Features And Specifications Manley All Tube Microphone Preamplifiers Mono or Dual Mono models available (specs same for both) • MANLEY input & output transformers with nickel laminations in mu-metal cases • Flat frequency response from 10Hz-60KHz • Mic input PHASE REVERSE switch • 2400 ohm mic input Z; 48V phantom power built-in • Hi-Z (100Kohm) 1/4" DIRECT INPUT • Noiseless conductive plastic INPUT attenuators • <0.05% THD @ 1Khz S/N ratio: 80dB • EIN: -125dB • Adjustable FEEDBACK / GAIN switch selects 5dB steps between 40 to 60 dB of gain • Hi-current drive <50 ohm LO-Z 1/4" & XLR outputs • AUTO MUTE w/ warm-up delay for power up/down • Max. input (with input pad fully open): 450mV • Max. output: +32dBu • Max. output (into 600 ohm load): (+15dBm) • Power consumption Mono units: 18 watts; Dual Mono units: 36 watts • Operating mains voltage: Units are purpose built for original destination country's mains voltage:   100V, 120V, or 220-240VAC as indicated on the serial number badge. Power transformer must be replaced in order to change mains operating voltage. 120VAC units may NOT be rewired to put the primaries of the power transformer in series for 220-240V operation or a large radiated field of hum will develop. If changing locations/voltages, the power transformer must be replaced with the dedicated one for the voltage at which it will operate. • Mains Voltage Frequency: 50~ 60Hz • Dimensions: 19" x 1 3/4" x 10" (occupies 1u) • Shipping Weight: 12 lbs. PDF Owner's Manual   Manufacturer's Suggested Retail Price Mono Microphone Preamplifier Monoblock: $1,600 Dual-Mono 40 dB Microphone Preamplifier: $2,400     Get the PDF: Manley 2001  Pro Catalog Micpre Page  Also, see COMBO units! PDF Owner's Manual   Manley Mic Preamp FAQ: FAQ#1: I've experimented with both the unbalanced and the balanced outputs, and I like them both.  Now that I know what they both sound like, I'd ideally like to use the xfmr outputs for certain types of sounds and the unbalanced outputs for other things, but I noticed that the XLR output gets muted when I plug in a 1/4" cable to the unbalanced out... makes it impossible to route them both to a patch bay... So, hey, not to hassle you or anything, but I'm wondering if there's a technical reason why it would be a bad idea to have both the XLR and 1/4" outputs active simultaneously? A couple of reasons: if you connected a lo-z load on both the 1/4" and the XLR at the same time, you would load down the output excessively and raise distortion; also, without the switching jack, the primary of the output transformer  would still be in the circuit so it would sound different out of the unbalanced  output than it does now. The 1/4" jack disconnects the transformer primary when plugged into. FAQ #2: I will soon buy a Mic preamp. The Dual Mono Mic Preamp could be the right one.  But it is very important for me, to chose a Preamp that I can use for different things.  Can I use  the Dual Mono Mic Preamp to warm up my recorded digital tracks too? What is the Difference to the Dual Mono Tube Direct Interface? Can I use the Mic Preamp as DI too? Yes you can pass a line level signal into the Manley Dual Mono Mic Preamp via the Direct Inputs and come out the XLRs to get the sound of tubes and the output transformer. If you keep the gain at the lower settings (with most global feedback being used) then you also have more rich sound which might be the thing you are looking for to warm up your digital tracks.   Yes of course you can use the Manley Dual Mono Mic Preamp as a DI. That's what the front panel Direct Inputs are there for! Bass players especially like the sound of our Mic Preamp DI circuits on the stand-alone micpreamps as well as the ones on the VOXBOX®. There is 20 to 40dB of gain available on those DI jacks.   The Tube Direct Interface has no gain. It is specifically for instruments passing through it to get from high impedance to low impedance for low noise and to be used as a splitter for the 1/4" to feed an amp head while the XLR goes to the console (or external mic preamp) MIC INPUT. You would use a Tube Direct Interface in addition to a Microphone Preamplifier. -- Cheers,    EveAnna Manley     OLDER VERSION INDENTIFICATION GUIDE: Here is a mini Manley micpreamp identification guide,  in case anyone else is a-wonderin': The oldest version of  "40dB Mono Microphone Preamplifier" was built from 1991 to 1993 at the old VTL factory: Gain was 3 positions 40-45-50 They had a rotary phantom power switch (which would be replaced by a big toggle switch when it broke like in the example below.) They were in the older steel "tray" chassis with a stainless-steel top as pictured below.     