Sovtek Mig 100 Plate voltage?

[Leevi]

What is the plate voltage of Sovtek Mig 100 which is using 4x5881.
I think it is pretty high. Maximum anode voltage for 5881 is specified to 360V!

http://www.google.fi/imgres?imgurl=http://www.blueguitar.org/new/schem/sovtek/mig-100h.gif&imgrefurl=http://blueguitar.org/schems.htm&h=2108&w=3180&sz=98&tbnid=YK1EMpDodnXDAM:&tbnh=85&tbnw=128&zoom=1&usg=__uLQInUE0E8sjHf1_yLIp0VZ4gH8=&docid=R4l0RiI8OKUoVM&sa=X&ei=YJ0jUuutBMSbtQbJ_oGYAw&sqi=2&ved=0CC0Q9QEwAA&dur=694

/Leevi

[stratele52]

You want to built one ? Or help a friend by mail ?

Nothing on Schematic ;  http://www.blueguitar.org/new/schem/sovtek/mig-100h.gif

But with two 300 volts filter caps in series ( good for 600 V with no safety margin ) I said between 400 and 500 / 550 v.

[SILVERGUN]

Last time I was inside my friend's Mig 50 it was 537vdc on 2 x 5881 

pretty standard stuff on those amps to be that high...

[SoundmasterG]

The early MIG 100U that I gutted and built into a Vox AC100 clone is about 480V or so. I kept the Sovtek power transformer but used a Heyboer OT. I still have the Sovtek OT and choke, and stuffed circuit board around here too if anyone is interested in them. If so send me a pm.

The specs on the 5881 were with the old standards....they changed to a new way of measuring and all the specs on all tubes went up a bit when they did that. New Sovtek 5881's can take just as much voltage or more than any 6L6GC today. They are very sturdy tubes! Not sure about the Tung Sol reissues, but I would expect they are probably the same as modern 6L6GC's for their specs.

Greg

[Leevi]

Thanks for the replies. Another thing I wonder is the wiring of the power amp.
There is a PT with CT but they use still a bridge rectifier? And furthermore the CT
is connected to the point between two filter caps. What might be the reason for this?
/Leevi

[PRR]

> a PT with CT but they use still a bridge rectifier ...  the CT is connected to the point between two filter caps.

That point is half-voltage.

If you ground the CT, you get the + and - supplies often used for audio op-amps.

If you ground the bottom you get +300V and +600V, suitable for large 6550/8417/KT88 amps with higher load impedances.

Here it is a convenient way to be SURE the stacked filter-caps take the voltage equally.

[Leevi]

So how much will be the voltage after rectifier in this case, let's say we have
PT with 250-0-250 secondary, 700v or 350v?
/Leevi

[sluckey]

700v unloaded