*tubes 4 hifi*
*"the path of least resistance is through a vacuum"*


HOME		Dynaco mods		Service & Mods		Downloads

page updated 1-3-2012

FAQ - #1 ?? is . . . . are instructions provided?

Documentation that is included with preamps is very basic instructions. PCB layout diagram, parts list, and schematic.
Wiring diagrams can be provided, but I assume a builder knows how to hook up the input signal, output signal, high voltage, and filament voltage.
Not much else to do besides that. Some people can't figure that out but most can, if you can't I can try to help via email.
For an EXAMPLE of a preamp build, see these pages

here's an excellent unbiased review and discussion of a couple of our preamps . . . .

SP6 preamp

also known as our VTA-Z preamp, this uses the same circuits used in our PAS3-Zmod upgrades, which are also the same circuits used in our SP8 preamp below,
but this version uses a smaller 12" chassis and comes on 2 small circuit boards rather than the one large board used in the SP8.
This version also does NOT have a regulated power supply, and the PH6 phono board is an optional addition.

photo above shows optional PH6, along with SP6 and power supply

SP6 line amp and power supply PCB set with parts kit (no tubes) $109 plus $6 shipping	assembled & tested SP6 line amp and power supply PCB set (no tubes) $159 plus $11 shipping
SP6 preamp kit with 12" chassis $599 plus $26 shipping in USA, includes all parts and tubes	assembled & tested SP6 preamp ready to plug & play $799 plus $26 shipping in USA, includes all parts and tubes

SP8 preamp
The SP8 has been our most popular preamp for about 5 years now
PLEASE NOTE - this preamp circuit does NOT have tone controls, if you want tone controls, order our new SP9 preamp
The circuit has a hi-gain phono preamp using a 12AX7 gain stage followed by a highly accurate passive EQ,
followed by another 12AX7 gain stage, for a total gain of 40 db.
The line stage uses a 12AU7 in a cascode SRPP gain stage for high gain with excellent linearity and low output impedance, for a gain of 15 db.
The power supply uses a 12X4 tube rectifier and voltage regulation for both B+ and filament supplies
Available in a new smaller size 12" chassis with two small power transformers or the larger 16" chassis with a huge 5" toroid power transformer for $20 more.
Also the SE version is a popular option for $80 more, includes 24 step volume attenuator and dual mono gain/balance 12 step attenuators,
instead of conventional volume and balance controls; plus premium PRP and Takman resistors, and SoniCap signal caps, and upgraded power supply caps

click here to check out several reviews of the SP8 preamp

SP8 PCB only $95 plus $5 shipping

SP8 PCB with parts kit (no tubes) $188 plus $12 shipping

assembled & tested SP8 PCB (no tubes) $288 plus $12 shipping

complete SP8 preamp kit with 16" chassis and all parts including tubes $720 plus $30 shipping
email me first to check schedule

add SE option for $50 more, includes 24 step volume attenuator and dual mono gain/balance 12 step attenuators instead of conventional volume and balance controls plus premium PRP and Takman resistors, and SoniCap signal caps, and upgraded power supply caps

add tube set to any of above, includes 2 low-noise 12AX7, 2 - 12AU7, and one 12X4 rectifier tube, for $70 more

for completely assembled preamp, ready to plug and play,
add $400 labor charge to chassis kit above - email me first to check schedule

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

SP9 preamp

this is a 4 tube line amplifier plus tube power supply and high quality TONE CONTROLS !!
If you need a phono preamp you can add our PH-6 or PH-12 phono circuits
Note - these photos also show the optional PH12 phono section added inside.

