Modification of Cathode subcircuit without capacitor
I was curious about alternative filaments=cathodes circuits.
Diyers example from Japan make something with diodes and transistor.
Could be fun
I was curious about alternative filaments=cathodes circuits.
Diyers example from Japan make something with diodes and transistor.
Could be fun
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QUOTE
It sounded hypnotic, even though there is no polarity reversal with headphones to invoke the H2 negative state. I guess one could install some kind of chassis switch to reverse polarity at the output.
Regarding that polarity bit and trials with positive and negative H2... are there simple ways to inverse polarity INSIDE the B1, be it at least temporarly while on the bench for sound trials... or even once finalised, just to play with it? It doesn't seem easy...
Claude
It sounded hypnotic, even though there is no polarity reversal with headphones to invoke the H2 negative state. I guess one could install some kind of chassis switch to reverse polarity at the output.
Regarding that polarity bit and trials with positive and negative H2... are there simple ways to inverse polarity INSIDE the B1, be it at least temporarly while on the bench for sound trials... or even once finalised, just to play with it? It doesn't seem easy...
Claude
What about try with this diodes CRD E-562 x3 or equivalents ?
https://www.mouser.com/datasheet/2/362/crd-1407.pdf
https://www.mouser.com/datasheet/2/362/crd-1407.pdf
Quote:
(It sounded hypnotic, even though there is no polarity reversal with headphones to invoke the H2 negative state. I guess one could install some kind of chassis switch to reverse polarity at the output.)
No harm is trying it both ways in main system. Right now I am using mine with no reversal and enjoying it as much as reversed. More forward vocals which I am enjoying at the present time. I may reverse at a later date. A lot of times the sound engineer will do much the same in the studio to suit his taste. I have a indirect heated 12AU7 tube linestage I built a few years back and compared the two. I would say very similar sounding other than the nutube being quieter with no music playing. Measures on scope and Arta much the same as well. Worthy project for a diy'er. Keeper.
(It sounded hypnotic, even though there is no polarity reversal with headphones to invoke the H2 negative state. I guess one could install some kind of chassis switch to reverse polarity at the output.)
No harm is trying it both ways in main system. Right now I am using mine with no reversal and enjoying it as much as reversed. More forward vocals which I am enjoying at the present time. I may reverse at a later date. A lot of times the sound engineer will do much the same in the studio to suit his taste. I have a indirect heated 12AU7 tube linestage I built a few years back and compared the two. I would say very similar sounding other than the nutube being quieter with no music playing. Measures on scope and Arta much the same as well. Worthy project for a diy'er. Keeper.
NUTUBE - playing TETRIS
Hello NUTUBE / B1 with KORG TRIODE-builders,
I am still moving around parts in my modushop case -
playing TETRIS with parts - funny!
And waiting for my frontpanel to come back home. It was running away to
SCHAEFFER AG (front panel express in Germany).
If you need your front panel then it decides to make 'vacation' in Berlin....
But Dirk is patient...
As a kind of revenge I decided to go in my garage and work on the motorcycles!
Hello NUTUBE / B1 with KORG TRIODE-builders,
I am still moving around parts in my modushop case -
playing TETRIS with parts - funny!
And waiting for my frontpanel to come back home. It was running away to
SCHAEFFER AG (front panel express in Germany).
If you need your front panel then it decides to make 'vacation' in Berlin....
But Dirk is patient...
As a kind of revenge I decided to go in my garage and work on the motorcycles!
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The circuit is designed for a 9.1v zener, and has a corresponding resistor in the circuit specified for that voltage. As I and others have found, these zeners can be off quite a bit, when ordering the "normal" ones that appear to be 10% tolerance. Mine is, as it turns out, a 9.7v zener, rather than the specified 9.1. ZM has suggested the possibility of a circuit change to sub a 7809 linear regulator for the zener. I decided to order ten 2% 9.1 zeners and pick the closest to 9.1.
I believe the issue is not audible improvement, but rather keeping the tube's dissipation within recommended limits.
Thank you for explanations.
They are cheap so now I plan to buy 10-20 pieces and measure wich fits best.
But BZX55B9V1-TAP is 500 mW.
And Zener diod from Nelson's article BOM is 1W.
I think BZX85B9V1-TAP (1.3 W) for similar price should fit just right.
P.S.: By the way. Any news when PCB restock at DiyAudio store?
Just putting this out here.... I've been having a play with different PSUs and what effect these have on the presentation.
The MeanWell 75-24 smps is great value for money at 12-15UKP and is easy to implement as there's nothing else to think about as a internal/chassis mount PSU. Almost a plug and play.
