These amps smoked the dynaco from the beginning of the bandwith to the last and final note. As requested dynaco mark iv high end capacitor upgrade kit. The dynaco dynakit mark iv amplifier uses a circuit derrived from the dynakits mark ii and mark iii amplifier kits which became world famous at. Kara chaffee described a modification for the mark iii which replaced the 6an8 driver. They put out a real 40watts per side less in triode, i will. The layout was changed to use the contemporary components and 6gh8a tubes. Dynaco mark iv amplifier audiogon discussion forum. Welcome to canuckaudiomart, a classifieds site for used audio and hifi.
The mark iv amplifier uses a circuit arrangement based on that of the dynakits mark ii and mark iii which have become world famous for superior quality while essentially simple and trouble free. The new 7199 tube is used as a pentode high gain voltage amplifier directly coupled to a cathodyne phase inverter. Picture of mint condition pair of dynaco mkiv mono amps. Dynaco mark vi 6 120 watts per channel rms mono tube amplifiers pair no reserve. If the dynaco st70 is great, then the heathkits are world class. Stereo 70 driver board 7199 board replacement modules a. Driver boards and parts for dynaco mark iv triode electronics.
The irons are still good as are the original driver boards. The dynaco dynakit mark iii amplifier is rated at 60 watts. The venerable dynaco stereo 70 by dan schmalle from. It follows the original wire hole layout, but it was modified to use widely available 6gh8 6gh8a 6kd8 ecf82 tubes instead of the obsolete and hard to find 7199 tubes. Our update kit for the dynaco stereo 120 lets you rescue your dynaco from demise in the dumpster and make it better than new. There was a nigher power amp the mark vi, but it wasnt widely available. Jun 28, 2016 the first thing i did was to look for a suitable replacement driver board. Introductioncircuit description the triode stpc i and mkpc i are intended to be drop in replacements for boards in dynaco st70 and mark ill amplifiers with no modifications necessary just bolt in and solder in wires to the pc board. Dynaco mark iii poseidon board vs original dynaco 6ana driver board. The dynaco dynakit mark iv amplifier uses a circuit derrived from the dynakits mark ii and mark iii amplifier kits which became world famous at the time for superior quality while essentially simple and trouble free. Their popular models include the stereo 70, stereo 35, mark iii, and mark iv.
Forty years of technological progress allows us to bring you lower distortion and greater efficiency, along with protection circuits that make your amp nearly bulletproof. Dynaco dynakit st70 vacuum tube stereo amplifier vtast70 octal driver board. I tried a few different driver boards and my ears told me that using the tubes4hifi vta driver board designed by roy mottram made a big difference in sound quality over what i could get out of these older original dynaco. Here are the instructions for changing thr mk4 to triode operation. This board shouldnt be doing to the amp what it is doing. Dynaco upgrades lets talk audio and diy 2channel home. Dynaco mark vi instructions for assembly operation pdf download. In 1955, the two men founded the dyna company later dynaco with the intention of not only producing transformers, but highquality audio circuitry. Pretty only the case and original trannies were retained on this full rebuild. This dynaco st70 driver board pc3 has been developed and designed to be a dropin replacement for dynaco 7199 board. The mark iv amplifier uses a circuit arrangement based on that of the.
Oct 24, 2011 the dynaco mk iii monoblock was introduced by dynaco was back in 1957, just after the mk ii and the pam1 preamp and two years before the famous st70. Get the best deals on dynaco vintage amplifiers and tube amps. All connections to the board are marked with the original number markings on the top and bottom silkscreen layers. Dynaco dynakit mkii manual power amplifier kit hifi engine. Dec 02, 2006 anyone here do any upgrading of their dynaco s themselves using the sds labs cap boards andor the various driver boards available.
There is a reason they were built as they were, and can sound very nice with a stock circuit. Poseidon driver for the dynaco mark iii, iv and diy. Nos pair dynacodynakit mk iii mono amp wextra board bob latino. Dynaco mark iii in the march 2001 issue of audio xpress there was an article titled the cure for the common dynaco mkiii. In the march 2001 issue of audio xpress there was an article titled the cure for the common dynaco mkiii. Hard to find parts including dynakit original dropin replacement components typically ship within 24 hours of ordering. Find great deals on ebay for dynaco mk iv and dynaco st 70. Our new boards for dynaco mk4 are identical circuitwise cascode input with longtail pair phase inverter to our.
