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Old 15th January 2009, 04:19 AM   #611
Salas is offline Salas  Greece
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ikoflexer:

Thanks for your effort. Our phono and shunt have been developed along 3 axis. Simulating, comparative listening, measuring. Everything that I have posted has been simulated on Circuit Maker 2000 and your results in LT Spice agree. Very nice for no loop feedback and a couple of FETS. I have also made some real measurements versus a $10K phono reviewed as amongst world's top 3 phono stages. Actually I have listened to our RIAA versus some extremely expensive dream machines, driven by exotic carts and TTs at the same time in the same systems. I won't discuss brands or my subjective opinion. I will only say, be confident about our RIAA & PSU. Also a macho 2 box phono & double mono PSU build, painstakingly tuned with money no object parts is something I owe to myself. Will do at a point when I will have a better cart that can do it justice. It will cost some money, but being simple it will not skyrocket.
Black line is non cascoded, non buffered Salas. Blue line is $$$ one.
The 100Hz usual ripple peak is absent due to my shunt PSU on the black line. The commercial phono uses a solid state/tube double mono shunt hybrid PSU and it is fully symmetrical audio circuit wise.
Expect 6-10dB better 50Hz hum with the unshielded toroidal transformer out of my tiny RIAA box, and more careful loop measurement. Also my USB card has about -100dB noise floor between 10kHz-20kHz and 0.007% THD residual.
Distortion & noise:
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Old 15th January 2009, 04:23 AM   #612
Salas is offline Salas  Greece
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RIAA curves of Salas and $$$. They are in love it seems.
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Old 15th January 2009, 04:33 AM   #613
Salas is offline Salas  Greece
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Default Re: get yr 2SK170's on ebay

Quote:
Originally posted by kstlfido
Coming from tubes, these cost peanuts to me!

-Kent
Hey Kent, how are you? How is your listening going?
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Old 15th January 2009, 04:59 AM   #614
es44 is offline es44  Denmark
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Anyone needing 2sk's can have a look here:2sk170bl sale
I bought 100, and it's the real deal, Spencer is a stand up guy.

Best regards
Ebbe
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Old 15th January 2009, 08:25 AM   #615
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Hi! I've been well. Still listening. I'm waiting on some parts to upgrade. As it is running into the power amp directly and no lack of gain (!!), I thought I'd try to take thr r-load back up to original 1K ohm. The result was an improvement on imaging. What I would like to do is put a pot there and find the optimum R value.

Another change was cables from the VPI to the RIAA. Originally, I was using some old Silver Sonic cable I cut up (I try to minimize RCA connectors where I can). Replaced it with two 24ga. 2-strand untwisted silver wire connectors I made up. Very susceptible to hum, I had to giggle them around to find a quiet 'zone' on my counter top. But I did I notice more 'fluidity' in the music; and I am not one to take in the audiophoolery that some cable companies benefit from. It could be that I am just using better connectors.

What is funny is I twisted them for kicks (to reduce some of the hum) and the fluidity went away....

I'm thinking of re-building it, too. My old-school breadboard layout looks cool, but a lot of lead wire is there; by making more compact, might it improve things?

Finally, I need to do some mods to my TP Buffalo so I can do an AB test with lp's to check for levels.

-Kent
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Old 15th January 2009, 02:13 PM   #616
Salas is offline Salas  Greece
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Hi Kent!

Whatever you do with cables or parts or Rload or VTA is going to be audible for better or worse. More compact layout is never bad as well. My suggestion is to always use coaxial shielded cable especially for such a low level input and so much gain. What I have found is that coax sounds more natural when it is thin in diameter, 2.5mm or under. See about Mogami. It has many thin ones. Better tune your tone with other parts like your caps and resistors but make it hum free.
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Old 15th January 2009, 02:49 PM   #617
iko is offline iko  Canada
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Quote:
Originally posted by salas

Thanks for your effort. Our phono and shunt have been developed along 3 axis. Simulating, comparative listening, measuring. Everything that I have posted has been simulated on Circuit Maker 2000 and your results in LT Spice agree. Very nice for no loop feedback and a couple of FETS.
Oh no, I thank you! Cool stuff. Something is a bit unclear though, you mention the non-cascoded, two jfet per channel version. Is that the version you recommend building? Sorry, but with so many changes to the schematic over the life of the thread it's a bit confusing which one is the one that you think is best to build.
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Old 15th January 2009, 03:20 PM   #618
Salas is offline Salas  Greece
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For MM I recommend what you simulated. Both the gain and Miller capacitance are right. What you have seen measured in replies #611 & #612, is what Kent has for 0.5mV MC. He added a buffer later. That is non cascoded input, since MC does not interact with the high 2SK Miller capacitance, due to very low self inductance unlike MM. You will have even better signal to noise ratio with your MM and lower gain. Keep the buffer, it has been proved transparent and matches better in most systems. Both Jonners and Kent found better matching with what they drive, and could not detect it sonically. Over the life of the thread, it was not about changes, but about specific versions for specific applications. Its just live, we do it together. DIY, not strictly engineering. Subjective comments and tunings about parts, cabling, TTs, carts, etc, and ''sounds good'' or ''bad'' are also welcome and seriously evaluated in this thread.
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Old 15th January 2009, 04:26 PM   #619
Salas is offline Salas  Greece
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Ikoflexer has done a nice open source sim. Congrats. Useful.
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Old 15th January 2009, 04:36 PM   #620
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Quote:
Originally posted by salas
Subjective comments and tunings about parts

Well today waiting the pcb(row hole) for shunt I mods a little the psu phono

-replace byv27-200 with stealth II
-put 0.1uf X2 in the secondy of toroid
-delete fuse on dc rail ( do not do!at last thermal brake on ac)
-replace power cable (computer) with old supra speaker cable

I still evaluate but for sure I don't lost time
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