Here is a beautiful example of the venerable Dynaco ST-70 power amplifier. Dynaco ST-70: A Timeless Classic Audiophile Nirvana Posted on June 28, 2016 by Jim Lansing June 28, 2016 David Hafler and Ed Laurent founded the Dyna Company (later Dynaco) with the intention of not only producing transformers, but high-quality audio circuitry. The unit seemed to run fine. Back issues of Audio Amateur and Glass Audio will give you many possibilities. Heavier construction, runs cooler, gives better regulation, won't buzz & hum like some originals do. 95 Dynaco ST-70 power amplifier uses a push-pull output stage, where two tubes divide the amplification function. Many of the controls were bypassed when I bought the amp but the mods were all done really well. Please provide phone number and I will call you back. Spider webs and other things to clean under the chassis of this power amplifier. The ST-70 builds upon the proven design philosophies of the original David Hafler-designed Stereo 70, w. The results that you state are pretty much what most would get after a change. The original Dynaco ST-70 electrolytic capacitor is 55+ years old, it tend to breaking down or loosing its capacity, producing the amplifier hum. Dynaco ST-70 Series 3 Stereo Tube Amplifier David Hafler's promise is fulfilled, again. The Dynaco ST-70 Series-3 has made extensive use of the most modem parts including: precision metal-film resistors, poly-composition capacitors and miniaturized high-capacity power supply electrolytics, devices that were unavailable at the time of the original design. Is there a thread or list of the currently available power supply boards/options for the ST-70? My ST-70 project will include the DIYtube driver, cloth-lead A470 OPTs, a new toroidal power tranny. Looking for Dynaco ST-70 Power Supply Info/Specs Hi guys, I've decided to work on a car tube amp project and I'd like to use the Dynaco ST-70 as a 1st revision design. The values needed can be built up with various. You can get seriously high-end sound out of your Dynaco Stereo 120 Power Amp, PAT-4 Preamp, or SCA80 Integrated Amp. The Dynaco ST-70 surely must represent the greatest amplification paradox of all time: It was arguably the best selling power amplifier of all time, and is arguably the most maligned such device as well. (I once fixed a friend's Dynaco ST-70, which was the cleanest ST-70. Ultimate Performance Dynaco ST-70 with professionally built and assembled Curcio Audio Engineering Driver and Power Supply Premium modifications. Silk Purse Dynaco ST-70 The Dynaco Stereo 70 must be the most popular tube amplifier in the world. Each voltage regulator also finds its own raw power supply, holding the. Also, can you consider ANY Dynaco that isn't a 100% per original design a true dynaco? I have listened to and owned a few with a modified power supply. Ignored for years by many tube enthusiasts, due to modest power output, it's become a hot item since the start of the new millennium, with new releases of complete amplifiers, clone boards, transformers, tubes and other parts. Dynaco ST-70 users beware! Replace the old power cable (see A300 section. power supply regulator mini 9V 0. It can now be wired for 220 volt / 50 Hz operation. ) presents the re-launch of a legendary tube amp, the ST-70 Series 3 tube amplifier, at the 2017 High End show. Power Supply Board for the Dynaco ST-70 with "failsafe" bias and balance Revision 1, February 2012 Classic Valve Design. Bolts in to ST70. Jan Erling Veiset (Norway). Hello again, am glad that the feedback I am getting from many of you indicates that you are happy with the information and ideas I have been describing. For example, the bass response of the ST-70 can be made greater by the switch to solid state rectification as in the Dynaco ST-70 Series II(see previous articles on original Dynaco ST-70 versus Dynaco ST-70 Series II in TNT Audio). Sure, some may quibble at that characterization, but I can’t think of any other amplifier – at least within North America – that has turned on more audiophiles to the possibilities of tube amplification. A great statement, sounding tight and yet extremely charming. (I once fixed a friend's Dynaco ST-70, which was the cleanest ST-70. The goofy octals here are part of the ST-70's