Nice. Well done. Show it to us again when boxed also don't forget.Here´s another MM riaa that delivers sweet musicSoon i will place it in a nice chassis. Thank´s Salas and Teabag
I have one more kit. Maybe i will make one for MC!?
What MM cart you use it with?
Yet another one for MC? Definitely. Spares are always handy
For MM and magnetically shielded mains transformer in a full length chassis you may escape hum. When the transformer itself and any AC (well dressed) cabling are farthest away from audio inputs & outputs.
For MC due to extra gain its far more difficult and a separate PSU chassis is a better bet.
The difference between MM and MC is the engine type. One moves a magnet the other moves a coil. When the moving parts mass (cantilever & tip) as well as their design and materials are the same between MM and MC they are not that far away in quality result but their signal level and the loading characteristics differ. MCs are free of TT wiring, IC cable, and preamp capacitance effects due to low self impedance but MM have more signal. Gain can be added more easily than taking parasitic capacitance to very low levels when there is a distance as in normal installations after adding most preamps capacitance characteristics. Usually the best cartridge examples with very good moving parts and general design as well as best materials tend to be offered in MC type by the industry with very few notable MM exceptions. MM don't deserve to be considered intrinsically inferior but the production realities had put it in a corner. Mostly using heavier pick up and exploiting the loading capacitance to an HF resonance than using light parts and asking for very low capacitance so to naturally extend in HF. Which is not that practical to find in real life as said. After all there had to be cheaper and more robust models with higher output for average users and DJs where MM suited itself better so MC was reserved for audiophile marketing. MM also has the benefit of exchangeable front end which is essential for DJs lets say or great in starter systems where there is not much care of proper usage but for the really good ones when its about 80% of the cost its not a big deal vs MC because in costly ones there is usually a trade in discount when their pick up parts also wear out.
For MC due to extra gain its far more difficult and a separate PSU chassis is a better bet.
The difference between MM and MC is the engine type. One moves a magnet the other moves a coil. When the moving parts mass (cantilever & tip) as well as their design and materials are the same between MM and MC they are not that far away in quality result but their signal level and the loading characteristics differ. MCs are free of TT wiring, IC cable, and preamp capacitance effects due to low self impedance but MM have more signal. Gain can be added more easily than taking parasitic capacitance to very low levels when there is a distance as in normal installations after adding most preamps capacitance characteristics. Usually the best cartridge examples with very good moving parts and general design as well as best materials tend to be offered in MC type by the industry with very few notable MM exceptions. MM don't deserve to be considered intrinsically inferior but the production realities had put it in a corner. Mostly using heavier pick up and exploiting the loading capacitance to an HF resonance than using light parts and asking for very low capacitance so to naturally extend in HF. Which is not that practical to find in real life as said. After all there had to be cheaper and more robust models with higher output for average users and DJs where MM suited itself better so MC was reserved for audiophile marketing. MM also has the benefit of exchangeable front end which is essential for DJs lets say or great in starter systems where there is not much care of proper usage but for the really good ones when its about 80% of the cost its not a big deal vs MC because in costly ones there is usually a trade in discount when their pick up parts also wear out.
Hi
i have a MM Excelsound A801-1 cartridge. this is an old one, and the TT is also old and not a reference in this matter. For now it is what i have. Because i didn't know the mv , i measured it with a DMM at the output of the TT. With the peak hold function on the DMM i get 3mvac after a while playing. Can i trust this value? is it the proper way to do this measurement? if so, can you advise on the resistor values? i have the kit from teabag. i use R14 47k prp and R5 6.75k prp. i am using only one 2sk369 because i suspect that will sufice.
thanks
i have a MM Excelsound A801-1 cartridge. this is an old one, and the TT is also old and not a reference in this matter. For now it is what i have. Because i didn't know the mv , i measured it with a DMM at the output of the TT. With the peak hold function on the DMM i get 3mvac after a while playing. Can i trust this value? is it the proper way to do this measurement? if so, can you advise on the resistor values? i have the kit from teabag. i use R14 47k prp and R5 6.75k prp. i am using only one 2sk369 because i suspect that will sufice.
thanks
If it was a test record with 1kHz sinewave at 0dB reference while looking on a scope it could show better. At least you know it works and has some healthy enough output. One 2SK choice is good. Use the 43dB option's recommended values from the FSP manual when reading its notes section named "gain". That should suffice. Don't devise any experimental values because they are all interdependent. For load resistor use the 47K R1 only by having all the DIP switch position open.
