[Kerry]

I'm about to etch another board next week just for the fun of it.

I was waiting on some more resist and have it now.

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif I'm at least somewhat to blame there...

Through some helpful pointers (thank you), I was able to find some great deals. Imageering has a new customer special of $25 per board (no minimum).

A board takes me about a day or two to make. I figured I was worth it.

 

[Emooze]

So I bought a Twisted Pear USB receiver/DAC to hold me over until I can afford an Opus or (hopefully) a Buffalo. I originally had it in a cardboard box:

I didn't like this. I decided to go with the board on a sort of plinth of some sort. Turns out the school machine shop has aluminum stock for the taking:

Whole thing weighs ~2 pounds now. It doesn't move. Fantastic.

 

[kshelton]

Quote:

Originally Posted by Ferrari /img/forum/go_quote.gif After tinkering with the circuits for about an half-year and tried out various tubes (D3a, Russians 6J52P, 6S45P-E and 6N30P-DR), I decided to settle on a pair of D3a. The other tubes are OK but, the D3a gives the best performance in my application… a single ended transformer coupled one-stage headphone amp. To my ears, this is the reference amp from all the tube/hybrid amps I have made until now... and a night shot...

Damn that is sexy!

 

[simwells]

My first project here and a Mini^3 very impressed with it and it's been free, doing a starving student now, and that lets me play around a lot more which is good.

 

[AffeX]

Quote:

Originally Posted by Ferrari /img/forum/go_quote.gif A couple of snapshots of something in the making…

Ferrari, I know this is an old post of yours, but I must say I am swept away by your fabulous builds. They are great samples of design and craftmanship!

I'm planning a build myself for my HD-800 and I think EHHA would be a good match. This may be a noob question, but you have to tell me, what is that 5.th tube for in the balanced EHHA build?

 

[ShaneP]

Quote:

Originally Posted by AffeX /img/forum/go_quote.gif Ferrari, I know this is an old post of yours, but I must say I am swept away by your fabulous builds. They are great samples of design and craftmanship! I'm planning a build myself for my HD-800 and I think EHHA would be a good match. This may be a noob question, but you have to tell me, what is that 5.th tube for in the balanced EHHA build?

It is for a "Magic Eye" level meter.

Here is a link to the circuit I think he used.

 

[Ferrari]

Affex, it's a "Magic Eye" level meter as ShaneP said, and the link to the circuit is indeed what I have used in my amp.
It's not a 100% accurate measuring device (as LEDs or LCD designs) but I think it looks cool in a tube/hybrid amps.

 

[FraGGleR]

Quote:

Originally Posted by Emooze /img/forum/go_quote.gif So I bought a Twisted Pear USB receiver/DAC to hold me over until I can afford an Opus or (hopefully) a Buffalo. I originally had it in a cardboard box: I didn't like this. I decided to go with the board on a sort of plinth of some sort. Turns out the school machine shop has aluminum stock for the taking: Whole thing weighs ~2 pounds now. It doesn't move. Fantastic.

That's really cool. I really need to look into finding a local woodworking shop as well as a machine shop. Radio Shack hobby boxes aren't cutting it for me anymore.

 

[FraGGleR]

Quote:

Originally Posted by simwells /img/forum/go_quote.gif My first project here and a Mini^3 very impressed with it and it's been free, doing a starving student now, and that lets me play around a lot more which is good.

Cool acrylic face plate. How did you make it?

 

[AffeX]

@ShaneP and Ferrari
Thanx for the explanation and fast reply, even if it was a total noob question

Ferrari, could I get you to describe some details in your build, such as:
- What tubes did you use - and what tubes do you prefer for the build?
- What did you use for heater supply, and where did you put it? I don't see room for much more than the EHHA boards.
- What gain did you choose for each board?
- What solution did you choose in terms of power delay, allowing heaters a head start?

 

[simwells]

Quote:

Originally Posted by FraGGleR /img/forum/go_quote.gif Cool acrylic face plate. How did you make it?

It's laser cut out of 2mm acrylic, quick and easy!

 

[Ferrari]

Quote:

Originally Posted by AffeX /img/forum/go_quote.gif .

Quote:

Ferrari, could I get you to describe some details in your build, such as: - What tubes did you use - and what tubes do you prefer for the build?

I have tried NOS 6GM8 and Sovtek 6N30P (new production) but finally settle on a pair of 6N30P-DR.
The 6GM8 is a fine tube for the money but I prefer the 6N30P-DR.


Quote:

- What did you use for heater supply, and where did you put it? I don't see room for much more than the EHHA boards.

There are indeed no power supplies inside the amp enclosure. The power supplies are housed in a separate enclosure (as all other balanced amps I have build so far).
For 6.3V heater, I use a DIY PS based on a 2 x 9V (50W) toroidal transformer and 2 LT1083 regulators, thus separate 6.3V DC heater suppies for L/R channels.


Quote:

- What gain did you choose for each board?

About 7.5x per board, thus effective gain in balanced mode is ~15x which fine for my AGK K1000.


Quote:

- What solution did you choose in terms of power delay, allowing heaters a head start?

At power up, only the 6.3V heater PS is on. The other PS can be manually switched on later, using a simple mechanical switch.

 

[AffeX]

@Ferrari: Thank you. It's info of great value for me.

 

[mojo]

Quote:

Originally Posted by simwells /img/forum/go_quote.gif It's laser cut out of 2mm acrylic, quick and easy!

That's a really good idea. The face plates are very expensive but laser cut acrylic or wood is very cheap.

 

[revolink24]

I just took this picture a while ago, it looks like all the other Starving Student PCB builds, but whatever.

Anyone care to enlighten me on how everyone seems to be getting custom faceplates for their builds? Local machine shops?