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In Reply to: Re: Try 0.47uF V-CAP teflon or realcap TFT posted by sherod on April 19, 2007 at 19:19:19:
My power amp is solid state with input impedance of 50K. Also very important detail is cathode follower - ecc82 in my pre, hence the output impedance is below 150 ohm. Also my pre fit well my friend’s 20w Hiraga power amp with 22K impedance.What pre, power amp and speakers you have?
Regards
Milos
Follow Ups:
Milos, I just did a calculation and based on the 50K ohms input impedance on your amp, using a .47uf preamp output cap would give you a -3db cut-off of 67.7 Hz. Doesn't that seem a little high for your Heybrooks?
Hi Sherod, thank you did you take into account the low output impedance of my pre - 100 ohm. Please post your calculation
Milos,
No, I didn't take into account your low 100 ohms output. I'm not sure what formula to use to take that into account. My preamp output is 600 ohms with amp input being 100K ohms. Could you post your method for calculating this -3db cut-off? I would appreciate it. I am using a chart provided me by Chris at Vh Audio who has the V-cap.
I am also not sure what formula to use but 100 ohms output is also important. Where did you find chart by Chris from Vh.
Milos, here is a recent thread I started about preamp output cap value. The next post gives the formula which is used in the chart that Chris sent me. I e-mailed you a copy of the chart, but I'm not sure if you received it.
Thank you Sherod I forget that I have 4uF input capacitors in my power amp, therefore total was 4+0.47....4.47uF.
Milos,
I'm not sure if this is the same thing. If so, then we have to start over and go back to my original post where I currently am using a 4.0uf cap in my preamp output. Thanks for all your input, though.
My preamp is the Audio Horizons TP 2.o. It has Siemens CCa(E88CC) in outputs. It is rated at 600 ohms output. My power amps are VAC Musicbloc monoblocks, rated 70W RMS, push-pull, KT-88 outputs and E82CC driver and splitter. Input impedance is 100K ohms. My speakers are Reference 3A Dulcet monitors.
My Heybrook HB-100 speakers also have main driver which is directly coupled to amplifier with simple high pass filter on the treble unit with only two capacitors. My Heybrook is little bigger, frequency response is 40Hz to 20 KHz, while your Reference 3A have 48 Hz to 20 KHz.
Also I believe that your speakers, because of mentioned direct coupled main driver, are very neutral, direct and transparent, so you will hear everything. I have also very hard time to make my speakers sound excellent and finally with very sophisticated pre and power amp they have some real magic in terms of speed, openness and dynamic.
Calculated cut-off at with 0.47 capacitors at 34 Hz, in the smaller room, with your speakers could bring some benefit because of yours speakers natural limitation in the deep bass.
From my personal experience I believe that you will have articulate bass without any problems after modification with V-CAP or Realcap TFT 0.47, 600V buffer capacitors.
Milos,
Thank you for your observations. Yes, the Dulcet speakers are very transparent with their simple one cap crossover as well as being time and phase aligned. They are extremely revealing of everything in the chain. I will try the .47uf V-cap teflon. If it doesn't work out, I can maybe use this value in another location. I appreciate your consideration.
Ok Sherod,
I will be very happy if 0.47 made magic. I ve never tried V-cap but Realcap TFT after 400 hours in my pre start to sound glorious.
Please post your experience with 0.47.P.S. Extremely revealing speakers like ours are great but painful.
Milos,
I will be glad to post my impressions of .47uf cap. Yes, our speakers are very difficult to extract that "magic", but once achieved, it is well worth it. I fully agree with you.
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