That's great, but then it has nothing in common with the FVP or SVP, and just looks like hundreds of other line stages that have been built.
Alex
I am building FVP5A amp and maybe someone can help me with some questions. There are in line stage tubes that are marked with ✱ star sign and these tubes need to have a separate heaters. Are these star marked tubes as one tube or two different tubes (on the right these two upper tubes)? Using this showed voltage divider where should I connect this elevated 150V? Says that to the negative side of upper tube heater supply but I do not get it. 
Any help would be appreciated.
Thank you!
http://www.vacuumstate.com/index.dna?rubrik=8&lang=2&a=%25AEs%2595Zn%25250A%25FC%25B1&b=738971.6676834152
Any help would be appreciated.Thank you!
http://www.vacuumstate.com/index.dna?rubrik=8&lang=2&a=%25AEs%2595Zn%25250A%25FC%25B1&b=738971.6676834152
@rchamber My focus with this schematic will be to get out the best possible sound. To make sure that I understood right.
Tubes in line stage marked on the picture as 1 and 2 are as one tube and this tube heater pin 5 is elevated +150V.
Do I need separate 6,3V heaters supply AC or +, gnd to connect this to the tube marked on the picture as 1 and 2 to heaters pin 4 and 5 adding this elevated +150V together with one heater supply pin 5?
Pin 4 is gnd or separate supply gnd or AC?
Is possible to use tubes 1 and 3 as a one tube and 2 and 4 as second tube and if it is then is there a difference in sound?
I am planning to use 6H23P tubes as a start and later 6DJ8 or 7308 tubes. Would these tubes work with this schematic?
Tubes in line stage marked on the picture as 1 and 2 are as one tube and this tube heater pin 5 is elevated +150V.
Do I need separate 6,3V heaters supply AC or +, gnd to connect this to the tube marked on the picture as 1 and 2 to heaters pin 4 and 5 adding this elevated +150V together with one heater supply pin 5?
Pin 4 is gnd or separate supply gnd or AC?
Is possible to use tubes 1 and 3 as a one tube and 2 and 4 as second tube and if it is then is there a difference in sound?
I am planning to use 6H23P tubes as a start and later 6DJ8 or 7308 tubes. Would these tubes work with this schematic?
viltsone said:
@rchamber My focus with this schematic will be to get out the best possible sound. To make sure that I understood right.
Tubes in line stage marked on the picture as 1 and 2 are as one tube and this tube heater pin 5 is elevated +150V.
Correct.
Do I need separate 6,3V heaters supply AC or +, gnd to connect this to the tube marked on the picture as 1 and 2 to heaters pin 4 and 5 adding this elevated +150V together with one heater supply pin 5?
Pin 4 is gnd or separate supply gnd or AC?
You will have to figure the heater supplies yourself.
Is possible to use tubes 1 and 3 as a one tube and 2 and 4 as second tube and if it is then is there a difference in sound?
No. No clue about sound differences.
I am planning to use 6H23P tubes as a start and later 6DJ8 or 7308 tubes. Would these tubes work with this schematic?
Bad idea...I would stick to Allen's recommendations. Either build it as designed or take his suggestion about trying 5687.
And, re-read the thread about what others have tried.
Best, and good luck,
Robert
@rchamber My focus with this schematic will be to get out the best possible sound. To make sure that I understood right.
Tubes in line stage marked on the picture as 1 and 2 are as one tube and this tube heater pin 5 is elevated +150V.
Correct.
Do I need separate 6,3V heaters supply AC or +, gnd to connect this to the tube marked on the picture as 1 and 2 to heaters pin 4 and 5 adding this elevated +150V together with one heater supply pin 5?
Pin 4 is gnd or separate supply gnd or AC?
You will have to figure the heater supplies yourself.
Is possible to use tubes 1 and 3 as a one tube and 2 and 4 as second tube and if it is then is there a difference in sound?
No. No clue about sound differences.
I am planning to use 6H23P tubes as a start and later 6DJ8 or 7308 tubes. Would these tubes work with this schematic?
Bad idea...I would stick to Allen's recommendations. Either build it as designed or take his suggestion about trying 5687.
And, re-read the thread about what others have tried.
Best, and good luck,
Robert
I use two separate heater supplies per channel in my SVP. Yes, they need to be electrically isolated from one another apart from the elevation circuits, so you need separate transformer windings, rectification and smoothing.
Allen grouped the triodes the way he did because of his strategy for elevating the heaters - the dual triodes share a heater, so they need the heater to be at a voltage that works for both halves. I don't think combining 1 and 3 in one envelope would work, for this reason. Why did you think this might be preferable?
Allen never said anything against 6H23P, but these have different bias requirements so you would have to alter the cathode resistors and really know what you are doing to get the target currents and voltages. I agree with Robert in this respect.
