Audio ResearchD-115usedAudio Research D-115 Tube Amplifier - Silver Faceplate**Please click here to check out our newly launched SkyFi Audio website with additional items for sale**Here is your chance to own a classic tube amplifier at a reasonable price.The D-115 delivers ...1999.00

Audio Research D-115 Tube Amplifier - Silver Faceplate

Listing ID: lis9c51e Classified 
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Ships fromRidgewood, NJ, 07450
Ships toUnited States
Package dimensions?" × ?" × ?" (100.0 lbs.)
Shipping carrierUPS
Shipping cost$99.00
Original accessoriesManual
Agon miniAverageResearch Pricing

**Please click here to check out our newly launched SkyFi Audio website with additional items for sale**

Here is your chance to own a classic tube amplifier at a reasonable price.

The D-115 delivers 100W using eight KT77 tubes (it actually measured closer to 115W before clipping) while maintaining the traditional warm and precise Audio Research signature sound.

This is a well-built American made unit, not a recent Chinese attempt at HiFi, weighing in at 68 lbs.  It is made from the highest quality components available at the time and was hand assembled with care and attention in their Minneapolis factory.

Condition is superb for an amplifier of this age. The paint is very clear with no noticeable scratches or dents. The faceplates are also very clean. There is no rust of signs of exposure to moisture anywhere. 

The unit was bench tested carefully and it passed with flying colors. All tubes were tested and all capacitors were inspected and tested for leakage. It was driven to its full power rating while monitoring distortion without hiccups. It then was moved to our listening room where it powered our vintage B&W Matrix 801’s with authority and precision and made a really nice and pleasant combination. 

Included is the amplifier with a printed owner's manual and the original box.

Click here for a PDF copy of the D-115 Owner's Manual

Technical Specifications:

Power output 
100 watts per channel minimum continuous power (both channels operating) at 16 ohms from 20Hz to 20kHz with less than 1% total harmonic distortion (typically less than .005% at one watt) Approximate actual power available per channel at "clipping" (both ch. op., 1kHz): 110 Watts

Power bandwidth 
(-3dB points) 12Hz to 60kHz 

Input sensitivity 
0.6V RMS for rated output

Input impedance 
75 kOhms, nominal

Output regulation 
Approximately 0.5 dB, 16 ohm load to open circuit.

Overall negative feedback 
19.5 dB

Damping factor 
Approximately 17

Intermodulation distortion: Less than 0.1% at 1dB below rated output (100V 
p to p, 16 ohms - SMPTE method).

Slew rate 
15 V/µs

Rise time 
5 µs

Hum & noise 
90dB below rated output - less than 2mV RMS - (Broad-bandwidth unweighted, inputs shorted)

Power supply energy storage 
280 joules

Power requirements 
105-125VAC 60Hz (210-250VAC 50Hz) 1000 watts maximum, 400 watts at "idle".

Tube complement 
(7) 6922
(4 matched pairs) 6550
(1) 6550
(1) 12AT7

D-115 MKII: 
(3) 6922
(4) 6FQ7
(4 matched pairs) 6550
(1) 6550
(1) 12AT7

19" (48 cm) W (standard rack panel) x 7" (18 cm) H x 16.5" (42 cm) D (front panel back). Handles extend 1-5/8" (4.1 cm) forward of the front panel.

68 lbs. (31 kg) Net; 84 lbs. (38 kg) Shipping

1983 -1989

Our Testing Process for Amplifiers (Tube) at SkyFi:

We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and tubes are inspected for signs of stress overheating or cracking.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If it all looks clean we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier the remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will also be tested.

We also test all tubes for output gain and leakage on our calibrated B&K 747 tester against the original manufacturers specifications. If needed, the tubes will be replaced from our vast NOS (New Old Stock) vintage or modern inventory. 

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage Kef speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.


Thanks for looking and please click here if you would like to receive a list of new equipment we receive weekly. We promise not to bombard you with junk email.



