Bingturong

I'm very curious about the driver construction though. Are they actually going to make it like the original SR-X with a mesh stator? Quite looking forward to seeing more info on them coming out. Anyway I actually think it's a good decision for Stax, the L300 is... not good and Stax does have a neutral/pro headphone hole without the 207 anymore

It's announced, the SR-X1. So I was close with the name~

The SRM-2705 I think is the big clue since its probably a SRM-2xx. Why call it the 2705 though and not a 270S? Unless that 5 is an S but it looks too different

SRM-2705?

Ahh, that makes sense. The German market really got a lot of unusual stuff, I've seen a Gamma Pro New before too. That looks like a thinner cable than the SR-007, maybe same as the L500? A new entry level round Stax? I'll bet 20 bucks they call it the SR-X Mk 4

Huh, I was thinking its a Lambda Spirit but it still has the mineral wool of the Pro so that made me confused. People would buy it~ Heck if I had the money I'd buy it. I don't know why exactly but the idea of having a bucket of Lambda drivers amuses me

So there's a sellar that popped up that is selling A LOT of Stax parts, including a literal bucket of SR-404 drives. But this caught my eye. STAX A-PRO New Kopfhörer Teile | eBay A Lambda Pro New? I've never seen or heard of anything like that. Something in between the Pro and the Pro Classic/Spirit? No headband or cable available though.

Sorry for reviving the thread but don't know anywhere else in the site I can post this, got something curious. A Napolex NSA-3

Another longtime update. Going through the amp I found that pins 7 and 8 on the phono connector were already jumped. After more thinking and pounding my head, I realised that the ground for the for EVERYTHING but the power/bias section is actually coming out of the phono board connector. In the schematic the ground for PB-300, PB-200 and PB-100 were all connected together with the ground wire coming out of the PB-100 board. For some reason PB-500 ground was connected that of PB-200 instead of PB-100 but anyway. I just rewired so the ground connection is at the PB-200 connector instead leaving the PB-300 connector essentially unwired except for the MAG input. The amp is now working flawlessly and is silent than ever!

I've been pulling my hair with the damn phono board to the point I might as well rebuild the entire thing leaving only the film caps. Is there anyway to bypass the phono board in the amp? Without the phono board there's considerable hum.

A strange update, so rectifier and a few other diodes replaced and yeap! That strange warbling sound is gone. Except now there's a significant amount of distortion on all channels. After trying some stuff, removing the PB100 board seems to solve it. Since reading the schematic, I assume that the PB-100 is not exactly necessary is it? Since it only does the mag pu?

Right so apparently I didn't read enough. I found an old post by spritzer that said it worked find with his C-series SRM-1 Mk2 and meant for amps that didn't come with a jumper. Though mine isn't a c-series it didn't ship with a jumper but heck it should work. Tried it out and it powers on, no explosions, no burning, nothing. Plugged in a headphones AND there is still not audio. Though I have discovered that the normal bias does not energise at all whereelse the pro bias does, there's also a hissing sound too only from the pro bias. A quick voltage test from the rails show mid to upper 360V so it seems the voltage change has been a success. Given that the caps I used are rated at 400V, I think I may go find some new ones... My biggest worry though is the transformer is a goner so I'll test that out.

I got an old type A SRM-1 Mk2 JDM, I want to convert it from 100v to 220v but there is no exterior jumper so I'll need to wire the voltage selector myself. From reading previous threads, what I should do is remove the jumper between green and brown and simply swap brown for blue right? Also even using a step down converter and having the amp successfully turned on there is still no sound what so ever. I replaced the electrolytics and there's power going into ever component I tested but complete silence. Curiously though the amp should be rated for 370V RMS but I'm getting around 420V RMS from the rails. I suspect it may be due to the stepdown transformer being rated 110-120v instead of the 100v, hence my desire to change the voltage.

I'll do it, alongside checking all the electrolytics again for any faults. What confuses me is that the humming is only in one channel... any other components that should be replaced?

I'm pulling my hair at this. I don't think its the transistors as there is no increase in distortion when playing music, except for when the IS is turned on that just makes everything whack. Are there any other components possibly failing on PB300? Or even the power boards? I did notice the diodes on the rectifiers are still stock.

Right, I noticed something else. Removing PB-100 and PB-200 does nothing. And there's less audible hum with the board that had the resistors replaced, but still noticeable.

Hello again, So I got the resistors and replaced aaaand still humming. So I started swapping boards and only playing with one board. Now its humming if either one of the boards are in. Before it just hummed on the one board with the resistor issue. What could be the issue now? All electrolytics and diodes have been replaced already. Also would a simple voltage divider from the 640v rail work for a pro bias?

Thanks! I'll go grab some Vishay ones. Also I got an SRA-3S and the pot has gone to hell. Any recommendations for replacing it?

Heya! Sorry for reviving this thread again but I got a little issue with my SRA-12S. I had serviced it (with the help of this thread actually) with all-new electrolytic caps and diodes and it has been working dutifully for quite some time until I moved countries. However I brought it out of storage and well, one of the channels is humming loudly. I tracked the problem down to one of the PB-300 boards as when I switch the boards the humming also switches channel. The sound is still amplified as I can tell but the humming is at a constant volume. I think it might be, what I think is, the 630v filter on the board because... Yeah... I think the 51k 5W resistor is burnt but I could be wrong, that's why I'm asking for help. If its just the resistor would any metal oxide 51k 5W resistor do or does it specifically have to be a TDO RS5B because I cannot find anywhere to purchase them? And what about wire-wounds or something else to replace the resistor? I would post more pics but I'm hitting the 500kB limit~ Thanks