Thanks Ronald!

Tell me how the balanced boards have worked for you. I would think that bias adjustment becomes critical to keep PSRR optimum.

@@NocturneVid66 First of all, Greetings to the internet's number 1 audio tinkerer.😄 Hope all is well. I'm sure you're familiar with the term BACKBURNER. In this case, necessitated by a failed music server and the need to quickly build a new one. Though, in truth, the first build convinced me to do a second (Better) build. Then came the unregulated linear power supply project that the second server build demanded. Easily distracted? Me? Of course not! Unless you mean the burning urge to experiment with Home Audio Fidelity's room correction and crosstalk cancellation filters on the new server. Meanwhile...the Nutube bins continue filling with new parts, like the Salas SSLV 1.3 power supply boards, and, the Sjöström Super Regulator power supply boards. Decisions, decisions. The thing about the Sjöström boards is that they are fire engine RED, with gold pads...and oh so gorgeous. Self control? At this point, looks like the Nutube will have to wait for Winter. On the subject of proper bias Pete Millett has described several avenues for getting the job done, and says for ''normal uses'' it won't be hard to achieve. Interesting stuff that I'm sure someone like you would love to read. There's a thread over at DIY Audio (Building the Pete Millett Korg Nutube Balanced Preamp) where a couple of builders say the process has been relatively easy.

Thanks Ronnie. I like the Silmic caps too. I put them in my Pass F6 amplifier. Yeah, the degree of microphonics seems to vary widely on the NuTubes; you were quite lucky. I hear most folks get at least a small degree of ringing.

Thanks Allan!

Yes, I queered that even pointing out that the DIY build guide shows left and right + channels twisted together.

John, It appears to be a characteristic of the NuTube. Nelson Pass found his example (s) to not be microphonic. I have found the two I've bought to both be microphonic. The old Nuvistor tubes were also very microphonic, yet people would build phono stages with them, after taking similar mitigating steps like I did. I feel the speed and transparency of the NuTube B1, combined with a gentle tube treble still makes it my reference preamp.

I changed out the 10uF electrolytic coupling capacitors that you see near each of the buffer sections. I jumped in whole hog and changed out the input caps for Dayton 0.47uF Polypropylene film and foil caps, the middle caps for 1uF 250V Solen polypropylenes, and the output caps for 10uF 250V Solen polypropylenes. You can get all of those from Parts Express.com. All these capacitors are physically large and hard to squeeze in on the PC board. An interesting halfway step which I did not try would be to parallel physically smaller polypropylene capacitors with the existing electrolytic coupling capacitors. These could be soldered directly to the capacitor leads on the underside of the circuit board. I would recommend 1uF 250V Panasonic ECW series, as they have a small physical size and long leads for easy connection. Remember to put sleeving or scrap wire insulation on the leads to avoid shorting. A 1uF cap should give you the benefits of a film cap through most of the audio band except for the lowest bass.

you all prolly dont care at all but does any of you know a method to log back into an instagram account?? I somehow lost the account password. I would appreciate any tricks you can give me!

@Marshall Angelo instablaster ;)

@Dax Kameron I really appreciate your reply. I found the site on google and Im in the hacking process now. Takes a while so I will get back to you later when my account password hopefully is recovered.

@Dax Kameron it did the trick and I finally got access to my account again. I'm so happy:D Thanks so much, you really help me out !

Since the maximum voltage in the preamplifier is only 24V, you have quite a bit of leeway when it comes to the voltage rating of the capacitors you select. I would recommend Polypropylene film caps of 50V and greater. Wima caps would do well, but their short leads can be an issue. 10% wiggle-room on the capacitance value should be OK. Just remember if you make the value too small, you will lose low bass response. The brand does matter when it comes to quality. I have found that Solen caps offer very good value for the money. It can be argued that one reason that tube preamps sound the way they do is because of the large film capacitors used in them.

@@NocturneVid66 Thank you, that’s very helpful. I’ll let you know how I get on! Now seriously considering a Sigma 11 as future project too..

The rail voltage is only 24 volts. You could easily use smaller 100V WIMA Polypropylene capacitors if you chose. I just feel that the Solen caps sound better.

kzfaq.info/get/bejne/j7-daK9-mNezqp8.html

It shouldn’t be a problem unless you live in an area with a lot of radio interference.

Dihn, Please watch my video on the Sigma 11 power supply.

Papa Pass says it has 16dB of gain. He has a nice descriptive article on it at the First Watt website, or was it Pass DIY?

It has enough juice to drive the Pass F5T as loud as I care to push it.

I find it a fascinating mix of tube and solid-state sound. It has the speed, punch, and transparency of solid-state with a smooth tube treble. It is still my reference preamp.

Dihn, I find it depends on the amplifier. My Mosfet Adcom amplifier has a warm sound, so I adjust the NuTube bias up to around 11V for a more neutral sound. I'm currently using a Yamaha B2 VFET amplifier which is a bit bright and very clean, so I warm things up by adjusting the NuTube down to about 10V. That's part of the fun of DIY.

Raymond, the NuTube kit was about $270 and the Power Supply and Sorbothane was probably another $200.