Want to to home-brew your own TriodeUSA Upgraded, Dynaco(tm) style, Mk3 mono tube amp kit? Here's the kit for you. The Mk3 was the top of the Classic Tube Dynaco line. Sixty all tube watts, in a compact design. This Kit includes our most requested Mk3 upgrades, and includes our upgraded boards, and latest chassis version with iec power cord cut out and holes for heavy duty binding posts, input jack, and bias point. Our Kits are a great choice if you really want to learn more about how your amplifier operates, too. You see, unlike many other Kits, you are not totally locked in to only certain components, nor are you stuck with unchangeable circuit values which limit the versatility of your amplifier and further modifications. There are no "big secrets", you don't need permission from a "guru" to change or tweak it, the manual has instructions for about every change you could imagine making. Instructions are included for triode connecting the output tubes, which will give you a taste of hi-end triode-itis for the cost of 4 resistors, about $1. So, you've got a choice..you can just plug in & play, or you can do your own experimenting if you'd like to, learn a lot and become your own neighborhood Dynaco guru. And you won't break the bank doing it, either.
The stock board and parts kit includes, transformers, choke, Upgrade Cap Board and Driver board, RCA jack, terminal strip, metal film resistors, polypropylene capacitors, wire, Precision Electronics (PEC) bias potentiometer, wire, and sockets. All of which make a great sounding amp..but if you like, you can modify many component values and try different or exotic parts and tweak to your heart's content. The boards will adapt to output tubes which need very low drive circuit impedance/ DC grid resistance like 8417's- or may be modified to whip out enough voltage to drive 300B's or 6B4's!!
The board sounds fine even with the off the shelf, current production tubes, and special grading and matching is not absolutely necessary. It is a good example of what can be done with the original type of circuit with improved components, and makes a good case for the virtues of simplicity and short signal path in audio design. The TriodeElectronics Mk3 boards emulate the simple but highly effective (due to the short signal path and single gain stage) original Dynaco circuit, but with lower hum, lower noise, less distortion, and a wider voltage swing across heavier loads, than a 7199,6GH8,6BL8/ECF80, 6U8/ECF82 or 6AN8 are capable of. Comes without tubes, see our "Tubes for Dynacos" link at bottom of page for them.
The board manual includes information on adapting the amplifier to different output & board tubes, adjusting resistor & capacitor values if desired, plus a comprehensive Troubleshooting Guide. An online pictorial manual can be viewed below.
A431 S Output Transformer:
The primary is wound the same as the original A431, same number of turns, sections and wire size, using the same patented Dynaco winding method, and made on the same core size and material. Only improved insulation material used (thus making the transformer more resistant to abuse) and nice long (10 inch/ 25 cm minimum) teflon insulated leads have been added.
This transformer has what you'd expect out of a Dynaco transformer, like healthy low frequency inductance, high resistance to distortion caused by output tube imbalance, and low distortion overall.
This type of transformer can be used with many tube types, such as 6550, KT88, KT90, 6CA7/EL34 (like Mk 2), 6B4G. It may be used with triode, pentode, or ultralinear (screen tap connection) wired tube arrangements.
Transformer specs are: 4300 ohms CT primary with screen taps, 4,8 and 16 ohm secondary. 20 Hz to 20 KHz response at 60W, within 1 db, 30 Hz to 15 KHz at 120 watts. Max DC per side (suggested) 120 ma. Exact same dimensions as the original A431 Dynaco transformer: Height 4 3/4 inches (120 mm) Width 4 inches (101 mm), Depth over covers 4 1/2 inches (114 mm), mounting centers are 3 inches (75 mm) by 3 1/2 inches (88 mm).
P782 S Power Transformer:
Replacement power transformer for Dynaco (tm) Mark 3 and Mark 2 amplifiers. Bolts directly on without modifications. Also a bolt-on replacement for 60 watt (2 6550's or KT88's) Rated 400-0-400V (800VCT) at 200 ma (actually, will deliver up to 300 ma continuous, albeit at a slightly lower voltage) , 5V at 3A, 6.3VCT at 5A, also has 60V bias tap. Primary 117VAC 60 Hz.
Transformer dimensions are 4 3/4 inches high X 3 3/4 wide X 3 3/4 inches deep over the covers, mounting hole centers are 2 7/8 inchs X 3 inches. Overseas Customers: see the dropdown menu below for our Export version 240V.
Replacement for chokes in Dynaco ST70, Mk2, Mk3 and Mk4. 1 1/2 inches (40 mm) tall on 2 3/8 inch (60 mm) mounting hole centers. 55 ohms, 1.5 henries, 10% tolerance, 2500 volt DC hipot tested, 200 ma DC. New unit made in Chicago, USA by transformer professionals with decades of experience manufacturing high voltage transformers.
Stainless Steel, Super Heavy Duty, Punched Chassis. Same dimensions as original. Our latest chassis version comes with iec power cord cut out, and holes for heavy duty binding posts, input jack, and bias point. Original or repro Mk3 cages will fit as on original. Nice stainless steel finish. Comes with top and bottom pieces. Custom built chassis made right here in the USA.
Our Mark 3 board uses a cascoded triode front-end, which gives "pentode gain with triode noise" and allows the use of a wide variety of possible tubes with pinouts same as 12AU7, by simply changing 2 resistors on the board.Our newest version includes a filament jumper allowing use of tubes with 9AJ or 9LP pinout, thus allowing use of 6CG7/6FQ7 or 6N1-P as a phase splitter with no changes required other than changing the board jumper. For more information, please see our Dynaco Page. The kit includes all off board resistors. Kits Also include Board instruction manual, but not tubes, each board requires 1 each 12AU7/ECC82 (or equivalent, 6189,5814,etc) plus one each of either 12AU7/ECC82, 12BH7, 6CG7/6FQ7 or 6N1-P. Standard coupling capacitors are Xicon metallized polypropylene. You can get Solen caps using the dropdown menu. You can also order without a driver board. See dropdown menu at bottom.
Upgrade Cap Board:
The Mk3 board increases capacity to 50-50-50-50 uF (two 100 uF in series per section)and the voltage rating to 630V per section to eliminate capacitor problems the original 525V rated cap has that are caused by high line voltages and allows the use of solid-state diode replacements as well as the original tube (5AR4/GZ34 or 5U4) rectifier. Capacitors supplied with the board + parts kits, are Panasonic TS Series parts, temperature rated 85 C. Boards measure 3 inches (approx 77 mm) wide by 4 inches ( 102 mm) long, with about 1/4 (6.5 mm) overhang on each side for mounting standoff. Tightens up the power supply for Commanding Bass.
Transformers come with manufacturer's 6 month exchange warranty on materials & workmanship.
"WITH TUBES" Option Includes: Sovtek 6550 Matched Pair, JJ GZ34/5AR4, & JJ ECC82/12AU7 x 2pcs.
If you purchase this kit with "SOLEN" capacitors, the coupling capacitors on both Driver & Power Supply Boards are upgraded from Xicon to Solen.
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