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Post by bluegrassdan on Oct 18, 2017 19:03:00 GMT -6
An entire year of research and design led to the product you see here. It would have been selfish to build just one for myself, so I am offering a (very) limited run of this two-channel tube preamp. It is available to anyone who wants a classic transformer balanced tube preamp, with high quality components and useful features, at a reasonable price. The DB Vacuum Tube Microphone Preamplifier is a classic transformer balanced tube microphone preamp with instrument DI. Features 63 dB of selectable gain, +48V Phantom Power, -20 dB PAD, phase reverse, and two custom switchable low shelf filters. The circuit includes special components such as Jensen transformers, paper-in-oil coupling capacitors, stepped gain attenuators, and NOS General Electric and Telefunken tubes from the 1960s.  The preamp’s key components are not easily found in modern production models. I tested numerous combinations of transformers, tubes, and coupling capacitors before deciding on the final tonal characteristics that sounded best to me.  Matched pairs of 1960s new-old-stock General Electric and Telefunken tubes meet or exceed published specifications of transconductance. The GE 5-Star 6072a is legendary for its larger-than-life 3D quality, while the Telefunken contributes its hi-fi soundstage, tight bass, and neutral highs.  Jensen has led in transformer research for decades. Their JT115k input transformer is designed for the highest practical 1:10 step-up ratio within their company’s design tolerances. This is a perfect transformer for a tube preamp.  Glass-sealed Russian paper-in-oil and Teflon bypass capacitors are used for coupling following tube gain stages. Polypropylene film and electrolytic caps are used elsewhere in the audio and PSU circuits.  High quality stepped-gain rotary switches are used instead of potentiometers for repeatable gain selection and to help maintain signal integrity. Features• 63 dB Gain • XLR Inputs/Outputs • 1/4" Instrument Input • -20 dB PAD • +48V Phantom Power • Ø Polarity Switch • Low Shelving Filters • Rear Panel Grounding Lug • 120 VAC IEC Fused Power Carefully-Selected Components• Jensen Input Transformers • Edcor Output Transformers • NOS General Electric 6072a • NOS Telefunken ECC82 • Paper-in-Oil Coupling Capacitors • Teflon Bypass Capacitors • Stepped Attenuators • DC Heater Supply • Toroidal Power Transformer • Turret Board Construction Specifications• 20Hz-20kHz (+/- 0.2 dB) • Noise EIN: -120dB (+/- 4 dB) • Input Impedance 1.5k ohms • Output Balanced 600 ohms • Low Shelf POS 1: Flat • Low Shelf POS 2: -3dB at 75Hz • Low Shelf POS 3: -3dB at 275Hz • Dim (3U): 19" W x 5.25" H x 11" D • Weight: 18.2 lb This unit is being offered at an introductory price of only $1,999.99 USD.
[SPECIAL OFFER] Make a $1,000 DOWN PAYMENT today, and pay the remaining balance in a few weeks prior to shipping.
Visit dansmusiconline.com/pro-audio for more info and to place an order. Allow 4-6 weeks for build and delivery.Hear the cumulative tone of the DB Vacuum Tube Microphone Preamplifier used on all tracks of the upcoming Christmas single Welcome Christ the Lord (Daysight Music, BMI. 2017) |
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Post by Johnkenn on Oct 19, 2017 12:48:58 GMT -6
That's some sexy shit right there. That recording has got me HOT AND BOTHERED. Fantastic.
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Post by Johnkenn on Oct 19, 2017 12:52:08 GMT -6
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Post by bluegrassdan on Oct 19, 2017 13:00:07 GMT -6
That's some sexy shit right there. That recording has got me HOT AND BOTHERED. Fantastic. Might be the first time a Christmas gospel song has caused anyone to be "hot and bothered." Tubes will do that to a man! |
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Post by bluegrassdan on Oct 19, 2017 13:10:18 GMT -6
Two realizations I have had through this whole experience...
Tubes do a masterful job handling transients, which has the affect of allowing a source to maintain brightness without, what some might describe as, "graininess" or "gritty" high frequencies. Now, that might not be what is needed for a particular source, but it is a characteristic I have found to be useful for vocals, some acoustic instruments (particularly fiddle and mandolin), bass, etc.
The other thing is how this transient-smoothing characteristic affects the signal in terms of dynamic limiting. If you're grabbing for a compresser/limiter anyway, which is to decrease transient peaks, why not try starting with a tube pre on the front end. It will have a very natural and "musical" limiting sound.
