[Old School]

I had a little hiss and hum first 10 hours or so, but than it just disappeared.
I finally plugged benchmark dac1 back into the system and it is a night and day in comparison . It is huge leap from glow dac, I finally got full bodied musical sound, with well defined bass and midrange and nice soundstage separation.
I compared headphone amp from benchmark to glow amp, glow only has about 40 hours or less on it, benchmark has cleaner, detailed soundstage, where glow is a bit muddied at the bottom, but it inserts a bit of air around the sound and you experience less fatigue while listening to it.
I will still burn it for few more days before any final conclusions .
So far, it is a good amp for the money , that tries to be jack of all trades, so if you are on the budget it might be a good purchase, but I suggest to invest in outboard dac

 

[stlblues]

I have around 200 hours (almost 24-7 for 8-9 days) on speakers, but very little time on headphones because the hum was pretty loud. I thought it might just be a bad match b/w the W1000's and the amp, but the 6 moon review has made me think there might be a defect. Hopefully Glow will get around to replying to my emails and maybe some from CanJan can share their thoughts on headphones they tried w/ it. In the mean time I will try to burn the headphone section in to see if that reduces the hum before I need to return it.

 

[Skylab]

Usually (but not always) that sort of hum is tube related. Any chance you have additional tubes you can try? In any case at some point you should upgrade the stock tubes to some better vintage tubes.

 

[stlblue]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif Usually (but not always) that sort of hum is tube related. Any chance you have additional tubes you can try? In any case at some point you should upgrade the stock tubes to some better vintage tubes.

I planned on upgrading the tubes once I was certain I was keeping the amp. I don't have any extra tubes, but I will let it burn in longer from the headphone jack. Again, I speak out of a lack of experience, but what has me stumped is there is no hum from my Altec 604's (100db), unless my ear is an inch or two from the horn driver (even then it is very, very little). Wouldn't the hum come from the speakers as well?

 

[Skylab]

Actually, I have found that with tube amps that will power speakers or headphones that a hum can be basically inaudible via speakers but audible with headphones, where by definition the driver is right by your ear

But of all the tube amps I own or have owned, I have been able to get them to be hum-free with headphones with the right tubes.

 

[Old School]

Well,
I have been burning glow amp for few more days, I'm still not sure if I want to keep it. It performs well with my speaker set, but as a headphone amp, I'm not to impressed, I get better clarity and dynamics, just listening straight from my dac1 headphone output

 

[NDamiani]

Quote:

Originally Posted by psc001 /img/forum/go_quote.gif Old school I totally agree with you about the Dac of Glow one. Everything sounds very thin and without body. Indeed, a nice Dac such as Bench Dac 1 should make a huge difference. I just wish Glow one had a little more power and came without the Dac. It's kinda annoying when they include Dac, which is very dismal compared to the headphone amp and speaker amp, which are very very good.

I've managed to make the DAC sound adequate running through ASIO configured Foobar2000 and modified EQ settings. It definitely helped the low end and "fullness" of sound through the DAC. I definitely like the clarity and quality of the music played through the DAC....unfortunate that the "body" of the sound isn't better.

 

[Old School]

I'm also thinking that k701 probably not the best choice to use with glow amp

 

[stlblues]

Quote:

Originally Posted by Old School /img/forum/go_quote.gif I'm also thinking that k701 probably not the best choice to use with glow amp

mrarroyo said the 701's sounded "lovely" to him w/ the amp. For the little time I've used the W1000's w/ it, the amp seemed to have a lot of potential (less the hum), but turning it past 7 o'clock (maybe 8) was as loud as I could tolerate. I wonder how Senns 600/650 sound w/ it?

 

[tfarney]

Quote:

Originally Posted by Old School /img/forum/go_quote.gif Well, I have been burning glow amp for few more days, I'm still not sure if I want to keep it. It performs well with my speaker set, but as a headphone amp, I'm not to impressed, I get better clarity and dynamics, just listening straight from my dac1 headphone output

Maybe you just have an ear for neutral. The DAC1 is built as a studio tool. The objective of its headphone amp should be exposition of detail, not tone.

Tim

 

[mrarroyo]

Quote:

Originally Posted by Old School /img/forum/go_quote.gif I'm also thinking that k701 probably not the best choice to use with glow amp

I love the sound of my K701 out of the Glow Amp One. The source was an Oritek V4.1 dac fed from an AV710 in my Dell computer. Files are apple lossless.

 

[stlblues]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif I love the sound of my K701 out of the Glow Amp One. The source was an Oritek V4.1 dac fed from an AV710 in my Dell computer. Files are apple lossless.

Have you heard the amp w/ any other headphones lately? I'm having hum problems w/ W1000's...

 

[mrarroyo]

Quote:

Originally Posted by stlblues /img/forum/go_quote.gif Have you heard the amp w/ any other headphones lately? I'm having hum problems w/ W1000's...

The amp is packed and ready to be sent for an audition by tfarney and dw6928. However I can tell you that I have use Grado RS1, Sen PX100, Ultrasone PROline2500 and HFI-780 with no issues. I assume you checked and you do not have 1) bad tubes or 2) ground loop. Correct?

 

[stlblues]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif The amp is packed and ready to be sent for an audition by tfarney and dw6928. However I can tell you that I have use Grado RS1, Sen PX100, Ultrasone PROline2500 and HFI-780 with no issues. I assume you checked and you do not have 1) bad tubes or 2) ground loop. Correct?

Skylab mentioned tubes as well. I don't want to upgrade the tubes until I am certain I am keeping the amp. I've suggested they send me a new set of tubes to try before I send the amp back, but no word yet. I'm guessing it's not a ground loop thing, as I had one stint of hum out of the speakers, but today all is well again. Could it still be a ground loop problem even though there's no hum out of the speakers? It will be sad if I have to return it. I like it a lot for my speakers. I can only imagine what NOS tubes would do for this sucker.

 

[Skylab]

Hey stlblues - I'm pretty sure I have a set of Chinese tubes that are what that amp uses (from my TMS Sweet 2) that are sitting in a box. I dislike the sound of cheap Chinese tubes immensely, and I have never used them. They are your free if you want them - just send me a PM.

When I got the Sweet 2 I immediately replaced the chinese tubes with Sylvania NOS tubes, before ever turning it on. Like the Glow amp, the Sweet2 uses EL84/6BQ5 power tubes and 5670/2c51 driver tubes, although the Sweet2 also uses a pair of 6X4 rectifier tubes.