Pp 6aq5 pt

[Scsoul]

  what pt requirments do you guys use for a pair of 6aq5?  i wanna build
A amp witph apair of 6aq5s and 3 12ax7 diode recto 250 to 270 plate voltage
Cathiode biased   thanks mark

[kagliostro]

6AQ5


EL90 (same tube)


Franco

[tubenit]

http://el34world.com/charts/Schematics/files/gibson/Gibson_ga17rvt.pdf


Gibson Scout (GA17RVT) carried 300v on plates of 6AQ5's.


If you can find a PT that is 250-0-250 & use an old 5Y3GT, you might be OK with that having around 275v.


OR ............   190-0-190 and use a 5V4 for around 230v.  If you went solid state rectifier using diodes , maybe around 270v?   


I would want a PT with at least 100ma.


275-0-275 & old 5Y3GT = about 300v same as Gibson Scout. You could install a VVR to lower plate voltages. I did this with a HoSo56 using 6AQ5's.


With respect , Tubenit

[kagliostro]

http://www.musikding.de/Power-transformer-230V-230V-20V-63V

Primary 230V

secondary 230V 0,12A, 20V 0,12A (or 230v + 20v = 250v AC @ 120mA)

secondary 6.3V 4A

but this only if you are on this side of the pond

Franco

[tubenit]

Since Doug doesn't carry a PT that will keep the voltages under 275v & has 100ma or more,  here is a source that has a 190-0-190 PT.

http://www.ebay.com/itm/PT190-2i-380Vac-POWER-TRANSFORMER-TUBE-240Vac-190-0-190Vac-120mA-/162279436680

With respect, Tubenit

[Scsoul]

   thanks tubnit forgot about MPS, Those look great,  i have some fender blues jr output transformers i was gonna try.  i have  a huge stash of 6aq5 i wanna get into. Was looking at soho and d-lite with 6aq5 built into 1 8inch combo   thanks mark

[tubenit]

I truly hope you will share your results with us along with photos.  The HoSo56 with 6AQ5's was a very expressive and touch sensitive amp.

IF I were doing a D'Lite with 6AQ5's,  I would do something like a non-adjustable VVR where the plates and screens of the 6AQ5's were seeing 250v but the V1 plates were seeing  160-180v range.  In other words, the VVR would just be lowering voltages on the power tubes.

With respect, Tubenit

[tubenit]

Here is an idea to consider that I think could be a great sounding amp.  One might want to use 100k/1.5k  plate/cathode resistors on V1 to get the voltages a little higher for a good clean tone.

With a 275-0-275 PT and a 5Y3GT, you could probably get by without a VVR?  You should have around 300v on the 6AQ5 plates and the Gibson Scout had 305v on the plates.  So, I am thinking you might be OK?

with respect, Tubenit

[Scsoul]

   after going through my Power power trany i found a couple good candidates one 280-ct-280 that i use a ez81 and  should work fine for a 10 watter and a couple 170-170 that with diode shoud get me in 300 ballpart i got these cheap from fleabay and as i reacll in a el84h build therse were very close  300vdc so i guess i tray with 4 6aq5  build for around 20watts so its the tale of 2 builds,  not sure what opt to use yet for for 4 6aq5 i have some 30watt ots that are 5.9k for 30 watt id assume a 40watt ot would be to large which ive found oversized ot isnt the way to go might try a hammond ao 43 chassis ot
   
Tubnit would you happen to have drill plas for a soho? im love on garolte and cant aforn a mess up? mark