[cat6man]

i have a srm-t1s driver for my stax and have recently found that the 2 channels are seriously imbalanced (they were fine up to a few weeks ago).

any suggestions on where i should look first (tubes would be my guess)?
any link to photos/diagrams/schematics of the unit?

thanks

edit: yes, i know about high voltages, etc and can handle most simple repairs my myself.

 

[n3rdling]

Check to make sure the volume pot is set correctly. There are actually two parts to that volume knob if you look closely.

 

[spritzer]

With the top of the amp removed, check to see if all the led's on the circuit board are lit and try swapping the tubes. Channel imbalance is far more likely in the phones though...

 

[cat6man]

Quote:

Originally Posted by n3rdling /img/forum/go_quote.gif Check to make sure the volume pot is set correctly. There are actually two parts to that volume knob if you look closely.

good idea............i've had to seriously misalign the 2 sections to get balance.....perhaps the connection to the knobs are loose

 

[cat6man]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif With the top of the amp removed, check to see if all the led's on the circuit board are lit and try swapping the tubes. Channel imbalance is far more likely in the phones though...

swapping tubes is a good easy test (and i've got an old tube tester if needed)..........what do the led's represent in the circuit?

if the problem is in the phones, i assume this means a trip to the stax repair shop? and if so, who does stax repair in the US?

thanks (and update on what i find later today)

 

[Dinan]

Quote:

Originally Posted by kds5000 /img/forum/go_quote.gif Thanks! Have very limited experience with Stax, so take my impressions with a large dose of salt. Here's my impressions for what it's worth:- I'd heard the O2 and HE60 through the Blue Hawaii at our local meet and wasn't blown away by it. Both had the clarity and detail, but not the lower and mid bass I wanted (especially for 80's rock music). Ironically, it was my friend's humble rig - SR-404 Ltd/T1 combo that got my attention. Had the mid-bass weight and very forward vocals that I was looking for. Decided then and there that I wanted the SR-404 Ltd. Went to my local distributor and, as luck would have it, he had 1 SRM-600 Ltd and was prepared to give me a good price for both on the last day of 2009... Brought my SRM-600 Ltd to my friend's place for a quick comparison with the T1 yesterday. Cans used were the Omega, SR-4070 and SR-404 Ltd. Through the SRM-600 Ltd, the SR-404 Ltd was the most forward and had the weightiest mid-bass. The Omega's mids were more recessed in comparison, but the clarity and low bass punch was breathtaking. All 4 of us liked the 4070 the least - we all said that it sounded like a dynamic can... As for the SR-404 Ltd paired with the T1 and SRM-600 Ltd, the general view was that the SRM-600 Ltd gave a punchier bass and had better overall control over the SR-404 Ltd than the T1. Difference wasn't so great to me, but my friend who owns the T1 said that it's pretty significant. I really like the SR-404 Ltd signature, so the SRM-600 Ltd seemed like the logical pairing. Even though they are fresh out of the box, I'm very happy with the combo, more so the more I listen with them (which isn't always the case). Half my dynamic cans will now have to find a new home... Glad I took the leap to Stax...

Thanks for the impressions and the pictures of your rig!

 

[krmathis]

Quote:

Originally Posted by kds5000 /img/forum/go_quote.gif <snip> Glad I took the leap to Stax...

Great first impressions. Thanks!
Really pleased to hear that you enjoy the combo, and that you have heard a handful (or more) other electrostatic headphones to compare it with.

Enjoy!

 

[cat6man]

checked a number of things but left ear is still louder than right ear

1. swapped R/L inputs (XLR input from wadia dac)
2. swapped rca inputs (from analog source)
3. swapped tubes between channels
4. swapped out headphone extension cord
5. see 3 led's lit (2 mid-board behind rear tube, 1 at front.....are there others?)
6. attenuator knob seems solidly connected, individually limit CW/CCW at same points
7. bias measured at 393V at B pin1
8. switched from pro bias to normal bias jack


so, any other suggestions? is there an internal differential voltage that needs to be tweaked to balance the channels?

as a last test (that i can think of), i'm going to try the phones with an old srd7 driver box that has been sitting in my basement for the last 10-15 years.....guess i have to find an amp to drive it though, so i'll hook up my patio portable (see sig)

if i have to send it out for repairs, i've found a link to

STAX Authorized Service Center

any feedback on Yama's? are there other options?

thanks

 

[TimJo]

Quote:

Originally Posted by kds5000 /img/forum/go_quote.gif I really like the SR-404 Ltd signature, so the SRM-600 Ltd seemed like the logical pairing. Even though they are fresh out of the box, I'm very happy with the combo, more so the more I listen with them (which isn't always the case). Half my dynamic cans will now have to find a new home... Glad I took the leap to Stax...

