I have a trafo with 310v/0,8A output that I thought of using with a SV572-10 SE,if I use a voltage doubler I get about 870v right?
and then use a solid state regulator to about 750-800v.Will this voltage doubling have any affect on the sound,hum,e.t.c?
I think it´s a little low to just use single voltage,about 435v.What do you think?
I have one pair of SV572-10-do they still make them?
Otherwise I have pair of 811-A to use when they burnt out.
and then use a solid state regulator to about 750-800v.Will this voltage doubling have any affect on the sound,hum,e.t.c?
I think it´s a little low to just use single voltage,about 435v.What do you think?
I have one pair of SV572-10-do they still make them?
Otherwise I have pair of 811-A to use when they burnt out.
The trouble with voltage doublers is that they have very poor regulation (the output voltage varies widely with load current). You might think that's not a problem as you're going to use a regulator, but it means that the regulator has to be able to cope with that very large input voltage swing and that invariably means that the series pass device has to dissipate a lot of power. Try modelling your proposed doubler in PSUD to see how it behaves, then calculate the implications on the regulator.
I'm more conservative than Tom Bavis. I would not plan on drawing more than 200 mA. of DC from a doubler PSU with that trafo. BIG caps. are in order in the doubler stack, as that keeps the rail voltage up and quite stable. As the doubler stack caps. increase in value, the conduction angle gets smaller. So, I^2R heating in the rectifier winding is significant.
Follow the doubler stack with a low DCR choke and more capacitance. Large caps. in the doubler stack reduce the ripple fundamental well, but introduce a fair amount of ripple overtones into the rail. The choke kills the overtones.
With higher working voltage parts, the topology used in the "El Cheapo" B+ PSU will do nicely. Schematic here.
Follow the doubler stack with a low DCR choke and more capacitance. Large caps. in the doubler stack reduce the ripple fundamental well, but introduce a fair amount of ripple overtones into the rail. The choke kills the overtones.
With higher working voltage parts, the topology used in the "El Cheapo" B+ PSU will do nicely. Schematic here.
200mA hm...maybee thats what i need, 100-110mA/tube.So you think I
should use a choke instead of regulator,how much voltage will I lose in the Choke?I have 2 BIG capacistors they are 1500uF/each,how big should it be after the choke?
Maybee I could go on with my questions.
I have a schema that uses a EL34 as driver,in katodfolower config.will this work and will it sound good,its triode connected.It has a EF86 as voltage amp.But that I won´t use,I want to use 6SN7 or 6SL7 or I have 2 "76" is it god to use?,I like trodes better,but I think it would bee fun to try sommething new with the EL34.
If somme one has links to schemas with the SV572-10 SE I apriciate if you post it. well 811 schemas too.
should use a choke instead of regulator,how much voltage will I lose in the Choke?I have 2 BIG capacistors they are 1500uF/each,how big should it be after the choke?
Maybee I could go on with my questions.
I have a schema that uses a EL34 as driver,in katodfolower config.will this work and will it sound good,its triode connected.It has a EF86 as voltage amp.But that I won´t use,I want to use 6SN7 or 6SL7 or I have 2 "76" is it god to use?,I like trodes better,but I think it would bee fun to try sommething new with the EL34.
If somme one has links to schemas with the SV572-10 SE I apriciate if you post it.
well 811 schemas too.
Whilst what EC8010 says about regulation is true and would deter me from using a voltage doubler to power a class AB1, AB2 or B PP amp, in your case your SE amp will perforce be operating in class A and hopefully the regulation will not be a problem.
As to your ideas about driver and voltage amp, I would think EL34 in triode-connected CF operation as a driver would be good and an EF86 voltage amp would also be good. I know what you mean about preferring triodes but many people have reported success with pentode voltage amp stages in SE.
