Those look to be original 196070s dynaco mark iiis to me. The st70 used four el34 output tubes, one gz345ar4 rectifier tube, two 7199 input driver tubes, two. Dynaco mark iii restoration and modification hudson valley hifi. So shannon, with poseidon boards you can mod mkiis and drive them with different tubes. Dynaco mkiii mk iii mk3 mk 3 tube amplfier restoration kit. Oct 08, 2017 dynaco mark iii mk 3 restoration part 9 final bg081 duration. 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. The dynaco mark iii is the highest power amplifier that was widely sold under the dyna name. Dynaco mark iv amplifier audiogon discussion forum. The el34s will be able to handle the 15 extra volts, as well.
My dynaco mkiiis are the dynakitparts version and i use the high gain tubes4hifi driver boards which use three 12at7s. Our newest version includes a filament jumper allowing use of tubes with 9aj or 9lp pinout, thus allowing use of. I was working on the ez260, but came across 3 beat dynaco mkiii mono amplifiers. Details about dynaco mkiii mk iii mk3 mk 3 tube amplfier restoration kit. This elegant dyna mk iii upgrade was performed recently. The dynaco dynakit mark iii amplifier is rated at 60 watts. This design coupled with the robust and high quality output transformers in. I have used a pair of dynaco mk iii amps in my home stereo system for over 15 years.
Biasing and balancing 1connect a voltmeter on a setting to handle up to 2vdc across either kt88 cathode 10 ohm resistor. Ii was sold for several years until its replacement in 1956 by the mk. Dynaco mark iii in the march 2001 issue of audio xpress there was an article titled the cure for the common dynaco mkiii. Dynaco mk 3 standard upgrade assembly, installation, and adjustment manual page 3 cae dynaco driver replacement module pc1u rev 2 iii. Thats when these things were laid out with black tape type material by the way. I am looking for input on the dynaco mk iii monoblocks.
Clearly, these are superb tubes to use in a reference dynaco st70. Each amplifier requires one 12au7 plus one each of either 12au7, 12bh7, 6cg76fq7 or 6n1p. A custom dynaco st70 kit diy audio electronics from. The kits i built up were the aforementioned dynaco st400 and pat 5, an early 80s heathkit tuner, the van alstine super pas iii, dyna mk iiis. Dynaco mark iii restoration and modification hudson. Iii and pam1 preamp allowed the company to offer some new products.
This kit will change the way your tired old dynaco st70 will sound and look. Dynaco vintage amplifiers and tube amps for sale ebay. Dynaco mkiii monoblock tube amplifiers curcio audio. Modifications for the dynaco tm mkiii mono power amplifier basic features. Dynaco dynakit mk iii amplifiers, serviced for sale us. Get the best deals on dynaco vintage amplifiers and tube amps when you shop the largest online selection at. Lets just say i used the board on a few dynaco s and i was happy with the results as compared to other mod boards and stock boards i tried. They have the upgraded driver boards and cap boards.
The tubes are all new, and the power tubes are brand new genelex kt88 gold lion tubes. Dynaco mkiii mono amplifiers completely restored and stunning. Unfollow dynaco mk iv to stop getting updates on your ebay feed. Building the pc board pc1u components are to be inserted on the non foil side and soldered on the foil side. Dynaco mkiii triode electronics driver boards x2 for. Recently we had an original owner pair of dynaco mark iii amplifiers brought to us for restoration and modification. Diytube mark iii poseidon driver board driver board designed by shannon parks over at. The amps had been serviced recently elsewhere and the work done was trivial compared to what was actually needed. I ordered the boards and components as a kit and sourced the coupling capacitors from mouser. I wanted two cabinets so i could use them as pedestals for the l100s if i so chose, or stack them out of sight. With the owner we decided on the new 6sn7 driver board from the guys at tubes4hifi. Really fun to build and a hell of a good time while learning to become much more adept at understanding schematics and the overall design of the dynaco mark iiis. Our driver circuit is a modern all triode driver design, for totally neutral uncolored sound.
