It's essentially a J2 modified to handle +/-50V rails.
Here's the latest version of the front end with its shunt regulators:
Cheers,
Jeff.
Here's the latest version of the front end with its shunt regulators:
Cheers,
Jeff.
Nothing special -- a 20-year-old NAD CD player that I've been using for all my auditions.
In use they get fed by Roon -> Metrum Ambre -> Metrum Onyx, but I can't easily get to the cables of my main system for comparison tests.
I'm in Louth if you want to drop by for a listen....
In use they get fed by Roon -> Metrum Ambre -> Metrum Onyx, but I can't easily get to the cables of my main system for comparison tests.
I'm in Louth if you want to drop by for a listen....
Sounds great Jeff, however I'm in the process of building one myself, I guess it may be interesting to see if they will sound different 🙂
Inspiring build!
Inspiring build!
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Jeff,
Any chance to compare the sound of the original to your version?
Can't think of any difference except possibly the power transformer, but who knows?
-Mark
Any chance to compare the sound of the original to your version?
Can't think of any difference except possibly the power transformer, but who knows?
-Mark
Mark, Jam said he spent a lot of time working on the transformer, so I suspect there is some difference there. There aren't a lot of HPA-1s in Ireland, though, so I'm not sure I'll get a chance to compare.
Hmm... Srajan lives in Ireland, doesn't he? Anyone know where-abouts?
Or maybe someone on the States could build one and then do a comparison.... 🙂
Hmm... Srajan lives in Ireland, doesn't he? Anyone know where-abouts?
Or maybe someone on the States could build one and then do a comparison.... 🙂
Liscarney, Co Mayo, Ireland
according
to his bio in 6 moons..... hope I wrote it ok, but you’ll know... it kould be an interesting visit and story.
according
to his bio in 6 moons..... hope I wrote it ok, but you’ll know... it kould be an interesting visit and story.
Liscarney, Co Mayo, Ireland
according
to his bio in 6 moons..... hope I wrote it ok, but you’ll know... it kould be an interesting visit and story.
according
to his bio in 6 moons..... hope I wrote it ok, but you’ll know... it kould be an interesting visit and story.
Were these ever posted Jeff? I thought I had seen them, but can't find them now...
There's a zip of them on my hard disk, which would suggest that I posted them. I thought it might be in the "Pictures of your diy Pass amplifier" thread, but I couldn't find them there, so who knows. 😕
Anyway, here they are (possibly again).
Anyway, here they are (possibly again).
I've been a drillin' and a tappin', a drillin' and a tappin'. Lots of progress, but it's fairly uninteresting to show.
Funny thing I discovered: mono blocks are twice as much work. 😉
Funny thing I discovered: mono blocks are twice as much work. 😉
Thanks Jeff. That is a large board 🙂
What specs did you use when you ran yours? Given the size of these, my initial thought had been 2mm board thickness with 2 oz. copper.
Funny, you share your name with my younger brother, but he isn't in Ireland 🙂
Very nice work on this and on your build, BTW.
What specs did you use when you ran yours? Given the size of these, my initial thought had been 2mm board thickness with 2 oz. copper.
Funny, you share your name with my younger brother, but he isn't in Ireland 🙂
Very nice work on this and on your build, BTW.