[Hirsch]

and delivered this...

The HAP-03 is small...about an inch of width and depth smaller than the RA-1

Early warning: Useless with low impedance cans. Forget it with anything under 150 ohms.

OTOH, there is some promise with Sennheisers...more to come as I get a handle on it.

 

[KR...]

damn, that gives the EMP a run for it's money in the cuttest amp contest.

Make sure to post a review.

 

[daycart1]

Are those Sovteks?

 

[Hirsch]

The driver tubes on either side are unmarked, but appear to be Sovteks and the input tube in the center is Yugoslavian...but only until a couple of packages get to my door...

 

[Nick Dangerous]

Review! Review!

Tonight! Tonight!

 

[Hirsch]

Quote:

Originally posted by Nick Dangerous Review! Review! Tonight! Tonight!

Errr....can I listen to it first?

OK, a quick impression (I actually got it yesterday, so it's got about a day of burn-in so far):

The larger unit in the picture is the power supply. The amp itself is tiny. There's a thick umbilical cable between the power supply and the amp. The amp has a headphone jack and a volume control. The LEDs glow bright cobalt blue when the amp is on.

Tube complement is a trio of 12AU7's. The center tube appears to be the input tube, which is flanked by two driver tubes.

Any low impedance can clips at low volume. Badly. Don't even think of using it with them.

The Sennheiser is another matter. Tonality is excellent. The HD-600 sounds relaxed and plays effortlessly. I'd been hearing a certain amount of dynamic range restriction with the ZOTL and the HD-600 combo...completely missing with this amp, thankfully. Also very good with the HD-560II.

This amp has a lot of balance. There isn't any one thing that stands out. Highs are good, but not great. Bass is deep and well-defined, but not as good as some of my other amps. Midrange is gorgeous. What's missing is the last word in fine detail. That might not be bad. It makes the ZOTL look absolutely merciless on a bad recording, and there's a lot of those. There's a lot to like about this little amp. It's not a killer amp, in the sense that you hear things on recordings that you never heard before. However, what it has is an excellent presentation of material. That sense of balance (that word again!) makes this amp interesting.

This amp is already appearing to be a better match for Sennheisers than the ZOTL or X-Can (I prefer the HP-1 or CD3K with ZOTL, and CD3K with X-Can. Still getting the measure of the W100..it hasn't found its spot yet). My Melos is still on preamp duty, and doesn't get a lot of headphone play these days, and my RA-1 is married to the SR-200's. So, this amp may be the one that brings my Sennheisers back into the rotation.

I'm missing a couple of important pieces of information that I will eventually need to rate this amp: I've never heard the MG Head, or the Earmax Pro. IMO, these are the amps that need to be compared to this one, in order to fully get its measure. My suspicion is that it will be very comparable to an MG Head, but I hate making blind guesses. If there's anyone in the vicinity of Wash DC area who has one of these amps and would like to get together for a listening session, please let me know...

I'll say a bit more about the sound after I've listened a bit...

 

[DarkAngel]

Hirsch's House of Tubes
The collection continues to grow, heh,heh,heh

Didn't Dusty first bring this amp to our attention? We can blame him for further depleting our finances.

 

[taoster]

that sure is a pretty pretty amp!

can i know how much(range) this little baby is going to set us back?

 

[Tomcat]

Quote:

Any low impedance can clips at low volume. Badly. Don't even think of using it with them.

Hirsch,
all you need is the HPA-04 Passive Impedance Converter to "make your headphone more warm sound"

:

Your description sounds like this is an excellent amp. Basically, a "gorgeous midrange" is all one really needs, I'd say. And "hearing things on recordings you have never heard before" can mean hearing distortion artifacts produced by the amp as well - because those would be things you have never heard before. I feel a balanced and homogenous presentation can be the more accurate one. And as you said, quite often, it is the more enjoyable one.

 

[markl]

Not to be a poop, but what's the point of an amp with such restrictions on the kind of headphone you can use? What if you change headphones? You have to sell the amp.

Also, if you recall from the Jan Meier visit to Senn post, even Senn admits that amps should have very low output impedence to properly drive HD600. Since this amp can't drive low-impedence phones, can we deduce its output impedence is higher than average?

markl

 

[Hirsch]

Markl,

Good point. I guess the dedicated Stax amps are useless.

We deduce from the high output impedance that this is a true OTL tube amp. Tubes have inherently high output impedances. (To get low impedances out of a tube amp, you need solid state output, an output transformer, a LOT of tubes in parallel, or Berning's Zero Hysteresis technology.) Since Sennheisers need very low output impedances, we can deduce that the HD-600 cannot be adequately driven by an OTL amp. Since the experience of many indicates otherwise, perhaps we should revise some assumptions here?

Tomcat,

I've seen the HAP-04...and have to decide if it's worth getting. I'm not sure I'm going to be using any other cans besides Sennheisers with the amp.

taoster,

The amp is sold on ebay. The reserve was $349.

DarkAngel,

Yep, Dusty found this one...and the little red needle on my wallet is pointing at "E". While that's always stood for "excellent" in my book, I guess it means I'm out of cash...

 

[RickG]

Quote:

Originally posted by Hirsch Markl, Good point. I guess the dedicated Stax amps are useless.

LOL, Hirsch...

 

[markl]

"Good point. I guess the dedicated Stax amps are useless"

I would argue that one of the most severe limitations of the Stax system is the inability to use anyone else's amp. So neener neener.

markl

 

[Hirsch]

Quote:

Originally posted by markl [BI would argue that one of the most severe limitations of the Stax system is the inability to use anyone else's amp. [/B]

I'm not sure I regard that as a weakness at all. Let's take a hypothetical example:

Someone builds an amp that is the best possible amp for the R-10. Nothing else comes close. However, it sounds lousy with other headphones. They can make the amp more compatible with other headphones, at a cost of minor sonic compromise with the R-10.

Would you accept a reduction in sound quality in exchange for compatibility, or would you want the best sound possible for the R-10, with all other considerations ignored?

 

[Hirsch]

Meanwhile, back on topic...

The HAP-03 continues to work well. It's hooked up using my double DI/O configuration right next to the ZOTL, running off of the same player. So, I'm flipping back and forth between the W100 on the ZOTL, and the HD-600 on the HAP-03. The W100/ZOTL combo was walking away with things, so I decided to try a different input tube (I've only got a couple singles of 12AU7's, at least until next week). Stuck in an old Sylvania to replace the Yugoslavian input tube. Hmmm...there's some promise here. The balance wasn't disrupted, but there's a bit more detail. Getting better! Now all I need is some replacements for the driver tubes...soon...soon...