Göran at www.Webb-Butiken.com sent me some russian "6N23P" I'm gonna try out. Just have to move one heaterwire to another pin. They suppose to "the best ever russian eq to 12ax7".
Right now I have JJ 803S.
Right now I have JJ 803S.
TDSL Tube data [6N23P (6Н23П)]
Are we talking about the same? Pinout looks like 12ax7 except heater.
Are we talking about the same? Pinout looks like 12ax7 except heater.
Attachments
Hi,
Correct.
6N2P is a 6.3V heater version of the 12AX7A so that's easy enough to do if the heater voltage is 6.3V already. Just be ware of pin9 which is the shield.
That's not impossible but I'd doubt it'll work optimally without any further changes though.
BTW, looking at the vendor's website you linked above I could only see a 6922-EH which could be the same as the 6N23Ps you'll receive.
I don't know if they actually are one and the same valve.
Ciao,
Correct.
6N2P is a 6.3V heater version of the 12AX7A so that's easy enough to do if the heater voltage is 6.3V already. Just be ware of pin9 which is the shield.
That's not impossible but I'd doubt it'll work optimally without any further changes though.
BTW, looking at the vendor's website you linked above I could only see a 6922-EH which could be the same as the 6N23Ps you'll receive.
I don't know if they actually are one and the same valve.
Ciao,
My octal sockets are in bad condition are in bad shape, I need to replace them all. Tubes are dangerous loose... When i do that i was thinking hardwire everything anyway so if someone have any suggestions of improvements for the mc100 i would gladly hear them.
One thing i notice that B+ has well over 40-50cm trace/wire before reaching tubes! Mount the last 3x22uf caps closer and add maybe 10uf mkp wouldn't hurt i think.
One thing i notice that B+ has well over 40-50cm trace/wire before reaching tubes! Mount the last 3x22uf caps closer and add maybe 10uf mkp wouldn't hurt i think.
Yes, replace the SRPP with mu-follower - it's really easy mod - since they are quite alike toplogy like.
If the total gain is pretty much higher then you need - then i would suggest try replacing the 12ax7 with 12ay7's and run then with approx -2v bias and 3mA current. Which would result in less then half gain in that stage (approx 45 vs 100) - but alot better drive and less noise. If you are using the amp as power-amplifier only - it would probably also let you input higher lever before clipping. (since 12ax7 is probably biased a bit lower).
If the total gain is pretty much higher then you need - then i would suggest try replacing the 12ax7 with 12ay7's and run then with approx -2v bias and 3mA current. Which would result in less then half gain in that stage (approx 45 vs 100) - but alot better drive and less noise. If you are using the amp as power-amplifier only - it would probably also let you input higher lever before clipping. (since 12ax7 is probably biased a bit lower).
I really wanted to use my russian 6n23p i just got if possible.
In England "tube distinctions" modded a mc100b (to just an poweramp) and removed the first stage. How's that possible?
Is there any simulation software so i can calculate right values for a mu-follower? Or so i can optimize it for use with 6n23p?
In England "tube distinctions" modded a mc100b (to just an poweramp) and removed the first stage. How's that possible?
Is there any simulation software so i can calculate right values for a mu-follower? Or so i can optimize it for use with 6n23p?
This Russian tube was designed for radio frequency amplifiers. It may not be the best for audio. For simulation you can start with LTSpice, which is free. Or find a way to get more advanced tools like Microcap with educational discount etc.
Hi,
That's not too hard to do and it will also allow to bias the heaters of the remaining input stages correctly and to run the Schmitt phase splitter at more appropriate current levels reducing distortion.
As it is now all but the output stages have their heater to cathode voltages severely violated.
And if your mains voltage happens to be higher the 220VAC none of the tubes will last longer than a few months as they're all being cooked.
As for the 6N23P, these actually fine sounding 6DJ8 clones. I quite like them actually.
Ciao,
That's not too hard to do and it will also allow to bias the heaters of the remaining input stages correctly and to run the Schmitt phase splitter at more appropriate current levels reducing distortion.
As it is now all but the output stages have their heater to cathode voltages severely violated.
And if your mains voltage happens to be higher the 220VAC none of the tubes will last longer than a few months as they're all being cooked.
As for the 6N23P, these actually fine sounding 6DJ8 clones. I quite like them actually.
Ciao,
Hi,
That's not too hard to do and it will also allow to bias the heaters of the remaining input stages correctly and to run the Schmitt phase splitter at more appropriate current levels reducing distortion.
As it is now all but the output stages have their heater to cathode voltages severely violated.
And if your mains voltage happens to be higher the 220VAC none of the tubes will last longer than a few months as they're all being cooked.
Ciao,
I have 230V at home and PT are rated 240V (marked on top on both)
I heard a french tube guy at elektor say similar things that the 6SN7 are not going "hot" enough. He recommended to give them a higher B+. This trough google translate so
Heater(s) 6,3V have all CT transformer.
There is very very little hum. I think a bit lower than my homebrewed preamp.
I can give LT spice a try later. And see how hard it is. But i'm guessing very hard (for me)
Hi,
If the power transformer primary is set to 240VAC and your grid voltage is 230VAC then the heater voltages are probably O.K.
B+ will remain the same but changing the resistor values of the splitter will allow for more current to run through them.
The French guy at Elector is Francis Ibre. A very knowledgeable person and author of various books on valves and audio.
The main concern, apart from the splitter is however the heater to cathode voltage violation. Short of installing a separate heater xformer (or doing away with the SRPP stage), there's nothing you can do about it.
Ciao,
If the power transformer primary is set to 240VAC and your grid voltage is 230VAC then the heater voltages are probably O.K.
B+ will remain the same but changing the resistor values of the splitter will allow for more current to run through them.
The French guy at Elector is Francis Ibre. A very knowledgeable person and author of various books on valves and audio.
The main concern, apart from the splitter is however the heater to cathode voltage violation. Short of installing a separate heater xformer (or doing away with the SRPP stage), there's nothing you can do about it.
Ciao,
Hi,
If the power transformer primary is set to 240VAC and your grid voltage is 230VAC then the heater voltages are probably O.K.
B+ will remain the same but changing the resistor values of the splitter will allow for more current to run through them.
The French guy at Elector is Francis Ibre. A very knowledgeable person and author of various books on valves and audio.
The main concern, apart from the splitter is however the heater to cathode voltage violation. Short of installing a separate heater xformer (or doing away with the SRPP stage), there's nothing you can do about it.
Ciao,
It is possible to replace cathode resistor in LTP with solid state CCS like made by IXYS. That way you can set almost any current and keep input stage intact.
As I said before I'm gonna remove whole pcb expect bias for KT88. (so i can keep the bias-adjustment possibility) Gonna cut up the board for this. After that alot of space. Also put a new alu.plate on top.
Many res/caps already out from the board.
Yes Francis Ibre is correct
I can mount a 6.3V (or 6V is easier to find..?) inside. I think a ringcore could fit in somewhere.
EDIT: IXYS; Haven't heard that one before. Have to read little bit i see =)
Many res/caps already out from the board.
Yes Francis Ibre is correct
I can mount a 6.3V (or 6V is easier to find..?) inside. I think a ringcore could fit in somewhere.
EDIT: IXYS; Haven't heard that one before. Have to read little bit i see =)
Last edited:
Hi,
B+ will remain the same but changing the resistor values of the splitter will allow for more current to run through them.
Ciao,
Which resistors are we talking about to be exact?
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