New Build Lives: High Plate, Skyliner, MusicMan HV DC

[ToneMerc]

Gotta love when it comes together just as planned.

Connected up the FET circuit, pulled the JJ'S and installed NOS JAN GE 12AX7WA in V1 and V2.

AC feed = 124.7V

Filament voltage = 6.41V

V1= GE 12AX7WA 186.5/191.5

V2= GE 12AX7WA 191.8/196.2

V3 = LPS balanced 12AX7A 274.8/281.3

V4-V7 = JJ 6CA7, biased approx -22

Plates = 712

Screens = 355.6

FET = 22.15/12.29

LNFB = approx 42meg

TM

[CHIP]

Beautiful amp.

[talbany]

Soooo.. How does it sound!!
I bias mine between 25 and 27 FWIW

Tony

[ToneMerc]

Soooo.. How does it sound!!
I bias mine between 25 and 27 FWIW

Tony

That is a very good question my friend . I'm just getting around to plugging an instrument into that 6V6 HRM build. I took the rest of this week off, but I have a kitchen faucet to replace, pressure washing, lawn work and some trim I need to paint and that's just my list. I have an EV12S coming so maybe before the weekend I'll get a chance to drop that into one of Taylor's large 1-12 oval port cabs and give it whirl.

The first circuit I setup at around 24 and this one will most likely wind up in that range as well once I burn it in.

Mike

[ER]

I really like the JJ6ca7's can't wait to hear how they sound with... HI-VOLTAGE!

(cough...sputter, glad you can't hear my terrible Bon Scott impersonation)

peace-ER

[ToneMerc]

Soooo.. How does it sound!!
I bias mine between 25 and 27 FWIW

Tony

Tony bias at around 22 did not sound that great, took it to around 25.5/26 with 709V or so on the plates which was much better. Everything functions great, custom PT unlike the stock replacement runs cool as a cucumber. However those 6CA7's @ 700V sure emit a fair amount of heat.

Any further testing is delayed as I have a bad NKK Z switch. The finger on the back side of the wiper isn't making good contact. It was indexed slightly off.

Mike

[amplifiednation]

TM this build is epic. I wish I could hear those tubes cook!! Those big PS resistors are super cool.

[talbany]

Soooo.. How does it sound!!
I bias mine between 25 and 27 FWIW

Tony

Tony bias at around 22 did not sound that great, took it to around 25.5/26 with 709V or so on the plates which was much better. Everything functions great, custom PT unlike the stock replacement runs cool as a cucumber. However those 6CA7's @ 700V sure emit a fair amount of heat.

Any further testing is delayed as I have a bad NKK Z switch. The finger on the back side of the wiper isn't making good contact. It was indexed slightly off.

Mike

Mike
Going on about a year with mine and about 80 or so hours and so far no problem.. The larger glass will dissipate some heat.. Just be sure they don't go thermal on you..@700v they will fry very quickly..Can you describe the difference in tone with the MM vs the 450v Twin style..

25ma is about 65%

Glad you got it working!!

Tony

[ToneMerc]

TM this build is epic. I wish I could hear those tubes cook!! Those big PS resistors are super cool.

Thanks just another build, but it's kind of cool in a way I guess. I think the only other scratch ground up 700V build I've seen here was back when Dogears demo'd Brandon's high voltage amp.

Personally, these builds are mentally and emotionally kind of draining, some form of a catharsis I guess. Part of me wants to quit, another part wants to build another. One thing is for sure though, I have no desire to do this for profit and I tip my hat twice to all of the pro builders. Although, the more I build the more I wish I had one these. I might sell a build and use it as seed money towards one.

http://www.amplitrex.com/about.html

TM

[LeftyStrat]

Although, the more I build the more I wish I had one these. I might sell a build and use it as seed money towards one.

http://www.amplitrex.com/about.html

TM

You and me both. We're all working off of poorly reproduced copies of 50 year old (or more) tube curves.

[ToneMerc]

Just be sure they don't go thermal on you..@700v they will fry very quickly..Can you describe the difference in tone with the MM vs the 450v Twin style..

25ma is about 65%

Glad you got it working!!

Tony

That was reason why I used the 2W Clarostat bias pot, I wanted to get the circuit as robust as possible. Wouldn't want to lose bias on 700V either.

Hmmm, initial observations, I don't think a Boogie 1-12L Thiele is the best cabinet for this combination, there appears more lower mids of which I found with the first build as well. I think the MM are quicker although not as quick as the 183, but you slap it, it slaps you right back. I'm thinking this would kill with a half open, half closed straight 4-12 cabinet.

However, with this build I made some OT changes which in theory should have increased output. I don't want jump to conclusions without more testing, but I have always wondered from the beginning that even with the larger iron, if that was even big enough.

Nevertheless, I might be in downtown Richmond either late next week or early the week of the 17th. If I get the selector switch replaced, maybe I'll drop it off to you.

As always thanks

Mike

[talbany]

Just be sure they don't go thermal on you..@700v they will fry very quickly..Can you describe the difference in tone with the MM vs the 450v Twin style..

25ma is about 65%

Glad you got it working!!

Tony

That was reason why I used the 2W Clarostat bias pot, I wanted to get the circuit as robust as possible. Wouldn't want to lose bias on 700V either.

Hmmm, initial observations, I don't think a Boogie 1-12L Thiele is the best cabinet for this combination, there appears more lower mids of which I found with the first build as well. I think the MM are quicker although not as quick as the 183, but you slap it, it slaps you right back. I'm thinking this would kill with a half open, half closed straight 4-12 cabinet.

However, with this build I made some OT changes which in theory should have increased output. I don't want jump to conclusions without more testing, but I have always wondered from the beginning that even with the larger iron, if that was even big enough.

Nevertheless, I might be in downtown Richmond either late next week or early the week of the 17th. If I get the selector switch replaced, maybe I'll drop it off to you.

As always thanks

Mike

Mike
Sounds good.. I should be in town..Let me know!!

Tony

[ToneMerc]

All dressed up with an Amp Nation widebody oval backed EV-12S loaded cab.

TM

[amplifiednation]

THAT looks killer if I do say so myself!! Great wok TM!

[dcribbs1412]

Congrats TM
Really nice looking build.

Darin