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Preamps
SP-6 preamp
this is our "mid-range" preamp with a sonic rating of "6",
which means it will compare favorably with commercial preamps
in the $1500+ price range.
It uses a classic tube preamp circuit which includes phono stage,
line stage, and power supply all on one PCB.
The PCB is sized so that it can be used in a new chassis, or will
fit into an existing Dyna PAS3 or PAT4 chassis.
This design will give you a high value on your dollar compared to
other DIY kits which sell each piece separately.
Available as a PCB only ($79) or PCB parts kit ($169 with NO tubes, or $209 with all tubes).
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 45 db.
The line stage uses a 12AU7 in a cascode 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 for soft-start, and uses
DC power for the filaments to reduce noise.
Uses a standard PAS3 (PA211) transformer for power (add $35 + $5 shipping).
You can also use a low cost 12" x 10" or larger Hammond chassis, our specially made
"Vacuum Tube Audio" preamp chassis (see info below) or put into your own chassis.
please note - NO shipping outside USA for preamp kit
to order bare PCB ($79 + $6 shipping) click here:
to order PCB with parts kit (NO tubes) for $169 + $10 shipping click here:
to order PCB with full parts kit (including all tubes) for $209 + $11 shipping click here:
to order preamp power transformer for $35 + $5 shipping ($40 total) click here: contact us by email if you wish to order extra parts such as the power transformer,
selector switch (highly recommended for PAS3 or PAT4 installation); or for other parts
such as our custom VTA preamp chassis or any of it's components separately (volume/balance/etc).
send us email at: info@tubes4hifi.com
this photo shows the PCB installed in a Dyna PAT4 chassis
this photo shows just the stuffed PCB (the "kit")
here's a photo of the custom front panel and preamp chassis
here's a photo of the rear panel
the front panel is machined and engraved; special order only,
the rear panel is drilled and labeled by hand since it's not a flat piece.
$80 for the chassis, $90 for the custom front panel, and $40 labor if you want us
to drill the rear panel.
$200 total custom chassis (as above) only; or $350 chassis package which also includes
premium volume & balance controls, selector switch, power/mute switch, and 5 machined knobs
8 pairs of gold-plated input/output jacks, and IEC input/power cord and fuse & fuse holder.
please note . . . WE NO LONGER DO A COMPLETE BUILD-UP OF A FINISHED PREAMP FOR YOU !!
We have been doing this in the past for approximately $850 with a delivery time of 4 weeks,but we just do NOT have the time available anymore - remember, this is a "do-it-yourself" hobby kit !!
Customer Comments . . . .
"Your kit certainly has a "faster" sound with better bass, both in quantity and in tone. I also find it very dynamic. Your price is well worth it.Listening this afternoon was a joy. In a word, the preamp is neutral. It allows you to listen to the work done at the mastering console. I'm able to hear microphone techniques and how the engineer mixed the recording. For me, that's how an amplifier is supposed to "sound". Transient response is quick, you can hear all the subtleties and nuances in the recording. I do so enjoy listening to vinyl records, therefore I spent a goodly amount of time listening to the phono section. The first thing that I noticed was the neutrality of the amplifier. When the recording was well mixed & mastered, the amplifier passed it on without adding or subtracting anything. Playing CDs through the line section is a joy. It's fast, articulate, and allows the subtleties to pass. One thing that comes to mind is that it sounds so relaxed while reproducing the source. Frequency extension is right there. The high end extends to the limits of the recording without making me want to turn down the volume, or worse yet, turn off the system. The bass end is very tight and extends as deeply as the source. The middle range, well, what can I say? It makes you sit up and listen, and not because it's pronounced. It simply sounds neutral. “Correct”, as my wife said last night. I'm listening to the preamp daily. It's such a joy to listen the music.
I just got this note from a repeat customer of mine, who just recently bought an Audio Research SP8 on Ebay for $1000 . . . . . I start loosing interest in the ARC SP-8 pre amp - it does not have the magic of music, the music is kind of harsh. believe me the VTA SP6 I borrowed from you is more pleasant to listen to, it is more musical and the music flows more easy, and the bass is way more detailed and controlled and extends way down. I am looking forward to listen to the new preamp you are building for me. Thank you
I got your pre amp today, thank you. I listened to the pre amp for about one hour. The SP6 is more musical than any thing I listened to so far, I think your sonic grade of 6 in your web site is underestimated and needs a reevaluation! Thank you
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