[Rock Ball]

Several of you have built the TU-8600 300B amp kit, and report that it works well with the NX-Tremes and NX-Oticas, including Danny.

Danny, what mods did you do to yours?

[Danny Richie]

I bought mine already assembled. I then went through it and made a few updates.

1. I wired the inputs straight to the boards with some OCC wire, and by-passed the volume pot and board traces.
2. I removed the binding posts and replaced them with tube connectors.
3. I replaced the input caps with Miflex Copper foil caps.

It also had a little hum to it when I got it. It is dead quiet now.

[Rock Ball]

Danny, the solder that you included with my speaker kits was very easy to use.  You said it was a very good quality.  Do you suggest using that to build the amp kit?  What brand and type of solder is it?

[mlundy57]

I use Cardas Quadeutetic solder. It helps a novice like me avoid cold solder joints.

[Jon L]

3. I replaced the input caps with Miflex Copper foil caps.

0.22 uF Miflex coppers fit under the board?  When I did a dry run fitting with Miflex, it looked like there would be zero space between the cap and chassis, i.e. cap would be rubbing on the chassis..

[Danny Richie]

Danny, the solder that you included with my speaker kits was very easy to use.  You said it was a very good quality.  Do you suggest using that to build the amp kit?  What brand and type of solder is it?

I get it from Erse. I don't recall which variation off the top of my head.

[Danny Richie]

0.22 uF Miflex coppers fit under the board?  When I did a dry run fitting with Miflex, it looked like there would be zero space between the cap and chassis, i.e. cap would be rubbing on the chassis..

They fit.

[Rock Ball]

I use Cardas Quadeutetic solder. It helps a novice like me avoid cold solder joints.

Thanks for suggesting this solder.  It works really well.

[Rock Ball]

I finished adding tube connectors to my TU-8600S.  Here are some photos of how I did it.

I wanted to keep the original functionality of the amp, such as the ability to use headphones and connect other types of speakers that that didn't have tube connectors.  I also wanted to be able to use the speaker impedance selector switch with the tube connectors.

Back of TU-8600S:








More filing of cutout needed to fit tube connector into place:


I cut a groove in the tube connector to hold it in place in the cutout:






I soldered the + to the output of the speaker impedance toggle switch:


I soldered the - to the - connections of the speaker connector board:






The bottom back edge of the transformer cover is bent at a 90 degree angle, providing a flat surface to hold the tube connectors in place:




With my new GR Research speaker cables connected:


This modification improved the sound of my system.

[Danny Richie]

Very good. By-passing the volume pot was also an improvement.

[Wigand]

Would the 8600S provide enough power for the X-LS or X-SLS?

[Danny Richie]

Would the 8600S provide enough power for the X-LS or X-SLS?

For small rooms and for some types of music it will.

[Wigand]

Thanks; just building out the enclosures for the X-LS.
Do you have a Amp recommendation for the X-LS? Maybe some other Tube Kit you like or somethink like ... something you know pairs well with the X-LS

Thanks so much

[Tyson]

If you want to stick with SET then you need a 211 or 845 amp to get you close to 20 watts. 

My suggestion would be to go with an EL34 or KT88 amp that gets you 30 or more watts in a push-pull configuration.  I find that push-pull amps work better with this type of speaker.