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A few quick(ie) questions.....

The "building bug" is hitting me again, and my new alumimum iMac is getting lonely and needs a tubed companion to soften the harsh, solid-state sounds from its headphone jack. So, I'm thinking of slapping together a Quickie for headphone use, something that would look classy next to my iMac on a dark, tobacco-red colored wood bankers desk. I'm thinking of putting one of these into a Seduction base, staining the base a very dark red or mahogany, covering the batteries with a black Hammond box, and using my spare S.E.X. non-shorting phone jack left over from when I put a shorting jack in. Here's a few questions, though:

a) Can the acrylic base be painted as-is with hammer-tone spray paint, or will it need to be primed (or sanded) first? I'm assuming it is pretty slippery....

b) Does one need to use a coupling cap to keep DC off the transformers if using the same Specos from the SEX amp? Or, considering that we're looking at 2 or 3mA here, would simply going into the primaries as-is work ok? If the former, what value of capacitors would I need? (I'm assuming in the neighborhood of 1uF?)

c) I would want to go from 8kohms to 250 ohms to power my Beyerdynamic DT880's. (I also have Grados, but I don't think this pre-amp would like the 32ohm impedance.) What taps on the Specos would I use to go from 8k to 250k instead of 8k to 8ohms like on the S.E.X. amp?

d) Would series resistors have to be used on the headphone jack if the output impedance ended up being lower than 250ohms? Conversely, will loading a 500ohm tap with 250ohms drag down the load that the tubes "see" on the primary side enough to cause problems? (I'm assuming not - 8k/2=4k, which doesn't sound that stressful).

e) any ideas on what size Hammond box would cover the entire battery arrangement? I've not worked with their enclosures before, and have no idea prior to seeing the amp how much area the battery boxes occupy.

I apologize if some of these questions have been asked elsewhere - hopefully, this thread might summarize some of the common ones so that others building their Quickies in a similar way might be able to have a reference.



Edits: 09/13/09 09/13/09

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Topic - A few quick(ie) questions..... - Dr. Toobz 20:34:25 09/13/09 (8)

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