[aos]

38mA per channel is fairly high, this is similar to what 4 HA3-5002 buffers would do (even a bit higher, I think). Higher current can translate into better sound but it's not portable (i.e. powering by battery is not practical) at this level of current draw. Still, most people probably plan on doing AC power only anyway.

 

[JohnFerrier]

Quote:

Originally Posted by aos 38mA per channel is fairly high...

From experience, that is about eight 9V alkaline batteries every 24 hours of play time. Currently burning through an eight-pack a week, until I find an alternative. (The sound is great, of course...else I wouldn't bother.) NiMHs last 1/4 the time of alkalines...

Of course, the thing about class A is it's like a constant current sink on power. Doesn't matter if the volume control is up or down, if music is playing or not. Power is consumed continuously, constantly.


JF

 

[Glassman]

Quote:

Originally Posted by aos 38mA per channel is fairly high, this is similar to what 4 HA3-5002 buffers would do (even a bit higher, I think). Higher current can translate into better sound but it's not portable (i.e. powering by battery is not practical) at this level of current draw. Still, most people probably plan on doing AC power only anyway.

it can be adjusted quite easily, either you assemble just one pair of output transistors instead of two and you're at 22mA or change two resistor values to lower the bias to whatever you'd like

but yes, I don't think most people threat their PPAs as 'portables' anyway..

 

[Karlosak]

Hi guys,
I'm really glad I can introduce Glassman's Diamond buffer to you...
We've been testing the prototype extensively today. And it does really look promising!
When we first plugged one triade in - Holly crap! The sound si now more detailed, with much stronger bass and better separation between instruments. These buffers add whole new life and sparkle to my beloved PPA. Yes, the highs seem a bit sharp and grainy but with proper burning-in this should be fixed.

Here are some pictures.
Enjoy...

Bye-Bye Intersil:

 

[dreamnid]

Looks pretty good

So when can we get 'em ?

 

[jamont]

Awesome photos, thanks!

 

[tangent]

Quote:

I guess it's meant to be similar to those rather expensive diamond buffers?

Glassman's design is very similar to the diamond buffer design from the Jung article you can find referenced in the sticky thread on diamond buffers in this forum. The LaRocco Audio diamond buffer is related to that design, but superior. I cannot say more -- it's not my place to plublicize that design.

 

[rayofsi]

great look, now i can add speed holes to my PPA and light shining through it =D

 

[Tobrew]

You gotta love the picture with the glowing LEDs. It makes you want to put a clear top on your PPA.

 

[ppl]

Quote:

Originally Posted by Karlosak Hi guys, I'm really glad I can introduce Glassman's Diamond buffer to you... We've been testing the prototype extensively today. And it does really look promising! When we first plugged one triade in - Holly crap! The sound si now more detailed, with much stronger bass and better separation between instruments. These buffers add whole new life and sparkle to my beloved PPA. Yes, the highs seem a bit sharp and grainy but with proper burning-in this should be fixed. Here are some pictures. Enjoy... Bye-Bye Intersil:

Congratulations on your new Design Glassman for a job well done. Those LED look real cool however you could rescale your resistors and use BLUE as a reference that would be a nice effect.

I experienced the same thing when first listening to my Diamond buffer for the PPA the TRIAD Module. The sound improved all across the board however the PPA straights still were preserved. The difference between op amps was greater and all headphones sounded like they moved up one quality grade or more.

Don’t be to quick to pronounce the opa637 stable as this can come back and bite you as it has me. When hot and loaded with something extreme like CD3Ks your output stage bandwidth will plummet and any sudden transients or other enormous gremlins can conspire to create stability problems and also evaluate with bass boost on.

Anyway Good luck and I am so glad the youth today are into constructive works. In addition with the art of analog and most importantly discrete component level designers fast becoming lost it is good to learn the old ways.

 

[aos]

Quote:

Glassman's design is very similar to the diamond buffer design from the Jung article you can find referenced in the sticky thread on diamond buffers in this forum. The LaRocco Audio diamond buffer is related to that design, but superior. I cannot say more -- it's not my place to plublicize that design.

As tangent said, and I can add that ppl spent a fair bit of time experimenting, both theoretically and empirically, to arrive to his final solution (he has even better ones but they wouldn't fit). I love how compact and small Glassman's boards are, that's exactly what I was hoping that someone will do, but do expect a lot of experimenting before you get the most out of it. This is certainly a good start, and the glow is cool.

 

[peranders]

Quote:

Originally Posted by tangent Glassman's design is very similar to the diamond buffer design from the Jung article you can find referenced in the sticky thread on diamond buffers in this forum. The LaRocco Audio diamond buffer is related to that design, but superior. I cannot say more -- it's not my place to plublicize that design.

Glassman took "my" design but changed the output transistors. Anyway "my" buffer has cascodes and Jung had not. I don't know how much they do but some I'll believe.

Nice patch, Karlosak! It's cool when you have lights inside. I used only dull diodes (transistors infact) for my reference voltages.

 

[Karlosak]

Quote:

Originally Posted by Tobrew You gotta love the picture with the glowing LEDs. It makes you want to put a clear top on your PPA.

Exactly! Now I just whisper for myself: "Why didn't I build it with a clear cover, Why didn't I build it with a clear cover......."

P.S.: This is not yet the final version. Glassman is still playing and fiddling with it intensively. So stay tuned

 

[ppl]

ya those parmetal cases will look real cool with these for sure

 

[tangent]

Quote:

Glassman took "my" design

He changed it back to the LED+transistor type bias setup that Jung originally used instead of the stacked transistors in your design. The former takes up less board space, which was helpful.