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The Entry Level Stax Thread - Page 51

post #751 of 1072
Thread Starter 
Quote:
Originally Posted by miceblue View Post

Yeah, I was listening to the STAX setup again during the wee hours of the morning with no noise around me and I couldn't hear any ham sounds. Strange.

Were the hogs and pigs asleep?
post #752 of 1072

They were still out flying.

post #753 of 1072

SRM-313 + SR-202 sure is a great combo. Diggin' it so far.

post #754 of 1072

My SRM-T1 has developed a failing left channel today, which distorts heavily at moderate volume. How can I determine the cause, and what are some common causes of this issue?

post #755 of 1072

Changing Tubes in a STAX Tube Headphone Amplifier

 

The following description is specific to the STAX 006t II vacuum tube output driver unit but much of the procedure is similar for any of the STAX tube units (SRM-T1, SRM-T1S, SRM-T1W, SRM-006t and SRM-006tA/II)

 

WARNING – DON’T BE STUPID. If you cannot read English very well, are uncomfortable around high voltages, describe yourself as “all thumbs”, “ham-fisted” or “awkward” and have never worked inside of any electrical component that has potentially lethal voltages DO NOT attempt any of the procedures listed below. Do yourself and your equipment a favor and find someone who can, or take a copy of this to a local audio/video repair shop and ask them if understand what is being described and can they can do it for you.

 

Disclaimer – I make no warranty and accept no responsibility for suitability of any materials listed below. I assume no responsibility or liability for errors or inaccuracies. Reader accepts all responsibility for any and all results obtained. Use of any supplied materials constitutes acceptance and understanding of these disclaimers.

 

STAX clearly states on the Operating Manual for the 006t II that “This product operates with a high voltage. It is extremely dangerous to attempt to dismantle or modify the unit in any way, and under no circumstance should any such attempt be made.” What I have done has clearly violated the manufacturer’s warranty – YOU HAVE BEEN WARNED!

 

 

What follows is a description of how I changed and adjusted the tubes in my personal STAX 006t II vacuum tube amplifier.

 

The tools I used were a philips screwdriver (to remove the cover), an insulated (plastic) slot head screwdriver (to adjust the internal potentiometers), and a good quality multimeter that is set to measure volts .... NOT AMPS!

 

Procedure I used:

 

I disconnected the headphones, unplugged the unit from the wall power, and using a Philips screwdriver, removed the four screws that hold the top.

 

I removed the two 6FQ7 (6CG7) tubes and replaced them with the new tubes (that were checked with a tube tester prior to insertion in the unit).

 

With the cover still off I plugged in and powered up the unit leaving it on for about and hour to stabilize. WARNING – at this point the cover is off and the unit is powered. I NEVER leave an electrical unit in this state unattended for any reason.

 

Below is a diagram of the earspeaker connector as it would appear if you were looking at it from the front of the unit. There are two of these connectors with the words “PRO ONLY” above them. They will not have "L+", "L-", "R+".... those labels identify the holes for the purpose of the discussion below.

 

*** See Attached STAX Connector image ***

 

WARNING - DO NOT under any circumstances put a probe into the socket shown on the bottom right labeled above as “Bias”. In fact, I covered it with a small piece of tape so that I wouldn’t have the possibility of an accident that could damage the unit or myself.

 

I set my multimeter to measure volts and inserted the positive probe into the slot shown above labeled “L+” and inserted the negative probe into the slot labeled “L-”. At this point I was measuring dc balance. My first measurement was in the 6 volt range, the reading could have been higher or lower, the goal is to get it under 1 volt. To adjust the value I used a plastic (NOT METAL) slot head screwdriver and adjusted the potentiometer labeled “TVR1” for the left channel. The potentiometer is EXTREMELY sensitive and the meter reading will have a tendency to drift around a bit. With some effort I was able to get the reading stabilized at about 0.250 volts.

 

*** See attached inside view of STAX 006t II ***

 

I then removed the negative probe from the slot labeled “L-“ and attached the probe to the ground post labeled “GND” at the back of the unit. At this point I was measuring dc offset. Initially, the dc offset was around 1.5 volts. Again, the object was to get the dc volts under 1 volt. To adjust the value I used a plastic (NOT METAL) slot head screwdriver and adjusted the potentiometer labeled “TVR2” for the left channel. Again, the potentiometer is EXTREMELY sensitive and the meter reading will have a tendency to drift around a bit With some effort I was able to get the reading stabilized at about 0.090 volts.

