I'd like to present here a complete phono stage project. It's been greatly inspired by the original phono cube and if you are interested in the specs, they would be similar (not mentioning the schematic).
In my approach however, I'm using much better parts and much better power supplies. I also wanted to be able to fit everything in a simple 2x3 aluminum tubing enclosure, having the PS integrated with the preamp.
The end result is the phono stage that can compete with basically anything out there, it is so good.
Looking at the board, you may notice that it is same form factor as my both DACs, the size is 2.75 x 8.75"
In my approach however, I'm using much better parts and much better power supplies. I also wanted to be able to fit everything in a simple 2x3 aluminum tubing enclosure, having the PS integrated with the preamp.
The end result is the phono stage that can compete with basically anything out there, it is so good.
Looking at the board, you may notice that it is same form factor as my both DACs, the size is 2.75 x 8.75"
Attachments
The PS is +/-15V shunt type. It produces quite a lot of heat, and since I wanted to fit it inside aluminum tubing, I had to figure out a smart way for heatsinking. I managed to do that with special brackets that are attach to power devices first and then are bolted from enclosure bottom after the board is inserted.
Attachments
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Attached is the schematic of a shunt regulator. I tested few other discreet regulator types with this circuit, but the one in attachment worked best.
The regulator can be separated form phono stage through a scoring line. It features completely independent grounds for both sides and can be suitable for many other applications. Of course I will be offering it separately as well. BOM coming soon.
The regulator can be separated form phono stage through a scoring line. It features completely independent grounds for both sides and can be suitable for many other applications. Of course I will be offering it separately as well. BOM coming soon.
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Attached are BOM files for both circuits. They were compiled by one of the forum members who already got the boards. The actual cost and parts selection may still need adjustment, but for now, it gives some idea what's involved.
The shunt regulator is based on a regulator posted in this link: http://www.diyaudio.com/forums/showthread.php?p=1905843&highlight=minnesota#post1905843
I tried it after i was also testing other, similar regulator (as in attachment), as well ALWSR, and this regulator sounded substantially better. Now, that you mentioned it, I'll be curious to try it without a cap as well.
I tried it after i was also testing other, similar regulator (as in attachment), as well ALWSR, and this regulator sounded substantially better. Now, that you mentioned it, I'll be curious to try it without a cap as well.
Attachments
Another observation: while single regulator shared between two channels sounds fine, going dual mono brings quite noticeable improvement. I was also testing phono stage and regulators separated by 4ft cord and didn't notice any particular degradation. In that case you will need C11/C12 and C4/C5. When all together, C11/C12 can be omitted.
For now it's the board only, down the road two versions of a kit as well. I can presently also supply some of the harder to source components.
Thanks Peter. So which are the hard to get bits? Transformer and some of the active devices? I feel a purchase coming on...
I can basically supply everything (except for Black Gates), just didn't organize it into kits yet. One of the harder to get semis would be J511, but I have them in stock.
Hm,
good to freak out PA....and now for the relevant part:
Nice work! I remember TL suggesting something very similar. Maybe he knows something....but I guess, your work is very similar to the 47 RIAA.
That said, what about including some SMD pads for OPA627/637 on the pcb?
J511 and the MJE1530x are the hard to find parts elsewere...any substitutes?
LG Carsten
good to freak out PA....and now for the relevant part:
Nice work! I remember TL suggesting something very similar. Maybe he knows something....but I guess, your work is very similar to the 47 RIAA.
That said, what about including some SMD pads for OPA627/637 on the pcb?
J511 and the MJE1530x are the hard to find parts elsewere...any substitutes?
LG Carsten