As to your ideas about driver and voltage amp, I would think EL34 in triode-connected CF operation as a driver would be good and an EF86 voltage amp would also be good. I know what you mean about preferring triodes but many people have reported success with pentode voltage amp stages in SE.
Voltage doublers were good enough for McIntosh
http://www.kbapps.com/audio/schematics/tubeamps/mcintosh/mc240.html
http://www.kbapps.com/audio/schematics/tubeamps/mcintosh/mc240.html
Ray,
The H/K Cit. 2 and Fisher's whole line used doubler B+ PSUs without incident. Stu Hegeman and Avery Fisher were anything but stupid and their PP AB designs worked just FINE, thank you.
FWIW, I followed Hegeman's lead in "El Cheapo". Large caps. in the doubler stack "stiffen" the rail. The choke cleans up both SS diode "hash" and ripple overtones.
The H/K Cit. 2 and Fisher's whole line used doubler B+ PSUs without incident. Stu Hegeman and Avery Fisher were anything but stupid and their PP AB designs worked just FINE, thank you.
FWIW, I followed Hegeman's lead in "El Cheapo". Large caps. in the doubler stack "stiffen" the rail. The choke cleans up both SS diode "hash" and ripple overtones.
I will buy a choke from Lundals http://www.lundahl.se/pdfs/datash/1638.pdf
when I can afford it,as I have a double chassie I am going to use.
And I got a couple of C3g´s in Sweden to use as a triod connected
input tube.And I found a couple EL 34 laying around in my house from my early days of tube building (EL34 P-P,ecc83 splitter and EF86 as input.Any suggestion on this amp are wellcome,for example is it possible to get rid of the signal cap in the first stage?As matematics isn`t my strongest side,yet.
811A/572b
Currently, Ive been experimenting with my old 811A P-P amp...
Its +B is just under 500v at the anodes, using a straight full-wave sand rec from a 350V secondary 200mA Tx...
Using the 811A and probably the 572B at these lower voltages is not only possible, but can produce suprisingly good results, I recommend driving them with a MOSFET follower stage such as 'Tubelabs' superdrive ideas....The valves need a +ve grid voltage and can draw significant grid currents at this low anode voltage so you need a good driver able to source quite high currents....Drive the MOSFETS with a phase-splitter and gain stage of your choice..
The bias current through each 811A Ive set at 60mA in my bread-board, The sound is 'full bodied' and clear with surprising power--I havent actually measured the full power bandwidth or any proper testing as yet.
This maybe a better option than using a Voltage-Doubler in the PSU....
Currently, Ive been experimenting with my old 811A P-P amp...
Its +B is just under 500v at the anodes, using a straight full-wave sand rec from a 350V secondary 200mA Tx...
Using the 811A and probably the 572B at these lower voltages is not only possible, but can produce suprisingly good results, I recommend driving them with a MOSFET follower stage such as 'Tubelabs' superdrive ideas....The valves need a +ve grid voltage and can draw significant grid currents at this low anode voltage so you need a good driver able to source quite high currents....Drive the MOSFETS with a phase-splitter and gain stage of your choice..
The bias current through each 811A Ive set at 60mA in my bread-board, The sound is 'full bodied' and clear with surprising power--I havent actually measured the full power bandwidth or any proper testing as yet.
This maybe a better option than using a Voltage-Doubler in the PSU....
As far as I know, higher inductance is preferrable. I used 2Hy because that's what I had. The resistance of the choke may vary due to different parameters and different models. My chokes have 50Ù resistance, your may have other. If you'd like to know what will be voltage drop on your choke, you can simply calculate it.
I am going to use it in SE mode,I´ve heard people saying that SV572-10 sounds best with a little voltage,750-1000v.as My trafo is 310v ac and 437v DC - some volt trough the choke I might have 410 -420v?
I think it´s a little low,thats why i thought of a doubler.I am going to use EL 34 triod connected as driver,would be nice if more who use SV 572-10 told what you think of the voltage. Thanks for the answers.
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