Gavin in Oregon

[Gavin Pursinger]

I have built several successful tube studio projects. I am building a Federal Am 864 clone. I have an old Merit 500 TO 10K CT line input transformer and a Merit 10K CT to 500 15 watt output transformer.I had to rob a nice single ended creation (5879 to triode connected 6L6) for this output tranny. I also have the option of and old Stancor PP output tranny from an ancient PA amp. (i guess it is 5-6k ct to 500 ohm tap (20 watt ???). i would like to use the Stancor for the AM864 because the Merit sounded so good on the unit i pulled it from and the tranny i replaced it with does NOT have the 'magic'...ALSO THE 864 IS A NEW BUILD SO I DON'T WANT TO TRASH THE NEW CHASSIS ON AN 'experiment'
CAN I USE THE STANCOR FOR THE PP 6SN7 OUTPUT ??? THX ( any info will be appreciated)

 

[ruffrecords]

Welcome Gavin. Good to see another tube enthusiast here.

Cheers

Ian

 

[Gavin Pursinger]

Thx Ruff...glad to be in this forum.
I have built tube gear for my studio mostly from carcass from the local salvage shop...learned alot and have been bitten a couple times!!!!
Units have started to look good and sound wonderful...finally...
I have read many af your posts...
My Best creations thus far are

1. Mic pre (5879 to 6L6 both triode connected)...very liquid
2 . Single ended variable mu comp (6L7 to 6L6 with 12at7 for gr section)
3. Massive tube regulated supply for an old huge differential broadcast line amp with huge Thorardson iron....it was not working when I bought it for $ 5.00...it is like a cannon to the gut...kick, bass & vox.

I have everything to build my am864 clone including a US Navy chassis that looks very similar to the Federal box...all components tested with my Eico. Can't wait to hear it....I will take my time to build it

Thanks for all your inspirational posts

Gavin

 

[gyraf]

Welcome!

 

[analag]

1. Mic pre (5879 to 6L6 both triode connected)...very liquid

This sounds interesting.

 

[Gavin Pursinger]

Hi Analag...

This mic pre was one of my very 1st successful creations. The triode connected 5879 wire up was right out of the RCA receiving tube manual...I upped the cathode bypass cap to 100mfd and the 6L6 is triode connected per the '8watt' 6L6 schematic in the same RCA manual. Input transformer is an ancient Electrovoice in-lined and output transformer is an old Merit 10k to 500 ct but is just wired single ended. Power supply is 5U4(could be a 5y3) and choke filtered. Power transformer is Stancor 175 0 175. Heater is bridge rectified with 10,000 mfd and voltage dropped by resistor. NO VOLUME POT On input but vol pot between 5879 and 6L6...I built it on a salvaged chassis and have a small round Tripplet meter. It can blow the top of the led ladder in my converter...so gain is plenty. It is very quiet...even with tube rectifier. Build it with SS would be better for old ribbons. I just like glow in the dark !!!!

 

[Gavin Pursinger]

Welcome Gavin. Good to see another tube enthusiast here.

Cheers

Ian

Hi again Ruff

I am curious regarding the use a the 2nd gain stage of a limiter like the BA6A. I get the need for massive gain that a radio station needs to drive miles of phone lines @600 ohms BUT the Federal 864 reportedly already has massive gain for studio use( I have read). I have NOT started my 864 build and have the xformers to make the interstage and a Stancor 6600 to 500 output for 6v6 pp output. if this 2nd gain stage is a VERY GOOD THING TO HAVE..
PLEASE ADVISE....thx

Gavin in Oregon