character, so I kept them. Dynaco (a division of Radial Engineering Ltd. The VTA ST-120 uses three custom wound USA made transformers and is available as a KIT amp or completely WIRED and TESTED. That made it easy for me to have my tech put it back to "original. ) The preamp used the amp's power supply. I only ship to the lower 48. , Dark Walnut DYNACO cabinet ), Chrome Bodied ST-70 Power Amplifier. Obviously because of it's age there may be other things in need of replacement, such as, main power supply caps, but if you aren't having any power supply problems don't needlessly spend your hard earned money. The Dynaco PAS2/3 preamp upgrade kits we offer are the best available on the market! Developed over many years, Erhard Audio is the ONLY and OFFICIAL seller of all these great upgrade kits, spare parts and more. 141) David, Glad that you made the switch to the upgraded "DynaClone" power transformer for your ST-70. It also survived three teenaged boys. Electrolytic power supply caps likely constitute the single worst liability in old audio, radio and test equipment. 95 in 1950s dollars. Dynaco Stereo 70 Power Amplifier Restoration Manual Detailed Procedure & Guide Page 1 R0 4-03 1 I. Dynaco ST-70 mystery hot power transformer - triode3 12:57:17 01/17/18 Mark Read; RE: Dynaco ST-70 mystery hot power transformer - coffee-phil 09:13:00 11/09/18 (0) RE: Dynaco ST-70 mystery hot power transformer - Audio Pete 08:56:00 11/09/18 (0) There are at least three different OEM power transformers for the ST70 - viridian 13:11:52 01/26/18. This is a story of rags to riches; turning an abused Dynaco PAS 2 into a very modern PAS 3. I found a direct replacement for this choke at Welborne Labs, located at. Both this power supply - and the Drake TR-3, now well over a half-century old - still work fine despite my having owned it decades (and some minor repair, replacement of a dried-out capacitors in the power supply) despite the fact that I've obviously abused the plate transformer. Amp vacuum tube. com on 2014-02-24, 17:11:37 (152. The great grandmother of the Ultravalve amplifier is the original Dynaco ST-70, no big surprise. Heavier construction, runs cooler, gives better regulation, won't buzz & hum like some originals do. Dynaco Stereo 70 Tube Amp Reviewed the Dynaco was a humble, affordable, easy-to-assemble work-horse which probably fed sound to more American college dormitory rooms than any amp of its era. Exact replacements for the original can capacitors are difficult to find. B-15 5AR4 diode mod I actually have a Dynaco ST-70 and the rectifier arced on power up a couple of weeks ago and I haven't turned it on since. Well known as the best-selling tube amp of all time, the iconic Dynaco Stereo 70 amplifier has been revamped and redesigned in a Series 3 model in the relaunched Hafler-Dynaco line, now under the auspices of Radial Engineering Ltd. Over 150 watts per channel (300 watts of stereo power), this stereo amplifier offers superb musical clarity and plenty of power in one compact chassis. The music flowed with a verve that. As with all Dynaco products, it is a masterclass in economy - in a relatively small footprint, we have a tube rectified (valued by many tube aficionados), adjustable bias amplifier with very good irons. The Electronic Industries ST-70 C2 was the second amplifier on the Dynaco ST-70 modification series. I have a dynaco ST-70 for sale. SOLD Please contact Jeff at 012-31712. I came to that realization the hard way. The C12DD kit dramatically increases power supply energy storage that improves output power and reduces distortion at low frequencies. in every way. Dynaco A-25 - $299. This classic tube amplifier used to be the best value on the block. 