[Dougie085]

Well this will be my first tube build, I've built quite a lot of solid state circuits though so I don't think this ones going to be a problem. the 6GM8's seem to be what most use.

Thanks for the info, I'll have to research a bit more. I wish there was some place to get a high quality chassis here in the states. Shipping costs from HiFi-2000 and the likes are crazy! Hah.

 

[smeggy]

dunno whether mosfet or bjt is better, but for tubes there are a number you can try depending on how you decide to do the heater supply. The standard tubes that come with the kits are ok, my preference is for either the 6n6p (cheap) or 6h30 (not cheap) the 6h30 does sound great but for the price the 6n6p is outstanding, both will be running close to their lower limits voltage-wise.

Both these tubes require a fair bit of heater current but luckily you can wire them as AC which means a cheap Radio Shack 12.6v 3.5A transfo can be used to power them directly. Some prefer a regulated DC supply but mine runs fine like this.

Another good tube is the Bugle Boy version of the original type. Very nice sounding and middling price.

 

[Dougie085]

Thanks. So with the 6GM8's you don't really have to do anything to the heater supply but with the 6H30's and what not you do.

How much would a matched set of 6N6P or 6H30's run?

 

[smeggy]

I bought a set of 8 6n6p tubes from Ukraine or similar for about $15.

6h30's are costly and some of the new ones like the sovtek version is complete crap. The Electro Harmonix ones are 30-ish per tube new and the 'supertube' version can run $70+ per tube.

Initially I'd stick with the supplied ones as they're perfectly good tubes and sound pretty nice anyway.

 

[Dougie085]

That's probably what I'll do, and when I start getting used to the sound and get it well broken in and get to the point of "what more can I get out of this?!?!?" then I may try swapping in some nicer tubes and what not.

 

[dBel84]

good choice , the amp sounds pretty fantastic with the 6GM8's..dB

 

[wiatrob]

I have been perfectly happy with 6GM8s on my (one of the few!) BJT build.

 

[Dougie085]

Guessing you haven't been able to compare it to the Mosfet version?

 

[Dougie085]

Here's another question, is one σ22 sufficient enough for a fully balanced version (4 mono boards)? What other PSU's do you guys use? The σ22 looks to be pretty nice so not really sure if any other option would really be that much better. If I add a lot more capacitance for the filtration would it better it much? I know when I've built large power amps the more filtration the better.

 

[sachu]

Quote:

Originally Posted by Dougie085 /img/forum/go_quote.gif Here's another question, is one σ22 sufficient enough for a fully balanced version (4 mono boards)? What other PSU's do you guys use? The σ22 looks to be pretty nice so not really sure if any other option would really be that much better. If I add a lot more capacitance for the filtration would it better it much? I know when I've built large power amps the more filtration the better.

Highly recommend sticking to the S22 as it does have very good performance at a reasonable cost.
Just a single S22 would be plenty enough for pure headphone duty and more stiffening capacitance would help I suppose.

Use a 100VA or higher rated toroid for the transformer.

 

[runeight]

Quote:

Originally Posted by Dougie085 /img/forum/go_quote.gif Here's another question, is one σ22 sufficient enough for a fully balanced version (4 mono boards)? What other PSU's do you guys use? The σ22 looks to be pretty nice so not really sure if any other option would really be that much better. If I add a lot more capacitance for the filtration would it better it much? I know when I've built large power amps the more filtration the better.

As sachu says you only need one s22 for headphone duty (even four channels) and the s22 is a good enough PS that you don't need any additional caps or other components. In fact, adding O/P caps the the s22 might destablize it. MHO is use a bare s22. It will do what you need it to do.

 

[rhester]

Got my 2 channel build all dialed in tonite and functioning. Now to find a suitable case big enough for 2 transformers, o22, 6.3V power supply and the 2 boards. what have others used? One case or 2?

 

[sachu]

I would just go with one case. Reduces the casework necessary. Try to keep the transformers away from the boards as much as possible.

Depending on the type of headphones you use, there should be no problem with respect to transformer noise. I don't have any and the transformer is only 4 inches from the amp board. I also like the fact that everything is in one case and compact.

Edit: Btw..congratulations!!

too early for first impressions?

 

[liwei]

Hey all. I've contacted Jeff about getting an EHHA kit, S22 kit and B22 kit so I guess I will be joining you guys. I was originally going to build the S22 and put it into a separate enclosure but after thinking about all that wiring, I've decided just to put it all into one box and buy another S22 when I build the B22 later.

I've got a question about the tube heater transformer and LDO. I'm going off of the 12.6VDC regulated supply given on the website. Any suggestions for the transformer (something like a Hammond 166J12?) and LDO?

 

[sachu]

Quote:

Originally Posted by liwei /img/forum/go_quote.gif Hey all. I've contacted Jeff about getting an EHHA kit, S22 kit and B22 kit so I guess I will be joining you guys. I was originally going to build the S22 and put it into a separate enclosure but after thinking about all that wiring, I've decided just to put it all into one box and buy another S22 when I build the B22 later. I've got a question about the tube heater transformer and LDO. I'm going off of the 12.6VDC regulated supply given on the website. Any suggestions for the transformer (something like a Hammond 166J12?) and LDO?

Nice..you won't be disappointed.

This transformer would be perfect for the EHHA heater supply.

You can wire it up in 12.6 volts (wire the secondaries in series) or in 6.3Volts (parallel the secondaries).


Peter Millet's DC filament supply is very nice and robust if you want to go the DIY route which is what I am using.

Just use the necessary resistors to set the output voltage on the LDO regulator (12.6 volts or 6.3 volts..look at the datasheet for that).

Alternatively you could just buy Glassware's heater supply which is actually very modestly priced.