Queston: C1 cap value for Poseidon

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Queston: C1 cap value for Poseidon

Postby logos47 » Sun Sep 23, 2007 3:08 pm

Dear Shannon, The MKIII Poseidons are installed, stuffed with nice Allen Bradleys along with some AudioCap Thetas salvaged from a previous project. Question is, the C1 cap value I have inserted is .47uF instead of the .22uF specified. Do you see any long term problem with this?
Bob
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Re: Queston: C1 cap value for Poseidon

Postby Shannon Parks » Mon Sep 24, 2007 5:42 am

logos47 wrote: Question is, the C1 cap value I have inserted is .47uF instead of the .22uF specified. Do you see any long term problem with this?


No problem. For the C1 coupling cap, bigger is better. We want this stage to have the dominant pole or low frequency cutoff. Note that this is not true of the second stage.
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Postby JW34 » Sat Feb 02, 2008 1:08 pm

Concerning the C1, C4 & C5 caps.....can these be Film & Foil istead of Metallized? I am planning my project and would like to use Hovlands.

Thanks,

Jay
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Postby Shannon Parks » Sat Feb 02, 2008 3:23 pm

Yes.
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What would be the optimum value for C1?

Postby EdStiles » Wed Feb 20, 2008 9:45 pm

For C1, I have 0.22 mfds, 0.33 mfds and 0.47 mfds (all 630v) available. What are the trade-offs? Which would be optimum? I'm using Ned's version of the Poseidon, optimized for 5751s and 12BH7s.

Thanks,

Ed
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Postby Shannon Parks » Thu Feb 21, 2008 6:48 am

Whatever fits in there best, Ed. There won't be a huge difference between the three, but the larger caps will be a ever-so-slight technical improvement.
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5751

Postby logos47 » Thu Sep 04, 2008 6:44 am

Ed, I saw you mentioned the 5751 and optimizing the board for that. I love the sound of mine, but just plugged 'em into the 12AX7 postion. Any tricks of the trade you can share?
thanks, DrBob
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Re: Queston: C1 cap value for Poseidon

Postby Wiesiek Lipowski » Thu Sep 04, 2008 12:27 pm

separks wrote:
logos47 wrote: Question is, the C1 cap value I have inserted is .47uF instead of the .22uF specified. Do you see any long term problem with this?


No problem. For the C1 coupling cap, bigger is better. We want this stage to have the dominant pole or low frequency cutoff. Note that this is not true of the second stage.


Is this C1 really necessary here? There is no cap in the MKIII upgrade article by Kara Chaffe, Audioxpess 2001. The topologies around the first tubes (12AT7 in Kara's) seem to be similar.
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