Pindac, I apologize if my earlier post seemed overbearing. I do respect that each of us has a slightly different "taste" in SQ, for want of a better phrase. What I assumed is that your phono stage was designed to provide what we commonly think of as MM levels of gain (anywhere from 39db to less than 50db), when using an ECC83, i.e., your phono stage was designed around the ECC83 input. I assumed or guessed that into that ECC83 input tube socket, you are now using an ECC81. This substitution would "work", but it would not be optimal for operation of the ECC81 (too little current, mainly), and as you know, there would be a significant penalty to overall gain of the phono stage. With such a phono stage using the ECC81, it is not at all surprising that you found it worked best with a SUT. In fact, if my conception of your phono is correct, I am surprised it works at all with an ECC81, when you use any typical LOMC cartridge, unless there is a second gain stage following the RIAA filter section. (I guess I also misunderstood you to say originally that you far preferred the ECC81/SUT configuration to no SUT; I now understand you to say that you like the sound both ways but that the character is different, not surprisingly.) Anyway, unless you are using a linestage with inordinate amounts of gain, into an amplifier with very high input sensitivity for full output, driving very efficent speakers, or some combination of these, it is no wonder you need to twist the VC fully over to achieve satisfactory sound pressure levels. So, first question, was your phono stage designed FOR the ECC81 as input tube, once you inter-acted with the designer, or for the ECC83? For slightly less gain in an MM stage, compared to the ECC83, many people use the 5751, which pops right in to an ECC83 design and is in between the ECC83 and ECC81 in terms of gain.
Running LOMC with MM (47K) loading
This is the way I run my Zyx 4D and my Benz Ebony L before it. I have a JLTi phono preamp which allows me to do this. I have been satisfied with this pre since buying it new. Yet I may be in the market for a new (Different) one. However some I have seen may not offer this ability. One that has great reviews also has the loading and gain all tied together. Not sure about Herron but it may be out of production. Not sure about others.
The question comes with @Atma-sphere comments on loading and circuit stability. He contends that the loading damps (stops) the cartridge cantilever from moving as freely as it was designed (my words) And it is better IF you can run with no loading. But that requires a stable circuit which not all have. Apparently my JLTi has a stable circuit because I have been running LOMC's this way for a 10-15 yrs.
That said, should I require this attribute to my next phono preamp? And might I be better off to send the JLTi to Joe Rasmussen (Allen Wright's partner) for upgrade to Pre and new Power supply?. That will be the cheapest and that is likely to be the step I take. However the question still exists. If the damping is as per Ralph's assessment, it would seem that the stability of the circuit is of greater importance than the ability to have a lot of loading options with unstable circuitry. Another question, Is loading a band aid for a circuit which is not at an optimum? I am not an electronic tech so I am not looking to stir the pot but for my own understanding Thanks
The question comes with @Atma-sphere comments on loading and circuit stability. He contends that the loading damps (stops) the cartridge cantilever from moving as freely as it was designed (my words) And it is better IF you can run with no loading. But that requires a stable circuit which not all have. Apparently my JLTi has a stable circuit because I have been running LOMC's this way for a 10-15 yrs.
That said, should I require this attribute to my next phono preamp? And might I be better off to send the JLTi to Joe Rasmussen (Allen Wright's partner) for upgrade to Pre and new Power supply?. That will be the cheapest and that is likely to be the step I take. However the question still exists. If the damping is as per Ralph's assessment, it would seem that the stability of the circuit is of greater importance than the ability to have a lot of loading options with unstable circuitry. Another question, Is loading a band aid for a circuit which is not at an optimum? I am not an electronic tech so I am not looking to stir the pot but for my own understanding Thanks
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- 37 posts total
- 37 posts total