[Pharmaboy]

*** New York Pharmaderby ...

(image of lame, riderless horse at keyboard)

 

[lauthoerer]

Agree, the Icon Audio HP8 is a fantastic transformer coupled amp. It runs both dynamics and planar HP's very well for me and the adjustable impedance works with all my ZMF's. It gets just a little warm on the casing and only the tubes are hot. I found mine used and it had an annoying hum as well. Recently I sent it to a certified Icon Audio distributer in Canada and they were able to replace a part that significantly improved the hum issue.

(Bringing this over from the Violectric thread)

The weird/annoying thing with the hum is that it’s practically all but gone with the E3 (27Ω), not that big an issue with the HD820 (300Ω), noticeable with the Bokeh (80Ω) and totally annoying with VC (300Ω), which makes no sense in my view. But the impedance setting basically governs the amount of hum, which probably does make sense. What’s worse is that the positive effect of the tubes and the overall enjoyment the HP8 brings to the music is equal (in reverse) to this rundown. E3 sounds pretty much the same on the US5. But when the band is playing in full, overpowering the hum, the VC sounds just amazing, probably even better than on my US5. However, on the US5, the background couldn’t be any darker and they also already sound great.

I got a power conditioner in for testing the other week (Lab12 gordian) and the first thing I tried was to tackle the hum. Connecting the HP8 first, then the DAC, I was able to localize the source of the hum in the connection to the DAC, being able to "play" sounds by tapping the RCA jack to the output of the DAC. So immediate result was: no change to the power supply I used before (only talking about the hum issue here). What did reap immediate results was using a Puritan Classic+ Cable for my DAC (instead of the Audioplan PowerCord S I was using). This reduced the hum, but sadly didn't get rid of it completely.

Next steps will be trying more/other power cables for the HP8 as well as for the rest of my chain. And maybe trying some grounding options, but would think the HP8 itself isn’t actually the issue, but the connection to the rest of the electronics…

 

[G8torbyte]

@lauthoerer When I was troubleshooting the hum issue on my own I ruled out no ground loop, isolated the HP8 so there were no other running electronics nearby (it is sensitive to wireless and EMF) and tried an ifi GND Defender but there was no difference. The hum in mine was not impacted by volume control and only went up with the impedance switch going from low to high. It was a low frequency hum that was tolerable in open backs but likewise with the ZMF VC it was significantly annoying. I sent it to an authorized Icon Audio distributor that I mentioned and they ran tests and replaced a failing part. I'm thinking it was an internal component associated with the power supply that was causing the issue. The tune up was well worth it for me because they got rid of the noise and I love this amp.
It works so well with dynamics and planars. Jamming on it as I type this with the Caldera Open

 

[lauthoerer]

Thanks for the insight, @G8torbyte ! The hum does increase with turning up the volume, but, indeed, when it’s negligible (E3, HD820), that’s only when turned up to a measure way too loud to listen to anyway. I guess I’ll write to icon Audio and see if there’s a shop in Germany they can recommend.

 

[G8torbyte]

Goodness, I always thought planars paired better with solid state but I can't put down the Caldera with the HP8.
Sounds great even with vintage recordings.

A blast from the past from an album my mom owned that started my love of music.


She had an awesome vinyl collection that unfortunately I played the hell out of them and scratched up several of her records on a cheap children's record player.
Bless her soul for being patient with me. She passed in 2021 and wishing she were still here so I could share the wonderful audio experience with her.
Thank you mom for the memories and Happy Mother's Day!

 

[JerseyD]

Curious how many sets of NOS tubes all you HP8 owners have. I just bought another 12AT7 (ECC81) and pair of 6SN7GT (VT-231) and am worried about rabbit holes and such.

Really thinking I should stop now, with 4 NOS 12A variants 3 pairs of NOS 6SN7s (in addition to the stock tubes the Signature model arrived with). Seems like enough, if I'm loving the sound, right? RIGHT???

 

[WorksUnit]

A blast from the past from an album my mom owned that started my love of music.