Alex
@Alex M for the heater do you use DC or AC voltages? For me putting together heaters DC voltage + and elevated +150V very strange. Does it work this way? Does this elevated +150V do not effect the DC regulator?
Basically 6DJ8 is 6922 and should work in this schematic? I could not find suggested suitable tubes for this schematic besides 6H30, 5687, E182CC.
Basically 6DJ8 is 6922 and should work in this schematic? I could not find suggested suitable tubes for this schematic besides 6H30, 5687, E182CC.
Allen recommended current regulation, which is what I started off with, but I found that the EH 6922s I used had a non-standard heater current, which meant the voltages were too low with a 300mA current. In the end, and to allow me to experiment with different versions of the 6922 valves, I switched to voltage regulation.
The voltage elevation only sets the voltage at one end of the filament, so no problem.
6DJ8 is basically a 6922, but with a different heater current and a lower maximum anode voltage rating (though Allen uses much lower voltages than some designs, like the ARC SP-10, for instance, so this is not an issue). If you use voltage regulation for the heaters you should be able to swap in any member of the 6922, ECC88, 6DJ8 family. 5687 is quite different, with a much lower gain.
Alex
Hi Alex, viltsone,
Unfortunately, Allen Wright did not include a page defining HT or heater supplies in his Tube Preamp Cookbook...that leaves much undefined about his opus preamps. It's a big sea to navigate and make things best. There do not seem to be any comprehensive tutorials available about how best to heat (and bias) valves with subcategoies for directly and indirectly heated valves.
I, as an ME not EE, am admittedly not up to the task of providing such a tutorial, even though as a student in an EE course back in 1959 or 1960 did lab experiments to define plate characteristic curves for a 2A3 valve. I can only offer some random thoughts on the subject of heater/filament supplies and biasing, and bring to view some of my findings here. I have no cookbook to offer, only the results of other authors on the web.
Thomas Mayer offers some thinking...for indirectly heated valves he (sometimes) maintains that ac heating is O.K.. See his Single Ended Amplifier Concepts Series on using the 6CB5A as a low cost output valve in a single ended power amplifier. He also favours the use of filament bias to eliminate the bypass capacitor requirement for the cathode bias resistor (Google <filament bias vinylsavor> to find his blog entries on this subject.
Rod Coleman has defined the heating of directly heated triodes for fifteen-plus years, now V9 version...Google <Rod Coleman Filament Regulators>. And they are not only for directly heated triodes...they can be adapted to heating of indirectly heated triodes in filament bias, see:
https://www.diyaudio.com/community/threads/idht-bias-with-rod-coleman-filament-regulator.374122/
I wish I could offer more, but that's it for the moment,
Very Best, Robert
Unfortunately, Allen Wright did not include a page defining HT or heater supplies in his Tube Preamp Cookbook...that leaves much undefined about his opus preamps. It's a big sea to navigate and make things best. There do not seem to be any comprehensive tutorials available about how best to heat (and bias) valves with subcategoies for directly and indirectly heated valves.
I, as an ME not EE, am admittedly not up to the task of providing such a tutorial, even though as a student in an EE course back in 1959 or 1960 did lab experiments to define plate characteristic curves for a 2A3 valve. I can only offer some random thoughts on the subject of heater/filament supplies and biasing, and bring to view some of my findings here. I have no cookbook to offer, only the results of other authors on the web.
Thomas Mayer offers some thinking...for indirectly heated valves he (sometimes) maintains that ac heating is O.K.. See his Single Ended Amplifier Concepts Series on using the 6CB5A as a low cost output valve in a single ended power amplifier. He also favours the use of filament bias to eliminate the bypass capacitor requirement for the cathode bias resistor (Google <filament bias vinylsavor> to find his blog entries on this subject.
Rod Coleman has defined the heating of directly heated triodes for fifteen-plus years, now V9 version...Google <Rod Coleman Filament Regulators>. And they are not only for directly heated triodes...they can be adapted to heating of indirectly heated triodes in filament bias, see:
https://www.diyaudio.com/community/threads/idht-bias-with-rod-coleman-filament-regulator.374122/
I wish I could offer more, but that's it for the moment,
Very Best, Robert
Hi
Does anybody can tell me if it is OK to use in FVP5 99 version (MOSFET) instead of 4uF output cap to use 1uF cap that is also shown on the FVP5a 2001 schematic? They are a little bit different schematics. Another question is if is OK to change in FVP5, IRF710 MOSFET with similar or like with Toshiba TK4K1A60F?
Does anybody can tell me if it is OK to use in FVP5 99 version (MOSFET) instead of 4uF output cap to use 1uF cap that is also shown on the FVP5a 2001 schematic? They are a little bit different schematics. Another question is if is OK to change in FVP5, IRF710 MOSFET with similar or like with Toshiba TK4K1A60F?