K&K Phono Preamp questions.

slaw. Dually noted on the updated tube type. Thank you for the input. 

Well, I'll call foul on the member that said Kevin designed around the Russian tubes. That may have been the case decades ago.....I spent several hours listening with Kevin in my pre-Trio stage. His tubes of choice then were Reflektors. Actually, the original Reflektors were replaced with a different batch that sounded more linear. We both agreed.

If the polarity switch is on the rear panel next to the IEC input for the AC cord, then I might imagine it is for input AC polarity. However, it is also true that the balanced circuit in at least many of the K&K phono stages permits switching the polarity of the audio signal. Like you, I would expect the switch for audio signal polarity to be on the front panel for easy access.

palasr 

Thanks for the feedback. The Russian Tubes have been entered into the notepad for future reference. 

Looking at the photos of other K&K phono stages, it appears the design changed to a single circuit board rather than multiple boards. 

This unit has a pair of Cardas Golden ratio 4.7uf capacitors. It appears as though many units used different types as well as combinations of capacitors in this position. 

Since it appears you have the oldest version of the K&K, I'm guessing it will use two 6N1P Russian tubes.  Any of the newer PCB based units will use two 6N23P tubes.  I've tried swapping nearly every known variant of the the equivalent 6922/E88CC/7308 etc, and I always come back to the Russian tubes.  Kevin designed the unit around that tube, and it sounds best with them IMO.

I had just assumed the polarity switch on my Trio was regarding the music signal, not the AC polarity.

@lewm ,

I don’t think the OP gave us a mirror example of how his phono looks. The link showed a blank front plate with no company logo or the switching options he talked about.

That picture leads me to believe it may have been a customer built kit?

Polarity flipping 180 degrees is made possible by the balanced circuitry inside.  I don't know what if anything at all it would have to do with mute or a mute switch.  Some folks believe selecting the "correct" polarity makes a big audible difference.  Others, not so much.

@wturkey,

My Trio uses 3 /6922 or variants. I would contact Kevin for accurate info. He actually has a blog on Audio Asylum which might be a better/quicker way to get in touch.

Gotcha. Thank you for the feedback. This K&K is a difference maker. As soon as the unit was fired up, it was a wow moment. Any tube recommendations from current or past owners? No idea what tubes are in this unit. They sound quite good, to these ears anyway.

Looks like the one you have is a pretty old version. Don't know how it compares with the new full PCB-based ones.

I can tell you that you have one very fine phono stage. I have owned mine for 20 years and is now the maxxed out version. I have no desire to change to anything else.

Oz

Thanks for the feedback. I'm not sure which exact unit this is. It's got the 2 cork knobs on the front. It's very similar to this unit. 

https://www.usaudiomart.com/details/649436923-kampk-se-phono-preamp/

Thanks again for the help.

@wturkey,

Millercarbon is correct, it's all straightforward. Which do you own, the Maxxed-Out or the Trio? I own a Trio.

Polarity + mute, eh? Good one. 

Polarity I know. Mute I know. Polarity + mute, that's a new one.
Oh wait, I see. http://www.kandkaudio.com/maxxed-out-phono-stage/
Turns out all the buttons and switches are exactly what they say they are:

The top button is mute.
Middle polarity.  
Bottom stereo/mono.  
Ground is ground. Connect your turntable to it.  

The switch in between the phono input RCAs is to switch the outputs. Select the one you use. If you get nothing out, flip the switch, you selected the wrong one.

Polarity can be AC, like on my Herron, or it can be reversing the polarity of the output. Either way it really could not matter less. The whole purpose is to let you try it both ways and use the one that sounds the best.