Latest Build - Three-Channel Maq Daddy 50W Head

[jhaas]

In the "New Year amp plans" thread, someone made the comment "we need more builds documented with sound clips". So, in the spirit of that, I'll share what I'm currently working on.

This is my most ambitious build to date, and I'm building this one for myself. It's pretty over the top, IMO, and part of it is just to challenge myself to see if I can make it all work.

Here's a list of features:
- Three channels: Clean, Drive and Lead
- Clean channel preamp is Rocket inspired
- Drive Channel preamp is Marshall JMP/JCM inspired
- Lead Channel is SLO100 inspired
- Power Amp is SLO100 inspired, with Depth and Presence, It's a 4-holer so I can run 4x6V6 or two big bottles, fixed bias so it will be in the neighborhood of 40-50W
- I'm using the Soldano power supply, relays for switching.
- standard Fender style Reverb, 12AT7 buffer and 1/2 of an AX7 for recovery
- Bias vary Tremolo from Fender design, I forget exactly what model
- Parallel Tube driven FX Loop

I've currently got the chassis bent, drilled and loaded, with the faceplates installed, seen in the attached picture. Next I'll be cutting, drilling and staking the G10 for turret boards.

The following dropbox folder has some more in-progress build pix, if you're interested:
https://www.dropbox.com/sh/uz1s3cc7matq35t/SBx2iTd3e5

[cbass]

Cool that's pretty ambitious to say the least.

[JoeCon]

WOW! A super job so far. Lots of pots too.
Which Edcor xformers did you choose?

[jhaas]

Yeah, I'm definitely going to be building and debugging this in stages - building/debugging the power supply before moving on to the power amp. Then get the power amp running properly before attacking the preamp channels, etc. I took this approach with the last complex amp I built and it went very smoothly.

[jhaas]

WOW! A super job so far. Lots of pots too.
Which Edcor xformers did you choose?

Thanks!

PT: Edcor XPWR178 - 330-0-330@200mA
OT: Edcor CXPP60-MS-4K - 4K primary into 4/8/16 secondary

I also ordered a big 10H choke from Edcor, but the first "gotcha" for this amp came when I received it and realized I used incorrect measurements when I made the layout. The chassis was already drilled and there was no way this choke would fit. So I subbed in a Marshall style choke I had on the shelf and will have to make due with that.

[harryk]

Hi! It is nice to see also other brave men building real 3-channel p-to-p-amp projects. We have already done several that kind of amps by now. We have a modular architecture so that customer can choose almost any preamp module he wants including modified SLO100 lead channel. Poweramp is also modular. You can choose any octals in pairs or even 4x6V6GT version with a half power switch. If you are interested in to see our version, go here http://www.bluetone.fi/eng/bluetone-crossroad-head/ Harry

[JoeCon]

You gentlemen are making me feel lazy with only Vol, Trbl, Bass, and Cut controls on my amps. So many nice features in one amp.

See that's a problem...with all those sounds the Mrs. would want me to sell all my other amps!!

Superb workmanship guys....

[Milkmansound]

Only 8 preamp tubes?

[jhaas]

Hi! It is nice to see also other brave men building real 3-channel p-to-p-amp projects. We have already done several that kind of amps by now. We have a modular architecture so that customer can choose almost any preamp module he wants including modified SLO100 lead channel. Poweramp is also modular. You can choose any octals in pairs or even 4x6V6GT version with a half power switch. If you are interested in to see our version, go here http://www.bluetone.fi/eng/bluetone-crossroad-head/ Harry

Wow Harry, I should have just posted "I'm building a Bluetone Crossroad clone". Many similarities. Nice looking site, thanks for the vote of confidence.

One other feature I forgot to mention is dual footswitchable PPIMVs - the LarMar type. I've never been real happy with any half-power switch I've tried, but I do like VVR in some amps.

[jhaas]

Only 8 preamp tubes?

No 10! Because they're cheaper if you buy ten!

You probably didn't count the two behind the reverb transformer, for the reverb and FX loop.

[Structo]

Man, that is a lot of pots!

Is the chassis stainless steel?

The labeling looks very good.

What did you use for the faceplates?

[harryk]

Hi! It is nice to see also other brave men building real 3-channel p-to-p-amp projects. We have already done several that kind of amps by now. We have a modular architecture so that customer can choose almost any preamp module he wants including modified SLO100 lead channel. Poweramp is also modular. You can choose any octals in pairs or even 4x6V6GT version with a half power switch. If you are interested in to see our version, go here http://www.bluetone.fi/eng/bluetone-crossroad-head/ Harry

Wow Harry, I should have just posted "I'm building a Bluetone Crossroad clone". Many similarities. Nice looking site, thanks for the vote of confidence.

One other feature I forgot to mention is dual footswitchable PPIMVs - the LarMar type. I've never been real happy with any half-power switch I've tried, but I do like VVR in some amps.

Our way to do half power switching is such that we do not lift one pair of power tube cathodes from ground. We do it in a way which does not alter sound at all. I also prefer PPIMV master volumes, but found out that VVR is not the best tool in fixed bias amps. Technically it works, but to my mind it seems to stiffen power supply too much. Harry

[jhaas]

Man, that is a lot of pots!

Is the chassis stainless steel?

The labeling looks very good.

What did you use for the faceplates?

The chassis is polished aluminum. I polished it myself using my bench grinder with polishing wheels. I can get a real nice polish on small chassis, but this one was just to big and unwieldy to get a perfect finish, but it looks "ok" close up.

The faceplates are very inexpensive, but a bit labor intensive compared to ordering a laser cut one. It's a high-quality printout I get from the local printing shop (UPS store) sandwiched behind a piece of clear acrylic I get from the local home center (Lowes).

Here's a faceplate closeup of another amp with the same type faceplate:
https://www.dropbox.com/s/38s6bcsfntwuy ... Resize.jpg

for that amp, here's the acrylic with the drilling template I made, also used to drill the chassis:
https://www.dropbox.com/s/7ddsfyyrpovyc ... plates.jpg

and here's the drilled acrylic with the printout
https://www.dropbox.com/s/ck63p9i5ij8x5 ... 0Shown.jpg

If you ever decide to try this, I strongly recommend using a stepped bit to drill the acrylic.

-John

[xtian]

Harry: great schematics/layouts on your site! Thanks for sharing!

[TUBEDUDE]

Just like that but in a 1 12 combo. [/img]