Joe Tritschler had a very nice article in October 2003 AudioXpress "Borberly's RIAA Amp with Tubes". He is now offering a kit of stereo boards on his website - and it should be much easier to work with as he has modified it for the 6DJ8
http://tpadevices.com/hifiproducts.html
for $49 a pair of boards it would seem to be a good deal !
fwiw, here's what the schematic for the original design looks like on the SIM:
http://tpadevices.com/hifiproducts.html
for $49 a pair of boards it would seem to be a good deal !
fwiw, here's what the schematic for the original design looks like on the SIM:
An externally hosted image should be here but it was not working when we last tested it.
jackinnj said:now, can we make it work with one ECC88/6DJ8?
if 1,7x smaller signal on output don't bother you .........
yes
choky said:
if 1,7x smaller signal on output don't bother you .........
yes
so we just have to crank the line amplifier a bit...
well I got a pair of boards from Titschler -- the results are shown below.
the boards which were delivered were quite a bit different from the design published in AudioXpress (and that's not a bad thing, 417A's or 5842's are expensive).
In the stock design 100nF/400V coupling caps were used -- and you can see the droopy LF -- so I inserted a 1.0 uF/ 400V WIMA PP and the results are much better.
I show comparison with the Audio Research SP8 and Koren phonoamp stages modeled in SPICE:
the boards which were delivered were quite a bit different from the design published in AudioXpress (and that's not a bad thing, 417A's or 5842's are expensive).
In the stock design 100nF/400V coupling caps were used -- and you can see the droopy LF -- so I inserted a 1.0 uF/ 400V WIMA PP and the results are much better.
I show comparison with the Audio Research SP8 and Koren phonoamp stages modeled in SPICE:
An externally hosted image should be here but it was not working when we last tested it.
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