Head-Fi.org › Forums › Summit-Fi (High-End Audio) › High-end Audio Forum › The Stax thread (New)
New Posts  All Forums:Forum Nav:

The Stax thread (New) - Page 1337  

post #20041 of 24765

Hi everyone!

 

I'm not sure if this the right place to post, but here goes!

 

I have been using the SR-507/SRM-600 Limited combination for about a year now. The thing is, recent usage has seen the right channel sounding crackled and distorted until it eventually died. Thinking that is was the phones, I brought it down to the dealer where he plugged it into an SRM-323 and was found to be working perfectly fine.

 

I now think the amp is faulty. Here's what I have done so far;

 

1) Tried a different source. (iPhone 5 to amp, didnt work, right channel still dead, the original setup was an Audio-Gd Reference 5 fed by an Anedio U2 from the PC)

 

2) Tried different interconnects, both SE and balanced, didnt work, right channel still dead.

 

3) Tried swapping positions on the interconnects (left to right etc), right channel still dead.

 

4) Tried swapping position of the tubes, right channel still dead, but the left channel started giving the same symptoms like the right before it died. (I did not re-bias the amp when I swapped positions, could that be why?)

 

Could I have done anything that could have killed the amp? Did I miss anything out when troubleshooting?

 

Any help would be greatly appreciated.

 

Thank you! :)

post #20042 of 24765

Do you have a multimeter?

post #20043 of 24765

 

 

Quote:

The down side staying in a oil sand work camp. I need a bigger night stand.

 

1000

 

 

 

 

Quote:

Yeah that looks pretty awful. rolleyes.gif

 

 

 

Stack needs to be at least 250% higher to get the "air".


Edited by wink - 11/10/12 at 6:24pm
post #20044 of 24765
Quote:
Originally Posted by Nanoframe View Post

Hi everyone!

 

I'm not sure if this the right place to post, but here goes!

 

I have been using the SR-507/SRM-600 Limited combination for about a year now. The thing is, recent usage has seen the right channel sounding crackled and distorted until it eventually died. Thinking that is was the phones, I brought it down to the dealer where he plugged it into an SRM-323 and was found to be working perfectly fine.

 

I now think the amp is faulty. Here's what I have done so far;

 

1) Tried a different source. (iPhone 5 to amp, didnt work, right channel still dead, the original setup was an Audio-Gd Reference 5 fed by an Anedio U2 from the PC)

 

2) Tried different interconnects, both SE and balanced, didnt work, right channel still dead.

 

3) Tried swapping positions on the interconnects (left to right etc), right channel still dead.

 

4) Tried swapping position of the tubes, right channel still dead, but the left channel started giving the same symptoms like the right before it died. (I did not re-bias the amp when I swapped positions, could that be why?)

 

Could I have done anything that could have killed the amp? Did I miss anything out when troubleshooting?

 

Any help would be greatly appreciated.

 

Thank you! :)

 

Do you have the schematic?

post #20045 of 24765

Thanks for the quick replies guys!

Quote:
Originally Posted by n3rdling View Post

Do you have a multimeter?

 

Yup, I actually measured the amp by following this thread and got very similar readings, in fact the only difference was pin 3 for both sockets, where the readings differed by 1 or 2. I hope I'm not doing this wrong... 

Quote:
Originally Posted by wuwhere View Post

 

Do you have the schematic?

 

Unfortunately I dont. :( I'll try searching around to see if I can find it.

 

 700

EDIT: Got it! I didn't realise it was in the manual. My bad!


Edited by Nanoframe - 11/10/12 at 7:49pm
post #20046 of 24765

That's not the schematic but you can find the near alternative by searching for the SRM-T1 schematic.  First thing to check with these amps are the LED's in the circuit and if they are all lit.  It also wouldn't hurt to get new tubes as if the right one had a short you probably killed the left channel swapping them. 

post #20047 of 24765
Thanks for the input spritzer! You can tell I'm not electronics savvy! redface.gif

I'll try looking for the schematics and try getting a replacement set of tubes.

If I accidentally killed both channels, I'll have to replace the whole amp?

Thanks again for all the help!
post #20048 of 24765

The amp should be repairable but it really depends on what happened. 

post #20049 of 24765
Quote:
Originally Posted by spritzer View Post

The amp should be repairable but it really depends on what happened. 

 

Ok, thanks a lot for the help! Fingers crossed while I find the exact cause.

post #20050 of 24765

Spritzer, I have a SRM-252S that blew the right channel.

I tracked it down to one of the little red LEDs, all of the transistors seemed to check out ok.

Before I solder in a replacement, could you tell me what the forward voltage rating of the LED should be?

post #20051 of 24765
Quote:
Originally Posted by livewire View Post

Spritzer, I have a SRM-252S that blew the right channel.

I tracked it down to one of the little red LEDs, all of the transistors seemed to check out ok.

Before I solder in a replacement, could you tell me what the forward voltage rating of the LED should be?

 

Can't you just measure the left channel?

post #20052 of 24765
Quote:
Originally Posted by wuwhere View Post

 

Can't you just measure the left channel?

I could but it would require that I de-solder the left channel LED to find it's "turn on" voltage.

Dont want to check the live circuit for this characteristic because the voltage drop shown on the DMM

may be influenced by other components in the circuit. Stax typically uses LEDs in the various stages of their amps

to act as a voltage reference for the rest of the circuit. To maintain correct functionality, the LED's Vf rating is crucial.

These LEDs are tiny, I am afraid by de-soldering the left channel, I could do damage to it.

 

Besides, it is easier to ask an expert who has torn into many of the same amp for their knowledge! smile.gif

post #20053 of 24765
Quote:
Originally Posted by livewire View Post

Spritzer, I have a SRM-252S that blew the right channel.

I tracked it down to one of the little red LEDs, all of the transistors seemed to check out ok.

Before I solder in a replacement, could you tell me what the forward voltage rating of the LED should be?

 

did you check to see if the LED is actually bad?  its probably an indicator that something else in the circuit is wrong.  but if you want to try to replace it 1.7V is a pretty typical value.

HeadAmp Audio Electronics - home of the Pico and Gilmore amps.  Now with Audeze, Fostex, HiFiMAN, Sennheiser, and STAX.
Find us at www.HeadAmp.com

post #20054 of 24765

Thanks Justin, I knew that 1.7V is a common value for this type of circuit,

although I've seen KG use LEDs up to 2.2V in some of his designs.

I just wanted to be sure what Stax specs for this part in the SRM-252 so as to avoid any channel balance issues.

 

Yes the LED is bad, it's open. All the others were lit.

I desoldered it and checked it with the DMM outside of the circuit.

I got the dreaded "OL" when reading it both ways.

Suspecting something else in the neighborhood might be borked as well,

I checked all the transistors and resistors in that part of the circuit and compared

the readings to the working left channel. All else seems A-OK.

post #20055 of 24765

I've never seen a Stax schematic where the LED's are marked with a part number, just "red led" so 1.7V would be the best bet. 

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: High-end Audio Forum
This thread is locked  
Head-Fi.org › Forums › Summit-Fi (High-End Audio) › High-end Audio Forum › The Stax thread (New)