141) David, Glad that you made the switch to the upgraded "DynaClone" power transformer for your ST-70. It is highly recommended that you purchase a matched quad of power tubes for this amp. The ST-70 Series 3 tube amplifier is 35 watts-per-channel and switchable between both 4 and 8 Ohm outputs. The Dynaco PAS2/3 preamp upgrade kits we offer are the best available on the market! Developed over many years, Erhard Audio is the ONLY and OFFICIAL seller of all these great upgrade kits, spare parts and more. Tube Heater Filament Power Supply Board For DYNACO PAS2 PAS3 Pre-Amplifier. I think this may the reason they sound different. Dynaco Dynaco ST 120 Amplifiers user reviews : 5 out of 5 - 2 reviews - audioreview. Also to consider is that the choke in the power supply of the Series II was lower than that in the original ST-70. How to build Tube Power amp Dynaco ST-70. You can retain the tube rectifier or elect to use Soft-Recovery Rectifiers which allows for a power boost to as much as 45 Watts/ch for ST-70 and over 70 Watts/ch for MK-III. 99 in factory-wired form), roughly 300,000 of them were produced from 1959 to the late 1970s. The Dynaco PAS2/3 preamp upgrade kits we offer are the best available on the market! Developed over many years, Erhard Audio is the ONLY and OFFICIAL seller of all these great upgrade kits, spare parts and more. The EL34s are operated in the Ultra-Linear configuration. The power supply upgrade (similar to one offered by Joe Curcio) plus the lower limit of around 14 to 16Hz and high end limit of 20kHz while the amplifier itself has a wider frequency range helps. It uses a patented circuit of outstanding performance characteristics, along with top quality parts, including the new Dynaco Super-Fidelity A. A much improved, larger main power supply reservoir yields more solid, clean bass and rock solid imaging. Thousands of Dynaco PAS preamps and Stereo 70 & Mark-3 power amplifiers were manufactured during the 1950's thru the 1970's. Aspen Pittman. This amp keeps to the circuitry of the original Dynaco ST-70. Dynaco ST-70. The unit contains two 40 watt amplifiers on one chassis with a common power supply. Dynaco Panor Pas-3 Series. Dynaco PAS-3X Preamplifier Description: The preamplifier essentially has five parts. Dynaco PAS-4 stereo preamp schematic p. 6 ohm power resistor originally removed from your amplifier and connect one end to pin 1 of V6. Now available for those that need a little more power is the Dynaco VTA ST-120. We also wanted the ST-70 Series 3 to be relatively affordable. These SDS Labs and TriodeElectronics Power Supply boards replace the original can capacitors in Dynaco Mk3, Mk2 and ST70. 00- This includes all parts except the large chassis mounted capacitors. (2) NEW Power Supply Caps [email protected] (for Dynaco PAS Tube Preamplifier) Dynaco ST-35 stereo tube. Heavier construction, runs cooler, gives better regulation, won't buzz & hum like some originals do. "VOX" CD1000 Single CD Player. Also, can you consider ANY Dynaco that isn't a 100% per original design a true dynaco? I have listened to and owned a few with a modified power supply. "The US tube legend, the ST-70, has been sold 350,000 times. Dynaco Stereo 70 Power Amplifier Restoration Manual Detailed Procedure & Guide Page 1 R0 4-03 1 I. Dynaco PAS-3X Preamplifier Description: The preamplifier essentially has five parts. A small power amplifier, but with very good quality of sound. Scan of the Dynaco Dynakit Stereo 70 (ST70) Tube Amplifier Schematic from the instructions manual. The goofy octals here are part of the ST-70's character, so I kept them. 75A by Transistor; Reduced Hysteresis Diac-Triac Phase/Power Control. How to build Tube Power amp Dynaco ST-70. Here is a beautiful example of the venerable Dynaco ST-70 power amplifier. Next the main power supply cap was under rated on these amps and you can go as high as 50uf on the first section after the. The hum is heard through both right and left speakers. The power supply uses a GZ34 tube rectifier and C-L-C filtering. This kit converts a standard class A/B dual 6L6GC power amp to a dual EL34 power amp. The passing grade for THD plus noise is less than 0. With new tubes, the bass should be much stronger and you should hear more detail, especially the texture. To replace the bias and power supply can-cap, I installed a SDS power supply board which uses modern electrolytics. No leaking or corrosion inside. Help me bias my dynaco st-70 than the original, and b) new capacitors placed in the power supply (the SDS labs boards are great), and c) It has reasonably fresh. Amp vacuum tube. $25: Shipping is $3 (each item) for USPS First Class mail within US and $4 First Class. 