SP9 PCB with tone controls and power supply (no transformer), all PCB parts except tubes, kit $188 plus $12 shipping	SP9 assembled and tested PCB $288 plus $12 shipping (not including tubes)	SP9 tube set is 4x 12AX7 and one 12X4, add $60
complete SP9 preamp kit with 16" chassis and all parts including tubes $720 plus $30 shipping email me first to check schedule	for completely assembled preamp, ready to plug and play, add $400 labor charge to chassis kit above email me first to check schedule

click here for more photos

SP12 preamp
last year (2011) this was our best preamp, and best seller. , a 4 tube line stage only preamp, includes tube power supply,
basic PCB kit, assembled PCB, or full kit including all chassis parts for complete preamp in 12" or 16" chassis (same style as shown above)
If you need a phono preamp you can add our PH-6 or PH-12 phono circuits
The PCB now includes as STANDARD premium resistors, and SoniCap signal caps, and upgraded power supply caps.
The SE upgrade is a popular option for $20 more, includes 24 step volume attenuator and dual mono gain/balance 12 step attenuators,
instead of conventional volume and balance controls; We supply better quality ECC802 or mil-spec 6189W tubes with kits.

one of our customers posted this review on AudioAsylum here http://www.audioasylum.com/forums/amp/messages/16/166938.html
and here are some additional photos of a custom SP12 build I did for a customer, with some followup comments.

SP12 PCB with parts kit only $189 plus $11 shipping (not including tubes)

SP12 assembled and tested PCB (only $70 extra) for $259 plus $11 shipping (not including tubes)

SP12 tube set is 4 better quality ECC802 or 6189W tubes and a 12X4 rectifier, add $70 to above.

complete SP12 preamp kit with 16" chassis and all parts including tubes $750 plus $30 shipping
email me first to check schedule

for completely assembled preamp, ready to plug and play,
add $350 labor charge to chassis kit above
email me first to check schedule

add SE chassis option (24step volume and dual 12step gain/balance)
to the 16" chassis package for $25 more

SP14 preamp

this is our newest (2012) and best preamp, a 4 tube line stage only preamp, includes tube power supply, the best preamp I've ever built !!
Same essential circuit design as our SP12 but with many improvements. Uses 6SN7 octal tubes, has dual mono regulated power supplies for each channel, for both B+ and filaments.
basic PCB kit, assembled PCB, or full kit including all chassis parts for complete preamp in 16" chassis (same style as shown above)
There is NO room inside the chassis for a phono stage, so you'll either need a separate phono preamp or get our SP12 with a phono circuit added.
The PCB now includes as STANDARD premium resistors, and SoniCap signal caps, and upgraded power supply caps.
STANDARD extras include 24 step volume attenuator and dual mono gain/balance 12 step attenuators, iso-damping chassis, iso-mounts for the circuit board, and more.

Get more complete info here

PH-6 phono
this is a 2 tube (12AX7) phono only PCB (no power supply), the same one used in our PAS3-Z mod.
basic PCB kit with parts for $65

PH6 PCB with parts kit only $65
plus $5 shipping (not including tubes)

assembled & tested PH6 PCB (no tubes)
$100 plus $6 shipping

tube set is two low-noise 12AX7
add $40 plus $5 shipping

all new PH-12 premium phono preamp KIT

premium grade phono only preamp using a JFET (10x less noise than a tube) as a current source in cascode with 6922 tube gain stage
for super low-noise cascode front end followed by passive RIAA EQ, and buffered output; followed by another 6922 output buffer; gain is adjustable from 45db to 55db with a jumper.
PCB kit with parts (no tubes, no power supply, no chassis parts) $119, or $189 with tube rectified and SS regulated power supply.
Full kit with chassis, transformers, and tubes for $479 !! This should easily compare to $2000+ phono only preamps from ARC and CJ etc.

PH-12 PCB with parts kit - no power supply $119 plus $11 shipping (not including tubes)	PH-12 PCB with parts kit AND power supply $189 plus $11 shipping (not including tubes or power transformer)	standard DIY (you drill holes) chassis kit (12" wide) with transformers & power supply, and all other parts (except tubes) for complete phono preamp, add $225 (includes shipping)	set of two low-noise 6922 tubes for PH12 add $40 plus $5 shipping
.	complete kit of all 4 items above (PCB kit, power supply, tubes, transformer, and complete chassis kit $449 plus $21 shipping ! email me first to check schedule	deluxe chassis kit, as above but with pre-machined and engraved front and rear panels add $100	.