B1 with Korg Triode

It’s working without any additional connections from PCB to chassis. TKD pot has made a big difference- makes you want to get up and dance instead of sitting analysing your system and source material. It’s worth upgrading the hook up wire too. This pre amp has been compared favourably against stuff being sold for nearly ten times as much so worth pursuing a few upgrades.
 
Thanks for the feedback on the TKD volume pot. I’ll order one soon. I upgraded my internal hook-up wire with Duelund DCA20GA Tin-plated, stranded Copper wire with cotton insulation. I used the same in my Pass DIY Sony VFET amp and I have been pleased with the results.

I just installed these vibration-isolating stand-offs used for drone controller circuits:

https://www.amazon.com/dp/B073NYV6RH/ref=cm_sw_r_em_apip_FR93dD78NDgRe

No more microphony!
 
TKD pot came from Hi Fi Collective in the UK with the cables and Elma switch. Ordered Sunday night here in New Zealand and delivered Friday morning by Fedex. Pretty good service from them and not my first purchase - recommended.

PS Elma switch 2 pole 6 way (stopped down to four for my use by a pin you screw in) is a work of art - feels great in use too.
 
I just built a DIYAudio Korg B1 kit.
I mounted the NuTube on double-sided foam tape.

The NuTube is intensely microphonic. It rings from airborne vibrations.
I can sit on my couch 7-8 feet from the preamp, claps my hands and the NuTube rings.
All my test voltages are spot-on. It passes a fuzzy but undistorted sine wave.
I've tried slathering the tube and enclosure with Dyna-mat. The stand-offs are not long enough to allow mounting rubber washers without removing the hex-nuts permanently.

Does this sound like a defective NuTube to you guys?
 
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I just built a DIYAudio Korg B1 kit.
I mounted the NuTube on double-sided foam tape.

The NuTube is intensely microphonic. It rings from airborne vibrations.
I can sit on my couch 7-8 feet from the preamp, claps my hands and the NuTube rings.
All my test voltages are spot-on. It passes a fuzzy but undistorted sine wave.
I've tried slathering the tube and enclosure with Dyna-mat. The stand-offs are not long enough to allow mounting rubber washers without removing the hex-nuts permanently.

Does this sound like a defective NuTube to you guys?

Hi Robert, sorry to hear that your NyTube is having issues. Others have mentioned it as well, and I can hear it as well but it’s no where as obvious as your build seems to have. My boards are mounted using computer fan silicone rubber standoffs and I can literally, barely hear any ringing unless the volume is way up and I’m changing my input switch. Have you read through the thread regarding the various things other builders have done to tame the michrophonic ringing? Diy being what it is you might need to experiment with different possible solitons to get it under control. Good luck, and don’t let this issue discourage you from this great, fun and pleasurable hobby! Please also post any solution you may find to help others in the forum.
 
I can knock on my chassis and can hear nothing in the speakers. I use a 100% closed alu box and damped it with bitumen. Nutube is soldered in and I used double sided foam tape under it but did not peel the upper layer off but pressed the Nutube down after soldering so I use the spring effect/permanent bending in the legs so Nutube has good contact with foam. Then it is easy to exchange it.....some day.
You may try to press the Nutube down a bit on the foam to ensure foam is compressed a bit?
A 100% sealed box should at least prevent ringing from clapping in the hands. If not it is really sensitive.....and something seems wrong.
 
I've only noticed the microphonic effect if I tap the case with something hard like your screwdriver when you're putting the lids in place. (Finger tap doesn't do a lot). I also notice it when I turn the source selector switch. Which is on the front panel with the Nutube. It's very short lived and not proving an issue in use.
 
My Nutube does not have issues with ringing at all. Best preamplifier I have heard so far. Aleph 1.7 after the Korg in same enclosure make it perfect. I brought it to our Copenhagen HIFI Club. Our BOZOZ was preferred by almost all. I went home and changed four components. One 3.3 ohm resistor in each channels supply and one capacitor in each channels input. Now it sounds fantastic. Capacitors from Panasonic MKP 6.8 uf to Kasei 50 uf 63 v.
 
