B1 with Korg Triode

[spades]

Thanks for the info will look in spares box later.Really enjoying this korgb1 having come from a b1 the soud gives my medallion horns with pm7 lowther some appearance of added low bass always with lowthers.Have not needed to fire up the rel storm mk2 sub.regards Spades.

 

[cubicincher]

answer to spades #1884

Hello spades,


enjoy the sound. The blue light gives you the blues...


Greets
Dirk

 

[Soundhappy]

I believe we could make an LTP with the Korg tube(s) if that's what you want,
in fact I think it would be easy using a CCS on the Cathodes.

Wonderful can be interesting experiment with different Nutube sound!
Please Mr. Pass could be possible show us the schematic with more details about CCS for Korg cathodes implementation ?
Ok with 2SK170 BL or J113 ?

 

[tubesguy]

I did want to insure that those with supplies down to 19V still worked.

With this info, I suddenly realized that I had a use for one of the little Allo cap multipliers that I've had in the basement for a year or so. Now running the B1 at 21.8v, and a closer to spec zener and it's perfect.

 

[dweightman]

Has anyone tried to make a balanced version of the B1 Korg by using one board for each channel?...I did this a while ago with the B1 boards to build a balanced pre which worked really well

 

[Leeuwarden]

Has anyone tried to make a balanced version of the B1 Korg by using one board for each channel?...I did this a while ago with the B1 boards to build a balanced pre which worked really well

I would like to know this too. Are there any reasons why one should not use a board per channel to use it balanced?

 

[Nelson Pass]

You certainly can if you like. Keep in mind that you will tend to cancel
that 2nd harmonic when you do.

 

[ichiban]

Help ! ...wrong voltages measured !

Hi,
I built up my xmas pcb with all parts except the korg/nutube.

I measure 24v in from a reg

T2 = 23v5

T7 = 21v87

T8 = 21v74

10v85 at L in

10v79 at R in

 

[Nelson Pass]

I believe that's close enough.

T7 and T8 are at rail voltage because no tube.

 

[ichiban]

I believe that's close enough.

T7 and T8 are at rail voltage because no tube.

Thank you!

Will put the nutube in now! Stand back!

 

[GASCo]

Nutube is better than notube!!!

 

[ichiban]

Oh yeah!

It's up and it's the bomb! Thumbs up to infinity!

All hail Mr. Pass

Thank you for the xmas present!

Next, got to finish the Sony.

 

[Soundhappy]

Nutube become popular

 

[jphabc54]

Just curious on this one. For folks using a regulated linear PSU, how close to 24.0v DC are you? I've built a sigma11 for my B1 Korg, but after testing literally 100 12v zener diodes, closest I can get is 23.8 or 23.9v. I'm sure it will be fine, but wondering what others have observed if they are not using a finely adjustable regulator (LM317, etc) or a wall wart that dials in right at 24.0.

 

[Nelson Pass]

It's not critical. Most of these are within about .2V, and the variation
it causes in performance is negligible once you adjust the T7 and T8
voltages for the common values or by THD measurement.

 

[cjfrbw]

Just curious on this one. For folks using a regulated linear PSU, how close to 24.0v DC are you? I've built a sigma11 for my B1 Korg, but after testing literally 100 12v zener diodes, closest I can get is 23.8 or 23.9v. I'm sure it will be fine, but wondering what others have observed if they are not using a finely adjustable regulator (LM317, etc) or a wall wart that dials in right at 24.0.

I just used one of these prefab ones. I prefer a linear supply if possible. They can be bought used to new on ebay for $30 to $60.

It measured spot on at 24V. The spec on ripple noise was 5mV, but I measured it lower than that at 1-2 mV. The final build is silent as far as I can tell with 88DB sensitive speakers. All of the circuit voltages check out quite close to NP's document.

 

[jphabc54]

It's not critical. Most of these are within about .2V, and the variation
it causes in performance is negligible once you adjust the T7 and T8
voltages for the common values or by THD measurement.

Wonderful -- thank you for the response!

 

[jphabc54]

I just used one of these prefab ones. I prefer a linear supply if possible. They can be bought used to new on ebay for $30 to $60.

It measured spot on at 24V. The spec on ripple noise was 5mV, but I measured it lower than that at 1-2 mV. The final build is silent as far as I can tell with 88DB sensitive speakers. All of the circuit voltages check out quite close to NP's document.

Neat PSU -- I'll check those out.

I have had really good luck with the sigma11 with my Graham Slee phono stage so I wanted to build another one for my B1/Korg. I love how it fits perfectly into the small Hammond case that Amb recommends, so I don't need to make any changes to my existing B1/Korg build.

I've powered the B1/Korg with a wall wart and a LM317 dialed to 24v. Both sound great, but I've been so happy with the preamp that I figured I'd build a high quality dedicated PSU and be done with it.

 

[Erlend Sæterdal]

A high current buffer IC or transistor aray at output would would be nice. I like dynamic sound.

 

[laverda]

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.

I only did this trial as over the years regs have had a large impact on the end result/presentation. Over these years I've spent loads of mulla and hours of building these various regs some with great success other not so. I'm amazed that this £15 box does all I want (and more) with little effort.

So I set up a raw supply off a 100va transformer 0-22v/rectifier/smoothing cap 10000uf which all the regs used (independently)

After many days/hours of trials with these alterative regs: All evaluated after 24 hours power up.

ALW/Jung super reg
Russ White Shunt reg
Avondale 317 tracking reg
Teddy reg and super teddy reg (I know)
MeanWell RS75-24 smps

The MeanWell RS75-24 comes out in top spot IMO (and others) in this application by quite some margin. All the other regs had a softness to the presentation, too soft, laid back 'limp' sounding as one listener put it compared the MeanWell.

The smps gives life to the music the others regs could not.