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

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TUBE PREAMPS

SP9 preamp

SP10 preamp

SP12 preamp

SP13 preamp

SP14 preamp

remote control option

PH-6 phono

PH-10 phono

PH-12 phono

PH-14 phono

PH-16 phono




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

 I charge for excess technical support on kits (more than 20 minutes total). Although this is rarely needed, if you send me 5 emails of questions 
and I spend 20 minutes giving you answers and you still can't figure out what you are doing, then I will be billing you for payment before answering 
additional questions for you ($1 per minute, 5 minute/$5 minimum).  In many cases I can build a product for you faster than I can answer questions 
for you, so you need to determine your knowledge level and skill level to determine whether you should be buying a kit or a finished product.


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


all preamp kits available as bare PCBs, PCB kits with parts, and complete preamp kits with full chassis, whatever works best for you!


for assembled preamps, ready to plug and play, click here!


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.

click here for more photos

Note - this is also available in a new OCTAL tube version, email for more info,
see photos of OCTAL version here

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 $268 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 $695 plus $30 shipping
email me first to check schedule
for completely assembled SP9 preamp, ready to plug and play,
click here

remote control option for preamps

see this page for info on remote control options
add a remote control to any preamp on this page, this remote also controls treble and bass tone!
so you can now have tone controls on any preamp on this page!

send us email at: info@tubes4hifi.com

SP10 preamp

This is a new preamp board to replace the older SP8 design. It uses the same circuit design as the SP8 did but with a new layout,
This is a line stage only, plus regulated power supply, the phono stage is not included but can be added as an option.
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
PLEASE NOTE - this preamp circuit does NOT have tone controls, if you want tone controls, order our SP9 preamp above
SP10 PCB only
$69 with free shipping (in USA)
SP10 PCB with parts kit (no tubes)
$129 with free shipping (in USA)
assembled & tested SP10 PCB (no tubes)
$179 with free shipping (in USA)
add tube set for SP10 preamp two 12AU7 and one 12X4 $35
complete SP10 preamp kit with 12" chassis (as shown in photos above)
and all parts including tubes $590 plus $30 shipping
complete SP10 preamp kit with 16" wider chassis (with room to add phono)
and all parts including tubes $610 plus $30 shipping
for completely assembled SP10 preamp in a 12" chassis, ready to plug and play,
click here
for completely assembled sp10 preamp in a 16" chassis, ready to plug and play,
click here

SP12 preamp

last year 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 PH6 PH10 PH12 or PH13 phono circuit
The PCB now includes as STANDARD premium resistors, and SoniCap signal caps, and upgraded power supply caps.
The SP12 preamp includes a 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
$159 plus $11 shipping (not including tubes)
SP12 assembled and tested PCB (only $70 extra)
$229 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 chassis and all parts including tubes
$725 plus $30 shipping
for completely assembled SP12 preamp, ready to plug and play,
click here


SP13 preamp

This new preamp design takes all the best design blocks of the SP14 preamp re-sized onto a smaller PCB using 6CF7/6FQ7 type tubes.
The SP13 circuit design is identical to the SP14 except for the tubes. The schematic is identical. The parts are identical.
Only the tubes are smaller, and the board is smaller. Also the chassis is our usual 4" height chassis,
rather than the taller 5" chassis needed for the SP14. This preamp is $120 less than our SP14.

Get more complete info here


SP13 PCB with parts kit
$229 plus $11 shipping (not including tubes)
SP13 assembled and tested PCB (only $80 extra)
$309 plus $11 shipping (not including tubes)
SP13 tube set - four EH 6CG7 and one 12X4 rectifier
add $100 to above.
complete SP13 preamp kit with chassis and all parts including tubes
$820 plus $30 shipping
for completely assembled SP13 preamp, ready to plug and play,
click here


SP14 preamp

this is our very 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 but a taller 5" height)
There is NO room inside the chassis for a phono stage, so you'll 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

SP14 PCB with parts kit
$269 plus $11 shipping (not including tubes)
SP14 assembled and tested PCB (only $80 extra)
$349 plus $11 shipping (not including tubes)
SP14 tube set - four 6SN7 and one 6X5 rectifier add $100 to above.
a complete kit of all parts to build is $940 plus $30 shipping
Chassis parts will be delayed about 2 weeks for shipment
for completely assembled SP14 preamp, ready to plug and play,
click 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 $60
PH6 PCB with parts kit only $60
plus $5 shipping (not including tubes)
assembled & tested PH6 PCB (no tubes)
$100 plus $10 shipping
tube set is two low-noise 12AX7
add $40


all new PH-10 premium phono preamp KIT

This is similar to the PH12 phono circuit but uses two 12AY7 tubes instead of 6922 types,using half the B+ and filament current.
Slightly warmer sounding then the neutral sound of the PH12. This circuit is also available as an upgrade for the PAS3 preamp.

