Pirx

My old T1 plays enough loud, power stage with 6C4C choke loaded plays louder. I don't need more voltage swing. I think many of us don't need as long as they have healthy hearing. Of course it is my opinion

What do you mean? Choke loaded triode doesn't need HV over 300 V, so low max Uak of 6C4C (360 V) is not limitation if you want to drive STAX. That is my opinion. But I am not sure if I have understood you correctly (my English suffer, sorry).

Tubes are choke loaded and Uak=300 V, Ia= 30-40 mA.

That is the reason I am testing 4x6BG4 (6C4C) in my new project for STAX. It is doable, it can play loud enough with magic of DHT's. But work is still in progress.

Looks very hot and nice, give us some night shots, please

I was using moded 727 with 507 and it also worked very well. Thank Spritzer for this mod

I realized you are making very nice sounding oven Which schematic, from hundreds in this thread, is the right for your Megatron?

OMG, looks crazy Don't you think that eight EL34 with no holes around them are going to be too hot? Even when you put them on the top of the case there will be no air from bottom. I would worry about temp. of PCB inside the case, temp of capacitors etc ...

True. I got this amp for two weeks. I can always replace this trafo in the future. Thank you All for help and suggestions. P.S. Perfect reason to build my own amplifier

Yes, it is possible. Who knows what history is behind this amp.

Sorry, I wasn't clear. Every triode has two 33k resistors in series. 150 V is on one of them, that gives 150/33000 - more less 4,5 mA. Output is close to 0 V (flows around zero). I suspect, this is the way my amp should work. It is very strange to me but everything seems to be ok but temperature of trafo. I need to look around for another T1 and check it.

Measurements shows about 4,5 mA/triode (probing voltage drop on anode resistors = about 150 V). But I have discovered this time there was not +320 V but only +308 V. That amp drives me crazy ;-)

Thank you Spritzer, the schematic helps a lot Voltages in my T1 are very close to those from schematic. Schematic my T1 320 V 319 V 350 V 344 V 48 V 48 V I have no idea why this trafo is so hot, everything seems to be ok

Thank you for your interest, Kevin. After one hour of working I can read AC voltages: 251 V, 268 V and 6,25 V. I have no idea if it's right for T1. But I have SRM-006 schematic and there are very similar voltages: 250 V, 270 V, 6,3 V.

Yes, from Wiktor There are only 2 tubes. Trafo is set to 240 V. In my opinion discoloration and temperature doesn't look good. I have schematic from SRM-006 only, but I am not sure if it is the same or similar to T1 There is no hum or noise in headphones, amplifier seems to work good.

Hello Everyone This is my first post here. I have done some research about T1 troubles here and didn't find any topic about hot trafo. In my opinion this trafo is too hot but I don't have another SRM-T1 to check. I have removed tubes and then trafo is only warm - seems ok. Picture shows where I put temp sensor (blue wire). Did anyone had similar problems? P.S. I have just bought SR-Omega with Mk1 driver and SRM-T1 - amazing sound My previous system was SRM-727 and SR-507 and it wasn't so good.