Thank you Salas. I've read the guide a few times. My doubts were in the gain section and input impedance. The input impedance is still a mistery for me. Dont understand how it will affect the sound. In the future i will try to acquire a thorens td320 mkii and a good cartridge for it. Can you point me to a good article on the impedance matter? Thank you
Happy christmas
Happy christmas
Mery Christmas to everyone. Please read Hagerman's article (one of many others) for carts loading and capacitance dependences.
http://www.hagtech.com/loading.html
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http://www.hagtech.com/loading.html
Sent from my iPhone using Tapatalk
For robust ergonomic & economic maybe this AT-LP120-USB Direct-drive Professional Turntable (USB & Analog) with AT95E Cartridge || Audio-Technica US
https://www.amazon.com/AT-LP120BK-U...sr=8-1&keywords=Audio+Technica+AT-LP120BK-USB
It even has an AT95E MM which is decent and you may upgrade to a Denon DL-110 high output MC at a point. Those together should make a decent budget LP source system.
The phono stage plays a big role also and with DIY you got that covered way above their league anyway, so no performance loss there.
https://www.amazon.com/AT-LP120BK-U...sr=8-1&keywords=Audio+Technica+AT-LP120BK-USB
It even has an AT95E MM which is decent and you may upgrade to a Denon DL-110 high output MC at a point. Those together should make a decent budget LP source system.
The phono stage plays a big role also and with DIY you got that covered way above their league anyway, so no performance loss there.
Alternatively in hi-fi TT style https://www.amazon.com/REGA-Rega-RP...r=8-1&keywords=REGA+RP1&refinements=p_89:REGA
Andrew mentions thermal-tracking, by instant-gluing transistors together and then circling with heavy copper wire. ( in post # 712)
If you want tracking at music-frequencies, e.g. >> 1Hz, the devices must be adjacent and on silicon. Why?
Silicon, as does any material, has a thermal time constant; that underpins "SOA" etc.
Silicon, cubic meter, has 11,400 second time constant.
10cm is 100X (1-0-0) faster, at 114 seconds
1cm is 100X (1-0-0) faster, at 1.14 seconds
1mm is 100X (1-0-0) faster, at 0.0114 seconds , or 11.4 milliSeconds, or 12Hz.
100micron (the size of the diffpairs in old opamps) is 100X faster, or 1,200Hz.
10 micron (modern diffpairs, non-interlaced) is 100X faster, or 120,000Hz.
1 micron (you get with FET diffpairs, interlaced) is 100X faster, or 12MegaHertz.
The black plastic has Rthermal 200X that of silicon (that value from memory). Thus the actual silicon die of two separate transistors, passing heat back and forth through black plastic, will be SLOW to track.
You probably can model this, in SPICE, using voltage-controlled voltage-sources, and a RC filter to introduce the delay. Distortion predictions will be interesting, in power amplifiers using diffpairs to convert 1vpp input into +- 60volt swings into the output buffers.
tank
If you want tracking at music-frequencies, e.g. >> 1Hz, the devices must be adjacent and on silicon. Why?
Silicon, as does any material, has a thermal time constant; that underpins "SOA" etc.
Silicon, cubic meter, has 11,400 second time constant.
10cm is 100X (1-0-0) faster, at 114 seconds
1cm is 100X (1-0-0) faster, at 1.14 seconds
1mm is 100X (1-0-0) faster, at 0.0114 seconds , or 11.4 milliSeconds, or 12Hz.
100micron (the size of the diffpairs in old opamps) is 100X faster, or 1,200Hz.
10 micron (modern diffpairs, non-interlaced) is 100X faster, or 120,000Hz.
1 micron (you get with FET diffpairs, interlaced) is 100X faster, or 12MegaHertz.
The black plastic has Rthermal 200X that of silicon (that value from memory). Thus the actual silicon die of two separate transistors, passing heat back and forth through black plastic, will be SLOW to track.
You probably can model this, in SPICE, using voltage-controlled voltage-sources, and a RC filter to introduce the delay. Distortion predictions will be interesting, in power amplifiers using diffpairs to convert 1vpp input into +- 60volt swings into the output buffers.
tank