instinct here. Peter

9/28/2000 3:02 PM

Peter S

Re: Trace, please post your results.

Trace,

"think Ken might have based it on a plexi with a cleaner (Vox-ish PI) and a few twists but that's my gut feeling talking (not fact)"

I posted a couple days ago about my experience(so far) with attempting to build one of these amps. If you read my post you can easily see that I resorted to my old standby....when all else fails, I always resort to a 5F6A derivative.......seems like you can't screw these amps up no matter how hard you try. Anyway....I had some extra time(and parts)...so I went back in and made the following changes:

1) I installed a Super Reverb PT with a 5y3 recto which brought the plate voltage up to 390 volts.

2) I changed out the OT for a BIG JUICY interleaved/paper 6.6K:16r OT.

3) Installed a Naylor SD 50 12" speaker

4) removed the negative feedback loop and changed the design of the PI to a Vox AC30 style.

5) cheanged the design of the tone stack to a Vox AC30 design.

Now the amp sounds incredible! Still not anything like the express clone schematics, but..... Beautiful sweet clear clean tone...Dynamics out the yang.....really cool output tube distortion. Amazing sustain for such a low volume/low gain amp. Now that I've got this thing sounding AWESOME, I'm stoked to play with it some more.

I think I'm going to try the following tonight:

1) remove the paralleled preamps and just use 1/2 of v1 for the preamp.

2) insert a gain stage between the tone stack and PI.

I'm going to leave the tone stack cathode driven, because I've always found that my amps always sound better with a cathode follower somewhere in the circuit. I'll post whether or not this is a dismal failure or a step in the right direction. I'm miles away from a wreck express, but I don't have access to the inside of one anyway, so I'm just going on gut instinct here.

Peter