[YtseJamer]

Call me crazy, but I still don't feel the urge to change the stock tubes on my QS.

 

[LarsMan]

Call me crazy, but I still don't feel the urge to change the stock tubes on my QS.

I won't call you crazy! But one nice thing about that amp is that upgraded tubes are not too expensive; I contacted Brent Jessee and asked him for recommendations, which he did and I bought, and there was a noticeable improvement. But unless you're doing A/B comparisons, you should be fine with the stock tubes...

 

[YtseJamer]

I won't call you crazy! But one nice thing about that amp is that upgraded tubes are not too expensive; I contacted Brent Jessee and asked him for recommendations, which he did and I bought, and there was a noticeable improvement. But unless you're doing A/B comparisons, you should be fine with the stock tubes...

Good point. For now I'm very happy with the sound of my setup, but I will probably try different tubes eventually.

 

[gonintendo]

I won't call you crazy! But one nice thing about that amp is that upgraded tubes are not too expensive; I contacted Brent Jessee and asked him for recommendations, which he did and I bought, and there was a noticeable improvement. But unless you're doing A/B comparisons, you should be fine with the stock tubes...

Would you mind sharing the recommendations?

 

[Vonx]

I've spent a few months with the QS HPA now and would like to leave a review. Test chain and favorite current configuration:

Pi2AES via bnc> Bifrost 2 > QS HPA (baldwin/matsushita 12au7, 60's hammond amperex el84) > HD6XX / HD800SDR

In short, the QS HPA is an very well made, point-to-point wired, very well priced and great sounding amplifier that has almost limitless adaptability and capabilities and can scale with a few small and non-expensive (relatively speaking) tweaks. It does some things amazingly well (stage, extension with the right tubes, clarity with the right tubes, mids presence with the right tubes) and has a few small drawbacks (mostly power/gain related) that can mostly be navigated around (with correct hp pairing or pre usage).

A pros/cons list can say a lot in fewer words, so here's one:

Pros:
- Huge, expansive stage can range from medium/large to limitlessly open sounding depending on tubes.
- Great width, good depth.
- Very good stock clarity, which can be significantly improved (and also harmed) by tube choice
- Can have great bass punch and extension, but tube dependent
- Can have great air and treble, also tube dependent
- Can be tuned to sound wet or dry, midcentric or v shaped depending on tubes

Cons:
- High Power/Gain and lack of gain switch limits the amount of headphones that can be used significantly, unless you attenuate with a pre (yes, do this) or digitally (don't do this)
- Stock pot (at least on my unit) really holds it back to my ears (sounds rather underwhelming under 10 o'clock, and not just due channel matching, sounds dynamically compressed and stage/air compressed under 10, and continues to get better until about 12 where it stabilizes). Without a pre, must listen loud to get what its capable of.
- Stock tubes and tube sockets are passible but underwhelming, but make sense as a place to cut for the price point

As can be gleaned from the pros/cons list, the amp is very adaptable and scalable in both wet/dryness and FR just by tube swapping, and the gain/pot issues can be mitigated with a good passive/active pre (or just by headphone choice that gives you more pot room). The differences in tubes is not subtle to me, at all. Not far off from the delta of switching tube amps or dacs. Obviously this is also dependent on how resolving the rest of your chain is.

Tube experiences:
After my tube adjustments, I have a setup that sounds balanced and well extended with an upper mids push (matsushita 12au7) that I love with both HD6XX and HD800SDR (says a lot), or lusher/wetter/n-shaped response with even more enhanced tonal thickness but slight truncation of air (RCA black plate 12AT7). I switch between these depending on the kind of sound I prefer at that time.

In the current tube configuration (matsushita 12au7/60s amperex el84), I almost can't fault it. Before rolling the right tubes, I loved the boost in technicalities and stage size over my Sunrise 3, but couldn't quite dial the euphony and connection in the mids/realism that I wanted that connected me closer to the music. The combo I currently have gives me everything (stage, euphony, clarity, heft, extension, presence, mid connection) all in one with essentially no downsides aside from occasional upper mids fatigue and slight bass slowness on the wrong recording (rare, but such is the best case scenario of tube tradeoffs for me).

Brent Jesse sells butt ugly RCA 12AT7's for around $40 matched which is a pretty good deal, and hammond and other various el84 organ pulls can be found on ebay for pretty cheap if you are willing to take a small gamble on measured but UOS (used old stock). Brent also sells those, but the decent el84s get pricey there and elsewhere especially when "new" old stock.

The stock JJ el84's are really quite good, and dirt cheap and available, and make a great budget pairing with the RCA 12AT7's in particular. The Matsushitas need the extra air, naturalness, and heft that the hammond amperex el84's provide, but once given, make my favorite overall pairing and accentuate the strengths of stock, bring the mids forward, whilst reducing weaknesses. The stock chinese 12ax7's... are passable at best and really just need to be replaced IMO, they don't truncate quality too bad but they do hold the amp back a lot of you are trying to achieve any sense of realism/naturalness/ease.

