diyAudio group buy Paradise R3 phono stage boards
- Thread starter Markus S
- Start date
misterdog
Not the canine kind
Cheers Si, we can have a chat next weekend when I drop off the n-Cores.
Let me know when is good for you.
sq225917
Bit of this, bit of that
misterdog
Not the canine kind
Dual phase motor speed controller for TT, or something connected to the Sharrow cycling club?
Is there a prize for the correct guess.
sq225917
Bit of this, bit of that
You had it right straight off.
Dual mono, class A, TT-psu, using a programmable sine wave generator to drive two chip amps, adjustable frequency to 0.01hz and adjustable phase lag to 0.1 degree. Drive voltage is adjustable via trim pots, 15-24v or thereabouts. USB input to control set-up and log motor run time to keep a measure of cartridge wear. I'm very pleased with it.
sq225917
Bit of this, bit of that
As far as I know he's still doing them. Hit him up on diyaudio or http://www.roehren-und-hoeren.de/phpBB3/ which is the replacement site for the one where his thread was originally.
He did say he was thinking of doing a new one, maybe adding a different phase offset for each speed, which would be optimal as it appears there's a slight difference in what is ideal for any motor at different speeds.
You want better than .7%, you want the input stage to be an exact numerical match if you can.
He did say he was thinking of doing a new one, maybe adding a different phase offset for each speed, which would be optimal as it appears there's a slight difference in what is ideal for any motor at different speeds.
You want better than .7%, you want the input stage to be an exact numerical match if you can.
Here's the current link to the motor psu thread: http://www.roehren-und-hoeren.de/phpBB3/viewtopic.php?f=79&t=7890
misterdog
Not the canine kind
Is that within each group, across the channels or both.
Think I have more measuring to do either way
sq225917
Bit of this, bit of that
The input stage is two complimentary quads, per channel. I match them all, 4 x quads, both channels to an exact numerical match if possible. The current mirrors not so important, but I still like them within a couple of hFe.
Here's Markus's.
Pre-regs are running high due to lower losses on rectifiers and high VA on the quieter transformers, so the dropper resistors need to be swapped out for higher values.
Here's Markus's.
Pre-regs are running high due to lower losses on rectifiers and high VA on the quieter transformers, so the dropper resistors need to be swapped out for higher values.
I am considering selling my part-completed Paradise boards if anyone is interested. Downsizing and a house move mean I am unlikely to finish them (or need them) before the rapture. Thought I would mention it here before putting up an advert.
The pre-reg boards are built (soldering is pretty good on these!) and working perfectly. Pre-reg boards have fairly quiet transformers, so I got lucky there.
One phono board is complete, the other is 90% there. Sadly the soldering on the phono boards is not as good as I would like (nothing catastrophic, but not up to my usual standards). I would blame the ground plane but the truth is probably that in trying to get them finished, I didn't give it the time it deserved. I found soldering the ground legs on components very tricky as the plane wicked away the heat, so probably a good inspection and some reflowing with good gear is needed.
All transistors were matched +-1 in their groups using a Peak atlas DCA (and +- 2 overall), but the one complete board has a lot of offset over the servo opamp, so I think it could use some attention. Both boards have OPA627s fitted in this position. All other parts are as per the BOM (I got the kits from a member on DIYAudio).
Also included are a (unbuilt) pair of Calvin buffer kits.
In total I paid around 350 euros for the kits, plus some more for extra transistors and the OPA627s. Would anyone like to make me an offer? I would prefer to sell everything together, but I don't expect to recoup all of my investment. I will be selling the Atlas DCA as well soon, so let me know if you want this as well.
Cheers,
Ed
The pre-reg boards are built (soldering is pretty good on these!) and working perfectly. Pre-reg boards have fairly quiet transformers, so I got lucky there.
One phono board is complete, the other is 90% there. Sadly the soldering on the phono boards is not as good as I would like (nothing catastrophic, but not up to my usual standards). I would blame the ground plane but the truth is probably that in trying to get them finished, I didn't give it the time it deserved. I found soldering the ground legs on components very tricky as the plane wicked away the heat, so probably a good inspection and some reflowing with good gear is needed.
All transistors were matched +-1 in their groups using a Peak atlas DCA (and +- 2 overall), but the one complete board has a lot of offset over the servo opamp, so I think it could use some attention. Both boards have OPA627s fitted in this position. All other parts are as per the BOM (I got the kits from a member on DIYAudio).
Also included are a (unbuilt) pair of Calvin buffer kits.
In total I paid around 350 euros for the kits, plus some more for extra transistors and the OPA627s. Would anyone like to make me an offer? I would prefer to sell everything together, but I don't expect to recoup all of my investment. I will be selling the Atlas DCA as well soon, so let me know if you want this as well.
Cheers,
Ed
misterdog
Not the canine kind
PM sent.