75A by Transistor; Reduced Hysteresis Diac-Triac Phase/Power Control. DYNACO Dynakit Stereo 70 Instructions For Assembly Replacement power supply rev e hardware (18 pages) Amplifier DYNACO ST-70 Assembly Manual. Buy your Bare Blank on the internet. Aspen Pittman. Dynaco’s original product description: The Dynaco Stereo 120 is an all silicon transistor basic power amplifier for use with separate preamplifiers such as the Dynaco PAT-4 or PAT-5, or for use with tape recorders or tuners such as the FM-5 or AF-6, which have their own volume controls. I'm selling my complete Welborne Labs Alan Kimmel designed Mu Stage Driver kit for the Dynaco ST-70 v1. I have chosen to compare a Dynaco/Dynakit ST-70 tube amplifier (Fig. No modifications required, wires have identical color coding as the original unit. The ST-70 Series 3 is not a simple remake of the original Dynaco Stereo 70. Review By Jeremy R. Dynaco ST 80-These are great power amps and a lot of people think they actually sound better than 120’s. Radio transmitters. Try a Quad in your ST-70, Marantz 8B, MArantz 9, QuickSilver MX-190 (Octet), or a Pair or Quad in your Marshall or any Guitar amplifier that uses El34 tubes. Another option is to build up the power supply from the various replacement capacitors making. The advantage of this choice is that original Dynaco accessories (such as the tube cage) can still be purchased and will fit. The Dynaco ST-70 is quite competent, and definitely lower priced than the amps it challenged in its day. Bias Repair Kit: Capacitors, diode & terminal for repairing bias supply. The blue power switch lamp/bulb was replaced. Dynaco ST 120- $195. The ST-70 Series 3 tube amplifier is 35 watts-per-channel and switchable between both 4 and 8 Ohm outputs. The unit contains two 40 watt amplifiers on one chassis with a common power supply. I cooked-up a nice modification for the A700 I think you will like very much. The fuse was on one 120-V leg, and the power switch on the other leg. For either ST-70,Mark 4, Mark 3 or Mark 2. Frequency response of both amps is rated at 20Hz-20kHz but is achieved very differently. The Dynaco ST-70 surely must represent the greatest amplification paradox of all time: It was arguably the best selling power amplifier of all time, and is arguably the most maligned such device as well. On the last page of the C22 Service Manual, there are some schematic notes 9300 • Dynaco PAS-2 • Pro-. dynaco st-70 hi end mica / metal film capacitor upgrade kit. Retailing for $99. The newsletter from July 29 1974 is announcing the release of the ST-70 factory rebuild, but that never actually happened. Introduced in 1959, the 35 watt per channel Stereo 70 (or "ST-70") was sold until mid-1990. Modifying an Original ST-70 the K&K Audio Upgrade Mk II Circuitry. The first Dynaco ST-70 wasn't called a Dynaco ST-70 Series 3. Aspen Pittman. Dynaco ST-70. Apr 28, 2019- This Pin was discovered by jane smith 20,000+ pins linked, ADD ME NOW!!. Internally, the chassis added much better parts and better power supply regulation. The amp has a slight hum with the volume control on my preamp turned all the way down. new power supply board was actually a much better design than the original circuitry that Dynaco used for the ST-70. The dynakit ST70 input stage uses a 7199 tube. After reading Louis Chochos, the owner of Omega Speakers, positive review of Bob's upgraded Dynaco ST-70 power amp on the Omega Speaker Forum I got in contact with Bob to get more information about his amp. Dynakit ST-70 Ampl/Mixer Dyna Co. Since acquiring the legendary Hafler and Dynaco brands in 2014, Radial Engineering has been carefully working on the Dynaco ST-70 Series 3 tube amplifier, in an effort to create a truly worthy successor of one of the most. A Dynaco SCA-35, after bypassing the tone controls and adding the simple EFB™ bias mod, has passed the VTA ST-70 above as my "go to" tube amp. Tube Heater Filament Power Supply Board For DYNACO PAS2 PAS3 Pre-Amplifier. The unit contains two 40 watt amplifiers on one chassis with a common power supply. Also known as “Supply B” on the original Dynaco power supply schematic. They rearranged the pins, gave the audio companies an ultra cheap price for OEM use, then guaranteed themselves an exclusive market for replacements. จากรูปวงจรต้นแบบไม่ชัดนักต้องขออภัยมา ณ. A stock ST-70 uses the front panel power The bias supply and controls can be removed, as they are. $25: