Review: Glow Audio Amp One w/ Denon Lawton D2000, K701, HD650, ER-4S, Audio Tech AD2000, DT880/600
Aug 15, 2010 at 11:43 PM Post #16 of 54

Kouzelna

500+ Head-Fier
Joined
Mar 18, 2010
Posts
571
Likes
25
Does anyone else have any experience with this?  If my Glow has a problem, I need to know about it before I wake up with headphones on to find I'm sleeping in a burnt-out shell of a house!  
eek.gif

 
I'm also anxious to try a Woo.  I love the Glow, but obviously I'm possibly missing something really great.
 
Aug 16, 2010 at 1:19 AM Post #17 of 54

upstateguy

Headphoneus Supremus
Joined
Dec 20, 2004
Posts
4,067
Likes
162


Quote:
Does anyone else have any experience with this?  If my Glow has a problem, I need to know about it before I wake up with headphones on to find I'm sleeping in a burnt-out shell of a house!  
eek.gif

 
I'm also anxious to try a Woo.  I love the Glow, but obviously I'm possibly missing something really great.


I seriously doubt you're going to burn your house down......  Skip the Woo though, check out an M^3 instead.
 
USG
 
Aug 16, 2010 at 1:41 AM Post #18 of 54

Kouzelna

500+ Head-Fier
Joined
Mar 18, 2010
Posts
571
Likes
25
I haven't heard a SS amp that I really liked.  Am I missing something?  Also, anyone actually selling them completed?  I have skills with assembling anything besides Chinese stir fry.  
wink_face.gif

 
Aug 16, 2010 at 10:57 AM Post #19 of 54

hodgjy

Headphoneus Supremus
Joined
Jan 20, 2010
Posts
4,148
Likes
876
Tube amps run hot.  My Woo runs hot.  If I use the RCA power tube, the thing gets hot.  If I use a Tung-Sol power tube, it's cooler.  It all depends on the tubes you use.  Tube amps are quite simple designs if you really think about it.  Most variation in designs is the choice of tube combination, with all of the associated capacitors that go along with that.  But that's really it.  One amp running hot vs. one that runs cool is probably associated with tube choice, not some shoddy design.
 
P.S.  For every amp out there, there's a hater of the amp.  Ignore the haters.
 
Aug 16, 2010 at 12:44 PM Post #20 of 54

Kouzelna

500+ Head-Fier
Joined
Mar 18, 2010
Posts
571
Likes
25
 
[size=medium]

By the way:
 
I recently switched MP3 players with my K701/Glow rig.  I dropped the Zen and hooked up my old Nano with a SendStation line out dongle.  
 
WOW!
 
Huge difference.  Hard to believe, but it immediately and noticeably did three things:
 
1.  Tightened up the bass dramatically.
 
2.  Increased the already amazing soundstage and panning effects.
 
3.  Best of all, brought out even more detail, and made things very clear that were very muddy off the Zen through headphone out setup.  (I know, two ways of saying the same thing).
 
Just goes to show... something.  
popcorn.gif

[/size]

 
Aug 17, 2010 at 7:41 PM Post #21 of 54

Kouzelna

500+ Head-Fier
Joined
Mar 18, 2010
Posts
571
Likes
25
 
[size=medium]
I recently solved a few problems.  I hooked up an Audio Technica AD2000 and that plug fit perfectly, with no modifications.  Thought it was worth a mention.
[/size]

[size=medium]
More importantly, I hooked a +90 resistance cable to my K701, and plugged the Glow into a different wall socket, and these two things together completely eliminated the hum problem entirely, at any volume.
[/size]

 
Aug 17, 2010 at 7:56 PM Post #22 of 54

hodgjy

Headphoneus Supremus
Joined
Jan 20, 2010
Posts
4,148
Likes
876
Great to hear that.  See, most problems have solutions.  Despite what other people may say, the Glow is a pretty nice amp and I seriously considered it for awhile before choosing something else.  Enjoy it!!
 
Aug 21, 2010 at 9:35 AM Post #25 of 54

Kouzelna

500+ Head-Fier
Joined
Mar 18, 2010
Posts
571
Likes
25
 

Just wanted to update this thread with some great stuff sent to me from Patrick at Glow, in response to the two problems I listed with my circa-2008 amp in my review on Head-Fi.  Those were, of course, headphone jack fitting and some hum with the wrong setup.  It also addresses the possibility of using European, as well as Chinese/Russian, tubes.  
 
While I realize some of the die-hards out there may take this in a negative light, citing other companies with better records, in Glow's defense I just want to remind everyone that it's a fairly new company.  Having worked in manufacturing, I can tell you there it is impossible to get a perfect product right out of the gate, and the first few models can require some last-second modifications after the units have already gone up for sale.  Even the guys at Head-Room have suffered design flaws which became apparent only later, after their obsessive quality review process!
 
Regardless, we're talking about very small, and very fixable, problems which by the way also include a useful tube mod.  And for those that have actually heard the amp, I hope you'll agree that its sound is nothing short of amazing, which makes it all worth it.
 
Anyway, I thought y'all would find it useful per our discussion:
k701smile.gif

 
 
Hi David,
 
The '08 amp used an "off the shelf" headphone assembly then available in China that is fairly complex, in that it cuts the signal to the speakers when the headphone plug is inserted, and then draws the headphone signal by tapping the output transformers. So far nothing radical with that arrangement, it is just a lot for a small component to handle. The signal from the output transformers was then stepped down in order to match for headphone use. This jack was one of the few that was available that would fit in the restricted space for the headphone jack within the amp's chassis, so we had limited options. 

