spritzer

I'm not the biggest fan of "balanced at any cost" but it really must be balanced for the audience but also being able to be used SE. No half-assed designs here like the WES and A-10. I'd really like to take a crack at "the ultimate" diff amp but it looks like 3 stages is the minimum we can go for. Even with a ECC83/ECC99 combo it simply doesn't have enough gain. Less volume means less good amp to a lot of people... Edit. You wouldn't believe just how much willpower it took to keep my Baldur SE only when the balanced input is better in every way.

Perfect excuse to fire up the BHSE...

That one should be close to the final version but I think we settled on +/-350V rails in the end.

I like that Frank, nice and simple. Have you ever messed with feedback in these amps? I used 150K and 1uf/630V in one of my Egmonts and it really helped stabilize it. I really like the idea of taking the diffamp to the max to see just how good it can be made. If we can find cheap chokes then I'm all for it but a simple pass transistor with a zener reference would probably be cheaper and easier to deal with. Even better to use isolated parts to kill any chance of shorts. Balanced input is a must have for the amp to be taken seriously and it really must have too much gain for the "MOAR LOUD!!!" people out there so ECC83 drivers with a bypass cap on the cathode. The idea is to try and make a high voltage amp anybody can build and be as cheap as is possible. It would also be a nice reference point to compare against the commercial amps. I think less than 400$ would be easy to reach with say 80$ for a transformer, 30$ for the PCB's, 50$ for the tubes and the rest for assorted parts. Not posted but I should have it somewhere, at least one version of it. That version is just a SRM-007t front end and a 6S4A with a 10M90 CCS and a trimmer+resistor on the cathode. I used Marc's Vulcan PCB's and modified them to become a KGST.

They are really something but the headband needs to be improved. I've been thinking about something like the LCD-2 approach, thin layer of memory foam to make them useable but can't find anything locally.

Very nice indeed!!!

Use a transformer to step down and another one to step up again? Nahh, even an Egmont would be preferable to that.. For the amp I'm leaning towards something simple like a quad of ECC8*'s feeding a pair of ECC99's. ECC99's need to be left floating so two filament windings at a minimum. Nothing else out there which fits "cheap, high voltage and reasonable power" though and we really could look into CCS loading the output tubes, hell CSS load the lot of them given the low currents involved. It just has to be weighed as a cost vs. performance issue.

This one will not sound like any 300B amp, that's way too much distortion for us. A triode is still one of the best ways of amplifying ever invented so why not cram three of them per phase for a brilliant cheap-ish amp. I've also been brainstorming recently with Kevin about making a true Volksamp for the people. Basically, what is the cheapest amp we can build without sacrificing our level of quality while having some strict design guidelines. This just expands on my vision at the start of the Exstata project but naturally learning from that clusterfuck. The BATE is an excellent amp but it's PSU is highly advanced and requires some advanced assembly with the correct parts (i.e. use the correct insulators or you will have trouble) and it uses tubes which are out of production. I want something which has all the parts in current production and easy to source, using a transformer which is available off the shelf at 117/230V and should just work if all the parts are in the correct spots and face the right way. Hell, I might even write up a "how to" guide for this one... Any ideas for good tubes or topologies are welcome... Ohh and then there is that truly insane idea, making a 'stat amp with miniature tubes. It would technically be portable...

Nothing wrong with running the wires underneath PCB's but stay clear of AC lines and use wire with ample insulation. I also hope you aren't running the amp with the transformer sitting on the metal chassis? I would recommend placing a rubber pad between them just to be safe.

Time for an update, the BATE prototype PCB's landed here yesterday so naturally I started assembly... http://i.imgur.com/dLaky.jpg http://i.imgur.com/0QITM.jpg Warning KG sized pics. I'm missing some parts so it won't be ready until Fedex shows up but it will be a neat little amp.

I have an even better way, just swap one phase from left to right at the Stax plug. Instant crossfeed!!!

Going on what few internal pics of the Pawel stuff there are it does look like a clone of the Stax circuit adjusted for the newer sets. They also had some amps but who knows what's inside...

The TTVJ amp works well because Pete knows his stuff. The gimmick comment was aimed at ALO since it is bound to be badly built garbage. Just look at the Rx, sounds like shit and they are up to Mk3 now because they can't seem to fathom that li-ion batteries do not behave as alkaline's. You can't just wire them with a CT and expect it to work...

Get the SR-009 then...treble head...

There were plenty of tubes designed to work at low voltages and made super small but using tubes is just a marketing trick. "Hey this one is different!!!" Then you ALO to the mix and it's probably horrible in every way.

There is more to it than that and the exact choice in output devices matters here plus the topology of the amps. Now if we talking about electrostatic amps then the fets would be a bad idea of biblical proportions. BJT's are much better suited to this role.

I made two of these boxes on the behest of Victor, one for him and one for me to try out ultra high end transformer solutions. Both look identical except one uses small stuck on feet and the other the rubber cones from Justin. Both used Lundahl LL1627 transformers which were a good choice in some ways but not in others. Too many windings and all the issues one has with that but the only real improvement over these would be a McIntosh style bifilar wound transformer. Sound wise these are the best transformers I've ever heard and shockingly transparent but not perfect. Transformers really aren't my thing and this project was to settle that once and for all. Same reason I'll take an SS amp over badly made tubes...

I cobbled together a version of this circuit when the A-10 first came out so I have a good idea how this one will sound. Thick with distortion and no output power what so ever. There are some tricks here though to try and make the SRPP circuit behave as it should (it only really works into a fixed impedance) so there should be a marginal improvement. For me the enjoyment is building this stuff even if it will sound sucky and with these tube amps it's a lot of fun to dig through my castoff bins to find the parts I need. All the terminal strips in this amp are from the ES-1, the plate resistors for the ECC83's are the brilliant TKD CM2's pulled from a SRM-T1 and the coupling caps are from my first ES-1 repair attempts. I never throw anything away... Sure, I still have a pile of the Alpha pots left.

Time for an update on the B-10 as it is now called. I decided it was just best to stick with Rays fubar amp design but improve on it where possible so the volume control was moved to the front of the circuitry (not in the middle as on the A-10), grounded DC heaters used for the input tubes and AC heaters used for the output tubes (hungry at 4A). Now using a SRPP setup in a single tube is rather stupid since it means there is too much voltage on the cathodes for the cathode/heater gap. Best way to mitigate this is to use a center tapped heater winding and float it on +300V so this only becomes an issue with the amp swinging 500V or more. Other than that the amp is pretty much stock and here are a couple of pics: The psu will be in a same size chassis but 2U in height. I designed a new PCB for it loosely based on the old GES supply which should arrive soon.

It would be a welcome change if these fit my head... I may get a set since I'm eternally curious about this stuff. On a similar note, I was talking to a friend yesterday who had a huge collection of very nice cameras but sold a lot of it to pay for a Leica S2 system to compliment his M9. He was at the local Fuji dealer and didn't even look at the new cameras they had there, the Leica system just killed any curiosity to try anything different. I do wonder why this hasn't happened to me yet with not one headphone ever coming close to besting my old SR-007 over the last 10 years.

Happy Birthday buddy! I made you cake but I... ehhh.... ate it. Might try again tomorrow but I fear the result will not be favorable...

That's excessive but expected.

In case anybody missed it over there, the Floats are coming back: http://www.open-end-music.de/vb3/showthread.php?t=4455 I have some issues with the driver mounting but they do look interesting if rather fugly.

Fear of the Dark is pretty amazing and she lives in Iceland...