B1 with Korg Triode

In any case , that Toroid is waaaaaaay too big, be it shunt reg involved or not

remember that Korg tube is sensitive to any vibration, and that big toroid is also having big magnetic field (well, comparing to small toroid) ........

there are sensitive and tiny wires in that tube ....... bathing them unnecessary in magnetic field is just ..... careless

OK, try it...... maybe I'm just too cautious
 
In any case , that Toroid is waaaaaaay too big, be it shunt reg involved or not

remember that Korg tube is sensitive to any vibration, and that big toroid is also having big magnetic field (well, comparing to small toroid) ........

there are sensitive and tiny wires in that tube ....... bathing them unnecessary in magnetic field is just ..... careless

OK, try it...... maybe I'm just too cautious
How effective is something like mu metal sheeting? Worth a try?
 

DNic

Member
2021-08-31 9:57 pm
Hi, I would like to put a Muses remote Control on my unit & am confused. the Audio Academy site advised that a DC blocking cap around 47uF should be fitted on the inputs with a bi-pass cap. However on studying all the implantations on this site I can find. I cannot find anyone who has done that. So are they needed & if so what would the best recommendation be. I have a separate P/S for the unit so this is no problem.

Cheers
 
hi, thanks for that, any chance of showing a photo or sketch of how you implemented . Mouser have FHP in stock for around $2, unless I am looking at the wrong part.

Cheers

I should have taken a photo before putting it back together, however it's almost identical to @WKCox implementation as shown here https://www.diyaudio.com/community/threads/b1-with-korg-triode.313612/post-6117998 - except he uses some (no longer in production) Panasonic ECQP's, and I use Wima FKPs. To my knowledge they're both foil-would polypropylene. The Wima's (at 100V) are somewhat larger than the Panasonic items. I managed to get it all int the same case with an extra nut between the PCB and the standoff to dial in some height.

The exact Mouser P/N I used was 505-FKP3D03104D0JF0. Close enough to $2 ea.

Yes, some will suggest that Vishays sound better and some will suggest uber audio caps sound best. They may both be right. This certainly sounds better and costs less than $12, which can't be said for the other options - I'd further argue that the nutube may not warrant as much (which isn't to suggest it isn't very very good, or that the B1 implementation isn't a lot of fun - which it is!)

Short version - $12 of FKPs and we didn't stop listening to music all night :) More detail, better transients.
 

DNic

Member
2021-08-31 9:57 pm
Hi, I actually was inquiring about the blocking caps for the input.
-Just to clarify, I am placing my Muses V/C before the B1 Korg, is that normal? or the Muses be placed after the B1 Korg. With the Muses placed before the B1 do I need the 47uF blocking cap & bi-pass as per Muses instruction sheet.
-So yes now I see how the the by-pass caps on the board, however the Wima at Mousers has a 33 week restock wait!! So I will have to find something else.

Once again, thanks for any advice. Cheers
 

Attachments

  • Muses Blocking Capacitor.jpg
    Muses Blocking Capacitor.jpg
    910.4 KB · Views: 62
Hi, I actually was inquiring about the blocking caps for the input.
Yep - sent you a PM to that end the second I realised!

-Just to clarify, I am placing my Muses V/C before the B1 Korg, is that normal? or the Muses be placed after the B1 Korg.
Yes, normal to be before.

-So yes now I see how the the by-pass caps on the board, however the Wima at Mousers has a 33 week restock wait!! So I will have to find something else.
If you wanted to use blocking caps you could use most any non-polarized type just to get it started. If you expect no DC, just start without them.
 
Well! Originally I was typing up a post to try to figure out why I was having some DC voltage on the right channel, but it turns out I put the input 10uF capacitor in backwards, flipped it around and I am an extremely happy camper.

I am absolutely in love with this preamp, I am still playing with the T7 and T8 voltages, I only finished things up last night, currently I have them at 10.5V and pleased with the sound. On my to-do list for this beauty is to put together a 24VDC regulated PSU in a separate chassis, probably not necessary but I have all the gear already so why not.

I'm also looking to refine my construction of the B1K as well. As you can see in the attached image, I used shielded wiring for signal, and the shields yellow wire all tie back to the orange wire nut, which then ties to the ground nearest the voltage input on the B1K board. I did it this way before putting a lot of thought into it, and I wonder if it would be better to shorten up shield wires and attach them to the nearest PCB mount, curious on what peoples thoughts are on that.
 

Attachments

  • B1K.jpg
    B1K.jpg
    768.8 KB · Views: 140
I finished putting together this preamp and I’m totally in love with the sound. All values are spot on or within the stated tolerances, no ringing unless I outright punch the valve in the face, no perceptible turn on/off thumps.

However I spotted an odd behaviour: when the preamp is switched off (and PSU is on) the green led is off; if the preamps is switched off and the PSU is off (for example the multisocket is switched off) the led glows very very dimly. I wanted to ask you gentlemen if it’s normal behaviour (before I either call an exorcist or take this thing apart and start investigating further).
Mind you I have used a 24v, 1.5A bravo audio PSU, but the wiring on the DPDT switch is in line with what’s on the guide published by 6L6
 

Attachments

  • bravo audio psu - Google Search.png
    bravo audio psu - Google Search.png
    86.1 KB · Views: 70
  • D080A0F4-E327-4910-A02C-F52F71C9C7F4.jpeg
    D080A0F4-E327-4910-A02C-F52F71C9C7F4.jpeg
    313.6 KB · Views: 72