Headphone Amplification

Hi everyone, I have a question: how do you select an output transformer for Stax headphones? I’ve built a circuit using 2A3 tubes, but I’m having trouble with the output transformer because I don’t know how to calculate the specs—though the LL1660 is said to be suitable. I want to order a custom transformer for 2A3 and 845 tubes.

I have a KGSS-HV that I acquired years ago from a local builder. It has Sanyo parts and +/- 400V BHSE power supply. I started using it again last week after years of storage and it seems to be working great with my L700. Question: Does the KGSS-HV need periodic maintenance? I ask because in troubleshooting my SR-009 hum on the right channel, I read about DC offsets and balance. Are these something I should be checking periodically?

AnTek transformers are made in China. I purchased the AS‑4T400 (400VA, 400V) transformer and the AS‑3T350 (300VA, 350V) tube transformer to build the Blue Hawaii and Carbon amps. The cardboard packaging had “Made in China” labels, and some of them were partially peeled off. If I had known they were made in China, I might have bought them directly from Taobao.

Damn you LAiV. Just after I’m satisfied with your Harmony µDDC and µDAC you release a new, cheap combo DAC-headphone amp. Yo Rob!

Does anyone know if the Headroom Portable Desktop Amp is center pin negative or positive?

Theres a new hybrid versions out ...would be great to get Spritzers or Kevin's view on it...https://wooaudio.com/amplifiers/3es

details -> scheme -> psu -> >Max output voltage: 280Vrms It doesn't seem like a very powerful thing. What do you think?

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so what do we have here stax 717 in a huge metal case now the weight has increased from 5 kg to 11 kg it seems like the case is made well, all the places for fastenings are made accurately the main thing is that it works

Reference Amplifier for Electrostatic --------->>>>>>>> what do you think? does it look good or bad? found this on the net today

Hi Everyone, Just got promoted and my Birthday is coming up soon, So I’d like to treat myself with a new Amp. I've just bought a Sennheiser HD 800s Headphones and I'm looking for an Amp to pair it with. Please note the following before answering my question. 1- I have a Marantz Cinema 30 AV Receiver supposedly a top-of-the-line unit that has a built-in DAC. 2- I will mainly use the Headphones for 80% Watching Movies, Football, Sports & 20% for Music " Heavy Metal, Rock and Movies Soundtracks". My Question, 1- Which Amp do you recommend to connect to my Marantz Cinema 30 and my Sennheiser HD 800s Headphones? 2- Is the DAC in the Marantz sufficient or …

I have the standard old school Stax SR X Mk3 , SRD 7 set up. What would be another amp to upgrade to? Thanks.

This looks interesting...

Hi, First post here. I am curious about building an electrostat HPA as I only have an SRD7 Mk2. I am interested in some of Kevin Gilmore's designs like the KGSSHV variants and the T2, but the legend about the KGSSHV seems to ring true that it is hard to build and hard to learn about. Is there somewhere I can read about these different designs in white paper format like Nelson Pass does with the First Watt amps? I can't even find schematics or a BOM. It's truly a nightmare, and I don't want to endlessly bother spritzer with questions. Frankly, I am not totally sure of the "authorship" of each of these amps which makes it harder to research. I was considering firs…

This was introduced at High End 2025 in Munich and here is a blurb about it There are no internal pictures at all but it sure looks like they stole some of our Megatron here. Yeah, if that is the case, that is not okey. At first I didn't know what driver tubes were used and since those look a bit like 6N6pi's... I thought "well that is stupid but it might kinda work if used with some transformers". No... it is far worse. Single tetrodes, likely triode strapped, so are they trying to out compete the Woo WES for the worst all tube electrostatic amp design...or maybe the Triode H1? Time will tell but there simply aren't enough tubes here if the EL34's are used a…

I tried to adjust tvr-1 and tvr-2 in srm-727, it seems tvr-1 is in 2-stage and tvr-2 is in first stage. I tried with traditional method which I was using in T1, measure R+/R- dc voltage and adjust tvr-2, measure R+ and ground then adjust tvr-1, both set to about 0 but found the amp stopped working. Then I restored to original value, the amp works again. Does any know the correct way to adjust tvr-1 and tvr-2 in SRM-727? Thanks. I also found 727 is a good paring with hifiman jade 2.

https://estatron.com/collections/all Somebody who studied Head Case is now building and selling a 'stat energizer. Kind of interesting because it's only $160. Worth it?

