jonarobb
Well-known member
Some of you might have seen this when it came up on Ebay last year. Well I grabbed it fully knowing it was a trainwreck. I work on amps and guitars here in NYC and have a soft spot for Boogies.
The Ebay ad had said it was heavily modded by some cat in Nashville, Sharpe something or another. He had put in an effects loop and hacked the preamp and power section to death. (This post should be affectionately titled: "Don't Mod Your Amp In Nashville")
Anyway, started from scratch. Gutted the whole thing. Spent ample time reflowing the the traces on the PCB. In spots where it was etched away from the so called mod, I used jumpers to put it back to spec. Had to rewire the whole input jack matrix as well since input 2 at some point had been turned into a footswitch jack of some sort.
While I was in I laid a full reverb circuit. This ended up being easier than planned because the chassis already had the cutouts for the tube sockets. I credit the schematics at Tubefreak.com, particularly the Mark IA schematic. I lifted that reverb circuit verbatim and it worked beautifully. More lush and deep than any other Boogie I've heard or played.
Mucho thanks to MB at Boogie. He was very patient with me. Through him I found out that between 1975 and 1978 there were no fewer than 10 different version of the Mark I. Subtle changes in various parts of the circuit as they addressed and responded to customers comments and complaints. I settled on a early 1976 circuit which uses the 12AT7 Fender PI circuit.
Power section is nice and spec'd out with the original value lytics.
The original JBL K120 that came with is had a nasty coil rub so I sent it out for recone. By the time it came back I had put in this early EVM 12L and am much happier with it.
Additionally, tubes in the preamp are all creme de la crop. V1 is a Berlin production Tele 7025, rest of the pre's are sprinkled with RCA's and Amperex's. I have tons of gravy power tubes laying around but I started using the newer Tung-Sol 6L6GC re-issue for my client work. Figured I'd give em' a whirl in this as well. Pleasantly surprised at both the tone and reliability. If you need a good new production and Boogie friendly 6L6GC, I highly recommend these. This amp gets alot of use now and with 450 volts on the plates every night for hours on end the Tung Sol has gone to the top of my list.
All work done by me. Needless to say this thing blows my mind when I play it. I had 2 other Boogies. A Mark IIa and a Mark I re-issue. I'll probably never play another amp again besides this. Aside from it being a rescue mission and a labor of love, this amp just has the "it" factor. I'm sure you guys/gals know what I mean.
J-
The Ebay ad had said it was heavily modded by some cat in Nashville, Sharpe something or another. He had put in an effects loop and hacked the preamp and power section to death. (This post should be affectionately titled: "Don't Mod Your Amp In Nashville")
Anyway, started from scratch. Gutted the whole thing. Spent ample time reflowing the the traces on the PCB. In spots where it was etched away from the so called mod, I used jumpers to put it back to spec. Had to rewire the whole input jack matrix as well since input 2 at some point had been turned into a footswitch jack of some sort.
While I was in I laid a full reverb circuit. This ended up being easier than planned because the chassis already had the cutouts for the tube sockets. I credit the schematics at Tubefreak.com, particularly the Mark IA schematic. I lifted that reverb circuit verbatim and it worked beautifully. More lush and deep than any other Boogie I've heard or played.
Mucho thanks to MB at Boogie. He was very patient with me. Through him I found out that between 1975 and 1978 there were no fewer than 10 different version of the Mark I. Subtle changes in various parts of the circuit as they addressed and responded to customers comments and complaints. I settled on a early 1976 circuit which uses the 12AT7 Fender PI circuit.
Power section is nice and spec'd out with the original value lytics.
The original JBL K120 that came with is had a nasty coil rub so I sent it out for recone. By the time it came back I had put in this early EVM 12L and am much happier with it.
Additionally, tubes in the preamp are all creme de la crop. V1 is a Berlin production Tele 7025, rest of the pre's are sprinkled with RCA's and Amperex's. I have tons of gravy power tubes laying around but I started using the newer Tung-Sol 6L6GC re-issue for my client work. Figured I'd give em' a whirl in this as well. Pleasantly surprised at both the tone and reliability. If you need a good new production and Boogie friendly 6L6GC, I highly recommend these. This amp gets alot of use now and with 450 volts on the plates every night for hours on end the Tung Sol has gone to the top of my list.
All work done by me. Needless to say this thing blows my mind when I play it. I had 2 other Boogies. A Mark IIa and a Mark I re-issue. I'll probably never play another amp again besides this. Aside from it being a rescue mission and a labor of love, this amp just has the "it" factor. I'm sure you guys/gals know what I mean.
J-
