The Designer Hand Crafted 2009 PreDAC Vacuum Tube Preamp- D/A Converter

Unique vacuum tube circuitry reveals micro-dynamic details in the recording with openness and air like no other Preamplifier on the planet. For added convenience the PreDAC includes 4 remote control selectable digital (or analog) Inputs. 2-Pairs of 24k Gold Analog Outputs +1 Mono Subwoofer Analog Output. Hand point to point wired tube circuitry under ceramic/gold sockets is encased in a cast aluminum black chassis that sits on top of a customized remote control input selector. A new generation Burr Brown jitter free DAC chip detects high definition harmonic rich sound. DAC chip balanced analog audio is wired directly to the tubes without filters or coupling caps - this difficult to achieve filterless direct connection design reveals recorded micro details. The PreDAC offers 192k/24-bit data speed and uses the desirable higher resolution I2S data bus internally between 192k input receiver chip and DAC chip. The high current external DC switching power supply creates a silent disturbance free background to further reveal the most subtle recorded details. The unique Tubyness control allows you to balance root tones with tube detected ear pleasing 2nd order harmonics in the recording - a TAD exclusive single knob adjustment that finds the most enjoyable living breathing playing live in the room sound from your system. The Tubyness feature makes all your music sound better than you ever though possible. Experienced golden ear audiophiles state their PreDAC sonically surpasses the most expensive DACs and Preamps they have tried. Remote control or the front panel button selects 4 inputs. The 5th always on digital RCA input eliminates the ability to use the 4-input selector - 5th is for single source operation like a regular single input DAC. Home Theater Bypass Input: Connect front L & R Analog RCA Home Theater outputs to the 2nd set of gold RCA outputs on the PreDAC. Click the Digital/Analog button on the remote to idle the DAC chip, Analog HT sound bypasses the PreDAC to play HT movie sound on your front L & R power amps/speakers using your regular HT system remote. Stop the movie, Press the Digital/Analog button or any input selection to resume playing 2-channel music sources using the PreDAC. Most use the PreDAC for their 2-channel digital and analog audio source selector and D/A converter. The PreDAC improves sound quality with the built-in vacuum tube adjustable Tubyness preamplifier. Highly refined unique tube circuitry combined with remote control input selection and remote volume control offers the best possible sound and convenience. The PreDAC is perfect for PC streaming digital audio. PC audio (especially Rhapsody.com) sounds like CDs using the PreDAC for D/A.

Some connection examples:

PC Internet Audio: Rhapsody.com, iTunes.com or PC/Mac stored music: [USB port] to [SPIFFY Data Converter] to [PreDAC].

PC or MAC with Toslink Optical Data Output, Plug it in.

[iPod] cradled in a [Wadia 170i transporter dock] - Wadia SPDIF data output plugged into the [PreDAC].

CD & DVD Player: Single Data Line SPDIF, plug it in.

Satellite or cable tuner TV sound (some may need to select 2-chan mode) optical SPDIF data, plug it in.

Sirus/XM Satellite radio SPDIF data, plug it in.

Whole house wireless streaming digital audio SPDIF data, plug it in.

Analog turntable with separate phono stage, plug it in(analog).

Once you hear the difference using the Tube Audio Design PreDAC for every source (digital or analog) there is no going back - expect to be blown away.

Basic Facts and Specs
Only Sold Here: www.TubeAudioDesign.com $1999 list price to compare, Click the ON SALE Tab to order
120-240VAC operation, 3-wire normal IEC power cord included
Separate high current DC power supply promotes a deep ultra quiet revealing background
Small and Heavy: 8-1/4" wide, 5" deep, 6-5/8" tall (includes 1-inch high black cast iron pointy spiked feet) - tall heels can make it tipsy using stiff audio cables. Best placing the PreDAC towards the front of the shelf with horizontal space behind to support heavy cables.
Everything packed weighs 6-pounds
Unique TAD 12AU7 tube circuitry for out of this world sound
Tubes run warm to the touch, up to 150-deg, not sizzling hot like conventional tube designs
Easy to find normal audio 12AU7 or 12BH7 types are what it takes(not included, sold here). I have hand select 4 digit US military 12AU7 matched pair and 12BH7A Electro-Harmonix in stock. Remember to order tubes through the On Sale Page when ordering your PreDAC. Old stock RCA 5814 black plate matched pairs have the most entertaining midrange, hard to find in select pairs (~50-years old). 1960's-70's Phillips 5963 tubes offer smooth rich midrange, a cost effective choice. The latest greatest tube discovery is the 12BH7 - finally a new production tube that sounds out of this world in this circuit - the 12BH7 offers deep fast bass response with the most entertaining harmonic rich high definition soundstage - my new favorite!
The Tubyness knob should be adjusted by ear after changing tubes to find the best possible harmonically balanced sound your system can produce. Warmed up tubes sound better than just powered on cold.
The PreDAC has 4 remote control (or faceplate button) selectable inputs
1 direct Digital RCA input, direct to the DAC chip, direct disables the ability to use the 4 selectable inputs
Only use the single Digital or Analog L & R input jacks for each individual selection, using both types on one input selection will combine and reduce fidelity
2 pairs of long barrel 24k gold L & R RCA Outputs
1 mono gold Subwoofer Output
Remote control Alps motorized volume pot turns slowly for precise remote volume adjustments.
Remote control Digital/Analog selector button suspends the DAC chip for hiss free analog input use, or use to quickly mute a digital source
192k/24-bit Cirrus SPDIF front end input receiver chip is internally I2S bus connected to a Burr Brown 1793 Advanced Segment Verification (jitter free) DAC chip - a technically superior up to date digital section, hand selected for how it sounds with my unique directly coupled tube circuitry. Balanced DAC chip audio output directly drives the unique tube circuit without filters. 192k DVD audio is possible, SACD surround sound is not.
The Burr Brown 1793 new generation Advanced Segment Verification DAC offers jitter free performance that blows away yesterdays jitter sensitive chips. Digital chips advance in giant steps, mind boggling how much better advanced segment verification performs. Burr Brown spec sheet says a 100-Meter long data cable will not lose a single bit. Translation: Expensive data cables, expensive clock enhancements, high end digital DAC modifications are no longer necessary - full frame verification = zero bit loss, 100% perfect, digital performance improvement modifications not necessary. You could do your taxes through one of these D/A converters and get exactly the same 100% perfectly crunched digital answer every time.

