Thanks for your interest and comments. The hula-hula heatsinks (whatever you mean there) are from thrown-away PC ups! My construction skills are basic and amateurish but somehow the results I get are quite satisfying (to me). There’s plenty of wasted space on my pcbs and the case is too large for an riaa amp… (I’m already thinking/dreaming of building another one with more compact pcbs, a different layout, and a nice-looking (not expensive) aluminium case with an engraved logo featuring Salas's project! But first I will enjoy my record collection...)
The input trimmer load to my Japanese MM (Nagaoka MP-20) is 75.8K. I thought this was rather high compared to the stated parameter (47K input impedance). But I decided to trust my ears rather than the specs. This thing of a trimmer as input load has been a revelation! It gives the user a lot of control on the sound.
Salas, talking of pentodes and valves, I’ve also been looking at your Valve Itch thread. It really describes the feeling of trying different topologies. If it’s as good as this one it should be worth building too. Got to do something with/for my valve collection!
Regards and best wishes to all.
Joe A
The input trimmer load to my Japanese MM (Nagaoka MP-20) is 75.8K. I thought this was rather high compared to the stated parameter (47K input impedance). But I decided to trust my ears rather than the specs. This thing of a trimmer as input load has been a revelation! It gives the user a lot of control on the sound.
Salas, talking of pentodes and valves, I’ve also been looking at your Valve Itch thread. It really describes the feeling of trying different topologies. If it’s as good as this one it should be worth building too. Got to do something with/for my valve collection!
Regards and best wishes to all.
Joe A
Nice that you found the trimmer working with MM. If it is a silent clean build and sounds balanced as you found, then making it compact has something little to offer, not much, mainly aesthetics. Personally I like classic DIY flavour builds like yours. The Itch has the characteristic of keeping the noise floor -80dB ref to 1kHz signal at 20Hz worse frequency for Riaa gain VS noise, dives another 40dB till 20kHz, its very good for silence as far as tube phonos go in other words, especially for using so easy to get and cheap Russian tubes in 1st stage. I would like to have it developed further for its second stage, see more tubes and bias points there, but I couldn't when I thought of it later. Was made to be given as a present. If you ever try it let me know so we can try stuff on it.
Regards and wishes from us here too, thanks, and happy vinyl replay!
Regards and wishes from us here too, thanks, and happy vinyl replay!
So you don't see anything wrong with such a high trimpot input load. The good thing about it is I can change it to taste. But so far I feel there is more presence throughout the listening spectrum and there is 'kick' to bass notes. I changed both channel output capacitors to 3.3uF K71-4 russian caps which are made of polystyrene. The two channels are more balanced now. Don't know what to expect with hi-Q polypropylene types.
Regarding the Itch I'll keep following the thread for developments and will surely join in when/if I tackle it. Your short and simple description of its features/development goals give a concise insight into its performance.
Finally, I'd like to thank you for all your help and patience during my build of this project.
Good luck.
Joe A
Regarding the Itch I'll keep following the thread for developments and will surely join in when/if I tackle it. Your short and simple description of its features/development goals give a concise insight into its performance.
Finally, I'd like to thank you for all your help and patience during my build of this project.
Good luck.
Joe A
Nothing wrong at all, it is supposed to do that. There was a Werner's article once I have linked before that shows how wrong just 47k and add some capacitor in the pF range can be for many MM carts. Takes flexibility. The only thing to further do more sophisticated is after you settle for all parts and have final tone and trimmer value well judged, use a good quality fixed resistor for that value. If playing with just one cart that is. Or find a very good quality trimmer to save the embedded flexibility just in case you change something in the system and you can balance out at the load point. Its a nice tool in a way. Regarding the Itch, I don't have it in hand so to make developments, will see if someone tweaks with it further and we get feedback and try stuff. The main thing about it is low noise easy, as I said. Then tube types in output, bias points, parts, are open.
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Yes I give 15.33nF as midpoint considering tonal differences in parts, carts, VTA etc. Don't know about Teflon there, can be leaner? It measures good also at 15.33nF. Sonata's 15.6nF works like 15.33nF in his MM though. Can be heavy or not in yours. How is it going with the balanced? Works with no noise, rewired to XLR floating cart?
I have to change RIAA position caps (see left side teflon cap 47nF new orientation) now all output caps 4.7uF
An externally hosted image should be here but it was not working when we last tested it.
I will use Erno Borbely PSU + your regs. of course
An externally hosted image should be here but it was not working when we last tested it.
It's a modified Pass Labs D1 I/V for Ess Sabre DAC
http://www.diyaudio.com/forums/digital-line-level/154866-new-take-classic-pass-labs-d1-ess-dac.html