Shipping is $3 (each item) for USPS First Class mail within US and $4 First Class. The power supply, long considered one of the original 70's weaker points, has been substantially revamped; the power transformer is now larger and better-regulated, the smoothing capacitance has been increased from 90 to 336µF, and the hard-to-find 5AR4 rectifier tube has been replaced with four 1N4006 diodes configured as a full-wave bridge. The scan below is the Dynaco Dynakit Mark III tube amplifier schematic from the instructions manual. On the other hand, I would strongly recommend a power supply upgrade at the same time you do an input board. The gallery has most of the pictures. Jan Erling Veiset (Norway). Greater capacitance in the power supply provides more bass and energy to musical passages. The results that you state are pretty much what most would get after a change. These newer parts are more conservatively rated than some of the original parts. SOLD Please contact Jeff at 012-31712. LB: How does an upgraded Dynaco ST-70 compare to a fully-modern AVA amplifier? FVA: Our Ultimate 70, with a complete new mother board of our own design, including four regulated power supplies, for the original Dyna ST-70 vacuum tube amplifier, within its 35W/Ch power limits, compares very well to the very best amplifiers out there of any design. The fuse was on one 120-V leg, and the power switch on the other leg. dynaco pat-5 pc-32 power supply capacitor kit. This classic tube amplifier used to be the best value on the block. One Heathkit W7-M Mono Tube Power Amp. The EL34 output stage is push-pull and the dynakit ST70 amplifier is rated at 35 Watts per channel. Nickel plated frame has been replaced, no rust. Dynaco ST 80- $175. Recently, I got bitten by the nostalgia bug and picked up a pair of old factory-wired Dynaco ST70s in pretty nice condition. I bought a stock-looking used Dynaco ST-70 that was dirty and had one bad tube. The ST-70 builds upon the proven design philosophies of the original David Hafler-designed Stereo 70, w. The unit seemed to run fine. Retailing for $99. In fact, there are tens of thousands of the original Dynaco tube amplifiers still in use around the world. The original Dynaco design had an ungrounded, non-polarized line cord. Dynaco Stereo 70 for sale. I found a direct replacement for this choke at Welborne Labs, located at. I actually got the idea from a post in the Bottlehead forum. 1968 Sunn. The refined Class AB Ultralinear Pentode circuit has given it fantastic sound and high reliability. Dynaco ST-70 amp (restored) "Stacked Advent" speakers; I hooked up the PAT-5 without the cover (just in case) and plugged in the turn table. 184: Dynaco ST-70 Power issues (3. The input circuit below realizes an equal power supply noise distribution by halving the power supply noise at the first triode's plate, as one half noise subtracts from one noise to yield one half noise at both outputs. I received my Dynaco St70 SeriesII+ today and fired her up. " It took a marginal amp and made it great. Steve; Yes the ST-70 is known for somewhat loose bass due to power supply limitations and too much gain on the low end. The goofy octals here are part of the ST-70's character, so I kept them. Dynaco PAS-4 stereo preamp schematic p. power supply circuit; Amplifier Circuit; Basic Circuit; LED and Light Circuit; Sensor Circuit; Signal Processing; Electrical Equipment Circuit; Control Circuit; Remote Control Circuit; A/D-D/A Converter Circuit; Audio Circuit; Measuring and Test Circuit; Communication Circuit; Computer-Related Circuit; 555 Circuit; Automotive Circuit; Repairing. 3 volts for rated power but I found that it severely distorted there. As with all Dynaco products, it is a masterclass in economy - in a relatively small footprint, we have a tube rectified (valued by many tube aficionados), adjustable bias amplifier with very good irons. Many of the controls were bypassed when I bought the amp but the mods were all done really well. Retailing for $99. com on 2007-12-30, 08:41:29 (64. It uses Class-A push-pull stereo topography that has long been characterized as a robust, reliable design of exceptional value. Dynaco never gave a parts layout on their PC-3 driver board for the ST-70. 