Review: Dynaco Mark IV Amplifier

Category: Amplifiers

Want to find a real "sleeper" amp for those of us on a budget? the Dynaco MkIV may be just the ticket to cheapo vintage nirvana! These are monoblock tube amplifiers using a pair of EL-34 as output tubes, a 7199 as the pre-driver and a good old GZ-34 for PS rectification. They put out a real 40watts per side (less in triode, I will get to that in a moment) and were/are spec'd at 10hz-20mhz + or - .5hz with 1% thd at max output and .05% at one watt (where many of us do most of our listening) and have 4, 8 and 16ohm taps for speakers. This is one of the most sought after Dynaco amps due to a simple fact, they each have the same transformer complement as an ST-70 but dedicated only to one side, the result? better dynamic headroom per channel than the already venerable ST-70. Since these were often kit amps you need to check them carefully before buying for good construction techniques but these units are very durable. The normal caveats for hot running, older tube amps remain; watch out for dried up capacitors, think about replacing the orignals even if they measure well, a few dollars spent on better caps can result in much better sound. While you're at it, swap out the resistors as well...why not? the things cost little enough and hot-rodding them is part of the fun. Many pages have been written about how to bring these amps up to date, start at the unoffical dynaco page http://home.indy.net/~gregdunn/dynaco/index.html and then get to work. The sound? well this a VERY GOOD EL-34 PP amplifier! When encountering "modern" designs I still see/hear the strong Dynaco influence, they have the guts to drive a variety of speakers to ear bleeding levels but give you that nice warmth and "truth" in the mid-range many of us crave. This would be a great starter tube amp before jumping into the buck-buck modern amps (Cary, CJ, etc.). With jazz LPs even CDs (they tame some of the digital grunge, some would hide, I would say WHO CARES they sound great!) these really shine, they perhaps lose a little ultimate bass control with large scale orchestral or even modern techno music but the lquidity of the midrange is intoxicating! A word about the triode mod, I have mine set up to switch between pentode operation (traditional for these dynaco units) and "triode" mode, One resitor per amp is all it takes to strap the EL-34s to triode operation. The result is even more luscious mids and half the power in triode. For those of you with Efficient speaker (I have Klipschorns) the triode strapped MkIVs at 20watts give a musical experience that, in my opinion, equals many other modern, much more expensive amplifiers. I have not used pentode since modding them form triode operation. But what the hell, cruise Audiogon and Ebay for a pair of these, pick them up for a song for yourself, plug them in, and begin to laugh histerically as you think about all those others out there not enjoying this level of sound for garage sale prices. Try it, you'll like it!

Associated gear
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Similar products
Dynaco ST-70, Scott, Marantz, Eico