The Stax Thread III

[zomkung]

if you can, add a switch to toggle between global/non-global feedback.

I went the other direction in my KGSS, added the non-global option to it and end up preferring the non-global (the feedback type used in 727).

Global feedback usually sound more impressive for the first 5~10 minutes, much cleaner sound and better control. But after a while I feel the sound has kind of a "sheen" feel to it. The way to say it, I guess, is that it is more "silky". While the smoothness is great, the "silky sheen" is not. Kind of irritates me a little after a while.
I usually switch back to non-global feedback after a couple of songs and just leave it there. More distortions? yes, but the emotion in singers' voice comes through better.

I mostly listen to vocal stuff so the more solid bass offered by global feedback is not big enough of a plus, in my situation, to offset the "sheen" irritation.

Sorry to ask,
What headphones are you using with the amp? and do you usually EQ your phone?
I am quite curious about the amp and its power. The transformer srd-7 could provide unlimited power to the can at a cheaper price. I've read somewhere and they said, while srd-7 is very good in terms of sound dynamics, but will lack the details comparing with the stats amp. I'm not sure about that if it affects the people who usually EQ the phone.

Thanks,

 

[AudioCats]

with the KGSS I mostly use the sr007 (the original, no mk #), occasionally sgl-jr.

I don't use EQ.

My rating of the phones I have: sr303 =< srx-iii < esp950 << HeAudio Jade < hifiman sgl-jr < sr007.

Transformer boxes can do ok on a pinch but is missing too much details. I'd say the srd-7 can drive the 303 ok enough. Any phones better should get an electrostatic amp.

You will likely not be able to find a transformer box that provides the level of details to rival a 717/kgss. I have a box with two large Lundahl output transformers inside. And it is still not detailed enough. Of course there is still the amorphous core (AM) version Lundahl to upgrade to, so all hope is not lost yet, but I doubt the AM will do that much better (I just did a quick check, the AM version transformers are $800/pair.)

 

[DecentLevi]

Does anyone happen to have an L700 compatible metal headband for a second-hand price? The plastic band broke for my L300 Limited Edition and only source I saw so far is $220 from direct source. Thanks

 

[zomkung]

with the KGSS I mostly use the sr007 (the original, no mk #), occasionally sgl-jr.

I don't use EQ.

My rating of the phones I have: sr303 =< srx-iii < esp950 << hifiman Jade (I) < hifiman sgl-jr < sr007.

Transformer boxes can do ok on a pinch but is missing too much details. I'd say the srd-7 can drive the 303 ok enough. Any phones better should get an electrostatic amp.

You will likely not be able to find a transformer box that provides the level of details to rival a 717/kgss. I have a box with two large Lundahl output transformers inside. And it is still not detailed enough. Of course there is still the amorphous core (AM) version Lundahl to upgrade to, so all hope is not lost yet, but I doubt the AM will do that much better (I just did a quick check, the AM version transformers are $800/pair.)

Sorry for bothering you.

I have a KOSS ESP 95X. I wanted to let it go since I didn't use it and thinking to buy any cheap 5-pin lambda as the second pair after O2-MK1. Since you rate the esp950 better than other staxs. I'm considering keeping ESP 95X and will buy the cable converter instead.

 

[French Penguin]

a "mini" chassis offers no room for larger upgrade parts, not ideal. (assuming you will work on it later).

I think the 717 will work well enough. Stax builds good quality stuff, kind of expensive but lasts forever. My srm-1 (non-MK2, probably made in the 70's) still works and sounds fine. The electrolytic capacitors might need to be replaced due to age, though.

Thanks, I'll keep that in mind, I haven't read enough to know about all the possibilities/variants the KG amplifiers can become, I just remember seeing two people believing it was enough but I do think they purchased them prebuilt instead of DIY since they were talking about larger price differences, do not quote me on that because I don't want to accidentally offend them.

Thank you, Take Care!

 

[AudioCats]

...
I have a KOSS ESP 95X. I wanted to let it go since I didn't use it and thinking to buy any cheap 5-pin lambda as the second pair after O2-MK1. Since you rate the esp950 better than other staxs.

I much prefer my 950 over my 303.
The adaptor cable on ebay seems to be super expensive though. If you still have the koss extension cable (in the 95x package), you can just add a 5-pin plug and diy an adapter. The plug is available from Allied, part# 86-71-6s.

 

[AudioCats]

Thanks, I'll keep that in mind, I haven't read enough to know about all the possibilities/variants the KG amplifiers can become, ...

sorry, I was under the impression that you will do at least some upgrade to the amp, in such case a mini-chassis is not as good as a large enclosure.

