[wwmhf]

I got the SHX-1 amp yesterday afternoon. Here are some early observations.

1. I like how the amp is packed in the box, it is wrapped in a black cloth. This is a fine touch. In addition to the user’s manual, there are three pages of testing report that show plots indicating the THD+N, freq. response, and spectrum analysis for this particular amp I bought. The test was done on 12/01/2003, and some one signed all the tests.

2. This amp is of version 0.5. I ordered it last week from AA.

3. The amp runs very cool. After running about one day, it stays at about the room temperature.

4. It performs obviously better than my Creek 11SE ver. B. In particular, the bass is much better controlled.

5. Compared with version 0.3, see the photo posted by emelius, the following are the differences I have found:

a. Version 0.5 uses fewer parts: two transistors (q19, q20) and two resistors (r30 and r32) are eliminated from version 0.3. This may reduce the gain, and reduce the hum reported for ver. 0.3.

b. Capacitors c29 and c30 are moved to different places.

c. A group of resistors r15, r34, r?, r?, r?, r? (six of them) are replaced by two variable resistors.

d. There are 7 more jumpers in ver. 0.5.

6. So far, the amp seems to work satisfactorily with a Sen. 600 and a Sen. 650. I am still debating which phone to keep. The differences between these two phones are not drastic enough for me to make a quick decision. However, I know one reason is that the Sen. 600 has been burned in while the Sen. 650 has been used for only a few hours. Any suggestions about which one to keep are appreciated. As for the amp, I think I will keep it.

7. Since this amp is running very cool, this makes me suspect whether it is really a class-A amp because the class-A amps I have used are all running VERY warm if not hot. I know that its user manual says it is of class-A, and so does the company’s web page. I wonder there is any way to technically confirm this, just for the curiosity.

That is all for now.

 

[Sean H]

Thanks a lot for posting that information, there's some good stuff there. Congrats on the new gear! I can't believe that many changes have been made! Two transistors removed???? Wow. You are right, I have to wonder if the amp is still that far into Class A and have to ultimately wonder how different (better/worse?) it is than the .3 - if at all. We need to have some DIY guys check out your post and see if they have any opinion. I'm going to PM Voodoochile, he and I have discussed the Perreaux before and he's viewed it's layout closely.

 

[mxs1030]

I'm also curious if the changes made the SXH1 sound better/worse.

or maybe there's no difference at all.

 

[wwmhf]

More observations:

1. The capacitors used on this amp seem to hold a lot of energy. I notice this because it can work for a quite after the power switch is turned off.

2. This one may not be good. This amp can pass a certain amount of signal from the CD player through to the headphone even if the power switch is at the off position.

3. Also, this camp can be easily upgraded by replacing some of the capacitors and the volume control. Any suggestions?

It will be really great if some of our DIY persons can investigate the status of the ver. 0.5.

It is also a great idea to just directly compare ver. 0.3 and 0.5 to see how much difference they sound. If they sound basically the same, then I do not care much about whether ver. 0.5 is in class-A or not.

 

[emelius]

i've posted a few .5 pics as well...i may take higher resolution shots so more details can be picked up...the obvious differences are the green board (used to be that orangish-brown) & the cover plate that now matches the face plate (used to be glossy)...& the wider hole for the volume knob...the placement of a few bits are different but i can't tell specifics w/o concentratin' pretty hard while i switch back & forth 'tween pics

...

i haven't had much phone time...but it seems to me that this newer revision is more of a refinement than an upgrade...

 

[rand]

why until now nobody try to use this amp wiht AKG-501??? I really want to get this amp, yes I have hd-600, but what about Grado and AKG-501 setup? help me pleeeezz....

cheers

 

[kugino]

i just sent in my .3 version for repair to AA b/c it had too much hum, especially when i used my er-4p (i know they aren't the best for head amps). when i emailed AA, they said all that was needed was "a simple resistor change." version .5 is much more than a resistor change...

 

[wwmhf]

After using the SXH1 amp and 650 for several days, I have found that

1. The Perreaux SXH1 seems to match 650 well. Even though the 650 is still in the break-in process, it does sound obviously fuller from the bottom up to the upper middle range. The drum and other percussions still does not sound as clean as the used 600, but I think the 650 will eventually turn out to be good according to the way the 650 has improved in the last three days.

2. The weakest link in SXH1 seems to be the potentiometer. The potentiometer itself is tiny and so is the knob. There is not much grip when it knob is turn. When the CD player is not playing anything, we did hear some scratch noise once in while, not always, when we were turn the volume knob up and down. I am seriously considering get it replaced. Any suggestions are appreciated.

3. As reported by other people, we can not hear any background noise from this SXH1 ver. 0.5. Here, “we” includes my wife who has a pair of unusually highly sensitive ears much better than mine and anyone around us.

4. My wife also commented that 650’s sound is richer and fuller. I think (hope) this is the approval/hint/suggestion for me to keep the more expensive 650 ($339) than 600 ($200 - $25 = $175). I still have a couple of weeks to decide.

Happy phoning,

 

[rsaavedra]

wwmhf did you keep the 650's? How did they sound with the Perraux after break in compared to the 600?

Cheers,
Raul

 

[wwmhf]

I did keep the 650 and return the 600. The 650 sounds obviously better to my ears.

 

[rsaavedra]

Wwmhf, any impressions on response vs. volume of your 650-Perreaux combo? I got the 650's just a week ago, and the Perreux not long before that.

Listening to Tool's Lateralus, if I set the volume of my Perreaux at about 1:00-1:30 pm the 650's are quite loud at that already, but pretty listenable for this music. If I turn it up even more, let's say 3:00pm, that's quite too loud for me, but I noticed it seems the mids and highs go up in volume correspondingly, but not so much the lows. Is this just a misperception of mine, or is it maybe that my 650's are not fully broken in yet (almost 6 days continuously playing now) ? Maybe hearing works this way, I hadn't explored too much these high volume listening levels with my SR60's before.

Cheers,

Raul