[project86]

Quote:

 
Yes, reinforces my view that a good 12AX7 really makes a big contribution to the sound of this amp.

 
I'd agree with that. Better to spend some money on upgrading that first rather than the other pair - they matter too, but not as much. 
 
That said, you still have to spend some money to get a reasonable improvement over the stock 12AX7. I have some basic (new) Mullard and Sovtek and EH and none of them really do a whole lot. My favorite cheap upgrade is the Genalex Gold Lion which can be had for like $40. I also really like the JAN GE long plate which is really nice for under $100. 

 

[mironathetin]

I'd like to come back to the hum of the HP8. Is it related to the electric environment or is it an inherent property of the HP8s noise floor?
 
I remember how the Leben amps were praised. Finally I listened to them at a local dealer and both, the CS300 and the CS600 produced a noticable hum in my HD 650. Since I like to listen at low volumes and also listen to classical a lot, their hum is certainly not tolerable. It completely rules out both Leben amps for me, although they do sound excellent.
 
That said, my Earmax silver amp is a terrific pairing with the HD 650, but a bit underpowered for the HD 800 and I'd like to find a new tube amp. The Earmax is absolutely free of hum, though. So it seems to be possible to design a tube based circuit without any hum.
 
Can someone comment on the hum of the HP8, please?

 

[project86]

Quote:

I'd like to come back to the hum of the HP8. Is it related to the electric environment or is it an inherent property of the HP8s noise floor?
 
I remember how the Leben amps were praised. Finally I listened to them at a local dealer and both, the CS300 and the CS600 produced a noticable hum in my HD 650. Since I like to listen at low volumes and also listen to classical a lot, their hum is certainly not tolerable. It completely rules out both Leben amps for me, although they do sound excellent.
 
That said, my Earmax silver amp is a terrific pairing with the HD 650, but a bit underpowered for the HD 800 and I'd like to find a new tube amp. The Earmax is absolutely free of hum, though. So it seems to be possible to design a tube based circuit without any hum.
 
Can someone comment on the hum of the HP8, please?

 
On my HP8, it ends up being caused by ground loop issues. I figured that out by feeding it from a battery powered DAP - it was very quiet in that situation. Not completely silent at full blast volume, but very few amps are..... 
 
I did some tweaking and eventually got the system as quiet with a regular transport as it had been with the battery powered DAP. 

 

[mironathetin]

So you would say, even in quieter passages of the music, the noise of the HP8 is not audible?

 

[project86]

Quote:

So you would say, even in quieter passages of the music, the noise of the HP8 is not audible?

 
Definitely not. 

 

[mironathetin]

Quote:

( ... )
 
I want to buy a new amp, but the problem is that I don't want to pay import duties, as the import duties is 45% of the price here in Sweden... I have to buy inside EU if I don't want to pay that. It's really hard to find any amps here in EU....
 
( ... )
 
If you have some tips on other tube amps I can buy in EU here's my requirements.
I'm looking for an amp that is leaning to the warmer side rather than the light.
My budget is a maximum of 700$
Good with Sennheiser HD650
 
 
( ... )

 
If you use the HD 650, I cannot help to recommend the Earmax Silver. It is the best amp I heard so far with the HD 650, and I listend to many (Earmax Pro, XCan V3 and 8, MF HP1, Black Cube Linear, Leben CS 300 and 600, Violectric (forgot which one) etc.).
 
I am not pleased enough with the HD 800 / Earmax combination. This may not the the fault of the Earmax though, I don't know. People say, it is underpowered for the HD 800 and that's why the combination is not stellar. But people say the same about the Earmax and the LCD2 and I cannot confirm that at all (see below).
But from time to time I like to get some ideas how to power the HD800 in a way, that I'll enjoy it as much as my HD 650 with the Earmax.
 
