Ok, understood. I am trying to tie this together in my head. So as of the last time I checked, I have voltages within range with the exception of A1, 9, B1 and 19 as indicated in my post on 6/19. Moreover, the issue of no sound in right channel unless I turn the gain to the max. Would this short you see be causing this?
Completed sex kit: No sound from right channel
- Thread starter mpent
- Start date
Well, I finally got it working!!! Voltages and resistances all check out. The right channel issue was apparently a short in the gain. I think the reason why I thought I previously fixed this issue earlier in the build was because I had the SEX acting as a power amp with the gain all the way up with a preamp connected. Since removing the preamp and notwithstanding the tube that went bad, the issue was there all along. I insured not components were touching and double checked the wiring...resoldered a few joint and still no sound from right channel unless gain was set to max. Playing with the gain, I pushed it past the max gently and this seems to have corrected the issue. Not sure how really but I am getting good sound across the continuum of the gain. I hope I am good to go now. PB, thanks so much for bearing with me and for all your advice.
Michael
Michael
Hi all....so unfortunately I have to revive this thread. The sound from my right channel is dropping again. There seems to be a short somewhere and I am not certain how to address it. Again, the problem is rectified when I turn the gain all the way up to the max...sound form the effected channel re-appears and I can attentuate across the continuum yet after listening for extended periods, the sound will once again drop out after a period of time. Any advice? I am wondering if I could have a faulty volume pot? Is that possible?
Michael
Michael
Doc B. said:
Ok, so I heeded this suggestion but it did not solve the issue. Again, when I turn the gain to max, sound will appear from right channel and will maintain across the continuum thereafter for an unspecified period of time. If I listen for several hours, at some point the sound drops again from right channel.
Moreover, after completing Reduction build and hooking that to SEX and turntable, no sound whatsoever from right channel. Even if I turn the gain to max on SEX, no sound appears. I hooked the Reduction up to another power amp in a separate system and it worked great so I think the problem persists with the SEX.
I am really at a loss. Paul mentioned earlier in the thread that if there is a tiny level of hiss/hum with the gain all the way down in both speakers that the problem should be at the input or gain control. I performed this test again and yes, with gain all the way down i do hear hiss in both channels...performed this with headphones as well to confirm. Any suggestions??
Grainger49
New member
This sounds just like a bad solder joint. Do as Dan says and report back. You don't need to add a lot of solder, that just makes "solder blobs" which are bad joints. A tiny amount is fine.
Just heat each joint with the soldering iron on the tube pin or terminal and touching the component lead/wire. When it becomes liquid count to three and let it cool.
Just heat each joint with the soldering iron on the tube pin or terminal and touching the component lead/wire. When it becomes liquid count to three and let it cool.
Unfortunately I need to resurrect this thread. So after last post I went through and re-soldered every terminal and pin. It seemed to have fixed the issue but only for a time. Yesterday, I turned the amp on and again, no sound from right channel. If I turn the volume all the way up to max then I will get a very weak output from the right channel. Went through visual inspection again...and resistance/voltage checks. All resistances check out ok. All voltages check out ok except:
Terminal 9, 19: Fluctuating reading 4-6mV; Fluctuating reading 7-17mV...the readings just fluctuate back and forth variably between these two numbers for each terminal respectively
Pin A1, B1: Same issue as above: 6-8mV and 10-12 mV respectively.
Any ideas?
Mike
Terminal 9, 19: Fluctuating reading 4-6mV; Fluctuating reading 7-17mV...the readings just fluctuate back and forth variably between these two numbers for each terminal respectively
Pin A1, B1: Same issue as above: 6-8mV and 10-12 mV respectively.
Any ideas?
Mike
Hello Michael,
Can you try connecting the two middle lugs on the pot?
When you do this, do you get both channels, same as before, or other?
Can you try connecting the two middle lugs on the pot?
When you do this, do you get both channels, same as before, or other?
Temporarily solder the same piece of wire to each of them. (Or use a clip lead)
fullheadofnothing
Moderator
By shorting the two decks of the pot together, you have made your amp mono. Not the worst thing in the world, but you probably want it to be in stereo.
The purpose of this exercise was to determine where your problem is, and you have now proven that both channels of your amplifier work, but one channel is not getting signal. You have a bad solder joint or a short somewhere earlier in the signal path, either at the pot, or the RCA jack. Check your RCA jack closely to see if there is any solder bridging the pin to the barrel. It is also possible that the problem is in your source or the interconnect cables, but I assume you've already checked for that by swapping cables.
The purpose of this exercise was to determine where your problem is, and you have now proven that both channels of your amplifier work, but one channel is not getting signal. You have a bad solder joint or a short somewhere earlier in the signal path, either at the pot, or the RCA jack. Check your RCA jack closely to see if there is any solder bridging the pin to the barrel. It is also possible that the problem is in your source or the interconnect cables, but I assume you've already checked for that by swapping cables.
Grainger49
New member
Nope, you have mono Left channel now. Next you want to remove the wire/jumper.
But you have located the problem to before the volume control. This means the connection at the pot from the left channel and at the RCA jack. Touch up those two solder connections. Verify continuity with your meter set on ohms from the metal on the RCA jack to the metal on the right side of the pot where the red wire comes in.
Or your source is not feeding both channels. There are very few possibilities.
But you have located the problem to before the volume control. This means the connection at the pot from the left channel and at the RCA jack. Touch up those two solder connections. Verify continuity with your meter set on ohms from the metal on the RCA jack to the metal on the right side of the pot where the red wire comes in.
Or your source is not feeding both channels. There are very few possibilities.
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