I made that one (from your drawing ) ages ago - it was part of Anzai preamp from Elektor ;
anyway - if you are going to CCS heating , you must use one reg per bottle - that's simply most convenient
😉
just leave it as is ;
play with variations when you have time and wish for that
as is now - both current and voltage are limited during start up
fact is that - I just like more CCS heating , and elevating heaters to max possible sane voltage , taking care about circuit specifics
just leave it as is ;
play with variations when you have time and wish for that
as is now - both current and voltage are limited during start up
fact is that - I just like more CCS heating , and elevating heaters to max possible sane voltage , taking care about circuit specifics
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I've sorted out the Borbely. INP1 should be the input in unbalanced mode with INP2 grounded. If you want balanced inputs then R8 needs to be changed to 1M Ohm and then the pre-amp is fully balanced.
I'm now ready to drive the F4.
I'm now ready to drive the F4.
The heaters are running about 200V above GND.
An externally hosted image should be here but it was not working when we last tested it.
Gain will not be a problem. I can either attenuate the inputs (as I am during testing) or add a bit of negative feedback (not really desireable I know).
The issue is getting enough output swing (~18 VRMS) for the Pass F4.
Although I bought 2 x SHUNTKY how compromised is a strero PUMPKIN with a single SHUNTKY. I ask as I have a lovely case that isn't quite big enough for two PSUs.
The issue is getting enough output swing (~18 VRMS) for the Pass F4.
Although I bought 2 x SHUNTKY how compromised is a strero PUMPKIN with a single SHUNTKY. I ask as I have a lovely case that isn't quite big enough for two PSUs.
use feedback ; make it SUSY stage ; best of "both worlds"
it is compromised with just one , comparing to regular - two Shuntys ;
but even like that - better than Pumpie with channel dedicated series reg .
your call , in any case ...... maybe - if you put xformer in dedicated case + umbilical - you'll gave enough place for Shunty per Pumpie ?
Hi ZEN-MOD, you've overtaken me with Three Letter Abbreviations (TLAs). What is SUSY.
What is PUMPKIN output at Vcc +/- 36V ?
What is maximum input before clipping ?
What is PUMPKIN output at Vcc +/- 36V ?
What is maximum input before clipping ?
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SUSY is Papa's patented Super Symmetric mumbo jumbo
white wodoo of modern electronic era
look for his patent and various pdfs on FW and PL site
even if from patent you'll understand nada ( I reckon even Papa doesn't understand what he wrote there
)
anyway -
is SUSY stage ; with +/-36V you'll have nearly 70Vpp on output - clean ........ that's almost good for driving tube booster amp
tnx to SUSY and few tricks - whatever you pour in Pumpkin - it will clip at said output level ..... at least when gain is set to 10++ times
anyway - if you need conversion of Papa Borbely's stage to Papa Nelson's SUSY - just say ..... and give me needed gain
( Mighty ZM like to see ECC83 just in phono stage ...... but even then - in old phono stage )
white wodoo of modern electronic era
look for his patent and various pdfs on FW and PL site
even if from patent you'll understand nada ( I reckon even Papa doesn't understand what he wrote there
)anyway -
is SUSY stage ; with +/-36V you'll have nearly 70Vpp on output - clean ........ that's almost good for driving tube booster amp tnx to SUSY and few tricks - whatever you pour in Pumpkin - it will clip at said output level ..... at least when gain is set to 10++ times
anyway - if you need conversion of Papa Borbely's stage to Papa Nelson's SUSY - just say ..... and give me needed gain
( Mighty ZM like to see ECC83 just in phono stage ...... but even then - in old phono stage )
Assuming most CD players feed out 2V RMS and the F4 requires 18V RMS I would need a gain of 10.
I'm delaying building the PUMPKINs one because of cost and secondly I can't find suitable small heatsinks. Farnell do the big ones but they are too tall to fit into a 1U case. I'm contemplating fitting an alluminium sheet within the bottom of the case and fitting the HOT semiconductors to it, dispensing with heatsinks completely.
Happy Xmas
Andy
I'm delaying building the PUMPKINs one because of cost and secondly I can't find suitable small heatsinks. Farnell do the big ones but they are too tall to fit into a 1U case. I'm contemplating fitting an alluminium sheet within the bottom of the case and fitting the HOT semiconductors to it, dispensing with heatsinks completely.
Happy Xmas
Andy
good thinking 😉
here it is ; observe parts with red values ; gain is 10 , as you wished
I'll increase value of output caps , at least to 3u3
Attachments
Many Thanks
I'll try it in the next few days.
Just managed to get a case on E-Bay for the Pumpkins.
Farnell do the big heatsinks, I have opted to fold some standard TO220 'sinks for the smaller ones.
Andy
I'll try it in the next few days.
Just managed to get a case on E-Bay for the Pumpkins.
Farnell do the big heatsinks, I have opted to fold some standard TO220 'sinks for the smaller ones.
Andy
Fortunately or Unfortunately, depending on how you think.
The Borbelly fitted into my 1U case and is fully finished now. (less your SUSY Mod)
The Pumkin won't fit into a 1U case so I've had to buy a 2U case (Good ole E-Bay)
As the PSUs are completely different I'm going to have to complete two completely separate Pre-amps. That'll be good as I will be able to compare them.
In the Pumkin you specify C1 and C2 at 5pF. This is a value of capacitor that has disappeared off my radar.
I can get 4.7pF +/- 0.5pF. Would you keep R5 and R6 at 100K or change them to 110K ??
Andy
The Borbelly fitted into my 1U case and is fully finished now. (less your SUSY Mod)
The Pumkin won't fit into a 1U case so I've had to buy a 2U case (Good ole E-Bay)
As the PSUs are completely different I'm going to have to complete two completely separate Pre-amps. That'll be good as I will be able to compare them.
In the Pumkin you specify C1 and C2 at 5pF. This is a value of capacitor that has disappeared off my radar.
I can get 4.7pF +/- 0.5pF. Would you keep R5 and R6 at 100K or change them to 110K ??
Andy
OK so I've now collected all the parts I need to build the Shuntky / Pumpkin combinations. How many of the jumpers between top and bottom layers need to be fitted.
The cookbook suggests that there is a choice but there again does not make it clear if only one is sufficient. I don't want to create any earth loops. I'm not using anything fancy just a bit of component leg.
Andy
The cookbook suggests that there is a choice but there again does not make it clear if only one is sufficient. I don't want to create any earth loops. I'm not using anything fancy just a bit of component leg.
Andy