nemomec

In my experience only the Lambda normal Bias (230V) has the resistor on the connectors, not the Lambda Pro! Lambda nomal bias with Pro cable?

Thats maybe the reason for this squeal issue, thanks for the hint! The Signatures has this mesh unprotected on the backside, only some last models of the Signature has the new pvc dust cover of the newer Lambdas and the Pro and the normal bias Lambda has the mineral wool as protect.

I think the problem is not so easy to detect. My experiance is, that this squeal issue is most on the SR Lambda Signature models, i had maybe more than 10 SR Signature models here and the squeal problem has about 60-70%, the other Lambda models haven´t this issue. Where are the problem, stator, mylar thickness or other!?

Don´t spend your money for a BHSE and don´t make a long journey of searching a SRM-T2! Its so easy take a Audiovalve RKV and a Verto Box and all is fine! http://www.ebay.de/itm/VERTO-Stax-electrostatic-dynamic-magnetostatic-transformer-headphone-transformer-/171460930132?hash=item27ebde2a54

I heard also the SR-5 Gold and the SR-X mk3, but i´m more impressed with the performance of the older SR-3 New.

Some users here with any experience with the very old stax headphones like SR1, SR2 or SR-3? I have here a SR-3 New and after some problems with channel imbalance and long charge up time it works now fine and i replaced also the pads with new ones. Now i´m very surprised that they sounds on my SRA-12S so good with a clear/transparent sound, huge soundstage and nice mids, the only big issue that i found is the lack of deep bass. I heard 90% of all models after this SR-3 New to SR-009 and i think what a amazing headphone quality was made by stax in 1971. How is the quality of the other very old Stax models and there are any other experience with this nice SR-3 New?

Hello spritzer, Its better to rewire it or take a new case. I have done the following things: 1. changed the 8 resitors for the two channels R73/74/75/76 and R35/36/38/39 to 100K. 2. thermal paste on the heatsinks for the transitors 3. removing resitors R9-R12 (2,2K) and rewire the input section with a new 27K Alps pot 4. new case with complete rewiring of the voltage input and grounding, new power button with relais Any other useful hints, i have a newer PCB F1a-1413? http://www.pic-upload.de/view-23329932/innen.jpg.html RCA/XLR switch has only a function for XLR mode, both together are not possible but thats not a big problem for me i use only one source. Its a lot of work, but the chinese KGSS sounds now after the modification very good with black background and no issues.

http://www.open-end-music.de/vb3/attachment.php?attachmentid=8856&d=1404570749 http://www.open-end-music.de/vb3/attachment.php?attachmentid=8858&d=1404571198 My opinion is i like of the new series the SR-407 more than the SR-207 and find the SR-507 horrible, but in the end the older lambda models are even better.

The modified Chinese KGSS is superior to the current stax amps like SRM-727/007TII, but you need to rewire the input section and the pot must be replaced. Also you must do some small changes like thicker cables for the voltage input section and its better to take a new a case for the bigger pot and better cooling. The Woo Audio GES is a good amp for the SR-407 and in my ears a better choice then the current Stax amps but not on the level of the KGSS. I prefer only the SR-407 in the new lambda series, but the older Lambdas like Signature, Nova Signature are even better.

No way for me to unsolder the pot without destroying the PCB, it has solding points on top and bottom. Next steps are: First i remove the resitors on the bottom of the pot and test what happens! Second step i make a plan to isolate this crapy thing? Its a Nightmare!

In my knowledge a normal Alps pot has ground/output/input, this pot on the PCB is wired with the input in the middle!? I think the best way is to unsolder this cheap pot and take a new one on the front with cables to the PCB.

Ok here are some infos: R40/R47 40K R37/R42 510 ohms R9-R12 2,2K 4 resitors on the bottom are at 23K with full volume setting. I have changed the 8 resitors for the two channels R73/74/75/76 and R35/36/38/39 to 100K. Crazy stuff, but sounds extremly good

I don´t understand/believe this, if i use a preamp to reduce the input gain the volume control doesn´t work correct! I think the pot is a false model or wrong wired!?

"4) RCA/XLR selection switch inject a lot of noise into the amp when RCA is selected. When XLR is selected no noise is injected, and funny enough RCA input also work in XLR mode." Same problem with my KGSS, RCA works also in XLR Mode, but the noise is gone after connect to my Stax SRA-12S preamp. The feedback resitors now changed to 100K but with no huge effect on the gain (grazy soldering on this manufactured board ). I have now ordered a ALPS RK27114 pot and hope they are works fine in this amp and solve the gain problem. The sound of this amp is very good and i hope we can solve the issues!

Ok, thanks Kevin, i think i change the pot and replace the resitors R73-R76 with 100K. I heard yesterday the chinese KGSS some hours and they sounds very very good with huge dynamic and strong bass extension (testet with Lambda Nova Signature). But the pot is horrible, i heard also a little imbalance and i full agree with justin that said "It was like trying to listen with IEMs on a high gain amplifier".

Here are the pictures: http://www.pic-upload.de/view-23329928/KGSS_1.jpg.html http://www.pic-upload.de/view-23329900/KGSS_2.jpg.html http://www.pic-upload.de/view-23329932/innen.jpg.html http://www.pic-upload.de/view-23329931/innen_revision.jpg.html http://www.pic-upload.de/view-23329937/innen_poti.jpg.html http://www.pic-upload.de/view-23329907/poti_unten_1.jpg.html http://www.pic-upload.de/view-23329908/poti_unten2.jpg.html Its the pot or not, good question. I measured now the resitors of the pot on the bottom of the board and they are increasing linear from 4 to 23K ohms over the entire pot rage. But the pot has only a audible range from 6 to 8 hour and is then extremly loud with massive distortion with a 1,6V cd-player source!? I use the KGSS now after a premap and it sound very good but this can´t be the final solution.

Hello Kevin, thanks for the infos! I have measured the resitors R73-R76 and there with 152K are ok, the bias and balance was also set to correct values. I think the volume pot ist the problem and ordered a new one. The pot has in the first quarter a very quick increasing of the volume but at the half to end there is nothing!? The design of my China KGSS is a little different from yours i post some pictures later, the Board has a new number F1a-1413.

Hello, my chinese KGSS is now received. Some positive things: - it has a voltage selector for 230V and 115V - it has a teflon stax plug - the bias voltage is adjustable over the pot TVR1 (you need a voltmeter with high impedance) - well built But I have one big problem, the gain is extremly high and i can´t adjust the volume pot over 8 hour without distortion on different sources. Where i can adjust the gain or which resitors must be checked? Edit: I think the cheap volume pot is defective

I ordered the chinese KGSS amp now on cart100.com, the 230V voltage is here in germany perfect. How ist the quality of the pot, it looks on the pictures very cheap also the cables on the Stax socket?