Icon Audio - MB30SE Tube Monoblock Amplifiers - British Made

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A Versatile Affordable SE/ Single Ended Tube Amplification Solution!

Beautifully Simple:
• 27 + 27 Watts RMS*
• 18 + 18 Watts Triode
• Low & High Sensitivity
• Choke power supply
• Valve Rectified
• Tung Sol KT150 Tubes

"The MB30SE is a versatile high quality very simple mono block amplifier for Full Range and medium sensitivity speakers. Using only 2 audio valves it has excellent bandwidth with the best qualities of SE* without the disadvantages of flabby bass, hum and low power that many designs suffer.

The new KT120 was chosen for its all round qualities and good power, it is also considerably cheaper than vintage triodes like the 300B which will only deliver 9W SE. The heart of a good Single Ended amplifier is the output transformer. Our specially developed Low Distortion Tertiary transformers allow the KT120 to really “sing” without constriction giving wide bandwidth and dynamics with excellent detail.

The MB30 is optimised for Triode and UL operation. 16 Watts being ample for most situations. Especially with our new “Full Range M” speakers and other designs such as Lowther and Fostex being ideal. But recognising that there are many speakers that require more power. The MB30 works very well in “Ultralinear” mode allowing the full potential of the KT120 to work its magic. Designed to be used either an active or passive pre amplifier, or direct from a single source.

The “easy bias” meters ensure that that amplifier is giving its best performance and also gives an indication of output power used. Very useful when you may need to know if you are likely approach the maximum available power. Ideal for: most situations where larger SE power is required by someone wanting a very relaxed sound. Well suited to larger more efficient speakers.

Specifications and Features
• 100% Pure Class A output power
• Class A, all Triode front end
• Valve rectifier, GZ34/5AR4
• Output power Triode (16W). Ultralinear (27W)
• Oversized choke regulated power supply
• 1x KT120 output valve (KT88/90 compatible)
• 1x 6SN7 (CV181) double triode driving valve
• All hand wired point to point
• Signal to noise level -86db
• Freq resp 20 – 20kHz +0 –0.8db 45kHz -3db(8w)
• THD typically less than 0.5% 1khz (8w)
• 4 & 8 ohm loudspeaker taps
• Low feedback design (no feedback on high gain)
• Solen/SCR hi fi audio capacitors Jensen upgrade
• Silver plated copper PTFE audio cable
• Tertiary winding output transformers
• Big custom wound PSU Choke
• Gold plated Input & speaker terminals
• 330mv (high) & 925mv (low) input sensitivity.
• 220/240volts 85w approx (each)
• C E, ROHS
• Size in mm W160, D380, H210, 12kg ea
• Packed 44cm x 25cm x 32cm 13kg 2 boxes
Typical values @ 235v AC (Specifications subject to change)

Tube Info:
(2) Eletctron Tube 5AR4 Rectifiers
(2) Vintage Sylvania 6SN7 
(2) Current Production Tong Sol KT150

All tubes tested on our modern and professional Amplitrex tube tester to above 70% of new. Both amplifiers achieved proper power output in both triode and ultra linear modes.

Cosmetic Notes:
• Small scratch on side of face on right amplifier.
• Minor corner dent on right amplifier output transformer.
• Left channel bias switch slightly bent.

MB30 Single Ended KT150 Power Amplifiers - MB30 SE - Sales Brochure

MB30 Single Ended KT150 Power Amplifiers - MB30 SE - User Manual

MB30 Single Ended KT150 Power Amplifiers - MB30 SE - HI-FI World Review July 2013

The SkyFi Testing Process for Tube Amplifiers:

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.

Please click here for detailed specifics regarding our specialized packing process that separates us from the rest.