SLO Mutant

[coolidge]

Almost there on my SLO mutant boards, a few more hours then I can move on to the chassis. Its been a painful process but I can see light at the end of the tunnel now.

3 channel SLO'ish, all 3 channels foot/panel switchable (relays) with indepenedent EQ/MV, dual external bias, DC heaters. All channels share V1b, crunch V1a, clean V2, OD V3, shared V4 stage and CF, pres, depth, bright switches x3, Metroamp effects loop. Its been a wallet melting project thus far.

Updated: 12/28/2010
[img466]http://www.coolidgeamps.com/pics/slombv4a.jpg[/img]

[img:622:959]http://www.coolidgeamps.com/pics/slom2.jpg[/img]

[xtian]

Thanks for spending the dough. Can't wait to see more.

[dynaman]

Dang, that's fancy! Did you try this circuit out already?

[Cliff Schecht]

Let me be the first to say HI!

I try to keep my amps as cheap as possible, if not free. I wouldn't bother building an amp if I could go out and buy one for the amount I spent to clone it (plus time spent building/designing).

Hope you at least had fun doing it! I just buttoned up an amp design I've been working on for months. Instead of having PCB's made or making them at home, I decided to emulate my layout with some snazzy gold turrets. Probably not so easy for an SLO though!

[ChrisM]

Very cool, what are you using to design the PCB?

[Cliff Schecht]

EagleCad is by far my favorite layout package. Once you learn it and set a few shortcuts you can knock out simple boards (most guitar amps are fairly simple) in an hour or two. The built in checking, if used correctly, has never failed me on the hundreds of boards I've cranked out in Eagle.

[dynaman]

The cab for your Highlander 100 sure is pretty!

[coolidge]

Very cool, what are you using to design the PCB?

I'm using DesignSpark PCB for the PCB/Turret boards for two reasons. Its free software and it outputs Gerber RS-274-X files which the PCB manufacturers need. http://www.designspark.com/pcb As free software goes its pretty good. I use OneCNC XR2 for 3D chassis work

[img:804:527]http://www.coolidgeamps.com/pics/designspark.jpg[/img]

Side note. This is my first go with PCB boards, I usually make my own turret boards. I contacted a local PCB maker and they cautioned me that many of the free PCB software programs out there PCB makers offer are encrypted/proprietary and to look for software that can output in the above common Gerber format.

[coolidge]

Dang, that's fancy! Did you try this circuit out already?

The circuit is bits of Fender, Marshall, SLO 100. I didn't invent anything new circuit wise. I started with the SLO 100 circuit, power supply is a SLO/Marshall mix e.g. SLO filtering but Marshall full bridge rectified. This is required due to my using a Mercury Magnetics Marshall PT 175-0-175. OT is a Mercury Magnetics Axiom Hi Def for 100 watt 6L6.

Like the SLO (and Marshall and a bunch of amps) the three channels share the 1st input stage (V1b ). In the SLO the clean and crunch channels also share the 2nd stage but the SLO clean channel doesn't have the biggest fan base so I decided to split the clean from the crunch so I can tailor tailor both independently.

The three channels come back together sharing the V4 stage and CF ala SLO but instead of the SLO shared EQ I split the three channels apart again via relays for independent EQ and MV. Finally the three channels come back together in the PI.

1. I added the Marshall JVM 410 guitar input circuit. This replaces the old 68k resistor between the input jack and first tube seen in SLO's and a ton of amps. I owned a JVM 410h and it was quiet and well behaved. So when I was hot rodding a Plexi a while back and the feedback was getting out of hand I gave the JVM input circuit a try and wow that tamed the beast nicely.

[coolidge]

Thanks for spending the dough. Can't wait to see more.

Here feast your eyes on the growing pile of parts Sadly I had to abandon the F&T axle caps in favor of Radials. The boards were just too large otherwise. My first cut at the main board was 22 inches long its now 14.5.

[img976]http://www.coolidgeamps.com/pics/slomparts.jpg[/img]

[coolidge]

Let me be the first to say HI!

I try to keep my amps as cheap as possible, if not free. I wouldn't bother building an amp if I could go out and buy one for the amount I spent to clone it (plus time spent building/designing).

Hope you at least had fun doing it! I just buttoned up an amp design I've been working on for months. Instead of having PCB's made or making them at home, I decided to emulate my layout with some snazzy gold turrets. Probably not so easy for an SLO though!

Cliff hi thanks for the welcome. This is just a hobby for me so half the fun is sourcing the best components I can (within reason), I don't really care what it cost. Yeah man I usually make my own turret boards but the IC's and components for the channel switching were going to look like crap on turrets and be a jumpered hairball. So I took a cue from Aiken and went with a PCB/turret hybrid board, 4oz copper, .125 thick, plated through holes. Turrets for most components so I can fiddle and tweak, PCB mount for the channel switching and power supply.

[dynaman]

Been a while since I looked at the SLO circuit, but I made one a while back and seem to recall the "clean" setting just being a switched resistor on the crunch channel that dumped a bunch of signal to ground. The channel bleed was kind of annoying but the SLO is still a bad mofo.

What's the JVM 410 input? I've seen a block diagram but not the schem. Got one?

Ahh, looks like you ditched the SLO loop in favor of SDM's solid state unit from Metro? I've not tried that. I used Ironsound's in a single channel Bogner thingy and it worked great, but I've been itching to try Metro's, now that I have an old set of SLO boards laying around.

[dynaman]

Oh yeah, "welcome" and all that stuff. At least Cliff shows some manners before pilfering info!

[coolidge]

Been a while since I looked at the SLO circuit, but I made one a while back and seem to recall the "clean" setting just being a switched resistor on the crunch channel that dumped a bunch of signal to ground. The channel bleed was kind of annoying but the SLO is still a bad mofo.

Yep that's why I'm using relays instead of photo's. No denying its a bad mofo, I'm pretty excited about this amp build.

What's the JVM 410 input? I've seen a block diagram but not the schem. Got one?

Sure see below.

Ahh, looks like you ditched the SLO loop in favor of SDM's solid state unit from Metro?

Yep the SLO's effects loop seems to be widely loathed so I yanked it. Metro is on hard times the poor guy has a lot going on. I think they closed the store, no parts no kits but are still offering the effects loop for now.

I just looked at Ironsounds loop, interesting there's more going on there than with the Metro loop. Metro wins on looking sexy though with its Ferarri red pcb

[img558]http://www.coolidgeamps.com/pics/input.jpg[/img]

[coolidge]

Oh yeah, "welcome" and all that stuff. At least Cliff shows some manners before pilfering info!

LOL no worries.