Rogue Audio M-150 Monoblock Amps, All TUBE

Rogue Audio M-150

Like New in Original Boxes with all accessories. Plenty of positive reviews on the internet so Im not going to go into much detail. Their slightly more powerful brothe, the M-180 was a Stereophile Class A Recommended Component.

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. The tubes were tested on a calibrated BK747 tester and measured strong.

Included is are the amplifiers, power cords and original boxes.

Available for pickup in Ridgewood, NJ or Union Square NY.

Here is the feature description from enjoythemusic dot com

Technical Details

Mark O'Brien started designing his own tube gear about 20 years ago. Having worked at Bell Labs in engineering physics he had access to superb lab resources as well as lots of help from electronics engineers who had received their degrees during the golden age of tube electronics. It's obvious to me that Mark has learned his craft well. It starts with the monoblock layout. It's nearly impossible for me to accept an amplifier as Reference class unless it is of monoblock construction. Two totally independent and isolated power supplies and separate signal paths result in ideal channel separation and stable imaging under dynamic drive conditions.

Both the single-ended (RCA) and balanced (XLR) inputs are connected to a wide-bandwidth Jensen input transformer. Although it's strictly not necessary in the case of the RCA input, Mark believes that it does a neat job of eliminating potential ground loops and smoothing out the top end. One leg of the secondary is grounded, so that only the positive going portion of the balanced signal is used. The signal is then fed to a long-tailed pair phase inverter consisting of a 12AX7 dual triode. The driver stage is more sophisticated than what one typically sees in a 1950s vintage amp. It's a series-regulated push-pull circuit, also known as a Mu follower or totem pole, which uses a pair of 12AU7 dual triodes. The output stage is comprised of two pairs of KT88s operating in parallel push-pull configuration. The output transformers are quite beefy and feature an ultra linear connection. They use E-I laminate cores of grain-oriented silicon steel and are custom wound to a frequency response spec of 10 Hz to 50 kHz (+/- 1dB). The windings are bifilar and are interleaved to reduced leakage inductance. The output stage mode may changed on the fly from UL to triode by the mere flick of a switch on the back panel. Of course, maximum output power is reduced by about one half in triode mode.

Instead of the more common cathode bias, a fixed bias scheme is used. There are no cathode resistors, a dedicated –100 VDC bias supply is provided. This is a far more efficient biasing scheme than self bias since the entire B+ voltage is useable as plate voltage. A very nice touch is the built-in current meter. The quiescent current of each output tube may be adjusted individually using a set of pots located under a plate near the meter. A special tool is provided for that purpose. The entire process only takes a couple of minutes to complete if there are a few pots that need tweaking. Note that the bias is set on the low side at the factory as a precaution because it is a function of the AC main voltage. The recommended bias current is 40 mA and it should be set accurately only after each amp has been running for at least one hour. One knock against self bias is that it is not self-regulating as is cathode bias with tube aging. I found it necessary to tweak the bias a couple of time during the first week of use. After that, there was little drift; I would recommend a once-week bias check under heavy usage conditions and a bimonthly frequency for the average user.

The power supply is solid-state rectified and features voltage regulation for the front end preamp tubes. The other important feature, mandatory really, for a fixed-bias amp is the soft start circuit which ensures that high voltage is applied slowly while the bias supply kicks in. Each output tube is individually fused as an added safety feature to prevent runaway currents should the bias supply be interrupted.

Both 4 and 8-Ohm impedance taps are provided. These ratings should not be confused with the amp's internal source impedance which determines its damping factor. The source impedance is said to be about 0.4 Ohm — quite low for a tube amplifier with moderate levels of global feedback (about 18 dB) — and resulting in a damping factor of 20 into an 8-Ohm load. I'm so fed up with insulated EU style binding posts that look fancy but are difficult to tighten. Hence, it was really nice to see good old US style un-insulated posts of hexagonal profile that I can really tighten down on with a nut driver.

WHO WE ARE

Skyfi.nyc 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 and 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 select 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, Project and Sony ES, we have access to OEM parts and service support. If you are local and are looking for any new equipment for the above mentioned manufacturers, please drop us a line as we can arrange both sales and professional installation in the tri-state area

PURCHASING GUIDELINES

If you would like to make an offer, please don't email or message us unless you are looking to trade something in.

If we are accepting offers, you will see a button on the listing page to do so. Please use it, as it is very hard to track offers through email or messaging. This way, we are all also better protected. If you don’t see a “offer” button its because we are not taking offers on this item. Please don’t bother to make one.

PAYMENTS

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. 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 are picking up an item, we don not accept PayPal, you must pay in person with cash, certified or bank check or wire transfer. If you make a PayPal payment it will be returned.

TRADE IN POLICY

We accept trade-ins of equal or lesser value under certain conditions. Simply ask and let us know the exact model, condition and what accessories are included such as a box, remote, manual, etc. 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 processors and mid-fi equipment of any type. We will offer a fair value for your equipment, but keep in mind we are running a business and will need to be able to sell 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 are looking for top dollar we suggest attempting to sell it directly to an end user.

SELL US YOUR GEAR (Working or Broken)

We will also purchase your used or broken gear and arrange pickup if you are in our local market. Just drop us a note for a quote, but be sure to include the condition and what is included.

HOW TO VISIT US

We are currently operating from a residence in Ridgewood, NJ. You are welcome to make an appointment if there is a piece of equipment you would like to see in operation before or after purchase. We have a well-equipped, dedicated listening room with tons of equipment of all makes and models. We are not a store, so please don’t make an appointment if you are just curious as to how a speaker or piece of equipment sounds. In essence, no tire kickers please.

If you are in NYC and cannot make it out to Ridgewood, we can arrange pickup in Union Square (14th Street) after the purchase. You can call or text (646) 852-2073 with any questions or to schedule an appointment. We can also arrange to install, calibrate and tune the gear in your listening room if you are in the local area. This is super useful when purchasing large speakers or heavy amplifiers. It is also great for ensuring your new turntable is setup correctly in its final resting place.

Thanks for looking and please send us your email address if you would like to receive a list of the equipment we receive from time to time. We promise not to bombard you with junk email.