MFA Systems M-75B monoblock amps (Moore-Frankland Associates), 75wpc, 1984-1989
These are very nice sounding and exceptionally well built amps. They were designed by Bruce Moore (Bruce Moore Audio Designs) and Scott Frankland (Wavestream Kinetics). They use top quality parts and are hand built in the USA, using the point to point wiring method. They have unregulated power supplies (no current limiting) and run in class A up to 40 watts output, and class AB1 above that. These will ship with a set of good quality but used Svetlana 6550 output tubes - two per amp. They can also use KT88s, KT90s, and KT99s. The amps were tested and biased using the 6550s and they run well. I will throw-in a set of KT90 or KT99 tubes (whatever I have), also used as the 6550 tubes have the keys broken off of them (they were cheaper that way
. I'll mark the key orientation with a marker, but it is easy to figure out for anyone familiar with tube amps and you wouldn't be reading this if you weren't... The amps are rated at 75 watts per amp into 4,8, or 16 ohm loads. They use some of the biggest transformers of any amps in this power range and are extremely wide bandwidth (16-80khz). They sound lush and detailed but with plenty of sparkle in the highs and lots of authority and control in the bass. These are classic designs of top quality and are quite rare. The amps are fitted with Cardas power cords without ground connectors, grounding is done through the connection to preamp. This was done to reduce or even eliminate hum. The amps also have AC balance pots to fine tune them. $1295 pair.
