I am kicking this off because as of this week several people have their pcbs in hand. And even if some of us don't get our build started immediately, we can still lay the foundation by coming up with a parts list.
Maybe others are like me in that they gather parts over a period of time because of cost. These amps can run into several hundred dollars, depending on what components we buy. So a gradual spending curve can be good.
I'll post what I have been working on. Values and such that are either documented on Mr. Millett's site, or on the pcb itself. I suggest everyone put the
Peter Millett Uniamp Project Page in their favorites and refer to it often.
Attachment:
Millett-UniAmp-Schematic.pdf
Attachment:
Millett-UniAmp-hookup-schematic.png
Attachment:
Millett-UniAmp-chassis-template.pdf
Peter Millett UniAmp BOM (Bill of Materials)We can also share knowledge of suppliers that may not be commonly known to everyone. And anything else helpful. And if I make a mistake in a listing or comment, please speak up. I'm not one to mind at all if someone points out an error I make.
ResistorsR1, R3 - 47K 1/2W
R2 - 910R 1/2W
R4, R5 - 47K 1W The pcb is marked 5W Mills, but documentation says 1W.
R6 - Open
R7, R9, R12, R13, R16, R19 - 1K 1/2W
R8, R10 - 470K 1/2W
R11, R21 - 100R 1W
R14, R22 - 400R 5W The pcb is marked for 12W Mills and 400R-5W. Audiocostruzioni in Italy uses wirewound 6W 1k and 6W 680R paralleled.
R15, R20 - 33K 1W The pcb is marked 5W Mills, but documentation says 1W.
R17, R18 - 220K 1/2W
R23 - 100K 1W The pcb is marked 5W Mills, but documentation says 1W.
Two 100R 1W off the pcb are recommended if you operate power tubes in triode.
CapacitorsC1, C6, C8, C9, C12, C13 - 100uf/450V Electrolytic
C2, C3 - .22uf/630V Film
C4, C10 - 330uf/50V Electrolytic
C5, C7 - .33uf/630V Film
C11 - 47uf/450V Electrolytic
Nowhere does the documentation say 630V film caps are needed, but I'm judging the voltage by the size alloted on the board and from other similar circuits. Plus that's a very common rating for film caps.
Tube SocketsZ1, Z2, Z3 - Octal pcb mount tube socket
Z4, Z5 - Octal chassis mount tube socket
Vacuum TubesVT1, VT2 - 6SN7
VT3 - 5U4
VT4, VT5 - KT88/EL34/6L6----300B and 2A3 possible with B+ and bias resistor change
TransformersT1- Phase splitter- Sowter 3575-C recommended
T2- Power transformer 800VCT(400-0-400)@200mA, 6.3VCT@4A, 5V@3A
T3- Push-pull output-6.6K recommended by Mr. Millett for EL34s, 6L6s, and KT88s
L1- Choke 5-10 henries recommended. Resistance is probably critical, but not specified in the documentation. I'm going with the Hammond 193J.
CL110 - thermistor
V230LA10 - varistor
Various switches and connectors
All these are for one channel, so we'll need to double numbers shown for pcb mounted parts. If building a single chassis design you can use one power supply. Anyone know if we can use a single choke for both pcbs?
I have purchased all resistors but R14, R22, and R23. Got some really nice 1% PRP from
Sonic Craft. They have every needed value in stock in the 1/2W and 1W.
I also got what I think are great deals on ebay on some Rifa and Nichicon Muse electrolytics in the values needed. Comparable to what general purpose caps cost at Digi-Key or Mouser. And free shipping. Can't beat that with two sticks.