|
Custom and stock versions of the Bottlehead Seduction
I was desperate to upgrade my Little Rat phono stage in a hurry, so I planned on building the Bottlehead
Seduction from a kit. However, once I ordered it, I decided to spend the extra time on a custom chassis that would match
the rest of my gear.
My preamp only has one input, so I have two sets of inputs on the phono stage --
one for the phono cart, and one for the CD player, that bypasses the active components straight to the outputs. The
selector switch choses between the two.
The box on top houses the power transformer on standoffs. The Cerafine cap on
top is a dual-section one, and adds two extra stages of power supply filtering.
Here's a photo of the stock kit, which I subsequently built for resale. I think it
looks pretty nice, too.
Here's the inside of the stock Seduction. The proto-board is my implementation of the
C4S circuit, featuring bypass caps on the LEDs to quiet them down a bit.
I thought the stock unit was very neutral without the C4S (as advertised). With the
C4S, it had a very revealing, musical sound that I much preferred.
Here's the inside of the custom unit. As you can see above, it is laid out as the mirror
image of the stock design. I needed the inputs and outputs on opposite sides from the stock design. The RIAA network
uses 1% tolerance AuriCaps. The values are a little different from stock, necessitating small changes to the resistors.
Coupling caps are Solen film and foil (not met poly) and output caps are Dayton film and foil (not met poly). These
Solen and Dayton film and foil caps are my faves -- dirt cheap compared to AuriCaps, and they sound excellent. I will
be putting C4S on this unit soon. Right now, with the AuriCaps, it sounds better than the C4Sed stock unit, so I'm eager
to see what it will do with C4S added. Without the AuriCaps, using Panasonic RIAA caps like the stock unit, it was too
neutral for my tastes.
Below is the Cree HV Schottky rectifier and the CLCRCRC power supply filter. The PT-1
transformer is above chassis on standoffs, and what you see below is the Allied C-1X 15H choke in the first stage, also on
standoffs. This keeps the choke from picking up PT hum. The second Panasonic electrolytic is bypassed with an
Orange Drop. The last two cap sections are Elna Cerafine 100uf (in a dual-section cap above chassis) and
the last section of the Cerafine is bypassed with another Dayton film and foil. (The big blue cap on the right
is for the filament rectifier.)
Here's another picture of my stock unit, without the C4S, to show the build detail more clearly.
It's a hell of a lot cleaner build than my custom unit, but the custom unit still sounds
better. My point here is that beginning builders shouldn't worry if their kit builds don't come out looking magazine-perfect.
It should still sound good! The important thing is to take the plunge and start building now!
|
