[svyr]

I asked spritzer/kevin the question about what else to replace and was told the el caps is sufficient and the rest aged pretty well. 
 
(my srm-1/mk2 had more parts replaced, since there was a dead bias resistor and we thought it wouldn't hurt to replace the blue caps/diodes around it... and a couple more for the lols, since the min order sizes were in 10s for me. Also upgraded some parts to higher spec ones on Birgir's/Kevin's advice. E.g. the 2pf caps to 1kv instead of 500v and 630v power section ones to 1kv)
 
I would say - if it works - replace the el caps (450v and the 35v ones) and leave everything else alone. 
 
Birgir would also tell you to adjust the bal/offset pots 

 
 
As for parts, you can order some from farnell, digikey, mouser, rs-components, etc (but it may take up to a week for delivery.on the other hand, my local electronics store carried very little of what I needed). I was told - if the tolerances are ok and the specs are ok, the brand doesn't really matter, unless there's a history of them exploding in people's faces or major reliability problems.
(funny story here - taller/wider caps are not better 

)
 
Quote:

Do you use just off the shelf parts for upgrading capacitors and new ones a lot smaller? I have an SRM/1 MRK/2 that I am thinking it may help to change the electrolytic capacitors. There is a electronic parts store here in town but the parts would be average new replacements.
Would there be anything else in this amp besides the electrolytics that would be a good idea to change? Thanks for any advice.

 

[jaycalgary]

Thanks I will keep it simple and just change the electrolytics. Is there any instruction on how to properly adjust the balance offset pots?

 

[spritzer]

These are just parts from Mouser.  Caps today are much smaller then they used to be but I just added these in a hurry so I didn't pay too much attention to the size besides from the pitch.  That has to be correct or you'll end up with stuff you can't use.  The 400V caps are snap in and made by Panasonic (part number ECO-S2GA101BA).  The smaller units are normal radial units with leads and I use either Panasonic FC's or Nichicon Muse. 
 
To adjust the balance and offset take a look at the KGSS build instructions at Headwize or how you setup the Exstata amps.  Basically you put the probes into the Stax output sockets (red in + and black in -) and you adjust balance for 0VDC.  Then you remove the black lead, ground it to the case and adjust the offset to 0VDC.  It's better to use two meters when doing this as adjusting one with affect the other.  Then to the same for the other channel. 
 
Also, speaking of the Exstata, I just finished mine.  It was originally done fully P-P but a boardset was gifted to me so it made sense to use the amp boards.  The build is about as far from stock as you can go with better transistors, much larger PSU and higher rail voltages. 
 

 

[Beefy]

Has your opinion of the sound changed at all with this build?
 
My stance that it sounds much better than a transformer box still holds, but with no other point of reference......
 
Quote:

Also, speaking of the Exstata, I just finished mine.  It was originally done fully P-P but a boardset was gifted to me so it made sense to use the amp boards.  The build is about as far from stock as you can go with better transistors, much larger PSU and higher rail voltages.   

 

[spritzer]

Ok, I had a nice long reply all typed up but then Huddler froze while bringing up the smiley menu.  Did monkey's write this crap?
 
Anyway, the presence of my rebuilt and XLR equipped SRM-1 Mk2 has only made my findings clearer.  The main issue for me is the bass, on the SRM-1 Mk2 is it tight and nimble even with the SR-007 but on the Exstata you have a bloated mess which doesn't reach deep when it is called for and obscures a lot of small details. 

 

[AudioDwebe]

I'm considering picking up a Stax rig and would like to know what a reasonably good price for a Lambda Signature and SRM-1 MK2 combination would be. 
 
Thanks.
 
'Dwebe

 

[sachu]

Quote:

Ok, I had a nice long reply all typed up but then Huddler froze while bringing up the smiley menu.  Did monkey's write this crap?
 
Anyway, the presence of my rebuilt and XLR equipped SRM-1 Mk2 has only made my findings clearer.  The main issue for me is the bass, on the SRM-1 Mk2 is it tight and nimble even with the SR-007 but on the Exstata you have a bloated mess which doesn't reach deep when it is called for and obscures a lot of small details. 

Completely opposite view here, though your views are no big surprise. I did use the two amps with an ESP950, LambdaPro and SR404. Exstata is way better and the SRM1-mk2 got sold fast. It was onlythe 717 that had better synergy with the O2 over the exstata for me. But the latter did better with the Koss and the 404.

 

[spritzer]

I take it that SRM-1 Mk2 was fully rebuilt?  If not how the hell are you going to compare a new amp with one that is 20-30 years old?  The PSU is the SRM-1 Mk2 is just RC so with caps well past their sell by date the amp has drifted out of spec.