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif Congrats! The SR-404 LE sound fantastic with an eXStatA DIY amp, which sounds better than any Stax brand amp I have heard except for a modified SRM-717 with new internal wire, jacks and switches which sounds close (and 3x the cost).

Well, I'm excited to read this because I just got my shipping notice saying my SR-404 LE's will arrive on Thursday, which means I'll finally get to listen to my new eXStatA hybrid amp. I can't wait. As soon as I have enough listening time on them, I'll be posting some impressions...

Being new to stats, do they need burn in time like dynamic cans, or will they sound accurate right out of the box?

 

[Bullseye]

They won't need burn in. The drivers will charge up almost immediately. You might need some time to get used to the sound. They are very comfortable (speaking about sr-202, but as they share design).

 

[kds5000]

Quote:

Originally Posted by HeadphoneAddict /img/forum/go_quote.gif Congrats! The ones I would keep from your list are: Sennheiser HD600 with APS V3; Grado HF2 or Grado PS-1, Audio Technica ATH-ESW10JPN, and Stax SR-404 Limited. Note off-topic: Grados respond well to a re-cable. I've heard the PS-1 with a Silver Dragon Cable, the Grado RS1 with the APS v3 cable, the HP-1000 with an SAA Equinox, and the HF-1 with APS v3 and a Jenna Labs cable - they all improved over the stock cable. I'm planning to re-cable my HF-2 with an 8 foot 4-pin APS V3 in the upcoming months, and sold the RS-1 recently. Note on-topic: The SR-404 LE sound fantastic with an eXStatA DIY amp, which sounds better than any Stax brand amp I have heard except for a modified SRM-717 with new internal wire, jacks and switches which sounds close (and 3x the cost). I hate to admit this, but the SR-404LE (and O2) sounded better on the modded 717 than my $2500 maxed Woo GES (which was darker sounding with them when using the Apogee mini-DAC), so I look forward to borrowing them back to try them on it. I seem to recall the SR-404LE were not as dark at RMAF when I was using the GES with the brighter PS Audio DAC.

Thanks for your suggestions Larry.

The dynamic cans which I intend to keep (at this point) are:-
1. SR80 (the can that got me started on this crazy hobby, and not worth selling anyway)
2. RS1 (nice serial number)
3. HF2 (birthday present from wife)
4. PS1 (to my ears, the ultimate Grado)
5. ATH-ESW10JPN (my portable can)

As for recabling the Grados, I've got this thing about modifying limited edition pieces like the HF2 and PS1 (especially). Maybe I'll send my RS1 to APS for a recable one day, but it won't be anytime soon.

I'm not familiar with the eXStatA DIY amp - is there a thread here where can I get more information on it?

I've a friend with a modded Blue Hawaii - hope to do a comparison between it and my SRM-600 Ltd through the SR-404 Ltd one day. The Blue Hawaii was there when we did the brief comparison with the T1. Unfortunately, it developed a problem before I arrived and I didn't get a chance to compare it with the SRM-600 Ltd.

Thanks again!

 

[cat6man]

and spritzer wins the prize!

tried the headphones on a srd7 and the same problem was observed (low volume in right ear)...........so, i guess it is either a wiring break somewhere or the stat itself has failed.

since i'm going to be sending these in (somewhere) for repair, is there anything else
that could/should be done at the same time while they are in the shop?

 

[cat6man]

and spritzer wins the prize!

tried the headphones on a srd7 and the same problem was observed (low volume in right ear)...........so, i guess it is either a wiring break somewhere or the stat itself has failed.

since i'm going to be sending these in (somewhere) for repair, is there anything else
that could/should be done at the same time while they are in the shop?

 

[TimJo]

Quote:

Originally Posted by kds5000 /img/forum/go_quote.gif I'm not familiar with the eXStatA DIY amp - is there a thread here where can I get more information on it?

Here's the website - Cavalli Audio

Here's the DIY thread - http://www.head-fi.org/forums/f6/exs...diyers-447950/

 

[spritzer]

Quote:

Originally Posted by cat6man /img/forum/go_quote.gif and spritzer wins the prize! tried the headphones on a srd7 and the same problem was observed (low volume in right ear)...........so, i guess it is either a wiring break somewhere or the stat itself has failed. since i'm going to be sending these in (somewhere) for repair, is there anything else that could/should be done at the same time while they are in the shop?

This is a relatively common ailment of electrostatics and is caused by a parasitic charge sitting on the diaphragm and impeding its movements. Most phones can be fixed by simply leaving them plugged in and periodically unplugging them and discharging the phones by touching all the pins and then plugging them back in.

If this doesn't work then the drivers would have to be replaced with current made units (Stax never stocks old units).