Audio Proz Service and Sales

A-PA1 Solid State Stereo Phono Pre-amp

Audio Proz Inv #: 27173

Stereo Phono preamp.

$ 24  Contact Us  

Accuphase C200

Audio Proz Inv #: 27016

Excellent preamp - one of the best ever made!!! All special design. Ground lifted all input. RF protected/shielded. Tape 1 to 2 copy. Tone controls are switched resistor/eq circuits. High variable frequency turnover. 3 auxiliary ins, tuner in, 2 phonos. Super quality phono preamp. With gain controls. Ultra quiet. Serviced, callibrated, cleaned and excellent condition.

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ADA MB-1 Guitar Preamp

Audio Proz Inv #: 59229

Super clean and low use condition. Original high quality tubes, Nationals made in China. These are super low noise version tubes REV 2.05. Low use time was used in personal studio, not roaded. 9/10 condition, very minor rack rash at holes, recent battery cleaned and calibrated.

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Audio Proz Inv #: 17208

Guitar Preamp, input replaced with rugged jack and level control, Unit is Rev 5 low noise modified tube/solid st. RFI modified ground mods tube front end modified to be truly warmer and thicker overdrive and solid state circuits have been more evenly matched. Slightly worn cosmetics, input replaced with rugged jack and level control.

On my website is a clear explanation about ADA MP1 and mods. Without a doubt the 3 tube mod is a waste of time and money and actually will make the ADA MP1 run incorrectly. This unit operates on the principal that the FETs control the tube voltage and carefully inject distortions into the cathode of the tube and also, the programming on the front panel changes plate voltages to tubes! A remarkably clever design! Obviously, the people who offer this 3 tube mod and double transformer mod do not understand this circuit or its operations technology and they are misleading concerned players.

The modification that I do actually lessens the tube gain, lowers the noise floor, and adds equalization that is better for todays vintage sound. Players want more versatility in programming usual guitar overdrive effects. The original design is way too screechy metal in its overdriven character for too many programs. My alteration allows a wider range of programming to go from the metal to warm, driven to crank, to a bluesy overdrive whereby the overdrive and equalization controls are calibrated more in the middle range of its programming numbers; i.e. Number 5 on the overdrive is now a nicely driven sound rather than a badly overdriven sound but the ADA MP1 will be still be able to be heavily overdriven on an 8 or 9 setting. These modifications were acceptable to the ADA engineer at the time. In fact, he commented that the electro acoustic sound with my parts change was similar to his thinking too, in that it allows for more flexibility for front panel adjustment for even more guitar tube preamping effects.

I have done this mod for 25 years!! No complaints yet. Please call me directly for more info.

$ 480  Contact Us  


Audio Proz Inv #: 42090

Tube Guitar Preamp. Version 2.00. This unit is in brand new condition in box, with manual. Mods are available, call for details.

$ 480  Contact Us  

Local customers, please do not come to the shop without calling ahead first - (617) 926-8020 - for an appointment, so that we can more efficiently help you with your equipment or sound recording needs.

ADA MP1 Tube Preamp (Rev 6)

Audio Proz Inv #: 40272

#8+ Condition, Excellent Audio, No rack Scratches, New Front Jack, Tube EQ Mod, Battery LED Mod, Battery Supply Mod, Audio Circuit Low Noise, 5534 op amp mod, upgrade k246 FET, super low noise mod. very rugged front panel jack, jack only works as guitar input, #8 condition, excellent audio, no rack scratches

$ 540  Contact Us  


Audio Proz Inv #: 40484

Midi Tube guitar Preamp, update noise gate/effects loop, good cosmetic condition (minor chassis scratches on top), excellent mechanical, virtually no running time (#8 overall condition), Update - noise gate, later power supply version. Stereo effects, tremelo, chorus. XLR out.

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Audio Proz Inv #: 53403

Unit has REV6 modifications. Engineering sample. Better Overdrive/ Tube EQ ETC. SN:807518. Super quiet. Replace jacks with high quality phone jacks. #8 condition.

$ 580  Contact Us  

Adcom GFP-750

Audio Proz Inv #: 27515

Minimalist version, no tone controls - volume only, balance control, processor loop, stereo/reverse/mono control, cd balanced input + RCA, balanced main outs + 2 RCA, cleaned controls, excellent conditon - with remote

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Adcom GTP-400

Audio Proz Inv #: 42302

FM/AM tuner, phono, CD, tape 1/2. Balance bass and treble controls. Unit has full service, including all cleaning and FM tuner alignment. Minor scratches on cover, some finger wear on controls, missing 1 memory button. #8 condition.

