spritzer

I wasn't sure about posting this but it kinda had to be done. Pic is from HF and the usual nonsense in the peanut gallery there: So this is the Sirrah V3 from high-amp.de...aka yet another slight twist on the Stax SRM-1 Mk2 or derivatives. For me it is just the build here and well... the total shitbox we have here. First off, what's up with all the hotglue? As somebody who has built hundreds of amps at this point... I don't even own a hotglue gun nor would I ever think of using this crap. Some other goodies, top of the transformer sanded for it to fit in the chassis, no insulation on the mains plug which means this would fail even the basic CE tests, nice bit of cloth underneath the pot there to presumably stop it from shorting something on the board and I just love all the transformer leads, not twisted in any way, coming really close to the input wiring. The hand cut heatpads on the output transistors are also nice and I very much doubt that tiny ballast resistor for the bias supply is rated to 600V.... On top of that, look up the design of this thing. Basically a SRM-212 with a full size power supply and some things changed. +/-200V rails, no CCS for the VAS stage and very little power.

Seconded

Yup, that is the same as on mine. I'm just going to order a custom made transformer which will also allow me to have some fun with the amp over all.

It's worse on the 006tS I just got, there is only a 100V winding and nothing else. The cut wires can usually be restored with some precision surgery but with just one winding, nothing can be done except a new custom made transformer.

Post some pictures of the inside towards the back of amp as there is no single way to convert them.

There is nothing wrong with DIY and we try to make the PCB's as simple as they can be but it is a whole other matter to sell that DIY design after butchering the basics...

Ahh my ebay feed is such a rich source of crap. Now this: https://www.ebay.com/itm/184390225946?_trksid=p11021.c100851.m5053&_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20170803121420%26meid%3D7c8a959dd9b44639b572f30ba9d29c74%26pid%3D100851%26rk%3D4%26rkt%3D4%26mehot%3Dnone%26b%3D1%26sd%3D143674134487%26itm%3D184390225946%26pmt%3D0%26noa%3D1%26pg%3D11021%26algv%3DDefaultOrganic&ul_noapp=true Pics here for when the listing goes down. Standard KGSSHV but with a few twists: Notice that their are no terminal blocks which is bad but one bonus, this amp will kill your headphones. Can anybody spot it? It's not the twisted output leads which are a terrible idea... The bias is tied to the "bias tp" which is just for measuring the bias... before the ballast resistor!! So yeah, no ballast so say goodby to your diaphragms.

Stax SRM-1 Mk2 and upwards.

I'm not sure where I wrote down the pinout for the Monoprice headphones so I'll have to dig through my archives to see if I can find it. If I find it then I can make adapters as soon as the local store opens up after the long holiday here. As for getting the most out of these, an amp upgrade would be the first port of call.

All Stax are balanced and even if an amp has two outputs... they are wired in parallel with both channels at both sockets. What benefit could be had from this is very dubious.

I agree, those are very nice indeed. Could be old stock but I doubt it. Most likely Stax just enjoy messing with us...

Is it a Mk2 or an A unit? Also, this week in stupid: https://www.ebay.de/itm/124250502104?ul_noapp=true Here are the pics in case the listing is taken down: So somebody chopped off the Stax plug on a Mk1 and fitted two for dual mono... why I don't get but then stupid is hard to understand.

Good point so the empty warranty card points to a Japanese unit and the sellers who export never fill out the warranty cards.

Stax serial numbers are in constant flux so no idea really. SZ2 and SZ3's were being sold right back in 2008 so could very well be. The dealer is supposed to fill out the warranty card but some don't do it.

Thanks for that and I had a lovely day. The weather was just about as nice as it gets in Iceland with great people and even better food.

No, none of the amps are left here but it is a very noisy thing. Plenty of high frequency noise in that thing.

Yes.

The bias in the E90 is run off the HV+ line so 600V. That is fine for Stax but the issue is that the ballast resistor is not the right value and there is a cap after it. Now you could just place a 4M7 resistor on the adapter but I prefer to go into the amp and modify it with a voltage divider and moving the cap. The issue there is opening up the damn thing...

Speed holes...

Those parts from Nikko were probably here as I returned them a decade ago as fakes. They did find real ones to replace them back then but yeah... took back the fake ones and are probably selling those.

Also cheaper not to buy the fuse insert. Clearly saving the big bucks here...

...wait, there is more!! I woke up early so what better than strip this shit down. First off was to remove the transformer and I found this: Notice the wire coming off the IEC and into the end of the fuse holder...and another wire connected to that pad? Yeah... I don't see any evidence that there had ever been any solder on that end of the fuse holder and the insert which holds the fuse is indeed missing. That would explain why, when the PSU blew it left this mark on the chassis At least the IEC input is nice... Gotta have that gold plating. I also don't understand how anybody could put "copyright" on this PCB with a straight face: It's two traces between two terminal blocks... ok. Now the real price, lifting the amplifier boards: Notice the nice line of standoffs...yeah not connected to anything: The heatsinks just sat on them, not connected in any way. So this thing has been shipped and the only thing securing the sinks are the transistor legs!! Spoiler alert but what could possibly happen... So 3 screws hold the amplifier boards to the chassis but no lock washers anywhere and everything was loose. What a great way to support some of the heaviest objects in the amp.

As many of you know, I for one have stopped releasing all new designs for a few years now after I got fed up with people building crap and claiming it was somehow connected to Kevin or I. Now this also means I don't release the PCB's for many of the older projects as I want to change something and often... make them smaller. So this hasn't stopped people selling crap with our circuits but at least they don't get any of the updates. Now here is an amp I saw come up for sale in Japan a while ago. The new owner contacted Kevin to try and trouble shoot it but yeah, we don't offer any real help with these things. Something about the PSU did peak my interest so when it popped up again for sale for not a whole lot of money, I snapped it up. So here it is: Standard KGSSHV here with some version of the offboard PCB's but the build... it is just so bad. All the wires are the same color which is just nuts. Also just cheap PVC China wire and I'll check if it is actually real copper in there. Here are some of my favorites: Support the sinks properly... that is for suckers. Also I don't know why the volume extender is wrapped in Kapton tape... The amp shipped like this, the sinks are just attached by the components. It takes no for to bend them like that. I think this is some form of the GRLV but shit is is cheaply made. Transformer wires thinner than 24AWG... yeah pure quality there. Terminal blocks clearly cost too much but stuff like this at +580V can arc over. Last but not least, no repairs are possible.... What I find truly fascinating about this thing is the PSU board as... well... they cloned my smaller KGSSHV design. That one was never released into the wild but I have posted plenty of high res pics of both sides and they seem to have made a new board from those. See this: Now all the written markings or most of them, look real. What is not real are all the part numbers as Rxx or Cxx is not a system we use. The packages are all also a bit wrong so the board is clearly a clone. I'll dig it out and post some pics next to the real thing. More coming as I strip it down.

I do always remove the damping inside the earpads so that's well worth it. The older ESP950's (remember they have been in production for 30 years) also had damping on the back of the drivers which has to be removed.

That really applies more to the older ESP950's as Koss have removed most of the damping by now.