Hi guys.
Recently i've buildt a stereo tube amp. But I can''t figure out why when I plug mobile phone or laptop sometimes there are no voices. Do you have any idea what could cause that? Thanks.
Recently i've buildt a stereo tube amp. But I can''t figure out why when I plug mobile phone or laptop sometimes there are no voices. Do you have any idea what could cause that? Thanks.
So you’re getting music but no voices? Are they totally gone or just lower? Make sure the speakers are in phase, plus to plus and minus to minus.
Most of the time they are really low but then for some reason the come again and then off again. It is recent build so new tube, new transformer.
Transformers have nothing to do with it. Try a different source of music the amp will not pass voices then stop passing them without changing the amp construction.
When I play like classical music and there are choruses they passes without problem, but when I play for example rock, they are very very low. I tried also cd player and it acts the same
Voice tracks are usually in the center. Are your speakers (or the secondaries of the output transformer) hooked up correctly? I did that once, where I reversed the polarity on one side, and everything sounded thin, especially the vocals.
Your plug is wired wrong. Taking the L and R "hots" without the common will cancel centered voices (solos; choirs are usually spread stereo).
An ohm meter may be helpful.
Phase reversal can be caused in various places.
Primary suspects are:
Primary suspects are:
- reversed OPT primariy or
- reversed secondary or
- swapped wires from OPT to spkr connectors or
- swapped wires in the spkr cable.
Sounds like you're only amplifying the difference between the two channels. I had that once in a phono preamp when I forgot a ground connection.
So I did one thing. I connected both rca hots to ground and connected one input to the rca common and it works. Any Idea why?😵
Huh? Sounds backwards. RCA hots to ground?
Shouldn't it be one (or both, depending on circuit) RCA negative to ground, red side to transformer output?
Sounds like what Miniwatt said:
"had that once in a phono preamp when I forgot a ground connection"
"had that once in a phono preamp when I forgot a ground connection"
Be aware that smart phone 3.5mm jacks are usually 4 wire and ground is the second ring, not the base sleeve connection. The sleeve is either video or microphone, and any switches for pause, forward, reverse, using different resistances. Using a 3-wire plug should short microphone to ground but using a 4 wire plug incorrectly could leave ground ~open. Also, Apple vs Android wiring is different so if your cable does not match the phone, it will not work properly.
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Although, as everyone has said, this is most likely a simple wiring issue (maybe even within your new amplifier), there is another possible cause. Modern digital sources can be stored as Dolby Digital with 5.1 etc. channels. These often have vocals mixed to the center channel, in classic movie format tradition. If your source is not outputting a 2-channel stereo compatible signal, you won't hear the center (dialog, vocals) channel, only the music bed (left and right fronts).
All good fortune,
Chris
All good fortune,
Chris
So I still can't figure it out. Only thing that I discivered is that when I short one signal input then I get proper sound but it is strange that when I short the one input I still have sound from both speakers