TW Clone Chassis Complete

[wallybob]

Just finished the electrical build of my TW clone tonight. Hope to test it out this weekend. Wish me luck guys!

[kalinowski]

is it a standard size chassis? it looks kind of shorter. Anyway looks cool

[wallybob]

It's 10" x 16" x 3" so it's a little different than standard. I found the wrap around in the scrap barrel at work and fabed the top plate out of sheet Al.

[fishy]

Cool......

I don't see a safety ground from the IEC to chassis.

Looks like you have a fast gradual switch on and moved the 2nd stage to V2. Any reason for swapping the 2nd stage?

You have a mighty small looking plate resistor on V3 too but my eyes could be playing tricks on me.

Pete

[Bob-I]

Any reason you used the non-Twreck grounding scheme?

I'm curious because I've tried so many schemes and no 2 amps seem to respond the same to grounding.

[billyz]

Nice looking build. What is the difference in having the split load on V2 instead of V1 ?

[skyboltone]

Any reason you used the non-Twreck grounding scheme?

I'm curious because I've tried so many schemes and no 2 amps seem to respond the same to grounding.

Hi Bob. Ya know, I've tried all kinds of variations. The standard Francesca scheme works pretty good, though I've had better luck floating the buss ground off the pots. I also now always run the (fixed bias) cathode grounds back to the main cap ground point. Also, for what it's worth mine also don't leave the shop without a hum balance pot, +50VDC on the wiper, outsides to the filament supply. Pretty quiet. I know Dana wouldn't approve but I'm just a rebel I guess.

[wallybob]

fishy - good catch - I forgot to install the safety ground wire. Better get that installed prior to puttin' the wood to it. I moved the 2nd stage to V2 just because it seemed to layout a bit better. However, I can understand why it's good to have the 1st and 2nd stage on V1 since in this case if you had a particularly kick-ass 12AX7 in V1 you would get the benefit in both stages. I changed the grounding scheme to look more like the Komet because the traditional long bus soldered to the back of the pots is terrible from a maintenance standpoint. I guess we'll see if the grounding scheme is adequate once I fire it up. Thanks for your comments!

[fishy]

Your right about the pot buss being a pain.
Good luck and chime in to let us all know how she sounds.

Pete

[RJ Guitars]

Any reason you used the non-Twreck grounding scheme?

I'm curious because I've tried so many schemes and no 2 amps seem to respond the same to grounding.

Bob,

You've got my curiosity up... I tend to ground in non-Trainwreck protocol with a preference for star grounding. I think Wrecks are typically quiet amps so I don't necessarily believe they are flawed so to speak, just not always build and maintenance friendly. I especially don't like that buss bar soldered to the back of the pots.

I learned star-grounding from HiFi guys who are super critical about noise issues but I've never heard them discuss noticeable differences in tone due to one one grounding scheme over another. I'll also freely admit there are some things I've yet to learn... so maybe you can enlighten me a bit further?

BTW Wallybob - this is a cool amp, I eagerly await the results to see how she sounds. I am kinda partial to hybrid amps based upon classic circuits. IMHO, I think these are important exercises in figuring out where the tone mojo comes from and can help us see through the "mojo smoke and mirrors" as well as see the solid logic in the classic designs.

Thanks,

rj