Tocos are highly regarded pots for their great sound/cost ratio. The only issue is the tracking matching with stereo pot, but you have two mono pots, so you get all the benefits with no tracking issue to worry about.

They have a different logarithmic curve, compared to Alps; hence the difference in wiper positions between two for the same volume level. That's quite okay.

The highest quality I managed to achieve, with potentiometers, was with TKD's. Very nice. Great tracking match as well.

Going higher in price, and further up in sound quality, warrants the relay switched ladder network (shunt). Otherwise, paying around $100 for Black Beauty may not yield the expected return is sound quality, compared to money spent for what is in reality, just a potentiometer where the wiper (with hopefully more that one contact!!) scrubs the whatever.... graphite or plastic conductive strip.
 
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I used TKD 2CP-2511 MC Motorized volume control as a direct drop-in replacement for the Alps Blus motorized pot. This TKD also has a plastic taper, but sounds really nice. I'd say it all depends on the rest of your system as well. For example, if there's perception that the TKD, due to its plastic taper, adds bass, you could offset that by the correct choice of the first sound coupling cap and/or correct choice of the hook-up wiring.
 
Hi,

Glad you are enjoying your Tocos!

As posted here previously in my A/B "reference" test (directly "air-soldered" high quality resistors for one given volume), it is really very close to perfection. If anything you miss a very small bit of low bass, and not the opposite. The difference is so small that trying to fit any other solution in between is quite worthless IMHO given the price of the Tocos, so that ruled FOR ME further tries with attenuators etc.

It would though be nice to hear how it compares with the TDK, but again air is thin at that level and the difference, in whatever direction, is probably more taste and colours (more bass for the TDK?). Biggest question mark isn't in fact the tracking, but the aging, as that one can only be told by time and we are few to have try that pot recently, but no big reason to worry IMHO given the Tocos specs and industrial use.

The tracking matching mentioned years ago on a UK site that sold also the TDK wasn't an issue at all "today" in my case as my measuremens showed, and at the end of the day I even found a trick to get it further down to ladder type pots level. Couldn't hear the difference though lol! But then to make a real statement, one would have to by thousands of pots. Note though that the advertised specs re matching from most sellers are excellent.

The volume knob position vs blue Alps isn't relevant at all for audio quality BUT the way you describe it, it could also be you inverted the left pin with the right one (I did it once). That's from left / middle / right pins on a given pot, regardless how you look at it, so perhaps your 2 extremes are inverted, as otherwise the log curve should be pretty much close with the Alps. But again not an issue re audio quality.

For me, bare aging that needs to be verified, it is more than a match to my Black Beauty on sonic qualities. But then the BB is a fantastic unit that didn't move one bit in 25 years... whereas some switches did after 10y... great piece!

I hope this helps

Claude
 
Any thoughts on using the Goldpoint V47 47 position atttenator, as compared to the TKD pot? It is 2.5 times the cost of the TKD, obtained directly from Goldpoint.

Also, does anyone have any comments on Goldpoint's view that MF resistors based upon nickel-chromium are better than typical MF made of ruthenium, and even the Caddock and bulk foils? Goldpoint identifies this as the reason they use NI-chromium resistors from KOA Spear.
 
I have a 47 position gold point in another preamp build, and a TKD in the Korg B1. The Gold Point is very smooth, but sometimes one channel won't hit the same resistor as the other channel, leaving a ~1 db imbalance between channels. Not really noticeable but it showed up in testing. The step is probably smooth enough not to trip the microphonics of the nutube, but if you use it you would probably want to take extra care to put the board on some sort of iso material.

I haven't compared them to each other the same build, however if you are going to spend that much money I would consider the Khozmo relay based board with remote (also includes inputs and switching).