DIY Audio Projects Forum
http://diyaudioprojects.com/Forum/

5AR4 not turning on? bad tube or bad circuit?
http://diyaudioprojects.com/Forum/viewtopic.php?f=9&t=6429
Page 1 of 1

Author:  steverw [ 30 Dec 2018, 03:24 ]
Post subject:  5AR4 not turning on? bad tube or bad circuit?

modded dynaco st 70 with octal triodes. it is hard on rectifiers, a sign of failure is when they start making popping noises. the GZ34 i had been using was allowing noises through even during softstart. a new sovtech 5AR4 does not seem to come out of softstart. all the tubes are lit up, but no sound, not even hiss. I know the amp and inputs are ok because the old reg tube did provide power enough for sound, just with loud pops. With the new sovtek it is iust dead quiet, no sound. Could there be an issue with a component, or does it mean the new 5AR4 is bad? i dont want to trouble the 5AR4 seller with a doa return without confirming if this could be a system issue or loose wire. i did the build myself and can open it up if needed. any advice much appreciated.

Author:  Soundbrigade [ 31 Dec 2018, 11:46 ]
Post subject:  Re: 5AR4 not turning on? bad tube or bad circuit?

Is the 5AR4 really capable of supplying the required current? Just asking, as I don’t have the schematics.

Author:  Steavis [ 07 Jan 2019, 11:55 ]
Post subject:  Re: 5AR4 not turning on? bad tube or bad circuit?

Sounds to me there is more going on than just a rectifier issue alone. Is it a recent build and did it have these issues from the start? Did you check all the voltages and bias in the amp? Does the amp still 'work' when you put the old GZ34 back in place?

Page 1 of 1 All times are UTC - 6 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/