spritzer

Do I even want to know how much voltage those things can handle? Something like this would make a 'stat amp for speakers "easy" to build., makes a lot more sense then to use a regular tube amp on an ESL. The sky is the limit here but mercury is a nasty stuff to deal with. I would probably go for a tube rectified PSU with no electrolytic caps and plenty of chokes. Might even regulate it with tubes too.

Happy Birthday!!

Very, very nice!! I just love "scrap" components, makes us look thrifty.

Yeah and a question so hard that 95% of all Icelanders would get it wrong. Reykjav

You need a UK IP-address to be able to access the i-player. Other great series would be Foyle's War and Wire in the Blood. Very different from anything US based...

Yeah... about that. That is one serious tube!!!

This concept has interested me for a while now given just how simple the amp could be made. Just two tubes per channel and then a phase splitting output transformer makes for a stark contrast to something like the T2. Now whether this simplicity is better or worse isn't the issue for me, I just want something different. I figured it was time to get the concept of these amps outside of the random thread on HF and PM's. I've been talking to Frank Cooter about this and given how happy he is with his D3a/KT88 amp I'm going to try something similar. I'm always a fan of using what I have (hence my Exstata is a bit different from all the others) so soemthing like the 3d21A or 7403 in place of the KT88 could work well. The 7403 does interest me since it can handle so much voltage. Any suggestions here would be welcome, the more obscure the better. As for transformers, they are a large part of the this project and no doubt, a large part of the over all cost. That said, people are willing to pay a small fortune for the updated output capacitors of something like the Woo WES for which you could get amouphous core Lundahls made. Since the transformers provide so little (if any) stepup they should be fairly linear. Given the currents and voltages involved, we could even get away with using stock interstage tranformers. Frank used the Electra-Print 3436 in his amp and at roughly 100$ each it's less then a V-cap. Now the 35mA might be a bit small but the 3035 model can handle 70mA and isn't that much more expensive. Now the true beauty of these amps, the ability to use DHT's without needing 12 of them. The same amp could also be used for dynamic headphones or even speakers with the right output transformer.

Brilliant to say the least.

The 7403 can handle 4000V on the plate....

LM7805 with a small transformer and a couple of caps?

While my headphone binge was fueled by upgraditis I'm all but cured now since there is nowhere to go from here until Stax releases something new. We are all but set with amps too so I think it is time to start working on something different rather then better. I'm going to build a D3a/KT88 amp like Frank Cooter's and then there are all the other crazy designs waiting for parts/time. One thing that I've been thinking about lately is revisiting my plans for an electrostatic headphone...

That doesn't always work. I started off with the SR-007 and then ended owning the majority any and all electrostatic headphones ever made, multiple sets of some too.

Less Than Kind

Yup, with the IEC off there is no power at all. With a 5VA transformer or less the "standby" circuit would eat up very little power. I'm thinking about doing something similar to the transformer boxes I'm working on, one transformer for the relays/indicator led and a second one for the bias supply.

With a latching switch you just need a small transformer/PSU to drive the relay that consumes next to no power. Use an IEC inlet with a power switch and you are good to go.

Doesn't change a whole lot. It's just me being OCD and going into overkill mode after drivers were knocked free during postage.

How about some T-1610's?

Woot a Sigma thread!!! To start off, I figured this was worth a repost with pics: Now I've done a few since I posted that but the only thing that has changed is how I handle the drivers. Now I remove the protective grill and mount it to the other side of the drivers so that I have easy access to solder the connections. It's more work but eliminates any potential issues. The last two sets have also had the drivers permanently glued to the baffle.

Ditto what Dan said, spray the contacts (which are inside the clear plastic housings, you need to clean all four sets) with a good contact cleaner like Caig DeOxit and then cycle through all the positions a dozen or so times. If that doesn't work then you might have a cold joint somewhere, probably at the input where the attenuator we replaced. The KGSS works well with the 4070/SR-007 so it is well worth it to have it running at 100%.

Happy Birthday Milos!! I made you a cake but I eated it...

I would have countersunk the screws but if these prove to be as good as they say it looks like a DynaFet is in my future.

Happy Birthday!!! [url=http://www.head-case.org/forums/newreply.php?p=348560&noquote=1]

The comments are just nuts.

Holy crap, has it been a year since I started a similar thread just to annoy Kevin? I'm glad Al's taking the heat this time. Happy birthday buddy and I can't wait for CJ!!!!!!!!!!!!!!