She had an awesome vinyl collection that unfortunately I played the hell out of them and scratched up several of her records on a cheap children's record player.
Bless her soul for being patient with me. She passed in 2021 and wishing she were still here so I could share the wonderful audio experience with her.
Thank you mom for the memories and Happy Mother's Day!

I remember setting up my grandmother with an HD650 and a recording of my late grandfather playing his guitar, magic.
Sadly near the end of her days to a stroke, I want to find a song they both played together.
Something like " Missipii are you ready"?

 

[jonathan c]

Curious how many sets of NOS tubes all you HP8 owners have. I just bought another 12AT7 (ECC81) and pair of 6SN7GT (VT-231) and am worried about rabbit holes and such.

Really thinking I should stop now, with 4 NOS 12A variants 3 pairs of NOS 6SN7s (in addition to the stock tubes the Signature model arrived with). Seems like enough, if I'm loving the sound, right? RIGHT???

... only 4 and 3 ?!! .

EDIT: left box = Brimar 12AT7, middle box = 6SN7, right box = other 12AT7.

 

[cats4cans]

Curious how many sets of NOS tubes all you HP8 owners have. I just bought another 12AT7 (ECC81) and pair of 6SN7GT (VT-231) and am worried about rabbit holes and such.

Really thinking I should stop now, with 4 NOS 12A variants 3 pairs of NOS 6SN7s (in addition to the stock tubes the Signature model arrived with). Seems like enough, if I'm loving the sound, right? RIGHT???

I haven’t even bought an HP8 yet, but I already have tubes squirreled away for when I do. Get more boxes and make some space in a closet somewhere. NOS tubes are only going to get more scarce and more expensive.

 

[JerseyD]

... only 4 and 3 ?!! .

EDIT: left box = Brimar 12AT7, middle box = 6SN7, right box = other 12AT7.

OK, OK! I guess I haven’t even glimpsed the edge of the rabbit hole!

 

[jonathan c]

OK, OK! I guess I haven’t even glimpsed the edge of the rabbit hole!

.... pfft! "edge, wedge" .... it's stygian depth that counts

 

[Rollnrock]

Hello, please let me present my candidacy to join this select and iconic group.

After much reading and researching (surely you all know what I’m talking about) I decided to go with the Icon HP8 for my first tube amp. I got this one from the classifieds last week. It’s not the Signature version, just MKII, but if it sounds this good, I can't imagine how fantastic the Signature version will be. My intention though is to update the Caps at some point, but for now I'm not letting it go anywhere

The HP8 MKII came with its original tubes, 2 x David Shaw and 1 x JJ 12AX7, but I also got two additional NOS tubes from the seller (well, NOS but used), one RCA 12AX7 from 1970 made by Mullard and one RCA 12AX7 Black Plates from 1950 (long plates)

I have tried the 3 driver tubes and to my ears there are subtle differences but always maintaining the wonderful sound signature of this fantastic amp

My first Wow moment came with the stock tubes, with that thick and bold sound yet very detailed, deep and tight bass, lush and liquid mids and very pleasant and controlled highs. Great holographic image with a good soundstage. The soundstage was not as huge as I expected, but it was still a very good size.

The RCA Black Plates brought more detail and air, with better separation and bigger stage. Also (even) better bass and extended treble. This tube works very well with rock, blues, etc, but with Classical the high frequencies are a bit harsh sometimes (violins for example) to my ears (maybe this is due to my chain too)

And finally, the RCA 12AX7 made by Mullard, that is my favorite now, gives a smooth, musical and detailed sound, with nice warm mids, which works very good with Jazz, acoustic and Classical, that are the main genres I tend to listen

I have read entirely this thread and there are plenty of tube recommendations (thanks for that!) But, among all of them, which would be your choice to get a smooth, musical and warm yet detailed sound with big and holographic soundstage? (Both power and driver). I think my next purchase will be Brimar 12AT7 CV455 KB/FB to get a bit more headroom in the volume pot, but I don’t know which is the sound signature that this tube can provide


Well, and that’s all. I’m very happy with this little but powerful amp, and now I can see how many people loves this lush and euphonic sound coming from theses little glass bubbles made 50-60 years ago

 

[jonathan c]

Hello, please let me present my candidacy to join this select and iconic group.

