Recently, I made a movement toward to a project that I have been contemplating for 5 years – I would like convert my Expressive Technologys SU2 and 2x834PT tandem into a final packaging solution.

For the last 5 years I have learned following:

1)     2 heavy phonostage boxes do not do well mechanically coupling via RCA jacks with heavy Expressive Technology transformer. They do well if they are not touched but if then moved frequently then the RCAs have tendency to lose ground and pick up some consequential noise.

2)     If I direct coupled the Expressive transformer with the 2x834PT’s input grid then I will lose the unnecessary RCA male-female and ~ 3 inch of wire. There is nothing that will make me more happy in analog then loosing unnecessary cable and unnecessary connectors in the secondly of 28dB gain transformer.

3)     I can make the entire new phonocorrector 2 times smaller – a good help for my always-challenged to of the rack’s real-estate.

4)     Since I do not have a good sounding solution for switching the .2mV signals of MC cartridges and all my attempts to do it had failed. Also, since I can’t imagine better performing phonostage I would like in a new phonocorrector to have a provision to switch the cables from my different tonearms. Currently I have difficulties to do.

5)     I would like to change the type of air capacitors that I use in the corrector 2x834PT, using larger  caps.

6)     I would like to change the diodes in the PS to new Silicon Carbide Schottkys.

So, the idea to take my existing two 834PT boxes, my separate 834PT power supply and my ET-2 transformer and arrange them in a separate accurate box with easy access to the RCA input s does look like very a reasonable project. It will not take a lot of efforts – a few hours no more.

I was thinking about the naming of my “new” phonostage. Considering the truly unparallel performance this corrector is capable and considering the fact that I know that I won’t be looking/thinking about another “reference” phonostages ever again I decided to name my new Expressive Technology SU2 + 2x834PT assembly as “End of Life Phonostage” . There is another dimension of Truth that is opens up to the people when they face the ends of their lifes. The “End of Life Phonostage” operates at the very same “other dimension” of listening awareness, presenting results form a perspective of completely different abstraction. You as a listener just need to be “ready” to understand it…

Paul S wrote:

Romy, I have noticed the same thing with the phono stage power supplies, that the big multi-chassis units with dual 100 lb. PS get no overall sonic advantage, all said and done. So how do we deal with the stupid, lousy AC that is too often present? I am happy with the good-AC sound from my modded K&K, but I do wish I could get its best more often. Have you managed to get your phono stage clear of bad AC, and if so, how?

Looking at my current 834PT phonocorrector I decide do not convert it into the “End of Life" Phonostage as it is good as it and I would like do not ruin it – I will always take advantages of a good MM phonostage. I took the Expressive Technologies ET-2 transformer and build another small board with 834PT RAAI correction circuitry.  It took 4 hours and I love how I mange to layout everything. It will be incredibly small and it looks that in my new enclosure I will have some extra space.

Now I am thinking about the PS. The old PS I would like to keep with old 2x834PT. This corrector will be not dual mono and I will be using both halfs of the 12AX7. With the incredibly low current that this corrector sucks I think I will not go for dual mono PS . The leading idea not is the following:  the filaments LCRCRC supply and the anode is LCRC +GGRC. The GGRC is a pair of my gas regulating tubes (0A2) that give exactly 300V that the corrector needs.

Romy the Cat wrote:

guy sergeant wrote:

I hope no one tries to build this based on the diagram above.  They won't get much output from it!  If you can't see what I suspect are deliberate mistakes, you definitely shouldn't be trying to build one.

I did not use the schematic above to build the corrector – I built it from my head as the circuit painlessly simple but looking on what I draw I do not see that anything different then what I have currently assembled. I did not measured the corrector gain yet but preliminary I feel as it should be  - I see no reason why the output shell drop after I went for fixed bias. Also, the corrector does a few mV ideal and when I touch inputs of makes under7VAC at output – the habitual voltage that I expected….

I will certainly measure and calibrate everything before I consider it doe but if you feel that there are any mistakes in there then please point them out. To me everything looks right so far.

Referring to the threads a few month back:

http://www.romythecat.com/Forums/ShowPost.aspx?PostID=4937

I wonder if I need to play with the coupling cap between the first and second stage. Now I have my beloved ElectrocuCube 950. In my former version I had the Multucap RTX, that I also found extremely good. The RTX are slightly more rough, positively-rough vs. Cube 950 have positively-slower upper bass. I can live with ether cap with no problem. Still, I wonder if I shell try those new caps. For $90 each I can get the V-Cap Teflon Film & Tin Foil or for double of it I might try Duelund caps. I have no experience with ether of them but I have $200 for check my gullibility… did anyone used the V-Cap. Do not say yes and I will be holding you responsible for me burning another $200… well, I probably shell try it….

guy sergeant wrote:

Isn't 330 ohms a little low as a plate load for an ECC83/12AX7 to be running into?  330K ohms perhaps? You often ask what is wrong with a given speaker installation, I thought you might be doing the same here.  Keeping us on our toes