Click for a bigger view of this oldie. VTL-built older "Dual Mono Microphone Preamplifier" were built in an aluminum "tray" chassis. Some (most?) of these VTL-built units used 6350 for the output tube which has a different pinout compared to 12BH7A or 6414. Here is an example of a really old VTL-built "Dual-Mono Microphone Preamplifier" (Spotted this on on eBay 2/2004) Note the five position "Variable Feedback" (aka GAIN) control. The ones we built here at Manley Labs physically look like the current models. They are in the "extruded side chassis" with removable perforated top and bottom. All use 6414 as the output tube. The older "40dB" named mono units looked like these. The upper photo represents early units built at Manley Labs, this one from 1994. Later, front panel Direct Inputs were added. Gain on these older units was 40-42.5-45-47.5-50dB If you can read French, here's a review of an older Dual Mono Mic Preamp en francais. We upped the gain from 40-42.5-45-47.5-50 TO 40-45-50-55-60 in the latest version. If there is an X in the serial number, then it is the latest version. The Higher gain version went into production 8/2000. Serial codes are 40MP(B) or (X) ### for the mono. DMMP### older dual channel version 6072A + 6414 DMMPB### Balanced Outs 6072A + 6414 DMMPX### and higher gain 12AX7A + 6414 They are all basically the same circuit. Higher gain is useful for ribbons. But yes with reduced feedback and higher gain you get a little more noise and more aggressive sound. At the 40dB position the EIN is -125dB which ain't half bad, folks. Older models are.... just older. The basic circuit hasn't changed much over the years. Current models are called "Manley Mono Microphone Preamplifier" and "Manley Dual Mono Mic Pre".  We don't call 'em "40dB anything" anymore. There was another model in a 1RU chassis with an extra tube stage called "Reference Microphone Preamplifier" built at the VTL factory from 1989 to 1992 and later a 1 1/2 RU version of this called "60dB Microphone Preamplifier" that was built for the first few years at the Manley Labs factory from 1993 to 1995. These models have been out of production for a very long time. The "Reference Microphone Preamplifiers" were born as a response to a request by a large organization who were shooting out any and all of the best mic preamps available at the time (late 1988, early 1989). This one won the shootout and they ordered 60 pieces of 'em and consequently launched the Manley Pro Gear division, then at VTL. So yes, this was Manley's very first pro studio model.  The first version of the "Reference Microphone Preamplifier" had a torroid transformer and tube-regulated B+ rail living behind the power switch. These proved not-so-reliable and actually unnecessary so later versions had that stuff ripped out and traditional solid-state rectification and pi-filtering without B+ regulation installed instead. Heaters were regulated with a TO-3 7812 solid state 12 volt regulator mounted to the rear of the chassis. Most of these units did not have built-in phantom supplies, although some did via provide phantom power by way of some zener diodes bringing some 48 volts into the orange center tap of the Sowter input transformer's primary. Units that did not have the Phantom switch had a Direct Input installed instead, as seen in the example below. That large organization was Pin 3 Hot at the time, so a lot of these might still be Pin 3 hot, unless I have gotten to 'em since and changed them. As mentioned above, these units had an additional first amplifying stage using a 6072 in cascade. After that, the signal hit the attenuator, (it went to up to 13) and then into a 12AU7 cascaded stage before hitting the final 12AT7 cathode follower output stage which provided an unbalanced output via XLR and RCA jacks in parallel. The Variable Feedback 5 position switch did exactly that (varied the amount of global feedback around the second stage) and provided 8dB of feedback and gain change in 2dB steps. This unit was housed in a black powder coated steel chassis with a stainless steel top. There was no silk-screening on the rear of the chassis. P-touch labels if you were lucky. Here is a VTL-Built "Reference Microphone Preamplifier" front and rear views.   Click on the pix for larger views of these  "Reference Microphone Preamplifiers" Thanks to Andrew Lewis for the photos! After Manley split out of the VTL factory in 1993, there were some 1 1/2 RU versions of the "60dB Microphone Preamplifiers" built in billet aluminum chassis also using a similar circuit to the older 1U model. If you have a good photo of any of these antiquities, please send it to EveAnna and she'll put it up here for everyone.   Top | Pro Main Page | Manley Home