After much reading and researching (surely you all know what I’m talking about) I decided to go with the Icon HP8 for my first tube amp. I got this one from the classifieds last week. It’s not the Signature version, just MKII, but if it sounds this good, I can't imagine how fantastic the Signature version will be. My intention though is to update the Caps at some point, but for now I'm not letting it go anywhere




The HP8 MKII came with its original tubes, 2 x David Shaw and 1 x JJ 12AX7, but I also got two additional NOS tubes from the seller (well, NOS but used), one RCA 12AX7 from 1970 made by Mullard and one RCA 12AX7 Black Plates from 1950 (long plates)

I have tried the 3 driver tubes and to my ears there are subtle differences but always maintaining the wonderful sound signature of this fantastic amp

My first Wow moment came with the stock tubes, with that thick and bold sound yet very detailed, deep and tight bass, lush and liquid mids and very pleasant and controlled highs. Great holographic image with a good soundstage. The soundstage was not as huge as I expected, but it was still a very good size.

The RCA Black Plates brought more detail and air, with better separation and bigger stage. Also (even) better bass and extended treble. This tube works very well with rock, blues, etc, but with Classical the high frequencies are a bit harsh sometimes (violins for example) to my ears (maybe this is due to my chain too)




And finally, the RCA 12AX7 made by Mullard, that is my favorite now, gives a smooth, musical and detailed sound, with nice warm mids, which works very good with Jazz, acoustic and Classical, that are the main genres I tend to listen




I have read entirely this thread and there are plenty of tube recommendations (thanks for that!) But, among all of them, which would be your choice to get a smooth, musical and warm yet detailed sound with big and holographic soundstage? (Both power and driver). I think my next purchase will be Brimar 12AT7 CV455 KB/FB to get a bit more headroom in the volume pot, but I don’t know which is the sound signature that this tube can provide


Well, and that’s all. I’m very happy with this little but powerful amp, and now I can see how many people loves this lush and euphonic sound coming from theses little glass bubbles made 50-60 years ago

For a 'first tube amp', HP8 Mk II is one hell of a start!! With the cap upgrades, select tubes -- music 'manna from heaven' is yours!!

 

[G8torbyte]

@Rollnrock Congrats! You got a very nice set up to start off. If you decide to upgrade the capacitors later the team at Audioarcan in Ontario were able to work on mine and it was a pleasure to coordinate with them. I've done a little bit of tube rolling with it and did switch out a stock ECC83(12AX7) Psvane valve that originally came with mine that seemed a bit bright/edgy. I used this guide: https://www.thetubestore.com/12ax7-tube-reviews?12ax7-tube-reviews=undefined&goto=5751

I'm using a NOS JAN-Philips 5751 to smooth the gain stage. For the 6SN7's I have a couple sets of vintage GE and Sylvanias. Currently I'm using a pair of new Linlai high shoulder tubes. It is hard for my old ears to tell much of a difference on swapping the 6SN&'s but I do acknowledge the powerful presentation of the music with the HP8. It immediately impressed with it's strong presence. All my HP's sound fantastic on it and the adjustable impedance tap works nicely with both dynamics and planar. ZMFs seem to like the Mid setting on the output impedance.

 

[JerseyD]

It is hard for my old ears to tell much of a difference on swapping the 6SN&'s but I do acknowledge the powerful presentation of the music with the HP8. It immediately impressed with it's strong presence. All my HP's sound fantastic on it and the adjustable impedance tap works nicely with both dynamics and planar. ZMFs seem to like the Mid setting on the output impedance.

Interesting... So far I have preferred the high impedance setting with my ZMFs. Will go back and listen some more at Medium just to check.