[David A Silva]

The QSHA arrived and is safely set up on my second rack. Oddly, it shares a shelf with a Parks Puffin - strange bedfellows, indeed.

I’m enjoying the music and am not doing any critical listening or analysis. Importantly, I don’t find anything wrong with how it sounds or functions (thank goodness). All I can say is this: with the OG HD650, it provides a pleasant, non-fatiguing experience with more than enough dynamics, detail, resolution, etc. to keep my toes tapping and to keep my mind on the music and off of analysis.

I predict you will appreciate it more once the tubes have settled in a bit. Congratulations, I hope you enjoy yours as much as I enjoy mine!

 

[luckybaer]

I'm listening to the 1987 pressing of "Abbey Road" - Denon DCD-1600NE > Gungnir MB > Quicksilver > DT-880 [OG].

Bass extension, macrodynamics, microdynamics... it is all there. Noise floor is very low - especially after I went direct from my DAC to the amp.

I bought a couple sets of tubes as backups. With prices going up, who knows how much these valves will cost if/when I actually need to replace the originals. I'm not engaging in tube rolling. Honest.

But I will try the new tubes, anyway. I doubt I'll notice anything. My ears aren't that great.

 

[ckhirnigs113]

From someone who has spent nearly as much on tubes as the cost of the amp itself, I suggest you try and stick with the stock tubes as long as you can. I think my fancy/expensive old tubes sound better of course, but ignorance is bliss, and the stock tubes sound great as well.

 

[luishi5000]

Depending on the day, I can hear the radio come through my QS - interestingly only on the left channel. It's very quiet when the volume knob is up (even when nothing is playing), but turning the knob almost all the way down makes the signal significantly louder to the point where I can hear it clear as day.

I just put 2.5" toroid ferrite cores on each end of the power cord - it worked! No more radio signal at all.

However I can still hear a very high pitch whining coming through at all times, I suspect it all of the 2.4ghz wi-fi signals around me. About to build a faraday cage around the amp and see if that fixes it.

Also, I have to turn my phone to airplane mode around the amp as it sounds like a woodpecker when it's periodically checking in with the towers - crazy!

 

[PointyFox]

Depending on the day, I can hear the radio come through my QS - interestingly only on the left channel. It's very quiet when the volume knob is up (even when nothing is playing), but turning the knob almost all the way down makes the signal significantly louder to the point where I can hear it clear as day.

I just put 2.5" toroid ferrite cores on each end of the power cord - it worked! No more radio signal at all.

However I can still hear a very high pitch whining coming through at all times, I suspect it all of the 2.4ghz wi-fi signals around me. About to build a faraday cage around the amp and see if that fixes it.

Also, I have to turn my phone to airplane mode around the amp as it sounds like a woodpecker when it's periodically checking in with the towers - crazy!

I somehow picked up what sounded like a SWAT team on my TV once. I also had an amplifier that would produce audible music with the headphones not plugged in.

 

[jonathan c]

Depending on the day, I can hear the radio come through my QS - interestingly only on the left channel. It's very quiet when the volume knob is up (even when nothing is playing), but turning the knob almost all the way down makes the signal significantly louder to the point where I can hear it clear as day.

I just put 2.5" toroid ferrite cores on each end of the power cord - it worked! No more radio signal at all.

However I can still hear a very high pitch whining coming through at all times, I suspect it all of the 2.4ghz wi-fi signals around me. About to build a faraday cage around the amp and see if that fixes it.

Also, I have to turn my phone to airplane mode around the amp as it sounds like a woodpecker when it's periodically checking in with the towers - crazy!

How close do you have QSA / audio gear to non-audio / computer gear? Is each type plugged into separate wall sockets / circuits?

 

[gefski]

How close do you have QSA / audio gear to non-audio / computer gear? Is each type plugged into separate wall sockets / circuits?

I think a minimalist amp like the QS has very little “protection”, so really benefits from isolated outlets. I can only get noise from mine with no music signal and volume control at 3/4+, which would be ear bleeding with music using most cans. The only cheesy device in the room is the Dell monitor, not plugged into either of my isolated outlets.

 

[luishi5000]

How close do you have QSA / audio gear to non-audio / computer gear? Is each type plugged into separate wall sockets / circuits?

