[Jonathan66100]

I also think : ) but the hole are very little.

 

[AnakBaru]

Reviving the old thread...
I just got my hand with an A series SRM1Mk2 and want to follow the mod steps underline here.
Question...what's the re-cap done to the sound quality, does it improve vs the stock one ?
Is it worth it ?
 
Thanks.

 

[jgazal]

  Reviving the old thread...
I just got my hand with an A series SRM1Mk2 and want to follow the mod steps underline here.
Question...what's the re-cap done to the sound quality, does it improve vs the stock one ?
Is it worth it ?
 
Thanks.

 
http://www.head-fi.org/t/228896/shelf-life-of-a-capacitor

 

[Eltsur]

Hi all, long-time lurker here.
 
I picked up an old SRM-1/Mk2 Pro off yahoo Japan based on the positive sentiment surrounding this model and this detailed refurb thread, so imagine my surprise when I cracked it open and the circuit layout was different!
 
I only just registered this account, so I can't attach images yet. The photo isn't very resolved, unfortunately.
https://bbbo9w.bn1.livefilestore.com/y2m24u9n__PjIaarRTksIsSiNAVyA6EqyPp2Ij3YEgdcl5gppaBNGOOtGtrhJ43xKf2dlFIMoiwDWpTDQA6SgvFYb0RXPrs4q8F3nyAE0zj2moQe4eEDEWPIJTNa-dKYrtR/image.jpg?psid=1
 
 

Different heatsinks, pot positions, and one less power supply cap, from what I see. It's serial number is A5200 with one pro bias and one normal bias output, if that helps. Would any of the local STAX experts happen to know of this layout? I'm particularly worried about the bias and offset pots, since I don't know whether they've been mislabeled on this board type.
 
That said, the amp is happily driving my SR-404 despite it's ancient internals. There was a LOT of dust in there.
 
Thanks for any advice.

 

[spritzer]

That's the first version of the SRM-1 Mk2  and it's a bit different to the most common model.  Not sure which pot is which on this but it's easy to check underneath the PCB.  The pots have three pins so look for the one which has two of the pins connected together by a trace.  That's the offset pot so the other one must be the balance. 

 

[kazcou]

Hi all,
 
I got a SRM-1 MK2 P.P > C5000. 100V version from Japan.
I rewired it and now is running under 240v.
 
I did the balanced / offset adjustment and I have not change to cap (the original cap are still working peerfectly).
 
Now I want try to put a balanced pot and change the RCA input for XLR, anyone know how I can remove the knob without breaking it ?

 

[numbercube]

What are the specs of the power transformer Bando D-25 61-9389? I want to replace mine because it still hums and vibrates after changing the caps and diodes.

 

[kazcou]

I think you should use a multimeter and measure each pair of wire or contact http://www.bando.com.my

 

[manywelps]

Minor Necro, but:
 
I have 2 STAX SRM-1 MK2 Pros that I bought very recently on ebay.
 
A Silver A variant, and a Black B variant.
 
The Silver A variant works flawlessly.
 
The Black B variant crackles and buzzes like mad in the either channel when adjusting the volume.
 
It moves around, though it tends to be stronger on one side.
 
When I first powered it on, it was doing it like crazy without me adjusting the volume.
 
Does anyone know what I'm looking at?  (I'm still within ebay buyer protection)  Is this normal for B variants?
 
It's also got a background hum that the A doesn't have.  Not that audible at listening levels, but turn it up and it's obvious. (not a ground loop)
 
Can I email stax directly and ask what's up?  (I didn't see an email address)
 
I've got a multimeter, are there offset/balancing instructions for the SRM-1 mk2 pro?

 

[crin]

sounds like a worn or dirty pot. get some contact cleaner or enhancer and spray some into the pot. that should do the trick. if not … replace the pot. (i've already misused WD-40 for this task, but there are "official" sprays that are better suited.)

 

[manywelps]

Yeah I went to town manually spinning the pot, and the noise has virtually stopped.
 
I should open it at some point and clean it properly.
 
Do I need to mess with offset/balance?  Does that drift over time?

 

[crin]

offset and balance will drift over time. no harm done by adjusting them… (try to do the adjustment thru the holes in the cover using a long thin screwdriver.) 
 
did the hum on the black SRM disappear? if not err … make that: in any case change the power supply caps as described in this thread. the original caps will quite certainly have become leaky over time. if it still hums after replacing the caps, you may have to change the pot. the dirt that causes the scratching noise will also cause hum.

 

[manywelps]

  offset and balance will drift over time. no harm done by adjusting them… (try to do the adjustment thru the holes in the cover using a long thin screwdriver.)

Are there good instructions for doing that properly?

 

[crin]

<http://www.head-fi.org/t/648596/stax-srm-1-mk2-re-cap/15#post_9163587> sums it up

 

[manywelps]

B Variant:
 
L+ L- : -9.7V
L+ Ground: 17V
R+ R-: -12V
R+ Ground: 12V
 
Looks like I've got some adjusting to do...
 
What objective effect do the bad offsets have?  No damage I hope...
 
 
Edit:
A Variant:
 
L+ L- : -5V
L+ Ground: 3V
R+ R-: 4V
R+ Ground: 2V