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Post by Quint on Oct 19, 2017 13:26:05 GMT -6
That's some sexy shit right there. That recording has got me HOT AND BOTHERED. Fantastic. Agreed. Damn fine sounding recording. |
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Post by Quint on Oct 19, 2017 13:27:12 GMT -6
Two realizations I have had through this whole experience... Tubes do a masterful job handling transients, which has the affect of allowing a source to maintain brightness without, what some might describe as, "graininess" or "gritty" high frequencies. Now, that might not be what is needed for a particular source, but it is a characteristic I have found to be useful for vocals, some acoustic instruments (particularly fiddle and mandolin), bass, etc. The other thing is how this transient-smoothing characteristic affects the signal in terms of dynamic limiting. If you're grabbing for a compresser/limiter anyway, which is to decrease transient peaks, why not try starting with a tube pre on the front end. It will have a very natural and "musical" limiting sound. Out of curiosity, what other equipment (mics, comps, eqs, plugins, etc.) we're used on this? |
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Post by bluegrassdan on Oct 19, 2017 15:32:11 GMT -6
It indicates the gear in the video.
Guitar and mandolin were recorded live together around a mid-side setup: Flea 47 (mid) and Peluso 2247 (side). Both went into the tube preamp followed by the plugins shown in the video. A Massey 2007 first to tame a few really hot notes, followed by Fab Filter multiband, eq, and limiter. Basically, treating the guitar and mandolin like its own stereo mix.
All vocals are Flea 47, tube preamp, and my hand-built La2a. You'll find minimal processing on these tracks. Nothing on baritone vocal, some low frequency roll off on tenor and bass, and a 2db low mid bump and 2db high mid dip on my lead vocal.
The master channel plugins are shown in the video.
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Post by hadaja on Oct 19, 2017 16:46:49 GMT -6
Just loved that Christmas song. Witty entertaining and masterfully produced and arranged.
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Post by donr on Oct 19, 2017 20:19:05 GMT -6
Gear looks and sounds great, Dan. Song is flawless. The product shots are great too!
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Post by c0rtland on Oct 19, 2017 22:26:51 GMT -6
Wonderful work. Sexy pictures. I like the straightforward all plugs up video. I love the song. Christ the Lord! It's never too early in the season to celebrate Him.
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Post by Johnkenn on Oct 19, 2017 22:39:43 GMT -6
Where can I buy a copy of the tune? (And can I have .99 off if I get the pre too?)
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Post by spindrift on Oct 19, 2017 22:49:38 GMT -6
Wow!
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Post by bluegrassdan on Oct 19, 2017 22:57:29 GMT -6
Where can I buy a copy of the tune? (And can I have .99 off if I get the pre too?) It will be out as a single around Thanksgiving. If you buy a pre, I'll throw in a few goodies - including the song. Sweetwater does a bag of candy in the box. I'm thinking antacids. Rolaids, TUMS, Pepcid chewables... Or perhaps an air freshener that smells like a vintage Gibson guitar case? |
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Post by wiz on Oct 19, 2017 23:28:55 GMT -6
Flawless
love the sound of your tube pre
great
cheers
Wiz
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Post by cowboycoalminer on Oct 20, 2017 10:55:17 GMT -6
Outstanding, Dan. My kind of music, too. Did you use the filter on the recordings?
Thanks,
C
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Post by stormymondays on Oct 20, 2017 11:29:20 GMT -6
That song is just incredible! Sound and performance. Congratulations! I'm out of funds and in Europe, so I don't even want to THINK about that beauty of a pre...
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Post by bluegrassdan on Oct 20, 2017 15:03:30 GMT -6
Outstanding, Dan. My kind of music, too. Did you use the filter on the recordings? Thanks, C I didn't use the built-in low shelf filters for this recording. Just did any slight eq in post. |
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Post by Johnkenn on Oct 20, 2017 19:52:12 GMT -6
So are these basically going to be made to order? Available now?
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Post by bluegrassdan on Oct 20, 2017 20:35:03 GMT -6
But on that note, yes the preamps are built to order and I'm offering for folks to make two payments - the first $1,000 to get the build started and $999.99 prior to shipping.
Thanks to everyone for all of the kind words and observations.
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Post by stormymondays on Oct 21, 2017 8:33:51 GMT -6
Any chance of a 240v version?
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Post by bluegrassdan on Oct 21, 2017 9:12:49 GMT -6
I don't have a 240v version yet, but let me look into it.
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Post by bluegrassdan on Oct 21, 2017 9:18:27 GMT -6
 Low shelf filter graph. I tuned these first by ear, then measured afterward. The first shelf is geared toward a pretty typical eq move I use with instruments. Clearing away the mud without getting rid of the low frequencies entirely. The second position I came up with while testing ribbon mics. With so many people recording in smaller rooms these days, most folks end up miking with ribbons closer to the source. This curve gently rolls down the proximity boost. |
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Post by Johnkenn on Oct 21, 2017 9:29:40 GMT -6
How gentle do those end up being? Cool approach. I know most are at -6 to -12...
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Post by bluegrassdan on Oct 21, 2017 9:42:53 GMT -6
Very gentle and musical.
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