The QS is on its own wall socket but not circuit, which has a lot of computer equipment and I suspect could be the culprit of the noise.

I built a faraday cage to test the QS inside of, and it did not work for removing the high frequency noise I'm getting, so I suspect that noise is electrical noise in the power and not being picked up over the air as I first thought.

Putting it on a separate circuit is not possible for me, are there any devices which isolate audio gear? Do they work?

I found this upon first search:

https://www.pcnation.com/web/detail...th-surge-120v-4-outlet-6ft-cord-hg-taa-is1000

 

[luishi5000]

After lots of troubleshooting, I found the high frequency noise is being generated by one of my 84 Gold Lions's.

I suppose I have to buy a matched pair instead of just replacing the one?

Is the potential difference in tubes manifested in output volume?

 

[gefski]

After lots of troubleshooting, I found the high frequency noise is being generated by one of my 84 Gold Lions's.

I suppose I have to buy a matched pair instead of just replacing the one?

Is the potential difference in tubes manifested in output volume?

My experience has been that matched pairs, quads, etc. is important with multiple tubes in the same channel, not noticeable in L and R. However, if you buy a pair now, you’ll have a spare. I’m very happy with old stock Polam EL84s in my QS not matched, but all test very good on my little Sencore.

 

[KC2020]

After lots of troubleshooting, I found the high frequency noise is being generated by one of my 84 Gold Lions's.

I suppose I have to buy a matched pair instead of just replacing the one?

Is the potential difference in tubes manifested in output volume?

So your tube had developed a harmonic, in this case at a high frequency. Did you try removing the tube and re-seating it ? A bit of oxidation on one or more of the pins or dust accumulation on the tube socket can cause tube noise. I new a gentleman here in Santa Barbara who was a very accomplished tube Amp Designer. On more than one occasion he told me that the most common issue with new tubes that were returned was the pins not being clean or properly seated.

I'm still running the original Sovtek tubes in my Quicksilver. I called them a couple of weeks ago and asked them to send me a set of whatever they're using now. They sent me a complete set of JJs. I'll play them some time soon and I'm sure they'll sound great. I just want to have a spare set on hand.

 

[luishi5000]

So your tube had developed a harmonic, in this case at a high frequency. Did you try removing the tube and re-seating it ? A bit of oxidation on one or more of the pins or dust accumulation on the tube socket can cause tube noise. I new a gentleman here in Santa Barbara who was a very accomplished tube Amp Designer. On more than one occasion he told me that the most common issue with new tubes that were returned was the pins not being clean or properly seated.

I'm still running the original Sovtek tubes in my Quicksilver. I called them a couple of weeks ago and asked them to send me a set of whatever they're using now. They sent me a complete set of JJs. I'll play them some time soon and I'm sure they'll sound great. I just want to have a spare set on hand.

Yes I swapped it back and fourth multiple times and the high frequency noise followed each time. I ordered a new pair of Gold Lion's and will see if they do the trick. I don't know if I should be expecting dead silent operation out of a tube amp to begin with as this is my first one. In fact the original JJ's have a small bit of noise as well but it is different in nature.

Interested to hear what you think of the new set!

 

[luishi5000]

The new 84 Gold Lions's are quiet as can be after warming up. Interestingly they also have a different overall sound compared to the ones I got 6 months ago, the highs are much smoother and I don't have to EQ them down anymore.

My final pet peeve with the QS is the blaring blue LED, it blinding to look at at night and looks "digital" on an otherwise analogue device. I have the same size LED in amber that I'd love to swap as it would match the same color as the glowing tubes, however I don't want to void the warranty. Maybe in 2 years after it expires....


Edit: I just noticed the QS website says all their amps have an input sensitivity of 1 - 1.5v, yet the DAC I've been running outputs at 2v! It has always sounded fine but I suppose I should turn it down if that's accurate.

 

[ckhirnigs113]

Edit: I just noticed the QS website says all their amps have an input sensitivity of 1 - 1.5v, yet the DAC I've been running outputs at 2v! It has always sounded fine but I suppose I should turn it down if that's accurate.

That's strange! Isn't the standard output for most DACs 2V?

 

[luishi5000]

That's strange! Isn't the standard output for most DACs 2V?

It sure is, I can't even turn down my DAC after all; however I've never heard clipping so it may not be clipping the input stage.