 

I confirmed that the dc balance was still below 1 volt by removing the negative probe from the ground post and re-inserting it into the slot shown above labeled “L-”. If needed I could have adjusted the dc balance again and lowered it under 1 volt, but it still measured close to 0.250 volts. This process of going back and forth between the adjustment of dc balance and dc offset could have happened several times.

 

At this point the left channel adjustments were complete. I followed the exact same procedure for the right channel with similar results for the measured and adjusted voltages.

 

With both channels adjusted I turned off and unplugged the unit. With the unit unplugged I attached the top using the four screws and then plugged in the unit into the wall power and I was done.

 

 

post #756 of 1072

DC and balance offset? Borked/shorted plate resistors? Bad tubes?

post #757 of 1072

Failing tube would be my guess. 

post #758 of 1072

Wow, this thread only started a few months ago and it already has 51 pages?  I got through the first 5 or 10 or so and couldn't resist any longer.  I've just ordered an SRS-2170 to be imported from Japan from a seller on Amazon (I work for Amazon, so I generally buy from/through them when I can) for $640 including expedited shipping.  Should arrive Friday or next week, if the shipping estimates are to be believed.

 

*cue me feeling like an idiot if the other 40 pages of posts have all kinds of horror stories about importing from Japan, or how the 2170 is crap, or whatever*  Hopefully not.  :-)

 

I'll be upgrading from HD-595s at home, and MB-Quart 400s (aka German Maestro GMP 400 from before the sale of the MB-Quart brand happened) at work.  The Stax will probably live at work (where I do most of my listening).  I've built my own headphone amps for my dynamics.  I'll post my impressions when I have my new phones-- sorry, earspeakers, and have given them a chance to break in.

 

Is there a way to consolidate things like "Here's a link to the best mods to the SRM-252S" so that I don't have to go searching through 51 pages of posts (and counting) to find what general consensus is?

post #759 of 1072
Quote:
Originally Posted by SmittyHalibut View Post
 

Wow, this thread only started a few months ago and it already has 51 pages?  I got through the first 5 or 10 or so and couldn't resist any longer.  I've just ordered an SRS-2170 to be imported from Japan from a seller on Amazon (I work for Amazon, so I generally buy from/through them when I can) for $640 including expedited shipping.  Should arrive Friday or next week, if the shipping estimates are to be believed.

 

*cue me feeling like an idiot if the other 40 pages of posts have all kinds of horror stories about importing from Japan, or how the 2170 is crap, or whatever*  Hopefully not.  :-)

 

I'll be upgrading from HD-595s at home, and MB-Quart 400s (aka German Maestro GMP 400 from before the sale of the MB-Quart brand happened) at work.  The Stax will probably live at work (where I do most of my listening).  I've built my own headphone amps for my dynamics.  I'll post my impressions when I have my new phones-- sorry, earspeakers, and have given them a chance to break in.

 

Is there a way to consolidate things like "Here's a link to the best mods to the SRM-252S" so that I don't have to go searching through 51 pages of posts (and counting) to find what general consensus is?

Welcome to the world of Stax. There's not really any indexes on information and stuff, you kinda have to read through reviews and Stax theads to find anything. There's no issue with importing from japan in general AFAIK (unless you buy used). The Stax earspeakers are durable if you take care of them, srs-2170 is probs not an exception, though 'stats in general might develope channel imbalance at some point (like in many years). The srs-2170 system is considered pretty good, but fairly bright AFAIK. Many compare it to the q701, though without many of its flaws and generally better. If you want the best value, you should go for vintage Stax gear.

^There's what I find to be the general consensus.Correct me if I'm wrong.

post #760 of 1072
207 or the 2170 package is far from crap it's going to be a night and day step up from the 598 and MB Quart 400. You'd only find the Stax disappointing if you like gobs of subwoofer alike bass.
post #761 of 1072
Quote:
Originally Posted by DefQon View Post

207 or the 2170 package is far from crap it's going to be a night and day step up from the 598 and MB Quart 400. You'd only find the Stax disappointing if you like gobs of subwoofer alike bass.


I like clean, clear, detailed bass, not muddy thumpy phase-distorted bass.  Let's put it this way:  What threw me over the edge into buying the 2170s is when I noticed that the amp was DC coupled.  I've designed and built a number of headphone amps in my time, and one of my pet peeves is the bass phase distortion caused by DC blocking caps, so I design my amps without them whenever I can.  This means dual rail supplies, good clean solid grounds, carefully matched components in places, etc.  A bit more complexity, but SO worth it.