The problem with the '08 was that some of the jack assemblies were not calibrated properly by the manufacturer, so that even when installed to the amp chassis properly, the fit was not correct for some headphones. This problem was not identified when the parts were sourced, as the test samples all performed fine. And the test headphones used in China - each amp was tested in the QC process - did not turn up any problem with the connection. But with some brands of headphones, as it turned out, the fit was imperfect ... hence the O ring remedy. For those headphones that have the fit problem, in most cases the O ring works. 
 
 
Finally, the '08 jack assembly itself was simply not very sturdy; even when performing perfectly when new, over time the assembly could become weak or loose, with repeated plugging in and out of headphones. The all metal jack components we would have preferred were not available in the size we needed. Replacing the stock headphone assembly with an all metal variant is not possible, as the space within the chassis is not sufficient to accommodate any of the all metal type jacks we are aware of. 

For the '09 amp we located a new type of headphone jack that would fit the limited space available, that has better overall quality and is sturdier, but is still not the all metal type we would prefer.  The connection problem was remedied, a snug fit was attained without need of an O ring.  (underlining mine -- Kouzelna)
 
 
The only problem with the '09 is that the new headphone circuit is prone to reproducing some level of audible hum with certain low impedance headphones. The issue is not apparent with all headphones, in fact with most commercially available headphones, the user won't experience any problems.  But some phones rated under around 120 ohms do produce audible hum. It is apparent on only some amps, with some headphones. It is not a predictable thing, as audible hum might be an issue in Joe's house but not Kevin's house. 
 
It has been the case that in several instances where a customer had a problem, the hum went away when the amp was connected to a different outlet in the same house.  (I experienced this myself -- Kouzelna).  Although we are not certain, we think that the capacitors and resistors used to step down the output from the transformers might be introducing the hum in some amps. The parts are from the same supplier, but may be from different batches. The parts might not  be consistent in their performance form one batch to the next.  Just a theory. 
 
The engineers spot tested the parts and found no measurable differences in the performance of the components, although they did confirm some of the parts came from different batches.
 
A  fix is available for those '09 amps that have audible hum by our authorized repair facility in Los Angeles...  (underlining mine -- Kouzelna)
 
 
While it is a tough issue to deal with given its unpredictable nature, this amp really does sound fantastic, with a deep soundstage and excellent imaging, and  many customers either opt for the free fix, or use higher impedance headphones if they are getting hum from their cans.  (I moved the amp off a surge protector, and put an Etymotic impedance converter cable between my K701 and the Glow, which together solved the issue.)  --  Kouzelna
 
While getting the (warranty) treatment for the headphone jack, many customers opt to include the (audio repair shop) mod that allows use of all euro and NOS EL84s.  For those wanting to do some serious tube rolling, this is money well spent.  

(underlining mine -- Kouzelna)
Overall, most of the '09 amps perform well with most any headphone, but we certainly will refund a customer (underlining mine -- Kouzelna) if an amp has an issue with audible hum when used with the headphones of his choice. 

-Patrick
 
Aug 21, 2010 at 1:27 PM Post #26 of 54

Armaegis

Modern Modder Man of Manitoba
HTML... uphill, both ways!
Joined
Oct 18, 2009
Posts
12,252
Likes
1,159
That's a rather in depth response that you got from those guys, so kudos to them. I do wish they could have gone into a more technical detailing of some of the issues as I found some of their explanations lacking, but that's the engineer in me.
 
Aug 23, 2010 at 1:48 PM Post #27 of 54

hodgjy

Headphoneus Supremus
Joined
Jan 20, 2010
Posts
4,148
Likes
876
In the business world, ignorance is bliss.  There's also another expression--you don't pick your nose in public.  Essentially, you only disclose problems and workarounds when the customer spots the problems.  If they don't notice anything wrong, why put that idea in their head?
 
I agree with you--I like all the info up front so I can make my own decisions.  But, that's not how the business world works.
 
Quote:
That's a rather in depth response that you got from those guys, so kudos to them. I do wish they could have gone into a more technical detailing of some of the issues as I found some of their explanations lacking, but that's the engineer in me.



 
Aug 23, 2010 at 6:19 PM Post #28 of 54

Kouzelna

500+ Head-Fier
Joined
Mar 18, 2010
Posts
571
Likes
25
I would disagree with you there, hodgjy:  that's how the corporate business world works - the world of sticking accelerator pedals, ruptured tires that cause SUVs to flip on the highway, computer software that never (ever) works, and spinach or (recently) eggs that kill your kids and grandparents.
 
Glow is a small company that appeals to a closed specialty market.  In that case, if you have issues with units you want to be quick - up front - and straightforward.  Then you:  1. state the correction that was made, and  2. offer the fix (or workaround), exchange or return for existing customers with the problem model year.
 
Too often these days, I think large corps feel its cheaper to lose customers and focus on gaining new ones with a re-image plan.  At least, they sure act that way.  Small companies go out of business if they handle a problem wrong, and Iacocca proved for all-time that immediately coming clean is the best way to keep existing customers, just as Toyota recently proved for all-time that losing your existing customer base by continuing to obfuscate can cost you an entire company.  
 
I don't think losing their customer base and starting over is something Glow can afford to do.  And I think Patrick sticking his neck out on Head-Fi to clear up the issue for all to see is pretty admirable, and tells you something about the quality of Glow customer service.  Don't you agree?
 
Aug 23, 2010 at 7:23 PM Post #30 of 54

Kouzelna

500+ Head-Fier
Joined
Mar 18, 2010
Posts
571
Likes
25
I'd sure like to see a head to head comparison of the Glow and the Woo 6/6+.  In fact, I'd really like to do a comparison myself using the K701 
k701smile.gif

 
I'm in Oceanside CA if anyone's near by with a great SS amp or a Woo 6!  Cold ones are in the fridge and the beach is 1 block away!
 

 

Users who are viewing this thread

Top