Monkeymatic Element 79 #1 (Gibson Goldtone GA-15 Velocette)

[xtian]

A gentleman recently asked <https://tubeamparchive.com/viewtopic.php?t=21354> to have a an amp built along the lines of the modern, Trace Elliott Velocette, which bears the name Goldtone and the model number GA-15, but bears little resemblance to the original Gibson GA-15.

I am just wrapping up today. My plate voltage is high (382vdc) but with a 360R shared cathode resistor, my dissipation is spot on, at 8 watts and 22mA each. I'm using GE branded NOS EL84s (thanks, Apex Jr!).

My plates are at 382, and screens at 378 with 1K5 2W resistors. Any worries about burning the tubes out at such high voltage? Or is the fact that I'm only dissipating 8 watts each mean the tubes are OK at this voltage?

[Leo_Gnardo]

My plates are at 382, and screens at 378 with 1K5 2W resistors. Any worries about burning the tubes out at such high voltage? Or is the fact that I'm only dissipating 8 watts each mean the tubes are OK at this voltage?

I've seen EL84 run well into the 400's (Mesa who else) so 382 doesn't look too bad. And plate diss at 8 watts out of 12 recommended limit, is wise. I think it'll be just fine.

I had to work on some of the original Trace Velocettes. Good looking amps but a propensity to melt tubes & transformers. I doubt yours will have any such problems. Neat looking build, lots of breathing space in there.

[xtian]

I had to work on some of the original Trace Velocettes. Good looking amps but a propensity to melt tubes & transformers.

+1. Had to replace melted plastic tube sockets. I doubled the value of the cathode resistor to bring it to not-a-fire-danger operation. Still sounded great.

[xtian]

Finished and ready to ship.

[M Fowler]

I like your amp it really looks great.

Mark

[Reeltarded]

It's Oooks great!!

[NickC]

Yes indeed, that looks mighty fine!

[mcgruff]

I'd really like to ask a question from someone who knows the GA15. Planning to build one soon but not sure what voltage I need on the PT secondary.

The schematic available online has 400-0 fed to the ss rectifier. I've also heard 275-0-275 suggested for a GA15 PT and then there's Mojo who sell one with 315-0-315...

Confusing

[Bob S]

Nice looking amp Aaron.
Original Velocette amps sound great so I'm sure you're happy with this little monkey.
I notice tantalum caps on 1st & 2nd pre stages catthodes - any thoughts on how they compare to lytics ?

[xtian]

I'd really like to ask a question

Sorry I can't help you out with this.

[xtian]

Nice looking amp Aaron.
Original Velocette amps sound great so I'm sure you're happy with this little monkey.
I notice tantalum caps on 1st & 2nd pre stages catthodes - any thoughts on how they compare to lytics ?

I have never used an e-cap with a value less than 10uF. So these tantalum caps spec'd at 1uF and 2.2uF were the only parts I tried.

I recently put this amp back in the "home practice" stack, and I'm really digging it. I installed a master volume late in the game, and it's perfect for single coils with the volume dimed and the master down low. It's got that mildly overdriven crunch that makes Teles and Strats snarl and growl like SRV.

[xtian]

Clips posted.

1992 Fender American Telecaster > Monkeymatic Element 79 > Shure SM57 > MOTU 828mk3 > no effects, no compression > MP3 at 192kbps

First section, until 2:20, recorded with master volume down near zero--overall volume level is a bit louder than normal conversation. Second section, after 2:20, recorded with master at about 3, which is loud enough to rattle windows.

http://amps.monkeymatic.com/2013-monkey ... ment-79-1/