Recently we had an original owner pair of dynaco mark iii amplifiers brought. For sale is a pair of triode electronics, dynaco mkiii driver boards, one board is fully assembled, the other board is new and unassembled. Here at dynakit you will find the right parts to restore, repair or upgrade your original dynaco vacuum tube amplifier. Dynaco mark iii poseidon board vs original dynaco 6ana driver. Many of my friends told me to join the 20th century when they first saw them, but i. Onto assembly of the triode electronics driver board. Im not aware of people going to mk 3s then ditching them for something else. Both it and battery bias options available where appropriate. Roy just a note to let you know how much i enjoy the driver. Triode usa tube amp kits transformers tubes dynaco. Finally realized it would have to be a 12 driver in order to keep the cabinet size reasonable. Dynaco dynakit markiii mk iii for sale us audio mart.
They have new 6sn7 driver boards with individual bias, a new multisection can cap, new 3d printed binding post plates and bias test points. St70 baseline2 dynaco sca35 st35 tube amplifier upgrade. I am happy with the product quality and the performance of the vta driver boards. The dyna mkiii has a basic design flaw that none of the other dynaco products have. Dynaco mkiii monoblock tube amplifiers curcio audio premium upgrades dynakit. This dynaco st70 driver board pc3 has been developed and designed to be a dropin replacement for dynaco 7199 board. With the help of bob tucker, the st70 was designed in 1959 to reduce distortion and improve audio quality with four el34 output tubes, a gz34 rectifier tube, two 7199 input driver tubes, two ultralinear output transformers and a power. There are currently several on the market, one called the poseiden from diytube, one from tubes4hifi that incorporates additional electrolytics on the board itsself, one from curcio audio and one from triode electronics. Maybe this is a later standard dynaco driver board. How to upgrade a dynaco mark iii a pictorial 2channel. The second deviation would be a more modern driver board for the mk iii.
Introduced in 1959, the st70 was available as a kit dynakit intended for assembly by the purchaser or as a complete factorywired unit dynaco. Dynaco mkiii mods diy canuck audio mart hifi and audio forum. This is for a pair of dynaco mark iii monobock amplifiers assembled from the triodelectronics kits. Dynaco mark iii poseidon board vs original dynaco 6ana. Stereo 70 driver board 7199 board replacement modules a. Kara chaffee described a modification for the mark iii which replaced the 6an8 driver. Dynaco dynakit mark iii tube amplifier schematic and 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. 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. Also popular are rebuild kits with newly engineered driver boards that one can use to improve an existing st70. The st70 used four el34 output tubes, one gz345ar4 rectifier tube, two 7199 input driver tubes, two output transformers, one power transformer. The triode electronics kit eliminates the superfluous holes in the chassis and makes use of a cap board inside rather than the tall quad cap, along with a different driver board. The scan below is the dynaco dynakit mark iii tube amplifier schematic from the instructions manual. I am still baffled by the input driver board however. It is indeed very poorly made and appears quite fragile. The layout was changed to use the contemporary components and 6gh8a tubes.
Dynaco mkiii quad cap replacement board january 25, 1998 version 1. Dynaco mark iii mono block tube ampspair mkiiidynaco. 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. Dynaco dynakit mkiii manual power amplifier kit hifi. The irons are still good as are the original driver boards. One of them is missing some parts like resistors and a can cap etc. The chassis and transformers from triode are much higher quality that from the other vendors. Dynaco dynakit mkii manual power amplifier kit hifi engine. This a drop in replacement for the original dynaco st70 pc3 driver board but with modern epoxy fiberglass pcb. Diytube mark iii poseidon driver board triode electronics. The original dynaco board used only a single 6an8 tube with some capacitors and resistors.
The driver tubes were also relatively new zenith labeled uncarbonized 7199s, of unknown american manufacture. Make offer dynaco mkiii mk iii mk3 mk 3 tube amplfier restoration kit. Turn off your mk iii and replace the pulled rectifier tube. Unfollow dynaco mk iii to stop getting updates on your ebay feed. With the exception of replacing one tube, they have given me many hours of listening pleasure. In addition, the bias circuit will now utilize two trimmers mounted on the top. 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. The other benefit of the dynaco is that at 60 watts, i could use them with a pair of paradigm studio 100s i have in storage if i didnt like them better than the fisher. The original dynaco 6an8 design we believe was inferior to the 7199 driver used in the stereo 70. This board is a must for any serious restoration of the dynaco stereo70 to full stock condition. Tubes for the dynakit mark iii mono amplifier antique electronic. The capacitors in the power supply are not rated at a high enough voltage for the power.