Your dynakit mark ii is a complete 50 watt power amplifier kit which offers the highest possible fidelity, at low cost and in a compact arrangement. The original circuit board was long gone, the tube sockets were shot, and the can cap had been replaced by a giant oil power supply capacitor. The owner of the amps wanted them restored and modified with a new driver board which will accept different driver tubes. Discussion in audio hardware started by dennis0675, aug 17. In case that website goes down, i repeat content of the instructions for mkiv kits from dynaco.
It used the a470 output transformer, same as the st70. Aug 17, 2017 what are the reasons to pass on a dynaco mk iii. There are several good aftermarket boards on the market for the dyna amplifiers. Each amplifier requires one 12au7 plus one each of either 12au7, 12bh7, 6cg76fq7 or 6n1p. Dynaco mark iii restoration and modification hudson valley hifi. The original workmanship was good and they didnt need a whole lot of work. The 7199 tube is used as a pentode high gain voltage amplifier directly coupled to a cathode phase inverter. I then had the urge to try this schematic on a pair of heathkit w7s. Dynaco dynakit mark iii tube amplifier schematic and manual. Description 60 watts dual pentode tube mono power amp 19641969. The dynaco 70 the dynaco 70 is the most important tube amplifier ever made. Modifications for the dynaco tm mkiii mono power amplifier. A fully gone through and rebuilt dynaco st70 with vta driver board.
The dynaco mark iii is the highest power amplifier that was widely sold under the dyna name. Dynaco mark iii mk 3 restoration part 1 bg066 youtube. Dynaco mark iii poseidon board vs original dynaco 6ana driver. The dyna mkiii has a basic design flaw that none of the other dynaco products have. Thats what we do positive feedback positive feedback online is first and foremost a community, composed of writers and creative persons from around the world. They do look to be near original with little work done to them, the only thing i can see that has been replaced up top is the one single yellow colored cap on the circuit board per amp. With the owner we decided on the new 6sn7 driver board from the guys at tubes4hifi. The basic modification consists of replacing the driver board, performing easily done minor modifications revising a few connections to the output tubes, and installing to the power. The mark iv amplifier uses a circuit arrangement based on that of the dynakits mark ii and.
The scan below is the dynaco dynakit mark iii tube amplifier schematic from the instructions manual. The basic modification consists of replacing the driver board, performing easily done minor modifications revising a few connections to the output tubes, and installing to the power supply, your choice of input and output connectors. The dynaco dynakit mark iii is a monoblock amplifier with a 6an8 input stage and a pushpull kt88 output stage. Dynaco mk4 tube amplifier assembly manual reprint dyna dynakit mark iv. Dynaco vintage amplifiers and tube amps for sale ebay. Dynaco mark iii restoration and modification hudson. Dynaco customs services and international tracking provided. Dynaco mark vi instructions for assembly operation.
The 12au7s have lower gain then the tubes used on tubes4hifi, but i think now the tube4hifi amp can be order with a lower gain version now. If the former, i would look at a sds power supply board and any of the available driver boards. You will need to replace the original screws with 632 x 34 and add two. Aug 23, 2016 dynaco mark iii mk 3 restoration part 1 bg066. Dyna mark iii amp and the sds labs quad cap board wife warming her toes on the mkiiis. Dynaco dynakit mkiv manual power amplifier kit hifi. Nov, 20 the markiiis used a different tube set in the driver and i think thats the primary difference. Well, i have bought just about every mod board available and have even done a few on others not sold mainstream from time to time. Dynaco dynakit mkiv manual power amplifier kit hifi engine. These are monoblock tube amplifiers using a pair of el34 as output tubes, a 7199 as the pre driver and a good old gz34 for ps rectification. Tone audio magazine online tone audio magazine forges the link between music and high quality audio reproduction with a 5050 balance between the two tone audio facebook music, gear and fun.
Review by don of santa fe, new mexico 2018 updated 092019. Restoration module this is an exact replacement for the original dynaco pc3 board fabricated from milspec materials. The driver mods vary from a simple changing of the traces on the driver. Roy just a note to let you know how much i enjoy the driver board i purchased from. This is my attempt to document the differences between the original dynaco design of the mark iii amplifier using the 6an8 vs a new design diytube poseidon driver board using a 12ax7 and 12au7 or. If the driver board in your st70 is damaged, new driver boards using the stock circuit sometimes modified for 6gh8s or somesuch, since 7199s are getting hard to find are available from.
