Good advices for a newbie (threading tools lathe)

[PJs]

Hi Stefano,

The FG looks pretty good on the inside but how did the signals look on the scope? Did they jump in amplitude or distort at any frequencies? Wouldn't worry about the SQ wave stuff as the manual states it isn't that good and slants, but good for quick checks...so you would have to compare before and after to really get any kind of clear picture.

One thing I noticed in the manual for the FG is the impedance and the ("Limited to" ) .25% THD. It's old school and built like a tank, which I love, but for modern audio...its what you have so keep it in mind.

Pg 7 shows it to be for a 600Ω resistive load for DBM. Pages 8-11 have good procedures to find out the impedance of the system, DB/DBM, the freq response and IM distortion...All good simple hookups and tests. The voltage out should be Ok (8V RMS) for your amp but figure max input for your amp and hold it just below that. Also in the manual the multiple warnings about connecting around the B+ is a good Warning...you will pop some components if not careful.

For a temporary Faraday you can use Al screen door material. Keep in mind it may become charged so make sure its grounded well in several places. Copper is always best and should be porous Screen or perf metal. Some older computer cases have some copper shielding if you can find an old case somewhere with it you might be able to salvage enough from it. MY old Dell XPS had a lot inside with nice finger grounding strips. Wish I had saved it now.

The Pot should be ok. As for the output of the pentode...Maybe you could devise an LR for it...but would be much better to use an Xformer if you can scrounge one up.

Personally I think you will be throwing too many variables into your working circuit by building something new with the 813. Again, You may be pretty close to the power you need with the gu50, imho...multiples in // will add other issues in matching impedance's and outputs with out buying matched components.

Please be clear these are Just my opinions and observations...it's your project and you have done Very, Very well so far.

Good luck and may the Force be with you.

~PJ