00- This includes all standard parts with the exception of the chassis mounted capacitors. The great grandmother of the Ultravalve amplifier is the original Dynaco ST-70, no big surprise. Power supply section has been rebuilt with a brand new Authenticap can capacitor, as. Ode to the ST-70 The ST70 is a beautiful and historic amplifier (and surprisingly compact if you see one in person). Dynaco ST-70 Series 3 Amplifier. One output tube handles the positive-going signal and the other the negative-going signal. Here is a beautiful example of the venerable Dynaco ST-70 power amplifier. Dynaco is best known for its highly regarded Stereo 70 vacuum tube amplifier. FOR SALE - Boston, MA - Dynaco ST-70 tube stereo power amp in full working condition. Dynaco Dynaco ST 120 Amplifiers user reviews : 5 out of 5 - 2 reviews - audioreview. This power supply contains a full-wave rectifier and a power transformer. I paid $250 for the amp shipped (it cost $50 to ship, so I'm pretty happy with the deal), and. The VTA ST-120 uses three custom wound USA made transformers and is available as a KIT amp or completely WIRED and tested. A Dynaco SCA-35, after bypassing the tone controls and adding the simple EFB™ bias mod, has passed the VTA ST-70 above as my "go to" tube amp. 1959 ~ 1980 (?) I decided to replace them all in order to make sure the power supply is up to par and will last for many more years. The Ultravalve is our lovely looking and playing pure tube amplifier with a polished stainless steel chassis and a silver anodized faceplate. The input circuit below realizes an equal power supply noise distribution by halving the power supply noise at the first triode's plate, as one half noise subtracts from one noise to yield one half noise at both outputs. This amp was designed to be inexpensive and to get maximum performance for dollar paid. The original Dynaco ST-70 had a 30, 20, 20, 20 uF quad cap for DC storage. The kit uses all new parts (stainless steel chassis WOW!) and modifications in crucial areas also. Obviously because of it's age there may be other things in need of replacement, such as, main power supply caps, but if you aren't having any power supply problems don't needlessly spend your hard earned money. Also to consider is that the choke in the power supply of the Series II was lower than that in the original ST-70. Dynaco has addressed this problem as follows: Use of an entirely new and larger dual primary power transformer with improved line regulation (due to added iron in its core). Maybe better power supply filtering is in order? Conclusions I hope to perform some listening tests on the ST-70. The Dynaco (or Dynakit) Stereo 70 (also known as the ST-70) vacuum tube amplifier was one of the most popular tube amps of its time. For either ST-70,Mark 4, Mark 3 or Mark 2. The driver board is upgraded to use 3 -12at7`s and has a bias adjustment for all 4 power tubes. My equipment is a Heathkit IB2-A impedance bridge. The power supply is one part and is common to both channels. Continuing my quest for quality music, I ordered a Dynaco VTA ST-120 tube amplifier kit from Bob Latino at www. pdf http://www. They completely did away with the factory Dynaco circuitry in the ST-70, using only the chassis and transformers from the original amplifier - the result was a stellar amplifier unique in tube amp history. JUST REBUILT FOR You Dynaco St-70 Stereo Tube Amplifier - NEW Chassis! - $850. ? ? A driver module based on the Mapletree Special Red SR-70 board developed for the Dynaco ST-70. Dynaco ST-70 Repair And Restoration. This transformer weighs about 5 pounds more than an original PA-060 power transformer. Here at Dynakit™ you will find the right parts to restore, repair or upgrade your original Dynaco™ vacuum tube amplifier. Blue groove tube El-34's. Power controllers, thermometers, heat How to build Tube Power amp Dynaco ST-70 - circuit diagram Power supplies. For Power Amps, see GA 1:1989 (Joe Curcio's Stereo 70 with solid state power supply regulation) GA 2:1989 (Paul Becker's simple Mark IV mods), and GA 1:1992 (Norman Koren's Stereo 70 triode mode mod). Dynaco™ replacement parts & vacuum tube audio amplifier kits. Boards for the Dynaco ST-35 Power Amplifier: ST-35 *EFB™ Power Supply Board Convert your ST-35 from cathode bias to Enhanced Fixed Bias for increased output power, lower distortion and extended tube life. Tube stereo power amplifier. The measurements are on a par with a typical, modestly designed tube amplifier. The unit contains two 40 watt amplifiers on one chassis with a common power supply. com on 2014-02-24, 17:11:37 (152. 