If your 717 has blue ALPS pot as volume control ( like what is in my 007t's), one "must do" mod would be to configure it to "shunt pot volume control" and add premium series resistors. It can bring noticeable SQ improvement. (Alps blue is kind of "dull" sounding)
flavor (relatively speaking) of difference resistors
If it is difficult to decide which series resistor to use.... get vishay z-foil, it is a sure bet. Very expensive parts but you only need 4 (or just 2, if you only use RCA inputs).

 

[French Penguin]

sorry, I was under the impression that you will do at least some upgrade to the amp, in such case a mini-chassis is not as good as a large enclosure.

If your 717 has blue ALPS pot as volume control ( like what is in my 007t's), one "must do" mod would be to configure it to "shunt pot volume control" and add premium series resistors. It can bring noticeable SQ improvement. (Alps blue is kind of "dull" sounding)
flavor (relatively speaking) of difference resistors
If it is difficult to decide which series resistor to use.... get vishay z-foil, it is a sure bet. Very expensive parts but you only need 4 (or just 2, if you only use RCA inputs).

No need to apologize at all, you were only helping and I thank you for the advice!

I will definitely take a look inside of the 717 to see when it arrives and perform the modification in the future if it does have the blue ALPS pots and thank you for the link with replacements which even includes descriptions of each one. I'll read up on them and determine which one I would prefer to compliment the sound quality of the 007A if applicable.

Thank you and again, no need to apologize for doing nothing wrong.

 

[zomkung]

I much prefer my 950 over my 303.
The adaptor cable on ebay seems to be super expensive though. If you still have the koss extension cable (in the 95x package), you can just add a 5-pin plug and diy an adapter. The plug is available from Allied, part# 86-71-6s.

Thank you,

How much improvement between the koss stock amp and the amp you have?

From what I've read, the koss has 600V bias voltage, and stax's pro-amps have 580 bias voltage.

I don't have the KGSS, and not sure about the bias voltage difference.

 

[AudioCats]

How much improvement between the koss stock amp and the amp you have?

The stock E90 sounds clean, but is rather sterile with very little emotion. Probably ok for instrumental stuff but unacceptable for vocals . The E90 can be improved upon but the combination I like can be tricky to implement, I actually don't want to recommend modding it (especially when you already have a 727). The E90 mod thread can be found in the DIY section.
I think you will love the 95x driven by the 727.
(if the 727 has blue Alps inside..... do the shunt volume control mod mentioned in the post above.)

From what I've read, the koss has 600V bias voltage, and stax's pro-amps have 580 bias voltage.

I don't have the KGSS, and not sure about the bias voltage difference.

E90 bias is taken directly off the + high voltage line, which is loosely regulated, it can vary from 560 to 620v.
Bias line inside the KGSS is done in the typical stax fashion, using voltage multipliers, it is not super precise either.

Bias voltage (for the phone diaphragm) is not that super critical, there is no need to hit exactly 580v or 620v. I have a SRD-7 with select-able bias settings, my Lundahl box has 4 bias settings as well. I think 450-500-580-620v in the srd-7 and 500-580-600-620v in the Lundahl. I did it just to experiment. Changing from 580v to 620v doesn't make that huge of a difference. If anything, I sometime prefer using a slightly lower bias voltage, say 500v, it softens the sound a little, making it more fun for long sessions.

 

[Menkau-ra]

Does anyone happen to have an L700 compatible metal headband for a second-hand price? The plastic band broke for my L300 Limited Edition and only source I saw so far is $220 from direct source. Thanks

I can buy them from you

 

[Menkau-ra]

I have brand new L700Mk2 with SRM-400S. For the source I use Schiit Gungnir A1 which is warm sound signature. I burned them in from about 100hrs. Why do I still have harsh trebles? I even purchased Schiit Loki+ but it's not helping. Used L300 LTD sounded PERFECT on the same setup.

 

[DecentLevi]

Hi guys, I've gotten a few inquiries for a "sale" of my L300 Limited Edition. Nope they're definitely not for sale, I'm lucky to have 'em, and just looking for a headband replacement.

 

[Menkau-ra]

Hi guys, I've gotten a few inquiries for a "sale" of my L300 Limited Edition. Nope they're definitely not for sale, I'm lucky to have 'em, and just looking for a headband replacement.

I've sold mine L300 LTD thinking that L700 would be better. But I was wrong, at least to my taste. How can I fix L700? Would L500 pads help?

 

[catscratch]

You can always try EQ. Use a test tone generator or sine sweep to hear where the peaks are and lower them. Though in my experience, treble harshness with new Lambdas is very fit dependent, and a simple headband replacement affects the sound quite a lot. I've tried Mk1, Mk2, and Mk1 with custom yokes and they all sound different. In any case, EQ is the most immediate solution and there are plenty of free software options.