$ 200  Contact Us  

Adcom GTP-502

Audio Proz Inv #: 55213

Tuner/Preamp. CD/Tuner/Aux1/Aux2/Tape in,out/Ext Processor in,out inputs. High blend/ Countour/Bass/Treble/Balance controls. 18 Presets, AM/FM tuner. Black slimline unit with black face and digital display. Super audiophile design, extremely well built, rugged relays. Has manual and remote. Unit is virtually unused, like new condition. Condition #9+
Other similar units are available.
**We also do work on Adcom**

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We are presently operating on an APPOINTMENT ONLY basis. Please call us first at (617) 926-8020 to schedule an appointment before you come into the shop for repairs, rentals, product recommendations, consultations, or anything other than minor purchases.

Advent MPR-1

Audio Proz Inv #: 41990

Pre-amp with 2 1/4" inputs, 2 RCA outputs (male cable end, 10" long), 18 VDC RCA power cable, can use 2 stacked 9v batteries for PS. Includes 2 dynamic mics with long 25' cables, black, slick design. 1/4" splicing block installed on pre, can be removed upon request. Please inquire for more info.

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Amber Preamp Two

Audio Proz Inv #: 54864

This Amber Preamp Two is in excellent condition and along with being serviced by AudioPro, has also received upgraded IC chips to 5532 and mute circuits. The back panel connectors have also been resoldered. -TAPE/AUX/TUNER/PHONE/ -Subsonic/Ultrasonic/Tape Filters -Mono/Stereo Switch/ Mute Switch -Balance/Volume Controls -Blackface 2 Unit Rack -Upgraded IC chips to 5532 -Upgraded Mute Circuit -Resoldered Back Panel Connectors

$ 240  Contact Us  

Amek System 9098

Audio Proz Inv #: 48664

High performance, solid state design, single channel, one rack space unit. Microphone preamp and equalizer can be used independently. All connections are balanced XLR. Excellent #9+ mint condition, includes manual, original box & packing.

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Ampex phono preamp 4010097-01

Audio Proz Inv #: 48142

Phono preamp with RIAA equalization. Uses 8-pin connector. Excellent #9 condition.

$ 38  Contact Us  

Aphex 107 tubessence

Audio Proz Inv #: 53204

2 mic in. 20db pad, gain control 80Hz low cut filter, polarity, phantom. With power supply. 9+ condition. Very low use time. Cleaned controls and switches. One rack scratch.

$ 148  Contact Us  

APT 201

Audio Proz Inv #: 52708

100 ohm input impedance, tested good, no mods

$ 100  Contact Us  

We keep our database up to date with almost 10,000 items in stock. If you see a part number and a price, we have that item in stock.

APT 202A

Audio Proz Inv #: 45886

Moving coil preamp. 75ohm input impedance. Super low noise top board. Serviced and fully tested, with some capacitor updates. Excellent #9 condition.

$ 240  Contact Us  

APT 202C

Audio Proz Inv #: 52699

super low input with super low noise board, tested, may need cap update soon, condition #9

$ 140  Contact Us  

Apt Holman 2014

Audio Proz Inv #: 61507

Mc pre-amp board. Complete. Good condition. Tested and working. Has original caps. #9

$ 148  Contact Us  

APT Holman Moving Coil Preamp

Audio Proz Inv #: 61575

Set for 100 ohm impedance, but can be changed per customer request. All caps updated w/noise check, EQ check. #9

$ 168  Contact Us  


Audio Proz Inv #: 61504

Sn 03812, Dark Grey Face with light grey anodized knobs. Fully cleaned, serviced & calibrated. Audio Pro Level III upgrade done. See details here: A few very minor paint chips at corners out of sight edges. #9-  condition.

$ 688  Contact Us  


Audio Proz Inv #: 61380

SN: 09603 Late version. Dark grey face with light grey anodised knobs. All level III update done. Few minor paint chips at the corner out of sight edges. A little tear at volume control. #8+

$ 588  Contact Us  

We have been selling and repairing professional and consumer audio equipment for over 40 years. (Read some of our customers testimonials here)


Audio Proz Inv #: 61610

Sn:9996 Nice look, light grey knobs on dark grey face. All level III mods done. ** Mute switch eyelids missing.  **very minor ding in right corner. Small toggle in high frequency position for 3 EQ position. Middle position creates analogue sound like vinyl or tape. #8+ 

$ 568  Contact Us  

APT Holman Preamp - AP Rev3

Audio Proz Inv #: 52347

Full Level III AP modifications done, super spec with all caps replaced with Tantalum capacitors. Includes kit of 16 crucial transistors, op amps, FETs, and caps for ease of future servicing. Excellent cosmetic condition.

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