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

[ToneMerc]

After an 8 month hiatus, I started back on a build I started last December. The first circuit I built in a CE chassis was a high voltage, skyliner using a MusicMan replacement PT, my spec'd output iron, all eyelets boards and PEC pots. I 've always wanted to redo that amp so I totally reworked it using my spec'd iron, the correct taper pots and AGB boards(HV board reconfigured as a doubler). The first build was around 712V on the plates and right at 350V on the screens, driving a quad of winged C EL34's. This one I expect right around 700/350 volts, I hope

Circuit: High plate Skyliner, #102 values
PT: custom Heyboer MusicMan style PT
OT: custom high plate voltage compatible Heyboer Twin style OT
Signal path : vintage 6PS orange drops, Piher CF, 30% taper pots
Tubes: quad JJ 6CA7, da fat ones



TM

[dcribbs1412]

Looks great TM...
you are inspiring with your builds lately.
are both OD pots 100K?
you keeping the Dale's on V1 and 2?

thanks for sharing

Darin

[ToneMerc]

Looks great TM...
you are inspiring with your builds lately.
are both OD pots 100K?
you keeping the Dale's on V1 and 2?

thanks for sharing

Darin

Thanks, yes both aree 100K and yes keeping the Dale 65's

YW

TM

[talbany]

Mike
The dropper for the PI should be around 43k 10w/w 750k bleeder on the plate side.. If you have room and an extra choke laying around choke the screens and pre amp..good Luck..The Fat boy 6CA's are big sounding..You will like them..Due to the higher voltage on the plates you might not need to filter it as much..I've seen both 50uf and 100uf..Choose your poison..

Tony

[ToneMerc]

Mike
The dropper for the PI should be around 43k 10w/w 750k bleeder on the plate side.. If you have room and an extra choke laying around choke the screens and pre amp..good Luck..The Fat boy 6CA's are big sounding..You will like them..Due to the higher voltage on the plates you might not need to filter it as much..I've seen both 50uf and 100uf..Choose your poison..

Tony

Tony, as a placeholder there's 40K/707K right now. The expectation was to drop in the 820K bleeder with the 40K, so I will try that first. The last config I only used a 5H choke on the screens, never thought of using a choke on the PA as well. Hmmm, I do have a Deluxe choke in the parts bin. I went +.625 thicker on the lam stack, which placed the OT slightly closer to the choke, but I should have room to pinch in the smaller choke if I do so,

Yes, went lighter on the filtering, theres's only 50uF.

thanks

Mike

[grtamp]

very good work!! , where do you found that phier resistors?

[Roe]

Does the MM PT and the twin OT work together? won't you have too high plate voltage for a 2k load?

[ToneMerc]

Does the MM PT and the twin OT work together? won't you have too high plate voltage for a 2k load?

In both cases I've had a Twin style OT specifically wound for this setup.

TM

[ToneMerc]

Drank a couple of Fat Tires and I was able to get it down inside the last 30 mins or so, beer is a great motivator.

TM

[ToneMerc]

I fused, powered it up minus the HT windings to check all the low voltage circuits and they all are a go.

AC = 124.8V, PT PRI = 120V
Unloaded filament voltage @ V1 = 6.85V
Unloaded max bias @ 270K junction = -40.0V, hopefully under load I can get it around -22 or so on the grids.
Relay supply = 5.99V

TM

[groovtubin]

I fused, powered it up minus the HT windings to check all the low voltage circuits and they all are a go.

AC = 124.8V, PT PRI = 120V
Unloaded filament voltage @ V1 = 6.85V
Unloaded max bias @ 270K junction = -40.0V, hopefully under load I can get it around -22 or so on the grids.
Relay supply = 5.99V

TM

awesome as usual Mike, i can def VOUCH for Qlines, OMG what a beautiful sound! I used just ONE in a critical junction, and it bLEW my mind, man, i miss my some of my older marshalls! Hopefully BAL wil come thru soon!

clips PLS!

Omegaamp jim

[ToneMerc]

I fused, powered it up minus the HT windings to check all the low voltage circuits and they all are a go.

AC = 124.8V, PT PRI = 120V
Unloaded filament voltage @ V1 = 6.85V
Unloaded max bias @ 270K junction = -40.0V, hopefully under load I can get it around -22 or so on the grids.
Relay supply = 5.99V

TM

awesome as usual Mike, i can def VOUCH for Qlines, OMG what a beautiful sound! I used just ONE in a critical junction, and it bLEW my mind, man, i miss my some of my older marshalls! Hopefully BAL wil come thru soon!

clips PLS!

Omegaamp jim

Thanks Jim, yeah I like the Pihers. This high voltage build turned out much better than the first one all around. While the first one functioned fine, I went about it the waay long way in some areas, the bias supply for example. Next, I'll hook up the HT and expect see around 700V+ on the plates and 350V or so on the screens. Hopefully this HV build won't bite me. The last one when playing with the PI string I got bit with 578V at back of the PI trimmer, that actually hurt for a sec.

If I can get the OD/PAB switching box built this week and connected to the 2290, the plan is to have it tested next Sunday at friends jazz gig and clips will follow.

TM

[ToneMerc]

Danger Will Robinson, Danger!

No FET circuit connected

V1 = 221/234.5

V2 = 216/227

V3 = 300/306

V4 = 21.0
V5 = 22.6
V6 = 21.9
V7 = 22.2

Plates = 718V

Screens = 358V

Time to hookup FET circuit for additional loading on B5

TM

[ampdork]

That's the stuff right there.

[ToneMerc]

That's the stuff right there.

Thanks Shad

Mike