I just upgraded to some higher efficiency speakers and started to notice a slight hiss when the volume is turned up all the way. The hiss starts at about the 12 O'clock point and increases until the volume is at maximum.
I've experimented with different electrical outlets, etc. but what I found is -
There is no hiss without the RCA attached.
If I attach the RCA cable to only the amp side, leaving other unattached, there is hiss.
If I attached the cables to the amp and DAC, without the DAC being turned on, there is no hiss.
Once I turn the DAC on the hiss returns.
I'm assuming this has something to do with the soldering and ground in the amp and I will probably take it apart this weekend but is there anything I should pay particular attention too? I really don't have a clear understanding of how the grounding and ground loops come about.
Thanks,
David
I've experimented with different electrical outlets, etc. but what I found is -
There is no hiss without the RCA attached.
If I attach the RCA cable to only the amp side, leaving other unattached, there is hiss.
If I attached the cables to the amp and DAC, without the DAC being turned on, there is no hiss.
Once I turn the DAC on the hiss returns.
I'm assuming this has something to do with the soldering and ground in the amp and I will probably take it apart this weekend but is there anything I should pay particular attention too? I really don't have a clear understanding of how the grounding and ground loops come about.
Thanks,
David
How loud is the hiss? Some hiss is normal. I have 92 dB efficient speakers and I usually listen at 9 o'clock volume and I can hear hiss if it put my ear up close to the tweeter. If it turned it to 12 o'clock the hiss can be hear from a few inches away. That being said I have had at lease 10 different amps with these speakers and all but 1 produced a hiss but it is not audible from the listening position.
Also have you tried another RCA cable?
Also have you tried another RCA cable?
Results were a bit worse with other spare RCA cables. Hiss at full volume is audible around 20cm from tweeter.
There is a very slight hiss without the RCA cables plugged in and that is what I am hoping to replicate The fact the the hiss is added when the cables are plugged in makes me think that something is wrong and it could be better.
I'd like to keep the volume at full and use my NOS DAC/computer to control the volume.
There is a very slight hiss without the RCA cables plugged in and that is what I am hoping to replicate The fact the the hiss is added when the cables are plugged in makes me think that something is wrong and it could be better.
I'd like to keep the volume at full and use my NOS DAC/computer to control the volume.
If it is audible at full volume from 20 cm that is pretty low. It is the same with mine. I also control volume with my dac since it is remote controlled. I am too lazy to get up to change the volume on the 8600. So I set the volume to 9 o'clock on the 8600 and I usually listen to music at 80-90 out of a 100 on my Auralic Vega G1. If I ran the 8600 at full volume and the dac at the lower volume I would be experiencing what you are too.
I have found that some inexpensive RCA cables introduce noise. Try some better inexpensive cables from Signal cable or Blue Jeans cable. I went with the “analogue two” from the first of those suggestions and am quite happy.
My 8600S is dead silent with volume turned all the way full. Speakers are highly efficient 104dB. Pretty amazing for a tube amp, never had one this quiet. I'm using Blue Jeans Cable LC-1 Low Capacitance. They're shielded, which is likely the difference since you say that it's quiet without cables.
I have my 8600s wired to ZuAudio mk3 omens which are 97 db and I have never ventured past 10 clock I have never heard hisses From my experience a hiss is a noisy tube. What happens if you move tubes or change them out completely?
I'm using DH Lab Silversonic, which are shielded. I tried other RCA cables to test for noise and they were worse.
My speakers are 105db so it is good to know that quiet at full volume is something that is possible. I need to find an old cd player lying around to see if that will produce noise or will be quiet.
The hiss is only really present at full volume. I can keep the volume at 2 O'clock and the amp is pretty quiet.
Right now, I only have this one set of tubes.
try taking a small metal can? and putting it over the 12ax7 and 12au7 tubes. those tubes can be extremely noisy if there is a lot of signals around like wifi routers and stuff. just a way to block the signals and see if its affecting your tubes. also might want to try another set of tubes to see if thats the problem, but then you are spending money trying to diagnose.
good luck figuring out what is wrong!
good luck figuring out what is wrong!