I have a CCS modded Stax SR-006t from Mjolnir Audio that stopped working back in September. For a few weeks I would get no sound until I turned it off and on, but now I get nothing. I've tried multiple sources and cables but no dice. I tested the DC offset between + and - of both channels and between the bias and both channels' - line. After that I tested the AC voltage playing a 1khz signal and followed it from the inputs to the vol control and got nothing. Spritzer repaired it back in April of 2023. The HV- line wasn't working due to a failed resistor and a capacitor was starting to fail. At the time the left channel was much quieter and had a buzzing noise before …

Hi all, I am hoping you can get me back on the right track in the world of Stax. A while ago I bought from Japan an SRD-7 mk2, a SRM-T1S, a Lambda SR Pro and a Lambda SR Signature Pro headset. The SRD-7 was bought just as an experiment, I did not really expect much from it. Besides I had read that the SRM-T1S should be better. However, from day one I have felt that the SRD7 mk2, coupled to a Pioneer M-22 power amp and a Pioneer C-21 preamp sounds much fuller/dynamic/better lower end compared to the SRM-T1S. The SRM-T1S seems flat or lifeless in comparison. I was sure there was something wrong with it, it is an old amp after all. I tried biasing to no effect. …

I have tried every possibility to optimize the circuit, but finally STAX has chosen the worst one. I'm pretty sure that STAX has gone with SMDs, it all fine, most parts in working will not generate lots heat, also SMDs significantly reduces the distributed inductance caused by PCB board through holes. ...... there some analyze and questions: 1, 4 large sized 7W 47kΩ resistors work as plate loads for 6SN7s, but higher value must be better, for example, two series 33K as 006T, or at least 62K 7W will far better than 47K, because 47K means too much current flow through 6SN7s, in my simulation is 9.5-10ma (grid at -9V), it's fine for 12AU7 or 12BH7, but 6SN7GT....…

Hi! I am renewing 25-years 717's and I observe strange things: I noticed a lot of wet places - as if sweaty - I suspect it has something to do with high voltage, have you noticed such symptoms in your old Stax? It's probably old flux - but these are places where it shouldn't be - output sockets, bottom of heat sinks (between PCBs). The second issue - how does the output protection system work - it draws voltages only from two outputs +L and +P? Because that's what I saw on PCB. What are the soldering points marked 81,82, 83 and Test: R,L,V for? I know that Kevi n had a diagram of this system somewhere, but it is no longer available .

I have a two speaker system and I'd like to incorporate a STAX setup into it. I'd like to continue to use my preamps remote control, and I want to use my preamps XLR output vs. my Rec Out's because well, I'm just funny like that. Is there a preferred way to adjusting the two volume controls when using a preamp and STAX amplifier? I know the 717 & 727 have a volume bypass switch, but I'm trying to open up my options to what amp I eventually get. Thanks

Removed due to wrong board post, please delete the thread

I'm doing a side gig reviewing headphones. Companies send me stuff and I give my opinion on things. I recently got a certain Moondrop Para planar which I thought sounded pretty okay. Then I saw the spec sheet and my hair stood up a bit- 101dB/V at 8 ohms. Or, when converted to actual efficiency figures... 80dB/mW. My question to the amp gurus here - will this load kill amps? It's a rare case of low efficiency combined with high sensitivity so people will be lulled into thinking that it's an easy load to drive. Like - hurr-durr, pot's only at 9'o clock and it's already hella loud! When in reality you're pushing serious mA and mW. And I'm not talking abo…

I was thinking of upgrading or supplementing my old Headsave Classic amp (3 x Burr-Brown OPA627, hooked up to an Arcam FMJ CD36 or Sony UHP-H1) with something new, not too expensive. I may still get a Chord Mojo 2, but this looks interesting at $219... just announced, with impressions coming out in a few days. The Schiit Midgard has a different discrete design, with a mixed-mode feedback and more power than the Magni+ I was looking at: