[atarione]

  I clean tubes I receive with ISO alcohol, wipe glass and socket. Never had big smell after. There can be an oily film of dirt on the surface from years in storage and it can smell when the tube heats up until it burns off.

mmm... old dusty (probably asbestos ) smell... yum..
 
you haven't had any issues with printing coming off when cleaning with the ISO?  .. j

 

[gvl2016]

 
mmm... old dusty (probably asbestos ) smell... yum..
 
you haven't had any issues with printing coming off when cleaning with the ISO?  .. j

 
No, printing is usually insoluble by ISO, but suppose you can get it off if you rub long enough

 

[tej789]

I originally posted this in the other tuberolling thread but since I found this part 2 I decided to post in here as well.
 
I just received my Darkvoice from Massdrop. I have noticed that when turning it up past 50% volume I start to get distortion and not much increase in volume. I have been trying to track it down to see if I can find a definite cause of it. I have tried using a Fiio E17K as an amp with both the headphone and output ports to see if it might be my headphones. With the E17K and turning the volume up on the darkvoice amp I can still notice some distortion, however, it is most noticeable when connecting headphones directly to the headphone port. Source is a turntable running through a phono preamp then into the Darkvoice. Headphones tested with are Klipsch Mode M40 and Audeze EL-8 Closed-back. My primaries are the EL-8s and I have to believe this thing should have no problem powering them and I shouldn't have any distortion. I am also thinking I shouldn't have to turn the volume up as much as I am having to.
 
I have read some things about the tubes being bad from the factory and I'm wondering if that could be it. If anyone else has any other ideas it would be greatly appreciated. 
 
Thank You.

 

[tej789]

I originally posted this in the other tuberolling thread but just discovered this one and thought I would put it in here as well.
 
I just received my Darkvoice from Massdrop. I have noticed that when turning it up past 50% volume I start to get distortion and not much increase in volume. I have been trying to track it down to see if I can find a definite cause of it. I have tried using a Fiio E17K as an amp with both the headphone and output ports to see if it might be my headphones. With the E17K and turning the volume up on the darkvoice amp I can still notice some distortion, however, it is most noticeable when connecting headphones directly to the headphone port. Source is a turntable running through a phono preamp then into the Darkvoice. Headphones tested with are Klipsch Mode M40 and Audeze EL-8 Closed-back. My primaries are the EL-8s and I have to believe this thing should have no problem powering them and I shouldn't have any distortion. I am also thinking I shouldn't have to turn the volume up as much as I am having to.
 
I have read some things about the tubes being bad from the factory and I'm wondering if that could be it. If anyone else has any other ideas it would be greatly appreciated. 
 
Thank You.

 

[gvl2016]

I had the misfortune to buy some bad RCA output tubes, they behaved like you describe, distorting past 11 o'clock on the volume control knob. I would bet on a bad output tube.

 

[tej789]

Would you suggest getting some new tubes to see if it fixes it? I was also concerned that the volume was not getting very loud. I mean yeah it is enough to block background noise but with the EL-8s being 30ohms wouldn't it be really easy for this thing to drive them, as in not having to turn the knob much. Could a bad tube also contribute to that or do I just not know what I am talking about with the ohms etc.

 

[gvl2016]

  Would you suggest getting some new tubes to see if it fixes it? I was also concerned that the volume was not getting very loud. I mean yeah it is enough to block background noise but with the EL-8s being 30ohms wouldn't it be really easy for this thing to drive them, as in not having to turn the knob much. Could a bad tube also contribute to that or do I just not know what I am talking about with the ohms etc.

 
This amp doesn't pair too well with low-impedance headphones as there is a significant loss of low frequencies with them, but it should have no problem driving 30Ohm without distortion to very loud levels. I suggest trying a different output tube as you want to replace the stock one anyways. The symptoms you describe is exactly what I experienced with bad output tubes driving 32 Ohm phones, other tubes work fine in mine, so definitely could be a bad tube.

