Hi,
I have been a member here since 2005 but always in the background learning as much as I could, mostly about speaker building. I have had a few vintage tube amps but I always turned on my Accuphase E-303 (which I no longer have). I kept haring about SE sound and I wanted to sample it. That brought me to the TSE.
I have a TSE board set up for type 45 tubes. I am using the Edcor XPWR131 power transformer Rknize designed (thank you by the way) and the GXSE15-8-5K output transfomer. I am using a Triad (tubelab suggested) choke in place of R4.
I started the initial checkout:
1/ no tubes
Filament 2-3v
B- 236v
B+ 0v
2/ 5AR4 installed
B+ 356v
B- 238v
3/ meters @ the grid of the output tubes to grd.
Adjust R12 and R23 to -115v and -116v
4/ install 5842's w/ meters @ coupling cap leads nearest 5842 to grd.
B+354
B- 238
Both meters read 91v. Adjusting the cathode pots R9 and R20 make no change.
I slowly brought up the voltage with a variac and the meters attached to the plates of the 5842 as described. I noticed the voltages @ the plates match the B+ to about 240v then the plate voltages drop as I increase the mains voltage to 120v. B+ is then 355v and the 5842 plate is 91v. I did stop when the mains voltage was at 60v, the B+ was 179v the 5842 plates were 178v and 179v. I adjusted R9 and R20 with no effect.
In my previous adventures it has always been some simple mistake on my part so I have put it aside twice and come back and checked my work but I haven't found anything yet.
Anything ideas?
I have been a member here since 2005 but always in the background learning as much as I could, mostly about speaker building. I have had a few vintage tube amps but I always turned on my Accuphase E-303 (which I no longer have). I kept haring about SE sound and I wanted to sample it. That brought me to the TSE.
I have a TSE board set up for type 45 tubes. I am using the Edcor XPWR131 power transformer Rknize designed (thank you by the way) and the GXSE15-8-5K output transfomer. I am using a Triad (tubelab suggested) choke in place of R4.
I started the initial checkout:
1/ no tubes
Filament 2-3v
B- 236v
B+ 0v
2/ 5AR4 installed
B+ 356v
B- 238v
3/ meters @ the grid of the output tubes to grd.
Adjust R12 and R23 to -115v and -116v
4/ install 5842's w/ meters @ coupling cap leads nearest 5842 to grd.
B+354
B- 238
Both meters read 91v. Adjusting the cathode pots R9 and R20 make no change.
I slowly brought up the voltage with a variac and the meters attached to the plates of the 5842 as described. I noticed the voltages @ the plates match the B+ to about 240v then the plate voltages drop as I increase the mains voltage to 120v. B+ is then 355v and the 5842 plate is 91v. I did stop when the mains voltage was at 60v, the B+ was 179v the 5842 plates were 178v and 179v. I adjusted R9 and R20 with no effect.
In my previous adventures it has always been some simple mistake on my part so I have put it aside twice and come back and checked my work but I haven't found anything yet.
Anything ideas?
Last edited:
Well, like I said, it's usually some mistake on my part. I looked over the board again and I had 4.7ohm CC resistors for R31 and R32, apparently thats what I ordered. I had some 2.2K CC resistors I installed but the problem still persists. I can adjust the voltage from about 88v to 95v but thats it. I can tell R6 and the 5AR4 are getting hot but I haven't left it on for more than a minute.
Any ideas will be appreciated but I'll keep checking my work.
Everett
Any ideas will be appreciated but I'll keep checking my work.
Everett
Do you have the jumper between DRV_B+ and B+ installed? It's around the mosfets and between the 4 pin sockets.
http://www.tubelab.com/AssemblyManualTubelabSE/FinalBoardAssy_TSE.htm
http://www.tubelab.com/AssemblyManualTubelabSE/FinalBoardAssy_TSE.htm
You can try different tubes, but I suspect there is a single problem, since both tubes act the same, maybe a wiring mistake that was made the same way on both tube circuits. Check the polarity of your capacitors on the back side of the board, seems an easy dyslexic type of error to make.
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