pabbi1
Cavalli Audio Spiritual Advisor
- Joined
- Jan 12, 2004
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This one was about $600, with all the tubes, IIRC.
This one was about $600, with all the tubes, IIRC.
A Yes, replaceing electrolytics in the signal path with film improves SQ. If you have senns you can get away with roughly 120uf cap for output coupling.
B Those hammonds get pretty hot, even within specs. Your setup skouldn´t be a problem.
C Ivé built mine as dual mono. It improved SQ for me, since I couldn´t do regals mod with one PS other than that I dont know. The extra power is hans when rolling tubes too.
I recomend you to try this too:
Regals mod
Remove cathode bypas caps
I dont think Ivé heard anyone who dont like regals mod, the bypass cap is moore a matter of taste. In theory its better without it.
SBoy:
I only know the calculation the other way around, how to calc -3db freq with a given resistance and capacitance.
fc = 1 / 2*pi*R*C
Just remeber to enter the capacitance in F and not uF.
If you have a texas ti 82 or similar you can enter this to get a graph on the cutoff.
319/sqr(319^2+(1/2pi*X*120e-6))^2 319 is the headphones impedance and 120 is the capacitor size in uf.
I tried some values, signal level @ 20hz into 600ohm
60uf - 97,6%
40uf - 94,9%
30uf - 91,5%
20uf - 83,3%
yiancar:
Regals mod will improve sq much more than perfectly matched resistors.You can buy a couple extra resistors and measure them yourself. If your really picky you can heat them in the oven first so the resistance settles.
I have a question too:
Will the choke mod improve the sound of the amp?
well, i do know how to calculate the value of the cap from the given db freq, but how much is of a drop is sufficient? is it totally up to our preference and we just play around with the value?
Heat them up in the oven? wow, i didn't know that! lol. let us know how it goes yiancar.
I want the amp to be "totaly" linear 20hz-20khz so I use a 120uf cap with 330ohm senns. It gives me -3db @ 4hz and 97.9% at 20hz. But of course its a matter of taste. I recommend a little NFB if you go big with this cap, the lowest bass feels slow and slobby without it, at least in my setup..
Edit:
Found this page: http://my.hrw.com/math06_07/nsmedia/tools/Graph_Calculator/graphCalc.html
Just enter 319/√(319^2+(1/(2π*x*0.000120))^2)
Replace 319 with you phones impedance at both positions, and replace 120 with you capacitor size in uf. This gives you a graph on the lower limit of the bandwidht.
If u plan to add both ur psu and ur amp in the same case, by adding one of those filters before the transformer, it would remove all emf caused buy the power grid So simply yes it would help