 

My listening rig at work (what I'm listening to right now, actually!) is what I call "DC from DAC to Diaphram."  If you put a DC value out that DAC, the phones would move and stay there.  I _DON'T_ do this, but I could.  There is no bass roll off, no phase distortion, no peaks, nothing.  It is the cleanest and clearest bass I've ever heard and I LOVE it.  My current favorite album to show it off is the "Audiophile Mix" of Nine Inch Nails' "Hesitation Marks."  There is some AMAZINGLY detailed bass in that album that gets COMPLETELY lost through all but the largest coupling caps.  (And don't get me started about what dynamic range compression does to those lovely baselines...)

 

The 207s claim a lower frequency response of 7Hz.  I assume this is -3db, though I've never seen it specifically stated.  If it is really that flat through 20Hz, I'm REALLY looking forward to delivery.  :-D

post #762 of 1072

So, on the subject of "New to Electrostatics," what music/albums do you all recommend as a way to really show off the benefits of cans like these?  Many of my friends are anxious to listen to what all the hoopla is about and I want to make sure I demo them correctly.

 

My fear is that I primarily listen to rock, metal, electronic, and some sound-track, which are generally not recorded with critical listening in mind.  There are some exceptions to this obviously, but as a generality it's true.  I'd love to hear what y'all's Go-Tos are for demoing the benefits of Electrostats to non-critical listeners.

post #763 of 1072
Quote:
Originally Posted by SmittyHalibut View Post
 


I like clean, clear, detailed bass, not muddy thumpy phase-distorted bass.  Let's put it this way:  What threw me over the edge into buying the 2170s is when I noticed that the amp was DC coupled.  I've designed and built a number of headphone amps in my time, and one of my pet peeves is the bass phase distortion caused by DC blocking caps, so I design my amps without them whenever I can.  This means dual rail supplies, good clean solid grounds, carefully matched components in places, etc.  A bit more complexity, but SO worth it.

 

My listening rig at work (what I'm listening to right now, actually!) is what I call "DC from DAC to Diaphram."  If you put a DC value out that DAC, the phones would move and stay there.  I _DON'T_ do this, but I could.  There is no bass roll off, no phase distortion, no peaks, nothing.  It is the cleanest and clearest bass I've ever heard and I LOVE it.  My current favorite album to show it off is the "Audiophile Mix" of Nine Inch Nails' "Hesitation Marks."  There is some AMAZINGLY detailed bass in that album that gets COMPLETELY lost through all but the largest coupling caps.  (And don't get me started about what dynamic range compression does to those lovely baselines...)

 

The 207s claim a lower frequency response of 7Hz.  I assume this is -3db, though I've never seen it specifically stated.  If it is really that flat through 20Hz, I'm REALLY looking forward to delivery.  :-D

Nice taste in music there! Hesitation Marks is a very good example of a record with so many layers of sound, it's awesome. I listened to "While I am still here" the other day with my Lambda Signatures on the modified T-1, and it was just great.

post #764 of 1072
Quote:
Originally Posted by SmittyHalibut View Post
 

So, on the subject of "New to Electrostatics," what music/albums do you all recommend as a way to really show off the benefits of cans like these?  Many of my friends are anxious to listen to what all the hoopla is about and I want to make sure I demo them correctly.

 

My fear is that I primarily listen to rock, metal, electronic, and some sound-track, which are generally not recorded with critical listening in mind.  There are some exceptions to this obviously, but as a generality it's true.  I'd love to hear what y'all's Go-Tos are for demoing the benefits of Electrostats to non-critical listeners.

Anything well recorded for demoing, lol. I have no first hand experience with the sr-207 and electrostats don't sound the same at all, but most lambdas sound pretty good with chamber-ish classical, piano and that kinda stuff. Also acoustic instruments in general. Try Ottmar Liebert – Up Close, which is a binaural acoustic guitar album.

Be prepared to develope your music taste with your 'stat setup ;) My lambda signature can be extremely pleasing, yet terribly demanding. Its one of the more extreme 'stats in the stax family, though.

I'll look forward to your impressions, let's see if you are ready for such a setup, lol :p 

post #765 of 1072
Quote:
Originally Posted by AManAnd88Keys View Post
 

Nice taste in music there! Hesitation Marks is a very good example of a record with so many layers of sound, it's awesome. I listened to "While I am still here" the other day with my Lambda Signatures on the modified T-1, and it was just great.

Yeah, a fellow signature/t1 owner :redface:

 

What t1 mods did you do? Unfortunately my signature is down with an imbalance cold atm, hopefully just dust/hair in the driver but I barely have the time to look into it... Music recommendation for the signature?

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