The IEC cutout. Far from a noob question, this is in fact one of the eternal imponderables of DIY. It is by a long shot my least favorite task of the whole process, and I haven't figured out a really good way... other than to somehow trick someone else into doing it for you.
I draw the cutout in marker on the box and drill 3mm holes all around the edge, as near to touching each other as I can. Then I use a circular file to cut away the material between the holes so the cutout eventually pops out. Finally I use a straight file to widen and smooth the sides until the connector fits in. It ain't pretty but it does the job. Still a pain though.
I draw the cutout in marker on the box and drill 3mm holes all around the edge, as near to touching each other as I can. Then I use a circular file to cut away the material between the holes so the cutout eventually pops out. Finally I use a straight file to widen and smooth the sides until the connector fits in. It ain't pretty but it does the job. Still a pain though.
I drill 4 corner holes and cut it out with a scroll saw; very little file work is needed after. If you have a template you could trim the edges with a router.
my p3 is up and running. It needs of cause a little time to break in and therefore i won´t tell too much. good bass, veery open. But… compared to my pearl (with ono MC) my glider has much less "super" resolution. Whith a load of 22k the glider is a king in resolution with the pearl, and "just " good with my p3. The pearl is "fresh" with a nice spot on the upper frequencyscale, the P3 is more "open" and really better in dynamics than the pearl.
Is there a way to tweak the superhighs like you can do it with the load in voltage amplificating phono stages?
picture will follow and thanks for board&support
stefan
Is there a way to tweak the superhighs like you can do it with the load in voltage amplificating phono stages?
picture will follow and thanks for board&support
stefan
At long last, hey?
re. the top end, there are excuses that can be given and modifications that can be made but please give it 2-3 weeks to break in first.
/rjm
Hi,
finally I completed my Phonoclone. It worked at my first attempt thank to your help! I could use for the first time a MC cartridge, a brand new Denon DL-103. I have no experience, but for sure the sound is much better when compared with my previous Grado Prestige Green MM cartridge.
The only problem I have, despite the metal case and the shielded wiring for the music signal, I have low level RF noise coming out from the speakers.
Thank you RJM and to everibody here
Renato
finally I completed my Phonoclone. It worked at my first attempt thank to your help! I could use for the first time a MC cartridge, a brand new Denon DL-103. I have no experience, but for sure the sound is much better when compared with my previous Grado Prestige Green MM cartridge.
The only problem I have, despite the metal case and the shielded wiring for the music signal, I have low level RF noise coming out from the speakers.
Thank you RJM and to everibody here
Renato
Attachments
Hi Renato,
Is that a shielded cable from the board to the phono socket? If so, try grounding the shield at the phono end.
Regards,
kffern
Thank you for your reply Kffern. I have not grounded the shield. I will do.
Please tell me if I am right: I'll connect the shield to the RCA input ground.
Since I used the same shielded cable to connect the phonoclone out to the RCA out, do I need, also for this cable, to connect the shield to the RCA out ground?
Thank you again for your help
Renato
Please tell me if I am right: I'll connect the shield to the RCA input ground.
Since I used the same shielded cable to connect the phonoclone out to the RCA out, do I need, also for this cable, to connect the shield to the RCA out ground?
Thank you again for your help
Renato
Yes, try connecting the shield to the RCA plug ground. If the external cable has a metal shield it should be grounded on one end. I can't remember whether it should be at the preamp or the phono stage. Best to use an ordinary factory terminated cable till the problem is sorted. For such short internal cabling I'm not sure if it's worth using shielded cable. Maybe someone will advise.
Kffern
Kffern
Re RFI you just have to try a few things to see whether it makes any difference. The OP27 has a bipolar input stage which is more sensitive to RF pickup than sat a FET opamp, so you might try switching opamps, or adding a small (500pF about) capacitor across the + and - input pins of the input opamp. Also try switching phono cables, for example, and making sure that COM is securely connected to the case at the ground lug.