PH10 PCB with parts kit only $75
plus $5 shipping (not including tubes)
assembled & tested PH10 PCB (no tubes)
$140 plus $10 shipping
tube set is two low-noise 12AY7
add $45


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.
PH-12 PCB with parts kit - no power supply
$95 plus $5 shipping
(not including tubes)
set of two low-noise 6922 tubes for PH12
add $45g
assembled & tested PH-12 PCB without power supply
$189 plus $11 shipping
(not including tubes)



PH-14 premium phono preamp KIT

This is the premium version of our PH12 phono preamp, and was designed as a standalone preamp rather than an option to add to a line preamp.
This circuit has added a 12AU7 tube buffered output for lower impedance, better drive capability, and enhanced and perfected RIAA EQ, plus it's own power supply board.

see more info here


all new PH-16 premium phono preamp KIT

This is an all new premium grade phono preamp that replaces our former top-of-line PH15, with several enhancements in the circuit design and power supply.  
This product is for someone that wants the ultimate tube phono preamp, but doesn't want to pay $2500 or more for an Audio Research PH6 or PH8. 
The 1st gain stage is our proven super-low noise JFET current source driving a 6922 amplification stage with the 50Hz and 500Hz poles of the RIAA filter. 
The 2nd gain stage drives the 2122Hz RIAA pole of the RIAA filter. Both of these stages are supplied with a regulated B+ voltage, one for each channel.
The 3rd and final stage is comprised of an AIKIDO style output buffer, with itís build in PSRR circuitry,
and this is also supplied with a regulated B+ voltage, one for each channel.
This stage gives a low output impedance of around 450 ohms and isolates the phono amp from interconnects and further amplification.
The B+ regulators also reduce PSRR by about 60db, with near zero ripple current from the power supply
Overall, this design delivers the sonic goods. It offers high amplification, super accurate RIAA EQ, low distortion, low output impedance, 
a great PSRR figure, and feedback-free amplification. 
This board has DIP switches to set the correct load (resistance and capacitance) for the input cartridge.

Here are two reviews from our customers:

"I finally found some time to put the PH16 into my dedicated vinyl system and listen to some of my favorite Lp's, 
and I must say it is a just a wonderful sounding phono preamp, I would have to say the best I have heard to date. 
I have been on a quest for the best affordable phono preamp I can find. I grew up with vinyl. 
I have listened to or owned Roy's PH6, PH12, PH14, PH15, and now the PH16. I have also built my own LCR type phono stage with Hashimoto transformers 
and Acoustic Dimension LCR modules. Cartridges I own include the Shure M97, a Shure V15 type 4 with JICO SAS stylus (my favorite), 
Ortofon 2M Blue and Black, Benz Glider SM, and Audio Technica ATN-150MLX. 
So what makes the PH16 so special? First, you have the ability to properly load your cartridge. 
This is very important, for example, the ATN-150MLX has a 7-8db peak at the high end if loaded with the recommended 47K. 
By loading it with 19K and 200pF, the high end smooths out substantially, it becomes much more listenable. 
The Shure V15 sounds great with a standard 47K load. The Benz Glider requires a 200 ohm load. 
I can bring out the best of all these carts with the PH16. Next, you need a first stage with a lot of gain and as little noise as possible, 
for this Roy uses a FET/6922 cascode stage, an excellent solution. The next stage utilizes another 6922, loaded with a constant current source. 
This is ideal, the CCS maximizes gain, minimizes distortion, and as a bonus, eliminates power supply noise! 
The last stage is an Aikido style cathode follower, which also gives very low distortion, eliminates noise, and, provides low output impedance. 
So what does it sound like? Well, I'm hearing more detail and ambiance, incredible bass authority, clean effortless highs, and freedom from overload. 
I'm hearing deeper into the recording than with any of the other phono preamps I have tried, with greater realism and fantastic dynamics. 
It's just a excellent sounding phono pre, at a down to earth price. Thanks Roy, you have done it again!"   - Troy M.

"The PH16 is quite remarkable, very smooth and clean, no brittleness or harshness in the high frequencies. 
I have it hooked up to a few different cartridges, low output moving coils(Ortofon Jubilee, Denon 103, Van Den Hul MC10 Special), 
using a Hashimoto HM-3 step up device. I might try and change the settings, but for now I am very impressed. Soundstage is BIG!!. 
I also have a Bottlehead and a Hagerman Cornet with a lot of expensive boutique parts, etc. But the PH-16 betters it, no question, more detail. 
It does so much more for the music! Opera vocals come through like never before and it can do complex orchestral like I've never heard it. 
The small nuances of concert hall ambiance takes me back... I can't think of any Phono preamps in this price range that can do what this can do."
 Thomas P.


see more info here


new reverse RIAA filter

for testing & evaluation of phono preamps, plug your CD player or sig gen into this, it does 40 to 60 db (selectable) attenuation,
and filters the frequency response in exact reverse of the RIAA EQ, so flat freq input going thru the filter and then thru your phono section give flat freq output!

reverse RIAA filter kit $39 includes shipping (inside USA only)

reverse RIAA filter assembled, tested, ready to use
$59 includes shipping(inside USA only)

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send us email at: info@tubes4hifi.com


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