Computer Digital Audio USB Port Adapter: The SPIFFY is a Plug & Play TAD custom modified cost effective no compromise Burr Brown chip USB to SPDIF adapter. Computer USB port powered. Windows PC and Mac compatible, plug & play, this USB streaming audio data converter offers true bit for bit jitter free performance. The best computer-USB to PreDAC interface device. This is a Behringer U-Control interface that is TAD reengineered for audiophile data use (stock design does not have RCA coax data output). The TAD modified version has SPDIF RCA Coax and Optical Output (use one, not both at the same time). The internal DAC is not used for conversion, USB data in = bit for bit SPDIF data out. Streaming internet music like Rhapsody.com or iTunes sounds better than CDs using the SPIFFY to connect PC to PreDAC. The SPIFFY USB adapter is the best way to connect Mac or PC streaming audio data to the PreDAC using RCA coax or toslink optical cable.

Some Useful Tips
Tubes are always on - this promotes longer tube life in this design, silent idle current cleans the cathode surface with reflected electrons. The PreDAC is placed in sleep mode by pressing the Digital/Analog remote button. Press any input selection (or the Dig/Analog button)to wake it.

To use analog inputs (L & R RCA) suspend the DAC circuitry by pressing the Digital/Analog button on the remote. This stops empty data jack input data hunting noise (hiss). The tube circuit is micro revealing, faint open input DAC data noise becomes audible. Suspend the DAC chip with the Digital/Analog button for hiss free analog source selections. Press any input button or the Digital/Analog button to restart the DAC chip.

Plugged in analog inputs (over 1V peak) that are deselected but still playing may occasionally lightly bleed into other channels. To cure, stop loud analog sources to use other inputs.

The PreDAC has RCA jacks - No XLR jacks built-in, 100% tube audio, no sterilizing op-amps in this design to drive XLRs (like the TADAC). The input RCA jacks are polished nickel, outputs are long barrel 24k gold. The small back panel print says video instead of data for SPDIF RCA data jacks.

XLR News Flash: August, 2009 A separate 2-Tube RCA to balanced XLR output converter box is being developed. I have a tube prototype circuit design in the works that will produce a perfect 50/50 phase split to drive balanced cables. Designed around old stock Russian ECC99 tubes, JJ makes new ECC99's too. The RCA>XLR box will be available soon.

S-Video input selection switching capability is a bonus feature, see if it works with your S-video capable screen.

So far I have not produced one PreDAC that is 100% chassis ding free - meaning a tiny very light construction related scuff occurred while I was drilling or assembling, can see if you look closely. I use protective masking materials and assemble on a static proof padded surface. Still someplace gets a small scuff - call it handmade character.

No PreDAC Headphone jack. An external tube headphone amp is recommended for this caliber of gear.

Blue LEDs keeping you up at night? Press the Digital/Analog button to extinguish the soft blue input selector LEDs to darken the room.

Questions or concerns? I'm always available through email. Please read the information above a couple times to become completely familiar with the PreDAC, most questions are answered above. I update this page when new information or better descriptions become available - I never supply a paper printed owners manual with TAD gear.

PreDAC Terms
US-48 State customers are welcome to order using the secure click button shopping cart system. A signature is required to validate high value shipping insurance. No private information is kept on file, I use a hired secure private order processing system (my 8th flawless year with Coolcart). Outside US-48, or shipping to an alternate address (work or outside the US) is your own risk after the courier tracking marks the package delivered. INTERNATIONAL: Outside US requires mailing a Post Office purchased international money order in USD (no cards or PayPal for outside US sales), outside continental US postage will be calculated - outside US please email for details. No in home trial/returns for sale priced items. An occasional light nick or scrape is part of the handmade charm. 2-year limited warranty covers internal circuitry against production defects. Chassis covers must never be removed, will void the warranty. Tubes are consumable parts, not covered, tubes will last a long time in this circuit -OK leaving the PreDAC on all the time (power conditioner with surge protection recommended). Carefully install digital optical cables and tubes (forcing rotationally incorrect can damage the sockets). Any sign of water damage (must use indoors, keep it dry) misuse or abuse, power surge/lightning damage or covers removed will void the warranty - can generally be repaired for a fee. System hum problems (or system integration issues) that cannot be duplicated here are not covered, need to isolate the cause on your end and make system adjustments- I will advise, I've cured hundreds of faulty audio system grounds etc, some pretty bazaar, always externally caused. Shipping to the Wheaton, IL warranty center and back is not covered. US customers include a $15 check to cover warranty return shipping, international customers please email for warranty shipping rates. Please Email questions - many technical problems can be solved through communication. Plug and play, extremely simple, built to last.

Note: Delivery damage must be reported within 3-days from delivery date to process a claim. Please inspect contents immediately, after 3-days damage claims are not possible.

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