With parts means all board parts, you solder on board yourself. Hi, the dynaco mk iv is designed to use a 7199, gz34 rectifier tube and a pair of el34 tubes. Diytube mark iii poseidon driver board triode electronics. The mark iv amplifier uses a circuit arrangement based on that of the dynakits mark ii and mark iii. Both mk iv kits include our new brown polyimide circuit board. The first thing i did was to look for a suitable replacement driver board. Our new boards for dynaco mk4 are identical circuitwise cascode input with longtail pair phase inverter to our mk3mk2 boards, but resized to fit the mk4.
Modifications for the dynaco tm mkiii mono power amplifier basic features. If you can loosen up the driver board and tube sockets, then take the screws out, and drop the innards down just enough to put a piece of cardboard under the chassis to protect the circuitry, then it will be a lot easier, leaving only the area around the trannies and ios to contend with. This kit is for the serious audiophile and contains all crucial metal film mica capacitors needed to upgrade your classic mark iv pc4 driver board associated circuits. Dynaco mark iii poseidon board vs original dynaco 6ana. The mark iiis used a different tube set in the driver and i think thats the primary difference. Fully rebuilt dynaco st70 with vta70 driver board upgrade. Unfollow dynaco mk iv to stop getting updates on your ebay feed. Amplifiers want to find a real sleeper amp for those of us on a budget. Amplifier dynaco dynakit stereo 70 instructions for assembly 16 pages. Vta driver board kit rebuild pages amplifier dynaco stereo 70 restoration manual 20 pages amplifier dynaco stereo 80 owners manual. Diytube mark iii poseidon driver board driver board designed by shannon parks over at. Dynaco dynakit mark iv amplifier schematic and manual.
A clue to the effect this has on output power is the 40 wpc rating of the mark iv, a monoblock cousin of the 70 with a separate power transformer and 90 mfd filter for each channel. With your circuit, one of the first things i noticed was that different recordings are clearly different, indicating to me that the amplifier is neutral, rather than co. During a visit to the new yorkbased brociner electronics the same year, hafler met an audio engineer named ed laurent, who had designed a novel singletube driver circuit for a power amplifier. The mark 3 amps were originally equipped with kt88 or 6550 output tubes. Here at dynakit you will find the right parts to restore, repair or upgrade your original dynaco vacuum tube amplifier. The white stripe side must be opposite ofthe v indicator on the board.
So shannon, with poseidon boards you can mod mkiis and drive them with different tubes. For more information please see our dynaco page here is the driver board instructions note that sprague 715p716p orange drop capacitors will not fit this board. Get the best deals on dynaco when you shop the largest online selection at. This board is a must for any serious restoration of the dynaco stereo70 to full stock condition. Those look to be original 196070s dynaco mark iiis to me. What would you want after 10 years of dynaco mk iiis. This a drop in replacement for the original dynaco st70 pc3 driver board but with modern epoxy fiberglass pcb. Ive heard the same effect on the dynaco mark iv, the monoblock version of. Power supply board by classic valve design for the dynaco. I tried a few different driver boards and my ears told me that using the tubes4hifi vta driver board designed by roy mottram made a big difference in sound quality over what i could get out of these older original dynaco st70s. Mounting pcb can be placed on the transformer screws as shown. View and download dynaco mark vi instructions for assembly operation online.
You also requested a simple and reliable quad capacitor replacement module. Oct 29, 2018 for other dynaco, haler, and phase linear kits. How to repair dynakit dynaco mark iv el34 tube audio mono. Mar, 2015 this is my attempt to document the differences between the original dynaco design of the mark iii amplifier using the 6an8 vs a new design diytube poseidon driver board using a 12ax7 and 12au7 or. A pair of custom dynaco mk iii monoblock amplifiers. I was fortunate to get a pair of the 60 watt mk iii amps that were factory built. I own a pair and occasionally run them to keep em alive. The triode board can use any common tubes, and i think that is what makes it a good design. I have a mark iv that has no rust but just dull and. Sep 29, 2008 dynaco amps were some of the most popular hifi amps ever sold. This new driver uses the classic modified mullard topology.
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