[YtseJamer]

That is pretty much a combination that led me to appreciate more music.
Tom Petty springs to mind.

I must say that this amp has made me fall in love again with all my dynamic headphones. I never knew that my Sennheisers and Grados could sound this incredible.

 

[geoffalter11]

I must say that this amp has made me fall in love again with all my dynamic headphones. I never knew that my Sennheisers and Grados could sound this incredible.

So happy to hear. I think the HP8 is the best unknown tube amp going. I wish it got the attention of the big boys as it is every bit as good. David Shaw is a genius who made a seriously amazing amp. I bet the 205D sounds the part too. I have stayed away just because those are really hard tubes to find as they are one of the oldest tube designs and finding high quality NOS 205Ds is not an easy task. Plus, I don't think it is needed. The HP8 doesn't leave me wanting.

 

[YtseJamer]

So happy to hear. I think the HP8 is the best unknown tube amp going. I wish it got the attention of the big boys as it is every bit as good. David Shaw is a genius who made a seriously amazing amp. I bet the 205D sounds the part too. I have stayed away just because those are really hard tubes to find as they are one of the oldest tube designs and finding high quality NOS 205Ds is not an easy task. Plus, I don't think it is needed. The HP8 doesn't leave me wanting.

Interesting, I had no idea they had an additional headphone amplifier. I'm currently listening to my Grado Hemp, and I'm absolutely blown away by their performance when paired with this amplifier. The sound quality is simply remarkable and it feels like I'm listening to a pair of headphones worth $2000.

 

[geoffalter11]

Interesting, I had no idea they had an additional headphone amplifier. I'm currently listening to my Grado Hemp, and I'm absolutely blown away by their performance when paired with this amplifier. The sound quality is simply remarkable and it feels like I'm listening to a pair of headphones worth $2000.

That is music to my ears. So happy for you. I agree, this amp is just incredible with dynamics. It is really good with planars too, but it is my dynamic secret sauce amp. It makes ZMF sing. It makes my TH-900s sing and is incredible with my P-SE. The only headphone I prefer on my SS amp is my Code X which is super power hungry. It sounds great on the HP8, but it is meant for my CFA3.

 

[ckhirnigs113]

What’s the price range in general for good vintage 6SN7s? I want to make sure the good stuff isn’t astonomical before I consider taking the plunge. I have a nice supply of 12AX7s, mostly Amperex to be honest, but enough to play around with.

 

[jonathan c]

What’s the price range in general for good vintage 6SN7s?** I want to make sure the good stuff isn’t astonomical before I consider taking the plunge. I have a nice supply of 12AX7s, mostly Amperex to be honest, but enough to play around with.

** per pair: $80 (Sylvania 6SN7GT) to $550 (CBS/Hytron 5692) …

 

[geoffalter11]

What’s the price range in general for good vintage 6SN7s? I want to make sure the good stuff isn’t astonomical before I consider taking the plunge. I have a nice supply of 12AX7s, mostly Amperex to be honest, but enough to play around with.

$125-$250 depending. I have paid around $200 for my best 6SN7s as a matched pair. Some for less one or two a bit more but most are around that price.

The amp works really well with 12AT7s as well. They run 50% less than 12AX7s for same quality. Sometimes less.

 

[geoffalter11]

A few 6SN7s to consider if you get this amp...

Ken Rad VT-231
Raytheon VT-231
RCA Grey Glass
Raytheon 6SN7GT (1950s)
RCA 6SN7GTB Narrow Gaps (1959-1961)
Any RCA 6SN7GT or GTB from the 1950s
Sylvania Brown Base 6SN7WTA or GTBs (1950s)
Westinghouse Golds 6SN7GTs (1950s)
Tung Sol Brown Base 6SN7GTB or GT Military Issue (1950s)
The RCA 5692s or CBS Hytron 5692s (These are more than I will pay)
The Hytron Military Issue 6SN7GTB (late 40s early 50s)

There are so many good 6SN7s ranging from $125-$250. I don't think you need to spend more than that. The holy grail 5692s or the Tung Sol Black Beauties will run you 2-3x as much. I set my limit right around $200 for a matched pair, but prefer to find stuff in the $150 range. I like the hunt so I am constantly looking and pull the trigger when I find something that I can't pass up. I mostly look on eBay with sellers I trust. Happy to send you the sellers I use... @jonathan c knows way more about this stuff than I. Almost everything I know has come down from him.

 

[ckhirnigs113]

This is great info! Thanks for a the useful tips. I had a nice listening session with my Quicksilver tonight, so I think I’ll just keep my eyes peeled for a used HP8 Signature to pop up for sale (though that’s pretty unlikely). I can’t swing for a new one unless I sell the Quicksilver or my Auteur, and I don’t think I’m ready to sell either one yet.

 

[geoffalter11]

This is great info! Thanks for a the useful tips. I had a nice listening session with my Quicksilver tonight, so I think I’ll just keep my eyes peeled for a used HP8 Signature to pop up for sale (though that’s pretty unlikely). I can’t swing for a new one unless I sell the Quicksilver or my Auteur, and I don’t think I’m ready to sell either one yet.

