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

PH-10 phono

PH-12 phono

PH-14 phono

PH-16 phono




send us email at: info@tubes4hifi.com



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-10 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 price $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 (in USA)
for completely assembled SP9 preamp, ready to plug and play,
click here
complete SP9 preamp OCTAL kit with 16" chassis and all parts including tubes $795 plus $30 shipping (in USA)
for completely assembled SP9 OCTAL preamp, ready to plug and play, $1095 plus $35 shipping (in USA)
click here

SP10 preamp

This is our lowest price preamp - a line amp stage only, although you can add the PH10 or PH12 phono section.
This circuit is identical to the line stage of our older SP8 preamp. 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.
Note - the top two photos show the smaller 12" chassis, the lower three photos show the larger 16" chassis
with optional PH10 phono section added inside.

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 $550 plus $30 shipping
complete SP10 preamp kit with 16" wider chassis (with room to add phono)
and all parts including tubes $570 plus $30 shipping

SP12 preamp

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 or PH12 phono circuit
The PCB now includes as STANDARD premium resistors, and SoniCap signal caps, and upgraded power supply caps.
The SP12 preamp includes a 21 step volume attenuator and dual mono gain/balance 21 step attenuators, (note - photos show older parts no longer used)
instead of conventional volume and balance controls; We supply better quality 12AU7 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
$149 plus $11 shipping (not including tubes)
SP12 assembled and tested PCB (only $70 extra)
$219 plus $11 shipping (not including tubes)
SP12 tube set is 4 better quality 12AU7 or 6189W tubes
and a 12X4 rectifier, add $70 to above.
complete SP12 preamp kit with chassis and all parts including tubes
$699 plus $30 shipping)
for completely assembled SP12 preamp, ready to plug and play,
click here


SP13 preamp

back by popular demand, this preamp looks exactly like an SP12 from the exterior, but inside the circuitry is identical
to our very best preamp, the SP14. The only difference is the tubes are 6FQ7, a 9 pin version of the bigger 6SN7
that sounds just as great in a smaller package! All the advantages of the SP14 in a smaller enclosure.
A popular option are the older and excellent RCA clear top tubes from the 60s era.


SP13 PCB with parts kit
$229 plus $11 shipping (not including tubes)
SP13 assembled and tested PCB
$329 plus $11 shipping (not including tubes)
SP1 tube set - four 6FQ7 and one 12X4 rectifier add $100 to above.
a complete kit of all parts to build is $920 plus $30 shipping)
Chassis parts will be delayed about 2 weeks for shipment

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 Russian K40Y signal output caps, and upgraded power supply caps.
STANDARD controls include 21 step volume attenuator and dual mono gain/balance 21 step attenuators, iso-damping chassis, iso-mounts for the circuit board, and more.

Get more complete info here

SP14 PCB with parts kit
$229 plus $11 shipping (not including tubes)
SP14 assembled and tested PCB
$329 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 $920 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



the 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.

PH10 PCB with parts kit only $80
plus $5 shipping (not including tubes)
assembled & tested PH10 PCB (no tubes)
$130 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
$90 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
$179 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 a premium grade phono preamp 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 it�s 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 $35 includes shipping (inside USA only)

reverse RIAA filter assembled, tested, ready to use
$55 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"