Summary:
I'm really happy to have a built-to-last, quality, super modifiable (both physically and sound profile wise), super scalable amp that exists for not-ridiculous prices. I can change the sound so much on mood that I really could not care less about further movements up-tree to super TOTL tier, because I get all the technicalities and sound profiles I could want in one. I'd still like to try a few changes to the caps and pot just to see how far it can go, like sticking a goldpoint pre in front of it (currently have a Nano Patch+ or just crank it with Senns to get past the low volume compression) and ideally rip the pot out of the circuit, but regardless, right where it is, I'm satisfied.

If you don't want to use a pre or touch digital attenuation, you do limit yourself a bit due to the pot which sucks the life out of the amp at low volumes (imo). Even with Senns, you have to crank them to get the QS to really sing and show what its capable of if you aren't using any good quality attenuation upstream. Super efficient dynamics are a no go (ad700x/2000x can't get past 9 without bleeding ears and sounding compressed, esx900/th900 also too efficient). However, if you know its capabilities and drawbacks and navigate correctly, it could be your last amp (probably mine )

Very, very happy with it! Thanks Quicksilver!

 

[joseG86]

Is this available in 230v? I wish I could try this amp...

 

[Deleeh]

Yes you can order them in 230 v version.

 

[LarsMan]

Would you mind sharing the recommendations?

I'm sorry gonintendo - I just now saw your question. Here is what Brent told me:

Thanks for your email. At the $100 per pair price, I would recommend you try the GE long plate 12AX7 tubes. They should deliver the tone you are looking for. You could just replace those for now. If you want to do the EL84 tubes as well, I suggest the RCA USA made 6BQ5. They are $109 per pair.

This is from February of last year, so some of these recommendations may have changed, depending on his inventory...

 

[LarsMan]

I've spent a few months with the QS HPA now and would like to leave a review. Test chain and favorite current configuration:

Pi2AES via bnc> Bifrost 2 > QS HPA (baldwin/matsushita 12au7, 60's hammond amperex el84) > HD6XX / HD800SDR



In short, the QS HPA is an very well made, point-to-point wired, very well priced and great sounding amplifier that has almost limitless adaptability and capabilities and can scale with a few small and non-expensive (relatively speaking) tweaks. It does some things amazingly well (stage, extension with the right tubes, clarity with the right tubes, mids presence with the right tubes) and has a few small drawbacks (mostly power/gain related) that can mostly be navigated around (with correct hp pairing or pre usage).

A pros/cons list can say a lot in fewer words, so here's one:

Pros:
- Huge, expansive stage can range from medium/large to limitlessly open sounding depending on tubes.
- Great width, good depth.
- Very good stock clarity, which can be significantly improved (and also harmed) by tube choice
- Can have great bass punch and extension, but tube dependent
- Can have great air and treble, also tube dependent
- Can be tuned to sound wet or dry, midcentric or v shaped depending on tubes

Cons:
- High Power/Gain and lack of gain switch limits the amount of headphones that can be used significantly, unless you attenuate with a pre (yes, do this) or digitally (don't do this)
- Stock pot (at least on my unit) really holds it back to my ears (sounds rather underwhelming under 10 o'clock, and not just due channel matching, sounds dynamically compressed and stage/air compressed under 10, and continues to get better until about 12 where it stabilizes). Without a pre, must listen loud to get what its capable of.
- Stock tubes and tube sockets are passible but underwhelming, but make sense as a place to cut for the price point

As can be gleaned from the pros/cons list, the amp is very adaptable and scalable in both wet/dryness and FR just by tube swapping, and the gain/pot issues can be mitigated with a good passive/active pre (or just by headphone choice that gives you more pot room). The differences in tubes is not subtle to me, at all. Not far off from the delta of switching tube amps or dacs. Obviously this is also dependent on how resolving the rest of your chain is.

Tube experiences:
After my tube adjustments, I have a setup that sounds balanced and well extended with an upper mids push (matsushita 12au7) that I love with both HD6XX and HD800SDR (says a lot), or lusher/wetter/n-shaped response with even more enhanced tonal thickness but slight truncation of air (RCA black plate 12AT7). I switch between these depending on the kind of sound I prefer at that time.

In the current tube configuration (matsushita 12au7/60s amperex el84), I almost can't fault it. Before rolling the right tubes, I loved the boost in technicalities and stage size over my Sunrise 3, but couldn't quite dial the euphony and connection in the mids/realism that I wanted that connected me closer to the music. The combo I currently have gives me everything (stage, euphony, clarity, heft, extension, presence, mid connection) all in one with essentially no downsides aside from occasional upper mids fatigue and slight bass slowness on the wrong recording (rare, but such is the best case scenario of tube tradeoffs for me).

Brent Jesse sells butt ugly RCA 12AT7's for around $40 matched which is a pretty good deal, and hammond and other various el84 organ pulls can be found on ebay for pretty cheap if you are willing to take a small gamble on measured but UOS (used old stock). Brent also sells those, but the decent el84s get pricey there and elsewhere especially when "new" old stock.