Best of luck finding one used. I hope you find one. I can't remember the last time I saw one for sale, but I hope you do! I have the same issue, just not ready to let my Auteur go. Even though it gets the least amount of head time... When it does get time, I love it!

 

[mudguardiain]

Recently picked up a signature version of the HP8 with shuguang Black Treasure tubes, not sure how these compare with some of the NOS tubes mentioned as this is my first tube amp, appreciate any feedback if anyone has any comparisons. Been very impressed with the amp so far, decided to move my Burson Soloist on as it was not such a good match with my Hifiman V2 stealths. The HP8 controls the brighter signature well, keen to try some ZMF phones as a comparison.

 

[geoffalter11]

Recently picked up a signature version of the HP8 with shuguang Black Treasure tubes, not sure how these compare with some of the NOS tubes mentioned as this is my first tube amp, appreciate any feedback if anyone has any comparisons. Been very impressed with the amp so far, decided to move my Burson Soloist on as it was not such a good match with my Hifiman V2 stealths. The HP8 controls the brighter signature well, keen to try some ZMF phones as a comparison.

I haven't tried the Suaguang Black Treasures, so can't speak to that. I have tried a Burson Conductor 3XP, but not the Soloist. I found the new Burson sound before they came out with the GT line to be a bit bright and not their normal super musical house sound of their older lines. I think the GT line fixed a bit of that, but in no way would I say that Burson's amps are in the same ballpark as the Icon HP8. It is like asking someone if they prefer Fenway or Yankee Stadium. Two different logical planes, in my opinion. Completely different design. topology and signature.

I can say that the HP8 and ZMF is a match made in heaven. You can use any of the impedance settings with great success. I use the high impedance setting for my AO and OG and the low impedance setting for the AC as it tightens up the bass and gives a more integrated whole. The HP8 is extremely flexible with sufficient gain and will get any of your headphones loud enough and then you use the impedance matching to get the best driver control. Tube rolling is a bonus and affects the sound by about 8-10% in my experience. About the same as the tolerances in the NOS tubes. More flavor than SQ. Bottom line, it is a special amp with incredible sound and function.

 

[JonT]

Recently picked up a signature version of the HP8 with shuguang Black Treasure tubes, not sure how these compare with some of the NOS tubes mentioned as this is my first tube amp, appreciate any feedback if anyone has any comparisons. Been very impressed with the amp so far, decided to move my Burson Soloist on as it was not such a good match with my Hifiman V2 stealths. The HP8 controls the brighter signature well, keen to try some ZMF phones as a comparison.

I also had the signature edition supplied with Shuguang Black Treasure CV181s. I enjoyed the sound stock. Around two years in a tube went crackly. When I discussed tube rolling with David Shaw he was quite adamant that the HP8 circuit design as whole is responsible for the sound and that swapping in-spec tubes would have little sonic effect. I replaced the Black Treasures with Psvane CV181-T MkIIs - so another made in China production tube - and the sonic difference was not subtle at all! I say this with all respect to Mr Shaw. (In this case, I did not care for the change either - but when I swapped out the stock EH 12AX7 for NOS Brimar 'Red' the sonic signature re-balanced favourably). On this basis, I think rolling can make substantial changes and @jonathan c and @geoffalter11 have a wealth of experience with NOS kindly shared with us all in this thread. Enjoy!

 

[jonathan c]

Two additions to @geoffalter11 ‘s comments: the Icon Audio HP8 Signature is electrically / electronically quiet when switched on; and HP8 is beautifully built.

 

[geoffalter11]

I also had the signature edition supplied with Shuguang Black Treasure CV181s. I enjoyed the sound stock. Around two years in a tube went crackly. When I discussed tube rolling with David Shaw he was quite adamant that the HP8 circuit design as whole is responsible for the sound and that swapping in-spec tubes would have little sonic effect. I replaced the Black Treasures with Psvane CV181-T MkIIs - so another made in China production tube - and the sonic difference was not subtle at all! I say this with all respect to Mr Shaw. (In this case, I did not care for the change either - but when I swapped out the stock EH 12AX7 for NOS Brimar 'Red' the sonic signature re-balanced favourably). On this basis, I think rolling can make substantial changes and @jonathan c and @geoffalter11 have a wealth of experience with NOS kindly shared with us all in this thread. Enjoy!

Thanks @JonT . I have had those same conversations with David Shaw. First, he told me that we would hear flavor differences up to the tolerances of the tubes. Which is 10%. Then he told me he couldn't hear any difference with tube rolling. I agree with what is written above, there are differences and although David might be protecting his branded tubes, moving to the right compliment of NOS tubes can really make a wonderful difference with the amp. You don't need to break the bank on tubes. One of the best ways to not break the bank is to switch from 12AX7 to 12AT7 in the driver slot. The 12AT7 NOS tubes are exponentially less money than their 12AX7 counterpart and they are also 40% less gain which gives you more volume play and better dynamics. Something I learned from @jonathan c . In addition, you can find wonderful 6SN7s online for under $200 for a matched pair. You just have to hunt a bit and make sure you are using a reputable seller who provides the testing info. Just saying it is NOS isn't enough. Seeing the test figures is very important to know you are getting a true NOS tube.