This item will be professionally packaged and insured for safe transit to your home. 

This item is also available for pickup in Glen Rock, NJ, with convenient parking near our building.

Click here for specifics on our specialized packing process that separates us from the rest.

If we don’t have the original manufacture’s packaging, we use heavy duty double-ply corrugated boxes with Instapak expanding foam custom inserts. In many cases this has proven to be better than the original packaging! We also use high quality fiber reinforced tape to seal our packages. Lightweight items will be bubble wrapped and shipped in a high-quality box. 

NJ Residents or anyone picking up without a resale certificate will need to pay NJ Sales Tax.

Thanks for looking and be sure to call us at 201-879-0000 with any questions. 



SkyFi Audio is a small startup business specializing in the purchase, reconditioning, and reselling of select high-end audio equipment. We only buy equipment the we admire and are passionate about. No mid-fi, no gimmicks, no junk.

Each piece of equipment is cosmetically restored and fully tested in our well-equipped lab by an engineer with 30+ years of experience in the HiFi world. If it does not meet or exceed the original manufactures specifications, it will not be sold.  We are very selective about the equipment we purchase, focusing on mostly analog, high-build quality, American, and European built units.

Through our sister company, which is an authorized dealer for McIntosh, Audio Research, Sonus Faber, ClearAudio, Pro-Ject Audio Systems, and Sony ES, we have access to OEM parts, service, and support. If you’re local and looking for new equipment from the above-mentioned manufacturers, please drop us a line as we can arrange both sales and professional installation in the tri-state area.


We do not accept or review any offers that do not go through the official Audiogon system. We have too many items for sale and it’s nearly impossible to keep track of offers outside of the official system. Please don’t message, email, or text any offers. 


We prefer working through PayPal which allows you to use a credit card or bank transfer. We do not charge extra for any payment fees if you purchase the item at the asking price.  You can also send us a personal check (which will need to clear before shipping), certified check, money order, or wire transfer. International clients without access to PayPal should use a bank wire transfer. 

If you’re picking up an item we do not accept PayPal. You must pay in person with a certified or bank check, or wire transfer. If you make a PayPal payment and are picking up the item, your PayPal payment will be returned. 


We accept trade-ins of equal or lesser value under certain conditions. Simply click here to submit your gear for full consideration. We will only consider high-end equipment from mainstream manufacturers such as McIntosh, Mark Levinson, Audio Research, Krell, etc. and will typically pass on displays, projectors, receivers, dated surround processors, and mid-fi equipment of any type. We will offer a fair value for your equipment, but keep in mind we’re running a business and will need to be able to resell the equipment at a profit after investing a great deal of time and resources in testing, certifying, repairing, cleaning, and packaging the incoming equipment. If you’re looking for top dollar, we suggest selling it directly on your own.

SELL US YOUR GEAR (Working or Broken)

We’ll also purchase your used or broken gear and arrange pickup if you are in our local market. Simply click here to submit your gear for full consideration.

SCHEDULING AN APPOINTMENT                                                                                                       

We are currently operating from our shop located inside our dedicated building in Glen Rock, NJ. You’re welcome to make an appointment if there’s a piece of equipment you’d like to see in operation before or after purchase. We have several well-equipped, dedicated listening areas plus a dedicated studio with tons of equipment of all makes and models. We’re not a store, so please don’t make an appointment if you’re just curious as to how a speaker or piece of equipment sounds. In essence - no tire kickers please.

You can call or text 201-879-0000 with any questions, or to schedule an appointment. We can also arrange to install, calibrate, and tune your newly purchased gear in your listening room if you’re local to our area. This is super useful when purchasing large speakers or heavy amplifiers. It’s also great for ensuring your new turntable is setup correctly in its final resting place.


Questions for the seller
your asking price says 1999 and in the body, you say 2500 - which?
Hi Tom, Apologies for the confusion. Just updated, confirming the asking price is $1,999 USD. Happy Hunting, SkyFi Audio LLC Store: News: Instagram:
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