A MeanWell wall wart device, didn't try this as I couldn't find one in 24v knocking about in my bins. But I did try a lap top computer type PSU, I have a Chinese 24v supply. 10-15UKP Almost a plug and play.
ALW super reg... now getting on in years but always does a good job in the digital domain. But with this or any other stand alone reg you have to factor in the associated raw supply bits, transformer/rectifier/smoothing cap etc. 80-100UKP. Quite a few hours build time, test, setup and install.
SupperTeddy reg... (I know I know they don't measure well) again now getting on in years but has its fans with Naim pre amp circuits. With this or any other stand alone reg you have to factor in the associated raw supply bits, transformer/rectifier/smoothing cap etc. 80-100UKP. + Quite a few hours build time, test, setup and install. next in test..
I have yet to try my Russ White shunt reg. Like the ALW s/reg quite a few hours build time, test, setup and install. Anyone??
A bog standard 317 or preset reg 7824 type....yet to try this also. Has anyone??
This is on going trial as I like to listen for quite some time before changing to a new reg type.
The winner thus far for me is the MeanWell 75-24 the super regs add a softness to the edges which is OK but for me, to soft.
The MeanWell 75-24 smps is great value for money at 12-15UKP and is easy to implement as there's nothing else to think about as a internal/chassis mount PSU. Almost a plug and play.
A MeanWell wall wart device, didn't try this as I couldn't find one in 24v knocking about in my bins. But I did try a lap top computer type PSU, I have a Chinese 24v supply. 10-15UKP Almost a plug and play.
ALW super reg... now getting on in years but always does a good job in the digital domain. But with this or any other stand alone reg you have to factor in the associated raw supply bits, transformer/rectifier/smoothing cap etc. 80-100UKP. Quite a few hours build time, test, setup and install.
SupperTeddy reg... (I know I know they don't measure well) again now getting on in years but has its fans with Naim pre amp circuits. With this or any other stand alone reg you have to factor in the associated raw supply bits, transformer/rectifier/smoothing cap etc. 80-100UKP. + Quite a few hours build time, test, setup and install. next in test..
I have yet to try my Russ White shunt reg. Like the ALW s/reg quite a few hours build time, test, setup and install. Anyone??
A bog standard 317 or preset reg 7824 type....yet to try this also. Has anyone??
This is on going trial as I like to listen for quite some time before changing to a new reg type.
The winner thus far for me is the MeanWell 75-24 the super regs add a softness to the edges which is OK but for me, to soft.
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Voltage drop through the 270 Ohm resistor is roughly 15V (24 - 9)
Consequently 55ma are running through this resistor
Out of the 55ma at about 35ma go to the heaters
Most of the remaining 20ma run through the 9V diode
This is still within the rating of a 500mW diode but not very conservative
With a 330 Ohm resistor we would have 10ma running through the diode
Should be enough
Maybe even a 390 Ohm could be ok
No idea why Papa chose the 270. Maybe he had a lot of them in the drawer, or just another good reason
Consequently 55ma are running through this resistor
Out of the 55ma at about 35ma go to the heaters
Most of the remaining 20ma run through the 9V diode
This is still within the rating of a 500mW diode but not very conservative
With a 330 Ohm resistor we would have 10ma running through the diode
Should be enough
Maybe even a 390 Ohm could be ok
No idea why Papa chose the 270. Maybe he had a lot of them in the drawer, or just another good reason
Right on both counts. I did want to insure that those with supplies down
to 19V still worked.
You are welcome to adjust the value as you like.
Also, the tolerance here on the zener is about 9.0 to 9.2V
If you are not within that, consider adjusting the resistors in series with the Cathodes.
Korg b1 Built
Finished b1 korg today added an led which is a bit bright will play around with the resistor value to get it not so bright.Wiring is a little messy but works as for sound quality feeding the f2j monoblocks iam using informative with plenty of depth sightly warm but very musical sat listening with my wife to some classical music on radio ulster,wife chips in very refined i could listen to this all day..As a classically trained pianist i take any praise from my wife happily.Nelson has done it again anyone who has not tried a korg b1 may be missing out on a superb piece of equipment .I look forward to trying it with my f1j once i get the parts to complete the other channel.Regards Spades.
Finished b1 korg today added an led which is a bit bright will play around with the resistor value to get it not so bright.Wiring is a little messy but works as for sound quality feeding the f2j monoblocks iam using informative with plenty of depth sightly warm but very musical sat listening with my wife to some classical music on radio ulster,wife chips in very refined i could listen to this all day..As a classically trained pianist i take any praise from my wife happily.Nelson has done it again anyone who has not tried a korg b1 may be missing out on a superb piece of equipment .I look forward to trying it with my f1j once i get the parts to complete the other channel.Regards Spades.
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