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SP10 preamp

SP13 preamp

SP14 preamp

SP20 preamp

PH-14 phono

PH-16 phono


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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!

please read our return/refund policy before ordering

SP10 preamp

a 4 tube line stage only preamp, 4 inputs, 1 output, remote control input and volume !!
Our newest preamp, a real bargain, better than many I've seen for over $800 !!

SP10 preamp, fully assembled & tested, with remote control, $520 plus $30 shipping in USA
the new SP10 is an incredible bargain, there is no way I could have built this preamp for under $900 
so yes, I have to admit it's imported from China.  But before you turn away, I want you to know I have 
personally and throughly checked this out, it's now in my own personal system.
This preamp is extremely well built, solid heavy chassis, excellent circuit design, and great sound from four 12AX7 tubes.
The assembled/tested/warranteed version will cost you much less than I could build it for.
Included is a remote control for motorized volume (ALPs volume control) and relay selection of four inputs.
One output, no tape loop, no tone controls, just a super nice package that delivers excellent tube audio music.
I'm not selling a full kit, because that would cost much more than this fully assembled/tested unit.
Size is 12.5" wide x 12.5" deep x 4.0" tall and it weights a hefty 9#.

SP13 preamp

the SP13 is back and is an incredible bargain. 90% identical design and parts
as the premium SP14 preamp, at one HALF the cost !!

same chassis as the SP10 above, but fitted with the SP13 circuit board, which uses four 12AU7 tubes. Dual power supplies for B+ and filaments.
SP13 bare PCB $95
SP13 PCB with PCB parts kit
$199 (no tubes)
SP13 full kit (PCB kit, full chassis, tubes)
$595 plus $25 shipping USA
SP13 assembled/tested/warrantied
$750 + $30 shipping USA

see more info on the SP13 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 716P film/foil output caps, and upgraded power supply caps.
STANDARD controls include 24 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


SP20 preamp

this is our newest preamp, based on the famous CAT SL1,
and using a new LCD display and remote control input select and 512 step volume.

see more info here

SP20 full kit $1095
not including tubes
SP20 fully assembled/tested/warrantied $1595

PH-14 premium phono preamp KIT

This circuit uses two 12AX7 tubes for gain and another 12AX7 as a buffered output for lower impedance, better drive capability,
and enhanced and perfected RIAA EQ, plus it's own power supply
PH-14 complete kit, chassis, PCB, transformer, tubes, all parts
$395 plus $30 shipping in USA
high quality phono only preamp uses a total of three 12AX7 tubes, two for gain, one as an output buffer;
gain is 44db for use with MM cartridges or medium to high output MC cartridges, you can add an external SUT for use with low output MC cartridges

PH-14 assembled preamp
$495 plus $30 shipping in USA
custom silver aluminum chassis
PH-14 assembled preamp
$375 plus $25 shipping in USA
black aluminum chassis

PH-14 assembled PCB
$139 plus $11 shipping in USA

PH14 PCB kit $119 plus $11 shipping in USA
power transformer for PH14
$36 plus $12 shipping

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 built 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 going thru the filter
and then thru your phono section give flat freq output!

reverse RIAA filter KIT $30 includes shipping (inside USA only)

reverse RIAA filter assembled, tested, ready to use
$45 includes shipping(inside USA only)

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