The stock JJ el84's are really quite good, and dirt cheap and available, and make a great budget pairing with the RCA 12AT7's in particular. The Matsushitas need the extra air, naturalness, and heft that the hammond amperex el84's provide, but once given, make my favorite overall pairing and accentuate the strengths of stock, bring the mids forward, whilst reducing weaknesses. The stock chinese 12ax7's... are passable at best and really just need to be replaced IMO, they don't truncate quality too bad but they do hold the amp back a lot of you are trying to achieve any sense of realism/naturalness/ease.

Summary:
I'm really happy to have a built-to-last, quality, super modifiable (both physically and sound profile wise), super scalable amp that exists for not-ridiculous prices. I can change the sound so much on mood that I really could not care less about further movements up-tree to super TOTL tier, because I get all the technicalities and sound profiles I could want in one. I'd still like to try a few changes to the caps and pot just to see how far it can go, like sticking a goldpoint pre in front of it (currently have a Nano Patch+ or just crank it with Senns to get past the low volume compression) and ideally rip the pot out of the circuit, but regardless, right where it is, I'm satisfied.

If you don't want to use a pre or touch digital attenuation, you do limit yourself a bit due to the pot which sucks the life out of the amp at low volumes (imo). Even with Senns, you have to crank them to get the QS to really sing and show what its capable of if you aren't using any good quality attenuation upstream. Super efficient dynamics are a no go (ad700x/2000x can't get past 9 without bleeding ears and sounding compressed, esx900/th900 also too efficient). However, if you know its capabilities and drawbacks and navigate correctly, it could be your last amp (probably mine )

Very, very happy with it! Thanks Quicksilver!

Great, detailed review - thanks!!!!! Interesting about your thoughts on gain and power. When I had mine, I used it with Utopia (GREAT pairing for 3-D, holography, and moving through space!), ZMF VO's and a few others, and it would have blown my eardrums right out even with the volume at around 12:00. Back then, I was using an RME for a DAC. I hope your review encourages more folks to check with Mike about his excellent amp....

 

[Vonx]

Great, detailed review - thanks!!!!! Interesting about your thoughts on gain and power. When I had mine, I used it with Utopia (GREAT pairing for 3-D, holography, and moving through space!), ZMF VO's and a few others, and it would have blown my eardrums right out even with the volume at around 12:00. Back then, I was using an RME for a DAC. I hope your review encourages more folks to check with Mike about his excellent amp....

No problem - it's a very versatile amp, and I think the OI at 2 ohm is right in the sweet spot for a ton of headphones. Low enough for efficient dynamics, high enough for high impedance Senns to sound good. I do wonder what the design goal was with the amount of gain that it has.. high impedance senns are usually on the harder side to drive and this thing gets them ear piercingly loud at 11 o'clock. Planars maybe? The high gain definitely doesn't harm the amp but it does force you to use less of the pot range, where I feel it dynamically compresses slightly. I've been looking to get a nice pre anyway so I guess this is a good excuse

 

[joseG86]

Yes you can order them in 230 v version.

Just got response from Mike, he doesn't have 230v...... D A M N I T !

 

[Willy 2 Streams]

Yeah, Mike Sanders makes keeper gear. I've had an (original) Quicksilver full function preamp that was made around 1982. Its (all tube, natch) phono stage still betters anything I've had in my system. But why SO much GAIN? The line stage in that pre amp was all but unusable, with 30db of gain, I couldn't get past 9 o' clock on the dual volume pots. I finally ended up bypassing it, and listening to the phono stage via the tape outs.
If this QS headphone amp had pre amp out RCA's, and a bit less gain, I'd be all over it!

 

[LarsMan]

Yeah, Mike Sanders makes keeper gear. I've had an (original) Quicksilver full function preamp that was made around 1982. Its (all tube, natch) phono stage still betters anything I've had in my system. But why SO much GAIN? The line stage in that pre amp was all but unusable, with 30db of gain, I couldn't get past 9 o' clock on the dual volume pots. I finally ended up bypassing it, and listening to the phono stage via the tape outs.
If this QS headphone amp had pre amp out RCA's, and a bit less gain, I'd be all over it!

As far as inputs, outputs, and connections, it quite literally cannot get any simpler. On/Off, volume, signal in, and headphone jack, and there ya go! But the quality of both the build and the sound is superb.....

 

[joseG86]

I got kind of depressed when Mike told me that the QS doesn't come in 230v.... I wonder if anyone would recommend a tube amp with similar characteristics, my last tube amp was the Elise MKII and I'd like to get something better...

Thank you so much

 

[dw8083]

If it was a ground loop, wouldn't the hum be there all the time. Not just when the graphics card kicks on? PCs powered on still pull 200-250w.

Just wait until you one day use a PS Audio Stellar Power Regenerator. CLEAN-CLEAN AC power. The noise floor drops with everything plugged into it. I run my computer on wall AC and hifi gear through the Regenerator. Sound improvement was obvious. # hifi buddies can over to check it out with some blind testing. All 3 count one within the next 2 weeks. Also help to have a hospital grade AC wall outlet for under $20 rather than the tired .97 cent one likely in the wall.

I'm also fortunate as my Holo Spring 3 KTE DAC has galvanic isolation for USB as well. The computer is completely electronically isolated from the hifi gear.