[Pharmaboy]

Is yours the “SE” version with factory cap upgrade ?

Yes & no. The SE version has several things the stock version does not: 2 David Shaw white ceramic CV181 (6SN7) output tubes, 1 Gold pin 12AX7 input tube and Mundorf coupling capacitors. The stock unit has brown-bottom Shaw CV181s, a JJ input tube, and standard coupling caps (I don't know what brand).

I rolled NOS tubes in all 3 tube positions anyway, so that doesn't matter to me. The previous owner had an electronics tech change the coupling caps to Mundorfs.

 

[The Jester]

Only an hour here and there so far,
12AX7 Is an EH gold which I don’t mind, tried both those and Gold Lion 6992’s in my CJ preamp and slightly preferred the EH ...
2021 here already so Happy New Year and a quick photo ....

Had mine a while now and still no urge to go tube rolling ….. yet … when the prices return to sane levels I might try a Gold Lion 12AX7
Nice you already have the upgraded Mundorf caps before some tube experimenting …

 

[Pharmaboy]

Had mine a while now and still no urge to go tube rolling ….. yet … when the prices return to sane levels I might try a Gold Lion 12AX7
Nice you already have the upgraded Mundorf caps before some tube experimenting …

The driver tube that came with mine is a Gold Lion 12AX7 the previous owner bought. It's a pleasant tube, for sure.

I'm discovering that so much of the HP8's excellent sound comes from the driver. In the next day or two I'll try a Brimar NOS CV455, a pair of which I've been burning in (w/6922-to-12AT7 adapters in my Woo WA3 OTL amp). Those CV455s are providing the most dramatic sonic makeover I could have imagined for the WA3. If the CV455 tube does for the HP8 anything like what it's doing for the WA3, I'll be one happy fellow.

Best part: you can get a CV455 for a little over $50 US, not much more than what the Gold Lion costs.

(to be continued)

 

[jonathan c]

The driver tube that came with mine is a Gold Lion 12AX7 the previous owner bought. It's a pleasant tube, for sure.

I'm discovering that so much of the HP8's excellent sound comes from the driver. In the next day or two I'll try a Brimar NOS CV455, a pair of which I've been burning in (w/6922-to-12AT7 adapters in my Woo WA3 OTL amp). Those CV455s are providing the most dramatic sonic makeover I could have imagined for the WA3. If the CV455 tube does for the HP8 anything like what it's doing for the WA3, I'll be one happy fellow.***

Best part: you can get a CV455 for a little over $50 US, not much more than what the Gold Lion costs.

(to be continued)

*** ask @geoffalter11 …

 

[JonT]

Had mine a while now and still no urge to go tube rolling ….. yet … when the prices return to sane levels I might try a Gold Lion 12AX7
Nice you already have the upgraded Mundorf caps before some tube experimenting …

Your mileage may vary, but when I swapped out the stock EH Gold Pin 12AX7 for a Gold Lion 12AX7 to my ears - inside HD800S - the whole feel, frequency response, and dynamics took a dramatic turn for the worse. In particular, the low end evaporated (not a helpful outcome for HD800S) and the midband became extremely thin. Up until that point, I'd prized the HP8 for the way it had added such body and timbre whilst retaining inner detail and dynamics. After living with the Gold Lion for a few listening sessions, the EH went back into V1 and the problem was resolved.

 

[JonT]

It says right in the Icon Audio manual's "Specifications and Features" page:

"• 1x ECC83/12AX7 first stage valve​

• Or use ECC81/12AT7 compatible for lower gain"​

I doubt Icon Audio would say this if an 12AT7 driver could harm the circuit.

After playing around with a couple 12AX7s to start with (one was a very good NOS Telefunken), I went to 12AT7s to drop the gain a bit (I have system gain issues to start with).

It's very subtle, but I think 12AT7s bring out a little more finesse, dynamics, and space than even great 12AX7s. I'm playing around with several top NOS 12AT7s (right now it's the 1056 Brimar CV4033), and the sound just keeps getting better.

Thanks @Pharmaboy - my bad for not re-checking the manual!

(and quite a kooky manual at that! - digging the Windows 97 typeface!)

 

[The Jester]

Your mileage may vary, but when I swapped out the stock EH Gold Pin 12AX7 for a Gold Lion 12AX7 to my ears - inside HD800S - the whole feel, frequency response, and dynamics took a dramatic turn for the worse. In particular, the low end evaporated (not a helpful outcome for HD800S) and the midband became extremely thin. Up until that point, I'd prized the HP8 for the way it had added such body and timbre whilst retaining inner detail and dynamics. After living with the Gold Lion for a few listening sessions, the EH went back into V1 and the problem was resolved.

