[spritzer]

Quote:

Originally Posted by edstrelow /img/forum/go_quote.gif My refurbishing of the Koss ESP6 is proceeding more successfully than my attempts to correct the imbalance of the Stax SRX3's. I have just done a third cleanup of the 6's, including scrapping some of the residuesfrom the boards, around each circuit component. Unfortunately, my contact cleaner didn't get all the crap off and I think it was somewhat conductive. So I thought that at least if I scrape a channel around each part, I might prevent some leakage of current. Whatever the reason, the 6's are starting to sound hi-fi, more forward midrange, significant treble and respectable bass. A quick comparison with the Stax Sigma/404, shows that the main deficiency of the 6's is a lack of "air" around the voices and instruments. I will try to get a review out with photos in the next day or so.

I used Brasso and Autosol Metal Polish on my ESP6 PCB's and they look much better. Resoldering the boards will also help because he solder used doesn't age well and develops a hard outer crust and it is resistive.

Looking forward to the review and some internal pictures. Knowing Koss your set might be very different from mine.

 

[mikeg]

He installed the necessary Jack for the HE90, and also perhaps adjusted the voltage output for it, at this outlet. You'll need to contact Jack Wu for the details.

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif What upgrades, if any, are in this amp over the stock unit? I'm considering the GES as my next jack of all trades amp and it will have to beat my modded T1.

 

[tubaman]

I get that some balanced amps have unbalanced and balanced in (Rudister NX-33) and some have DAC inputs (Headroom), then balanced out for the headphone to connect, for versatility of connections and benefits of balanced headphone.

Stax's more expensive models have XLR inputs but they don't appear to have balanced out to the headphones, why not?

 

[spritzer]

Quote:

Originally Posted by tubaman /img/forum/go_quote.gif I get that some balanced amps have unbalanced and balanced in (Rudister NX-33) and some have DAC inputs (Headroom), then balanced out for the headphone to connect, for versatility of connections and benefits of balanced headphone. Stax's more expensive models have XLR inputs but they don't appear to have balanced out to the headphones, why not?

All Stax headphones (and most electrostatic phones in general) are balanced and have been sine 1960.

 

[milkpowder]

Some person contacted me with the following problem. Could you possibly help him out?

Quote:

I have 2 pairs of stax at the moment, a pair of SR X Mk 3 and a pair of gamma, both driven with a SRD-6 self biasing energiser (I have 2 systems in different rooms). I have had these for some considerable time. Unfortunately, both have developed a fault. The fault is that the right earspeaker loses emphasis with the sound biasing to the left as a result; don't know what causes this although the gamma fault occurs just very occasionally. Blowing directly into the earspeaker clears the fault in the SR X but only for about 5 minutes!! If you have any ideas on this they would be appreciated!!

Thanks on behalf of the both of us!

 

[edstrelow]

If both phones show the same fault, first, I would want to check the SRD6 for a fault before assuming that both have the same channel imbalance problem.

 

[mikeg]

For reports regarding the Woo GES amp's performance, take a look at the following postings:

Posting #318 at http://www.head-fi.org/forums/showth...236593&page=13,

and Posting #234 at http://www.head-fi.org/forums/showth...22#post2899122


Quote:

Originally Posted by spritzer /img/forum/go_quote.gif What upgrades, if any, are in this amp over the stock unit? I'm considering the GES as my next jack of all trades amp and it will have to beat my modded T1.

 

[spritzer]

Quote:

Originally Posted by mikeg /img/forum/go_quote.gif For reports regarding the Woo GES amp's performance, take a look at the following postings: Posting #318 at http://www.head-fi.org/forums/showth...236593&page=13, and Posting #234 at http://www.head-fi.org/forums/showth...22#post2899122

I never take much stock in meet impressions unless they are by people that are very familiar with the system the device is in. I'll wait for your impressions with anticipation.

I believe this can be a great amp though in stock form it is let down by the parts quality. This has to be done for the low price but another 1500$ in parts and this amp should rock. Add to that some mil-spec Mullard tubes and it should wipe the floor with the Aristaeus.

 

[mikeg]

I will compare it to my McAlister EA-4, and I (and others) will also compare it with an Aristaeus at our forthcoming June 9th meet. In case that I find it lacking, I'll probably be willing to ship it back to Jack Wu for upgrading of parts, even if a substatial additional cost is involved. But, that's all still in the future.

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif I never take much stock in meet impressions unless they are by people that are very familiar with the system the device is in. I'll wait for your impressions with anticipation. I believe this can be a great amp though in stock form it is let down by the parts quality. This has to be done for the low price but another 1500$ in parts and this amp should rock. Add to that some mil-spec Mullard tubes and it should wipe the floor with the Aristaeus.

 

[patrickamory]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif I never take much stock in meet impressions unless they are by people that are very familiar with the system the device is in. I'll wait for your impressions with anticipation. I believe this can be a great amp though in stock form it is let down by the parts quality. This has to be done for the low price but another 1500$ in parts and this amp should rock. Add to that some mil-spec Mullard tubes and it should wipe the floor with the Aristaeus.

What parts in particular do you feel are problematic? The Solens? What would you upgrade to -- Jensens? the metal film resistors? (what are they, Vishays?) Maybe the tube sockets are plastic not ceramic? I'm going by the pics on the Woo site here.

 

[mikeg]

For more comments regarding the Woo GES amp, See posting #425 at the following thread: http://www.head-fi.org/forums/showth...236593&page=17
Sure look like it's a real winner.

 

[ericj]

Power transformer sure is close to the audio circuit. And not just on the GES, seems to be a design flaw of their entire product line.

 

[mikeg]

If it's a flaw, how come performance is flawless?

Quote:

Originally Posted by ericj /img/forum/go_quote.gif Power transformer sure is close to the audio circuit. And not just on the GES, seems to be a design flaw of their entire product line.

 

[Veniogenesis]

Quote:

Originally Posted by mikeg /img/forum/go_quote.gif If it's a flaw, how come performance is flawless?

The correlation is vague. While a design flaw can be quantitative, performance flaws can not be quantitatively measured. Yes, placing a power transformer near audio signal elements is quite undesired and has a quantitative effect. How much of an effect sonically is debatable. I don't think it's safe to say that just because performance is good that the design is not flawed. As a matter of fact, we know of many amps out there that have serious design flaws but sound quite good according to those who have heard it.

 

[spritzer]

Quote:

Originally Posted by patrickamory /img/forum/go_quote.gif What parts in particular do you feel are problematic? The Solens? What would you upgrade to -- Jensens? the metal film resistors? (what are they, Vishays?) Maybe the tube sockets are plastic not ceramic? I'm going by the pics on the Woo site here.

Solens are horrible caps so that is an obvious first step. Replace them with V-Caps or Audio Note Silver caps and also use some as bypass caps for the PSU. Swap all resistors for Audio Note Tantalums and all PSU caps with Black Gates. Teflon tube sockets with solid copper contacts would be nice and a Furutech IEC power inlet and some WBT silver Nextgen rca sockets. The volume pot should be replaced with either a P&G RF15, an Alps RK50 or a stepped attenuator if you can stand the damn things. All wiring should be soft solid core silver in cotton or teflon/air when working with high voltages. If you want to go for the full assault on the high end add some Tamura or Tango transformers but that is at least an extra 600$ or more.