spritzer

Sorry about that, I had the thought of modifying the board so the same one could be setup for L+R instead of just balanced while writing the post. Stock it can't be done but I'll see about changing it. Might just change the board and offer a single ended one as well as I'm not really a fan of cryptic jumpers etc. It should just have all the parts on the PCB, stuff it and it works.

This one has been brewing for a while now but since I wanted to build a nice balanced amp it moved up in line. Basic setup is the same as the old Dynalo but now with Super Symmetry input, higher rail voltages and naturally a bit more power. Input stage changed to THAT340 which is a quad bipolar transistor array with matched NPN and PNP pairs. It is cheap and easy to source so no jfet drama. The other transistors are new as well and the pinout is different to reflect that. Here is a look at the new PCB design which is pretty much ready: It is 138*86mm. Another thing from the same vein is a fully discrete unbalanced to balanced circuit that we have been working on so no DRV134 garbage. I'll start with this one though and order some proto boards this week.

A new ECC83/12AX7 is less than 15$ so that would be my first step.

It's airing now in Canada. Ep 2.03 was yesterday....

I can't spare any room there... The end result is a truly lovely headphone though. Closer to the HD6x0's in balance but with that super quick response and lean bass of the HE60. Doesn't hurt that it was practically free, only paid for the cable and new earpads. Rest were either pulled parts from repairs that I reconditioned or parts given to me.

Yes but I went the other way and recessed the drivers inside the cups. It helped that I used HD600 parts for this...

Well they had to angle the drivers somehow. I do wonder if they would achieved a better balance by pushing the drivers further away from the ears. I just did this with a set of HE60's and the effect is far from subtle. A lot less bright...

Ok. I'll give him that.

Why would anybody do business with Headphile?

RTFM!!!!

Purrfect!! You are not the first one to make that mistake though.

I just told Enrique by PM but I should point out that the above is 100% the wrong way of using the PCB. The pot goes on top of it with the shaft pointing where "front" is written.

Looks good. The only thing I'd change is to use male XLR's for the loopout so that is conforms to the XLR standard.

Good point.

That I truly don't get.

I know, see my post above.

That's how Pass does in on the F amps. Makes sense if neutral and live were swapped.

I use 2AT (slow blow) on 230V but I never tried anything else. No thermistors either. How are you using just one thermistor on 117V? I'd put one on each leg just to be safe. Using one on 230V works as it's in series with the windings.

A third series of Luther is due this year...

Never had it either, even on PSU's I fucked up in the design phase and had to fix, exposing the ground next to the pads. That was at 700V...

You can add insulation to the board with tape or something like that. Nail polish works very well to to mask exposed traces.

Just connect a wire to the nearest part on the same trace. Does the same thing... Edit: One thing, try to use just enough solder when soldering the caps and not drown the joint in solder. Just enough to bridge it and there shouldn't be any issues.

Not really as I bought just over one thousand of them off ebay some years back and they were custom made for some company by S+M.

It's all tube so transportable would be a better description. The heaters are hungry...

There was a card sized KGSS back in the day intended for portable use. The circuit is very linear in terms of bias current so it is certainly possible to make it portable. We are working on something else though, an all tube "portable" miniature amp for Stax.