| Romy the Cat's
personal site dedicated to advanced audio and evolved music reproduction
techniques
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Hi N-set,Yes I added big cap bank to the second stage cathode. Yes it is possible to use filament power supply for fixed bias like Romy did.But I have a stereo EAR834p with a single filament PS. So, I was afraid that one PS for both channels can caus...
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Hi Romy,I read about EAR834p modifications in number of forums. And I never found any explanation how does RIAA feedback work.Only from you I heard about Miller capacity that used in this RIAA.I tried to do my calculations and as I understand the Mil...
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Hi Paul,My question was of cause about my phonostage based on EAR834p and "End Of Live" modification with air capacitors and LCLC + 0A2 power supply.A couple weeks before I increase the second stage ECC83 cathode capacitor value to 43400uF (Kaisei no...
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Hi Guys,The output impedance of ECC83 in cathode follower is around 625 Oms. But 1uF capacitor makes output impedance very big on low frequencies (around 8K Ohm at 20Hz). And in this schematics the global feedback doesn't work at low frequencies. So ...
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Do you use input 50KOhm Z-foil resistor between input tube greed and GND?Does Z-foil sound colder compared to Dale RN60D?U used Dale before. Now I use Shinkoh tantalum resistor. It has similar to Dale tonal balance but sounds smoother.I heard a lot o...
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Hi N-set,Thank you for information.What kind and producer of capacitors do you use?Regards,Alex. ...
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Hi,I have the phonostage with the similar schematics that Romy has.The power supply use SiC Schottky diodes in bridge and 15H choke load exactly like on the scheme in this thread.Is it possible to bypass each Schottky diode by 10-100 pF capacitor?Doe...
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Does anybody try to change shunt regulators OA2 to 15K Ohm resistor?I heard from number of people that OA2 is too noisy for phonostage.For example, in this article wrote about this http://www.audionote.co.uk/articles/tweak_ai_p2_phono_mod_0...
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What about filament?Is the filament ground connected to the common ground?Is the filament ripple is small?...
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This is my ECC83 Amperex picture.
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I tried Amperex ECC83 "Bugle Boy". They sounded bad in the EAR RIAA. I like more modern Amperex ECC83, Holland made with orange-red prints....
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Romy,Thank you.I think I should to give some break-in time to Sylvania 0a2.50 hours is enough? Previously I used in my EAR the next set of tubes ECC83: 1-Amperex (red print), 2-Amperex (red print), 3-Sylvania 7025 (yellow print).When I built "End of ...
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Hello Romy,What brand of 0A2 do you use in your phonostage?I used RCA, but after 1.5 years of work it began to spark when phonostage is switched on.I tried Siemens, Mazda and now Sylvania 0A2.Siemens has "disco sound", without mids, just metallic hig...
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Romy,I have rebuilt my phonostage (the pictures after update are added to Picasa):1. Fixed filament. Now a ripple about 1mV (unmeasured by my Fluke). The filter is: C-L-C-L-C
30000uf-3mH-30000uf-3mH-30000uf. I put two 3mH chokes & Nichico...
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Romy,Yes, I measured my cartridge-tonearm combination with test disk. The resonant frequency was completely different compared to calculation with http://www.mh-audio.nl/MySystem/RF.asp.7 years ago, I tried Fidelity
Research FR-64FX with Grado Sona...
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Romy,I use Ortofon Rondo Bronze with Nottingham Spacearm and Spacedeck. I hate Spacearm because bad tracking. Also, I can't add mass to Spacearm.I going to try a heavy tonearm.Fidelity Research FR-64FX with Ortofon Rondo Bronze (compliance is 15mm/uN...
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Romy,I used second tube grid resistor, 1.8Meg Holco. (I couldn't find 2 Meg chip and good quality resistor: Dell RN60D or Holco or even Caddock MK-132.)But I felt the deep bus was cut. I tried 1.8Meg Holco & Riken 220K in serial. The deep bus inc...
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Romy,I try to remove the step-up transformers & short the
input grid, the hum has gone.Than, I did next changes:1. Twisted wire from input RCA to step-up transformers. Connect transformers input & output ground directly (not thought ground ...
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Romy,I tried before to cover transformers by foil sheet, it didn't help. Now I try “disconnecting
trick”. The hum was disappeared after phonostage had switched off, while music continued to play.The filament ripple is 32m Volt (5% from DC level). I...
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Hello Romy,I just have build the postage used your "End of Live" scheme and Altec step-up transformers.http://picasaweb.google.com/alex.berger73/Phonostage#I have original EAR. After of 100 hours of working, the new Phonostage sounds more dynamic, ...
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