 

[sachu]

Gotcha. So, any other mods to your srm1-mk2? changes to circuit,device swaps,etc?
 
Assuming the exstata has had little to no burn in..do your impressions change with a few hours (5-10) of burn in?

 

[svyr]

nomnomnom. i want my transistor-amp v3 to be delivered. 

 

NOW! lol. (last pic before normal bias socket was put in)
 
Still a week to go. DHL is too slow and too expensive. 
 
 
Then compare it to SRM-1/mk2. Not sure if converting it to bal outputs makes any difference in sound, but the bass is as you describe it on my rebuilt unit...Nice and tight. 
 
Quote:

Ok, I had a nice long reply all typed up but then Huddler froze while bringing up the smiley menu.  Did monkey's write this crap?
 
Anyway, the presence of my rebuilt and XLR equipped SRM-1 Mk2 has only made my findings clearer.  The main issue for me is the bass, on the SRM-1 Mk2 is it tight and nimble even with the SR-007 but on the Exstata you have a bloated mess which doesn't reach deep when it is called for and obscures a lot of small details. 

 

[spritzer]

Ahh so you bought one of those.  Very nice and it should be a good upgrade over the SRM-1 Mk2.  Very similar circuit but higher rail voltages and a better PSU design. 
 
Quote:

Gotcha. So, any other mods to your srm1-mk2? changes to circuit,device swaps,etc?
 
Assuming the exstata has had little to no burn in..do your impressions change with a few hours (5-10) of burn in?

No circuit mods and the only real changes were two new resistors (needed to make it fully balanced) and new 5466 output devices.  If this amp was made today then Stax would use these which are pretty much identical to the stock units.  The rest is just a 4PDT switch, a 4 gang RK27 and mini XLR's, 
 
There is no such thing as burn in so that is hardly going to change matters.  Now adding a CCS instead of the load resistors and fixing other issues with the circuit will but then you'll just end up with a SRM-323.

 

[sachu]

k...i do believe in burn in..but the 2-5 hour variety. Anyways..what i really need now is a good stax headphone. 
 
Going from my offline discussions with a reputable stax HF user, the LNS shhould be right up my alley as I wait for an o2Mk1 to pop up, or lose all sanity and swing for a C32 when it is indeed released....Should have an ESP950 on its way over to me as well towards the end of the month.

 

[Currawong]

The LNS I regret selling in many respects, as they have the right overall "sound" for me--at least, did with the thicker pads that were on mine.

 

[svyr]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif
 
 
Ahh so you bought one of those. Very nice and it should be a good upgrade over the SRM-1 Mk2. Very similar circuit but higher rail voltages and a better PSU design. 

 
 
Thanks spritzer 

. Well good to hear, I'll probably like it then. Yep, bought it at some point when before realizing the SRM-1/mk2 was fixed and Musiland MD11 was outputting DC on line out lol.
Looked like good build quality, a touch of personalization (engraved faceplate), solid case, nice parts and a good price.
Plus a pre-built unit was available, and customizations only took 3 weeks (as opposed to finding a decent builder and waiting until eff knows when). Peter Rill who built it, is also very nice to deal with.http://peter.family-rill.de/
 
soundoholic may have talked me into it lol. It's not as input/output range sexy as his fancier named tav3 http://www.head-fi.org/gallery/album/view/id/0/user_id/160021 / http://peter.family-rill.de/Blog/Neuer-Stax-TransistorAmp , but same circuit

.
 
updated the link to the insides to a larger pic btw.
 
 
Might get an SR-507 as well, but first need someone to buy my stuff =( http://www.head-fi.org/forum/newestpost/521340  http://www.head-fi.org/forum/newestpost/519530 (yes, I am rather shamelessly linking to it but at this point I'm broke

)
 
 
 
 
Quote:

The rest is just a 4PDT switch, a 4 gang RK27 and mini XLR's, 

 
Hm, forgot about the vol pot. I take it if the R/L measure ok with test tones and there's no crackling on adjustment = good/don't need to swap?

Quote:

Originally Posted by sachu /img/forum/go_quote.gif
 
Going from my offline discussions with a reputable stax HF user, the LNS shhould be right up my alley as I wait for an o2Mk1 to pop up...Should have an ESP950 on its way over to me as well towards the end of the month.

why not add a few $ and get a new design sr-407 any other one when the reviews are in?
 
Quote:

k...i do believe in burn in..but the 2-5 hour variety. Anyways..what i really need now is a good stax headphone. 

 
I'd be more concerned about warm-up. Much more tangible and you can measure the drift. (re: bal/offset adjustments)

 

[spritzer]

If the pot works then it works.