If you are interested, here are two posts about the Earmax, that I wrote:
http://www.head-fi.org/t/473691/comparison-lehmann-back-cube-linear-earmax-pro-x-can-v8p-with-hd-650
http://www.head-fi.org/t/635784/lcd-2-amps-earmax-silver-and-lehmann-black-cube-linear
 
And a similar post from Jornfin, who happens to have the same amps and headphones, that I use. Very nice review, btw.
http://www.head-fi.org/t/232635/earmax-pro-over-mf-and-lehmann

 

[Xcalibur255]

I have not experienced any audible hum with either the dt880 or the lcd-2.

 

[khaine1711]

I have a very slight hum with the He-6 - couldn't hear it with music playing but not as dead silent as my other valve gear. The He-6 is so insensitive that it is quite immune to hum/hiss -  this makes me worry a bit since I don't have my other cans here with me to check out (hd800 and dt990/600 mainly).
 
However with the Dt1350, the hum is very loud. Anyone has portable/iem they wanna try with the Icon?
 
I'm pondering if I should send it back to Icon for a check-up

 

[project86]

I get some hash type noise with IEMs, which is similar to most other Class A tube amps out there. But I can't imagine the HE-6 is normal. When you say "hum", is it independent of volume level or does it get louder as you turn the knob? Also, have you tried to listen with no interconnects and see if it's there? What about different outlets, in different parts of the house? All things I'd try before sending it back. 

 

[khaine1711]

Quote:

I get some hash type noise with IEMs, which is similar to most other Class A tube amps out there. But I can't imagine the HE-6 is normal. When you say "hum", is it independent of volume level or does it get louder as you turn the knob? Also, have you tried to listen with no interconnects and see if it's there? What about different outlets, in different parts of the house? All things I'd try before sending it back. 

I think it's a transformer hum. It's independent of volume level or whether there's a source plug in or not. It's really faint with the He-6 though, similar to the noise level of a silent (~500rpm ish computer cooling fan).  The only thing that can "increase" the hum is the impedance tap.
 
Do you get a transformer hum on IEM or just the hash noise (symptom of too high gain)?

 

[mironathetin]

Thanks guys, keep going. This is THE interesting information.
I don't know what's typical for tube gear in general. My Earmax silver is completely silent as was my X-Can V8 (which is a hybrid).

 

[Painterspal]

When no music is playing and if the house is completely silent I can just faintly hear a hum. It doesn't change with the volume so I assume it's caused by the transformer. Icon Audio actually mention in the information sheet that a slight hum is to be expected and is completely normal. It's slightly louder on the highest output impedance setting but I can't hear it at all during music playback at any setting, even during the quietest pianissimo passages of classical music, so it's a non-issue for me.
 
Like Project86 I did have problems initially with ground loop hum, but as it's also raised its ugly head with my speaker rig I assume it's more to do with the electrical supply in the house. However, once I cured it all has been fine for me.

 

[mironathetin]

Internet research: 
Earmax Silver Signal to noise level > 95db, hum, vol. max.: < -85 dB
Icon Audio HP8 Signal to noise level 90 db
X-Can V8 Signal to noise level > 100 db
Leben CS 300 - no info to compare numbers

 

[Xcalibur255]

I have to say the genalex gold lion is the first new production tube I've ever really been impressed with. Very smooth and airy with better staging and imaging than the NOS Sylvania. I think the syl still has it beat on low level detail retrieval but the genalex is still no slouch. Well done, New Sensor.

 

[tigerkg13]

[size=small]Big thank yous to Painterspal, Project86 and Spudharris for helping me in making the decision to order one (the upgraded version). I really appreciate the time they took to reply to my PMs and this helped explain a lot of my queries. The unit is on the way at this very moment! As regards the hum issue this is what Adrian from Icon Audio has to say:[/size]
 
 
 
[size=small] "This unit has been fully tested  (referring to my unit) and the hum level is normal and only audible at full volume (at which the music would be too loud to listen) and certainly never audible at normal listening levels. Some people use the HP8 MkII near to other units and this can lead to the HP8 MkII picking hum from external sources/magnetic fields such as motors and transformers, or they use extremely sensitive headphones at the same time, so please bear this in mind when you position your HP8 that it is not near to other motors/transformers." [/size]
 
 
 
 
[size=small]Hope the explanation from Icon Audio helps.[/size]