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The Stax Thread III - Page 92

post #1366 of 2795
Quote:
Originally Posted by 3X0 View Post
 

In my case, it is not a SRM-T1S but rather a SRM-323S. The seller advertised it as a 120V USDM amplifier but I see quite clearly now on the back that it is labeled 220-240V 50/60Hz. The internals were not tampered with so I highly doubt it was wired to 120V input.

 

I hadn't noticed any hiccups in performance or operation using it up until I had noticed this (several months). I'll have a bone to pick with the seller for sure.

 

In the case of a solid state amp, it becomes considerably more likely that it'll seem to be working since there are no filaments. The only way it can actually work properly with either voltage is if it had a switching supply, which I'm guessing Stax amps never do. 

 

That leaves two possibilities, either it was modified, or you're using it at half voltage. In most amplifiers, this would take stages out of proper bias, reduce voltage swing by a factor of two, and greatly hurt amplifier linearity and sound quality, but it'd likely still act as an amplifier. In most but not all cases, there'd also be severe 60hz humm since you wouldn't be over the linear regulator dropout. It seems unlikely you wouldn't know if this is the situation, but I could certainly see it as conceivable. (Inconceivable if you have a lot of experience with Stax products and would notice half volume, poor linearity, etc.)

 

Kind of puts you in a sticky situation, since if it was modified to operate on 110v and you connect 220v it'll blow up! I would definitely contact the seller and ask for details on the input voltage.


Edited by dude_500 - 1/23/14 at 11:23am
post #1367 of 2795
Quote:
Originally Posted by dude_500 View Post
 

 

In the case of a solid state amp, it becomes considerably more likely that it'll seem to be working since there are no filaments. The only way it can actually work properly with either voltage is if it had a switching supply, which I'm guessing Stax amps never do. 

 

That leaves two possibilities, either it was modified, or you're using it at half voltage. In most amplifiers, this would take stages out of proper bias, reduce voltage swing by a factor of two, and greatly hurt amplifier linearity and sound quality, but it'd likely still act as an amplifier. In most but not all cases, there'd also be severe 60hz humm since you wouldn't be over the linear regulator dropout. It seems unlikely you wouldn't know if this is the situation, but I could certainly see it as conceivable. (Inconceivable if you have a lot of experience with Stax products and would notice half volume, poor linearity, etc.)

 

Kind of puts you in a sticky situation, since if it was modified to operate on 110v and you connect 220v it'll blow up! I would definitely contact the seller and ask for details on the input voltage.

Thanks; this is just the type of answer I was seeking. I don't suppose it was converted as I received it brand new.

 

I guess the other option would be to open it up with the intent of switching to 120V, with the potential of being pleasantly surprised.

 

It sounded "better" than either my 120V SRM-T1 or SRM-T1S ever did, but seems significantly less sensitive on the dial than the latter of the two. Guess it's time to crack it open...


Edited by 3X0 - 1/23/14 at 1:58pm
post #1368 of 2795

 

The Liquid Lightning mk2 is such a delightful sounding amp. I have been enjoying both pairs of my Stax headphones on this amplifier so much. Stunning performance..................

post #1369 of 2795
Quote:
Originally Posted by Pier Paolo View Post
 

Hi, I have a question for Kevin or Spitz (or for everyone that can help me).

I have an SRM-600 LTD and I would try to transform it in a 006Ts.

I think that I have to change the 4+4 plate resistors (with what kind) and to change some contact in the valves sockets and then use two 6CG7.

May someone be more precise so I can proceed in this transformation?

Also: do you think that is a good idea (I have a 507 to drive) or not?

 

Thank You in advance

PP

No answer?:popcorn:

post #1370 of 2795

just noticed this.  You have to rewire the socket for the filament difference

or make an adapter, and then the tubes won't fit in the case. Otherwise

no other circuit changes. You will have to adjust the offset and differentials.

 

If the srm323 is wired for 240v, its not even going to make any music

when plugged into 120v. Or if it does make music its going to be very distorted.

A 240V model would have all 6 wires on the transformer, so the conversion to

120V is easy. Its the 200V or 100V model that is the problem.


Edited by kevin gilmore - 1/24/14 at 7:38am
post #1371 of 2795
Quote:
Originally Posted by kevin gilmore View Post

just noticed this.  You have to rewire the socket for the filament difference
or make an adapter, and then the tubes won't fit in the case. Otherwise
no other circuit changes. You will have to adjust the offset and differentials.

Welcome back, Kevin, and thank you.
I though that I had to change the plate resistors. I have (4+4)X30Kohm now with the ECC99.
And which tubes you can suggest? Or it would be better to stick with the 99?
Also, when you say "You will have to adjust the offset and differentials" are you talking about the same bias setting procedure (set near to zero V) that I use when I change the tubes?
post #1372 of 2795

bias settings, yes. which really are not bias settings.

 

you should check out how the filaments are actually wired first.

I think its 6V, but it may be 12V. If it actually is 12V, then you

have to wire the 6cg7 filaments in series because those are 6V

tubes only.

post #1373 of 2795
Quote:
Originally Posted by kevin gilmore View Post

bias settings, yes. which really are not bias settings.

you should check out how the filaments are actually wired first.
I think its 6V, but it may be 12V. If it actually is 12V, then you
have to wire the 6cg7 filaments in series because those are 6V
tubes only.

Ok, Kevin, I will try. Have you an srm-006 ts schematic, please?
Edited by Pier Paolo - 1/24/14 at 10:46am
post #1374 of 2795

What?!?.  No posts for 6 days?

 

I'll post something.

 

Quick survey-

 

1. How many days a week do you listen to headphones?

 

2. How many minutes or hours in a typical session?

 

3. What percent of listening is with electrostatic headphones?

 

 

 

My answers:   1. 2    2. 2 hrs   3. 100% for about the last year.  Tried going back to some ortho's and dynamics but that didn't last long, immediately went back to my electrostatics.

post #1375 of 2795
1. 2

2. 2 hours

3. 100% DIY electrostatic headphones. smily_headphones1.gif
post #1376 of 2795

1. 4-5

2. 90

3. 100%

 

Edit: 100% when it comes to headphones. On weekends I listen to speakers.


Edited by AManAnd88Keys - 1/31/14 at 5:01am
post #1377 of 2795
4, 2-3 and 30 other 70% is speakers.
post #1378 of 2795

1) 5 days a week, about 15 hours per week or 75% of my music listening through electrostatics (rest is in-car or through speakers).

post #1379 of 2795
7, 8-10 hours (if you count passive listening as a 'listening session'), 100% electrostatic!
post #1380 of 2795

1. How many days a week do you listen to headphones?

 

7

 

2. How many minutes or hours in a typical session?

 

2-3

 

3. What percent of listening is with electrostatic headphones?

 

100%

 

The questions are only related to headphones time, but out of my overall listening time speakers are 40%, headphones 60%.

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