[FallenAngel]

Looks cool, kind of like a diamond buffer with gain.

 

[rjm003]

I like to think of it as a diamond buffer input, current mirror "pumps" for voltage gain, and a Sziklai pair output buffer.

 

[HiGHFLYiN9]

Looks very nice! Any feedback regarding targeted balance of sound (e.g. warm / neutral / completely flat response / detailed)?

 

[rjm003]

The open loop and closed loop configurations sound slightly different, open loop having more 2nd harmonic and therefore more 'bloom'.

From someone else who has built one (and with whom I am in 100% agreement):

"natural, clean, airy, and revealing recording space like nothing else I've heard."

http://www.diyaudio.com/forums/head...ktop-headphone-amplifier-116.html#post5063467

If it can be described as anything I'd say it sounds "analog". It fills in over the digital "dots" and makes the music sound more natural while still maintaining a very high level of performance in absolute terms. RMAA data below for unloaded, closed loop, 25 dB gain. Distortion does not vary appreciably with load at the measured 0 dB output, so the figures can be taken as largely independent of the headphone connection.

 

[arteom]

I've been itching to start a new DIY project, this looks pretty attractive. Has anyone else given it a go?

 

[rjm003]

I've been itching to start a new DIY project, this looks pretty attractive. Has anyone else given it a go?

It's more likely you'll find someone to answer that over at the development thread on diyaudio.

Current revision is 4.1t, photos are of rev 4.1m, cosmetic changes only.

 

[Riversalt]

It's more likely you'll find someone to answer that over at the development thread on diyaudio.

Current revision is 4.1t, photos are of rev 4.1m, cosmetic changes only.

Did this project die or can you still buy it?
If possible I would like a kit already assembled, but I would be happy with any possibility of purchase.

 

[Zulkr9]

ould like a kit already assembled, but I would be happy with any possibility of purchase.

I would assume it would be better if you mailed him at his website or something

 

[Riversalt]

Did this project die or can you still buy it?
If possible I would like a kit already assembled, but I would be happy with any possibility of purchase.

I found no means of contact on the site, no visible link there.

 

[Zulkr9]

I found no means of contact on the site, no visible link there.

There you go http://phonoclone.com/diy-sap4.html
I heard good things about it.

 

[micmacmo]

Contact info on this page.
http://phonoclone.com/rjm.html

 

[rjm003]

Kits and boards are available for $150/$25 US, respectively, including shipping. (link)
Updates, feedback, questions, and discussion at diyaudio (thread)

Current board revision is 4.2b, though the circuit has remained unchanged since the Sapphire 4 was first introduced a few years back. It's not the simplest of projects, but interest in it has remained steady over the years and those who have built it have reported very positively on their experience.

 

[Zulkr9]

Kits and boards are available for $150/$25 US, respectively, including shipping. (link)
Updates, feedback, questions, and discussion at diyaudio (thread)

Current board revision is 4.2b, though the circuit has remained unchanged since the Sapphire 4 was first introduced a few years back. It's not the simplest of projects, but interest in it has remained steady over the years and those who have built it have reported very positively on their experience.

Hi I wanted to know if I were to build a balanced version 4 boards would be required right ?
Also whats the power output for an SE hp amp

 

[Thunder240]

A sapphire 4 (not sure which minor version) was at the Bay Area Audio Enclave hificon meet today in San Jose. I completely concur with the person who wrote “natural, clean, airy, and revealing recording space like nothing else I've heard.”. I used this unit as a reference amp to compare headphones. Great job @rjm003

 

[rjm003]

Hey, thanks for the nice feedback. Note that there is/was only one version of the Sapphire 4. There have been a couple of minor changes to the board layout for different size caps and so forth, but the circuit is unchanged.