Thanks for sharing ..
Not in any hurry to start tube rolling just yet, I much prefer the 6992 gold lions over the EH gold in my preamp, but that’s different valves used in one pair per channel for the output stage, where my system is right now all I’m doing lately is buying more music …

 

[geoffalter11]

Found that Brimar CV455, mine should arrive in a couple of days.
No complaints with the David Shaw CV181 and Mullard 12AX7 combination I have, but for 50 quid why not roll some dice

Let us know how the CV455 works out. Hoping you love it!

 

[geoffalter11]

*** ask @geoffalter11 …

The CV455 is a revelation. A truly wonderful driver tube with incredible musicality, slight warmth, and perfect harmonics. The lower gain has not affected the volume, but has opened up the soundstage and provided a more insightful sound.

@jonathan c & @Pharmaboy have become my tube rolling buddies with the HP8. I now have a pretty nice collection of both 12AT7/12AX7s and 6SN7s. Honestly, I like them all. I just like this amp. No other way to slice it. This amp is just incredible. Right now I am using a 1950's Telefunken Grey Plate 12AT7 and a pair of Raytheon VT-231s. The sound is nothing short of perfect to my ears. I am listening to my Auteur OG and wondering where this sound has been my whole life.

 

[Pharmaboy]

I now have a pretty nice collection of both 12AT7/12AX7s and 6SN7s.

Understatement!

Yes, I'm having fun rolling tubes in not just the HP8, but also the Woo WA3 where, thanks to @jonathan c's advice, I recently had a breakthrough with these terrific Brimar CV455 + adapters.

Up until the last couple weeks, most of my tube rolling experiments didn't pan out. Things seem to be turning around.

It surely doesn't hurt that the HP8 (which I'd never seen or heard before buying one F.S.) is obviously a rock-solid design with the best transformer I've encountered, huge power for a 3-tube design, the best bass I've heard in any tube amp, and real responsiveness to tube rolling. The sound seems just as solid as the design, no matter what tubes are used.

 

[geoffalter11]

Understatement!

Yes, I'm having fun rolling tubes in not just the HP8, but also the Woo WA3 where, thanks to @jonathan c's advice, I recently had a breakthrough with these terrific Brimar CV455 + adapters.

Up until the last couple weeks, most of my tube rolling experiments didn't pan out. Things seem to be turning around.

It surely doesn't hurt that the HP8 (which I'd never seen or heard before buying one F.S.) is obviously a rock-solid design with the best transformer I've encountered, huge power for a 3-tube design, the best bass I've heard in any tube amp, and real responsiveness to tube rolling. The sound seems just as solid as the design, no matter what tubes are used.

It is such a wonderful amp. Great feedback and awesome to hear the optimism for what’s to come.

 

[geoffalter11]

It is such a wonderful amp. Great feedback and awesome to hear the optimism for what’s to come.

And yes @jonathan c has provided countless hours of fun and learning with his knowledge and generosity. He is a wealth of knowledge and has helped me to transform what was already a wonderful amp into something exponentially better. Next stop, Synergistic Research Purple Fuse!

 

[jonathan c]

And yes @jonathan c has provided countless hours of fun and learning with his knowledge and generosity. He is a wealth of knowledge*** and has helped me to transform what was already a wonderful amp into something exponentially better. Next stop, Synergistic Research Purple Fuse!

*** because of Head-Fiers such as bcowen, Paladin79, L0rdGwyn, WesS, LoriWiv, Ripper2860, Pharmaboy, Until Then…and quite a few more .

 

[geoffalter11]

*** because of Head-Fiers such as bcowen, Paladin79, L0rdGwyn, WesS, LoriWiv, Ripper2860, Pharmaboy, Until Then…and quite a few more .

You deflected my compliment. Take the compliment!

 

[WorksUnit]

So, some days on the Brimar that Jonathan C linked.

I found it fatiguing on Hyland Jupiter-1s compared to Mullard 12AX7, though a revisit will happen...
What is has done for me, at least, is breathe new life into Quad Era-1...
Never had a better impression of drumkits in a mix, whilst still being able to nail overdrive pedals.


Fantastic suggestion, secret tube rolling cabal