Here is my PhonoClone:
Standard BOM. HiFi2000 cases, Trafomatic potted transformers. Neutrik SpeakOn + AQ power cable for umbilicals.
Mundorf MCap on outputs. I have ZN coming soon...
...what is not standard is my contraption for easy loading. I attached a small PCB with 300, 400, 500, 1000, 1500 and 2000 CNF55 resistors [or close enough values].
Using MB style jumpers, I can select any combination of those in parallel and get a much larger degree of loading steps. Current combination yields ~170ohm which seems quite suited to the Ortofon Rondo Red I have installed.
Initial Thoughts
No perceivable hum or noise on normal listening levels. Some noise after 2PM on the volume dial... still quite negligible. Will give it a few days and see what happens. Happy happy right now.
More to come. I hope.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Standard BOM. HiFi2000 cases, Trafomatic potted transformers. Neutrik SpeakOn + AQ power cable for umbilicals.
Mundorf MCap on outputs. I have ZN coming soon...
...what is not standard is my contraption for easy loading. I attached a small PCB with 300, 400, 500, 1000, 1500 and 2000 CNF55 resistors [or close enough values].
Using MB style jumpers, I can select any combination of those in parallel and get a much larger degree of loading steps. Current combination yields ~170ohm which seems quite suited to the Ortofon Rondo Red I have installed.
Initial Thoughts
No perceivable hum or noise on normal listening levels. Some noise after 2PM on the volume dial... still quite negligible. Will give it a few days and see what happens. Happy happy right now.
More to come. I hope.
Attachments
Thanks! Means a lot, especially being my second project.
First one was a tubed output stage for my HD 990.Now... I know I had asked this question before, and I did get an answer from RJM, but I keep wondering...
...anyone try any opamp rather than OP27/37? I saw a reference earlier to an issue with the bandwidth on the AD797, but maybe an LT1028?
RJM, I remember you said that you feel the best part for the job is OP27, but a guy wonders...
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Phonoclone 4?
Another year.
I'd like to share the potential direction the phonoclone circuit development will take in the coming months.
I'm thinking along the lines of the B1 Buffer from Nelson Pass / Firstwatt. A single ended transistor buffer circuit to isolate the op amp output of the phonoclone output stage from the cable capacitance. Some sort of two transistor design, either JFETS or bipolar, creatively wired to the Xreg. The low output impedance of the op amp suggests bipolar.
Note that board space is a bit of a premium, so unless this is made as a separate board (which has its attractions) the parts count has to be kept to a minimum.
Thought and suggestions (links) welcome.
/rjm
Another year.
I'd like to share the potential direction the phonoclone circuit development will take in the coming months.
I'm thinking along the lines of the B1 Buffer from Nelson Pass / Firstwatt. A single ended transistor buffer circuit to isolate the op amp output of the phonoclone output stage from the cable capacitance. Some sort of two transistor design, either JFETS or bipolar, creatively wired to the Xreg. The low output impedance of the op amp suggests bipolar.
Note that board space is a bit of a premium, so unless this is made as a separate board (which has its attractions) the parts count has to be kept to a minimum.
Thought and suggestions (links) welcome.
/rjm
...anyone try any opamp rather than OP27/37? I saw a reference earlier to an issue with the bandwidth on the AD797, but maybe an LT1028?
RJM, I remember you said that you feel the best part for the job is OP27, but a guy wonders...
Hi,
I said it before, that I liked best the AD797 in the second stage and AD811 in the first, but made it on veroboard, as those are less forgiving than op27. In fact, this combo didn't run smooth with the old v2 (or was it v1?) boards, I got to much offset at the input, never a problem with op27. You might try the opa627 in the first stage, I guess many people would like it, I didn't (too soft and weak bass). The LME49710 might also work good in the 2nd stage, but I didn't try. I didn't like the 1028 in the second stage too much, this one will most probably not run in the old boards, I have no exp. with the actual v3. I never managed to have them in the first stage without problems though (offset, oscillation, strange pops and the like).
Rüdiger
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