 

[Mr Rick]

  Would you suggest getting some new tubes to see if it fixes it? I was also concerned that the volume was not getting very loud. I mean yeah it is enough to block background noise but with the EL-8s being 30ohms wouldn't it be really easy for this thing to drive them, as in not having to turn the knob much. Could a bad tube also contribute to that or do I just not know what I am talking about with the ohms etc.

An OTL amp like the DV really works best with hi-z headphones like Sennheiser 600/650 or the Beyer 600 ohm models. That is what I use with my DV and I seldom get the volume above 9 o'clock.
 
I've only used it one time with my Philips X2s (30 ohm) and it REALLY sounded poor.

 

[tej789]

Originally Posted by gvl2016
 
This amp doesn't pair too well with low-impedance headphones as there is a significant loss of low frequencies with them, but it should have no problem driving 30Ohm without distortion to very loud levels. I suggest trying a different output tube as you want to replace the stock one anyways. The symptoms you describe is exactly what I experienced with bad output tubes driving 32 Ohm phones, other tubes work fine in mine, so definitely could be a bad tube.

Using my Klipsch Mode M40s exhibited the same audio characteristics and those are 32Ohms, right at the lower ohm limit of the amp.

 

[gvl2016]

  Using my Klipsch Mode M40s exhibited the same audio characteristics and those are 32Ohms, right at the lower ohm limit of the amp.

 
Are you saying you had distortion with the M40s but no distortion with higher impedance headphones? I had no issues pairing Philips SHP9500s with the DV even if there is a slight loss of low end, and they actually sound good. I tried other 32 Ohm headphones as well, they didn't sound as nice but there was no distortion. With the bad tubes there was distortion always, even when using the DV as pre-amp with no headphones attached. Btw this is something to try to eliminate the headphones as potential problem. Burning the tubes in may help too, but if the tube is gassy there won't be an improvement running with a gassy tube isn't good for the amp.

 

[tej789]

   
Are you saying you had distortion with the M40s but no distortion with higher impedance headphones? I had no issues pairing Philips SHP9500s with the DV even if there is a slight loss of low end, and they actually sound good. I tried other 32 Ohm headphones as well, they didn't sound as nice but there was no distortion. With the bad tubes there was distortion always, even when using the DV as pre-amp with no headphones attached. Btw this is something to try to eliminate the headphones as potential problem. Burning the tubes in may help too, but if the tube is gassy it isn't good for the amp.

No I am saying there was distortion with the 32ohm as well. I could try burning them in for a while. How would I know if the tube is gassy?

 

[gvl2016]

  No I am saying there was distortion with the 32ohm as well. I could try burning them in for a while. How would I know if the tube is gassy?

 
You'd need a tube tester to know for sure. Purple glow around plates would be one symptom but not guaranteed.

 

[tej789]

   
You'd need a tube tester to know for sure. Purple glow around plates would be one symptom but not guaranteed.

I did not notice any purple, just the orange glow.
 
I saw one thing about burning in the tubes in this amp and they suggested removing the 6AS7 tube and leaving the amp on for three days. Is it common practice to remove the large tube for burn-in?

 

[gvl2016]

  I did not notice any purple, just the orange glow.
 
I saw one thing about burning in the tubes in this amp and they suggested removing the 6AS7 tube and leaving the amp on for three days. Is it common practice to remove the large tube for burn-in?

 
If you're burning in just a new 6SN7 sure, as there is no reason to run the output tube unless you are actually listening to the amp at the same time. In your case you need to try to burn-in both tubes, so need to leave both tubes in. There can be some leftover gasses from the factory inside the tube and it takes some heat and time for the getter to absorb them, so burning them in might help.

 

[tej789]

   
If you're burning in just a new 6SN7 sure, as there is no reason to run the output tube unless you are actually listening to the amp at the same time. In your case you need to try to burn-in both tubes, so need to leave both tubes in. There can be some leftover gasses from the factory inside the tube and it takes some heat and time for the getter to absorb them, so burning them in might help.

Is there any chance of this thing overheating? That large tube gets pretty hot and I don't want to leave it on when I am not there.