Of note however, this is an area where heathkit really shined, steering very clear of such. Dyna mark iii amp and the sds labs quad cap board wife warming her toes on the mkiiis. Here is a kit to electrically restore your dynaco mk iii to like new condition. Dynaco dynakit mkiii manual power amplifier kit hifi engine. Restoration module this is an exact replacement for the original dynaco pc3 board fabricated from milspec materials. 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. A nos 5ar4, a cap board, and a choke will provide the best regulation. Triode electronics sds labs capacitor board for dynaco mk3, mk2 and sunn ampufiers easy installation instructions. I own a pair and occasionally run them to keep em alive. But when i put the boards in it took on a new life form. One of these tubes has been replaced, for reasons which will be discussed further in the section on the driver board.
The board was very well laid out and a quality part. Here is a beautiful pair of dynaco mkiii mono amplifiers. 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. Driver boards for dynaco mark ii and mark iii triode electronics. The dynaco dynakit mark iii is a monoblock amplifier with a 6an8 input stage and a pushpull kt88 output stage. There was a nigher power amp the mark vi, but it wasnt widely available. Page 1 cae dynaco driver replacement module pc1u rev 2. Dynaco mkiii mods diy canuck audio mart hifi and audio.
Amp is sold, but you can still find these on ebay, so be happybut buy a restored one, or take it to a tech, because you are only dreaming of plugging one of these into a wall socket, without starting a fire or having the thing blow or burn out. It uses a circuit of outstanding performance characteristics, along with top quality parts, including the new dynaco a430 output transformer the finest available. This driver uses the classic modified mullard topology with constant current source in the tail of the phase splitter a perfect mix of performance and. Also, is it possible to use other tubes with the original desgin. Therefore applying the same circuit that we developed for the stereo 70 to the mark 3 resulted in a dramatic improvement over the stock amplifier topology. Dynaco st70 6gh8 6gh8a ecf82 driver board pcb pc3 kit dyna.
Abj amplifier banana jack upgrade kit for the dynaco stereo 70, mark iii. Some of the driver boards were just plated copper without even silk. These have been completely updated with new quad cap power supply filtering. Power amplifiers a variety of new and custom designs using all manner of dht and beam powerpentodes are available. One each of the other tubes is used per channel as a combined phase splitter driver in a longtailed pair configuration. 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. One half of the first tube is used for each channel as a voltage amplifier. This dynaco mk iii sports a specially designed driver board produced in the 1980s at musical concepts. Dynaco mark iii poseidon board vs original dynaco 6ana driver board duration. A variety of new and custom designs using all manner of dht and beam. Many of my friends told me to join the 20th century when they first saw them, but i soon changed their minds after listening to my system. While you can select any of the vacuum tubes presented below to complete your tube set for the dynakit mark iii amp, dynakit recommends the following. New 6sn7 octal driver use for dyna mk3, vta m125s or vta m70s the bare. Mar 16, 2003 hi, the dynaco mk iv is designed to use a 7199, gz34 rectifier tube and a pair of el34 tubes.
Does anyone have any specific details about this article. Topologically it is really very similar to the amp board above, but with some provision for power supply atop the driver board. In 1955, the two men founded the dyna company later dynaco with the intention of not only producing transformers, but highquality audio circuitry. All connections to the board are marked with the original number markings on the top and bottom silkscreen layers. 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. Put a set of nos tung sol 6550s gray plate no holes or black plates, nice driver tubes like a 6an8 and a mullardhammond gs 34 or 37 even better. Rio is a 50 ohm, sw resistor, used rather than the choke shown on the hookup diagram notes for sunn amplifiers.
All four boards make use of two driver tubes as opposed to the stock versions single tube. Mar 01, 2003 dale walkers modified dynaco mk iii nice work. All caps, resistors, and tube sockets are included to make a complete working board. Last few pics show updated caps on the driver boards, and high voltage multi section.