Amp/Preamp Asylum

BAT VK-30 preamp and EDGE M8 Victor K. help!

68.8.153.30

Cougar

A

I was wondering if I could ditch the 330uF input coupling cap in my EDGE M8 amp since my BAT VK-30 preamp has a 1uF output coupling cap. I wanted to do a 6 pac version on the BAT VK-30 which would bring the output capacitance to 3uF and if so, Just get rid of the 330uF input cap on the amp?

I'm so confuse now on the Corner frequency adjustment for my amp that I just want to get rid of that cap if possible.

The EDGE M8 has an static input impedance of 33kohm when measure after the 330uF input coupling cap to ground.

any help is greatly appreciated.

Follow Ups:

RE: BAT VK-30 preamp and EDGE M8 Victor K. help! - Victor Khomenko 06:04:53 01/31/15 (0)
Sorry, didn't see your post earlier, but on the surface, 330uF seems to be awfully high, if, indeed, followed by just a 33k resistor. However, we don't know the particulars of the circuit - the 33k might not really be the resistance at that node.

Another issue, as CB mentioned, is whether there is some DC voltage at that node - sometimes the case with the solid state circuits.

So I too am curious about your findings.
Thank you to everone for the help. - Cougar 19:29:09 01/25/15 (3)
I contacted the designer and got the info I needed from him.

Thanks again.
- Don't say it; show it - madisonears 21:39:25 01/25/15 (1)
  Show your thanks by sharing with us what you found out. We can all learn from it.
  
  Peace,
  Tom E
  - RE: Don't say it; show it - Cougar 07:36:13 01/26/15 (0)
    Relax, I always post back results of my findings. I just need to put this into action and when it's finished and the tests are all done I will post back. I don't want to post something now without confirming that will CONFUSE others or lead then down the wrong path.
- Sorry, meant Thank You to everyone. - Cougar 20:53:46 01/25/15 (0)
  nt.
RE: BAT VK-30 preamp and EDGE M8 Victor K. help! - Caucasian Blackplate 18:06:40 01/24/15 (1)
Is there any bias voltage at the first stage of the M8?

Edits: 01/24/15
- RE: BAT VK-30 preamp and EDGE M8 Victor K. help! - Cougar 10:52:34 01/25/15 (0)
  To be honest, I don't know because I don't have any schematic on this amp and I'm in the process of trying to draw up a schematic to at least get some idea of how to do all these calculations for that Corner Frequency.
  
  The input cap of 330uF Electrolytic cap on the amp seems excessive and I may be able to get better sound with a proper value input Coupling FILM or PIO caps. I just don't want to add any issues to this amp just want to make it sound better.
  
  Since the BAT VK-30 preamp has 1uf output coupling cap and the amp has 330uf don't know how this will affect the input capacitance on the amp. I was thinking it may be in series preamp output 1uf + 330uf input = 3.3uF since there is a resistor in series after the 330uF cap and that resistor is then in parallel with another cap and resistor that goes to ground. so the with a R33k and C3.3uf the 1/(2*Pi*33k*3.3uf) = f 1.46hz X10 = 14.6hz. But without knowing the actual Impedance while the circuit is active I can only go by this input Rin = 33k. I have seen some sites explaining how to calculate this by finding out Beta*Re to help figure out the true Rin but since I don't have the schematics to help it's kind of hard.
  
  Thanks

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