00 GE Interlogix 515R1 Card Cage 15 Slots with 6 Amp Power Supply. Dynaco ST-70 Power Supply Board. Plenty of dirt to clean on this Dynaco ST-70 tube amplifier. It's pretty much the same circuit as the original, but with easier to get tubes than the 7199. Today, Dynaco is best remembered for its highly regarded vacuum tube stereo amplifier, the Stereo 70 (ST 70). $25: Shipping is $3 (each item) for USPS First Class mail within US and $4 First Class. By combining outstanding output transformers with simple but effective circuitry, they deliver audible performance that is comparable to some of today's highly regarded amps and preamps costing much more. It had the the new power capacitor mod but other than that was stock. The ST-70 builds upon the proven design philosophies of the original David Hafler-designed Stereo 70, with contemporary design techniques resulting in exceptional performance improvements that meet the requirements of modern audiophiles. or if a large. " More than 350,000 ST-70 amplifiers had been sold when production finally ceased, making the ST 70 the most popular tube power amplifier ever made. The original Dynaco design had an ungrounded, non-polarized line cord. The power supply uses a GZ34 tube rectifier and C-L-C filtering. Everything powered uo OK and both left and rifgt bias leds are light. I just bought a Dynaco ST-70. Dynaco Panor Pas-3 Series 2 Ii Phono Mc Mm Tube Preamp W/ External Power Supply. A small power amplifier, but with very good quality of sound. Dynaco Stereo 70 for sale. A good test bench for this idea is the Dynaco ST-70, as the 6SL7 and 6SN7 could fill the two front 8 pin sockets and two 6550s could fill in the two back sockets. The Dynaco ST-70 is quite competent, and definitely lower priced than the amps it challenged in its day. It was built and modded by Richard Gray, the power supply guy. 1968 Sunn. The unit contains two 40 watt amplifiers on one chassis with a common power supply. This one has four 6550 output tubes, driving a (potted, 23 lb) Dynaco A-451 OPT. A matched pair of EL34 tubes is included with the kit. This indicates either a restriction in the power supply (open or high resistance windings in transformer or choke, bad rectifier tube) or excessive current draw (caused by leaky filter capacitors, or shorts in tubes or output transformers) pulling down the voltage. "The US tube legend, the ST-70, has been sold 350,000 times. Well, as you remember I bought a Dynaco ST-70 off ebay. As soon as we announced the price, the first reaction from the audiophile community was that it was not expensive enough. 37) Posted by [email protected] The HIGH END show 2016 in Munich marks the re-launch and advanced design of the newest iteration of the Dynaco Stereo 70 (ST-70). Dynaco (a division of Radial Engineering Ltd. The ST-70 builds upon the proven design philosophies of the original David Hafler-designed Stereo 70, with contemporary design techniques resulting in performance improvements that meet the requirements of modern audiophiles. Triode Electronics Dynaco ST-70 Input Board. Heavier construction, runs cooler, gives better regulation, won't buzz & hum like some originals do. They were originally power takeoffs for a Dynaco preamp (I can't remember which one off-hand. Now these aren't True Dynaco's either but rather an upgrade from the original. Little off the guitar path, but does anyone use a dynaco st 70 for their hifi amp at home? Any recommendations for this unit? The modded ones are an option also. The original Dynaco ST-70 electrolytic capacitor is 55+ years old, it tend to breaking down or loosing its capacity, producing the amplifier hum. Introduction This document provides a step by step instruction for rebuilding and restoring the Dynaco Stereo-70 power amplifier. The Dynaco (or Dynakit) Stereo 70 (also known as the ST-70) vacuum tube amplifier was one of the most popular tube amps of its time. This amp was designed to be inexpensive and to get maximum performance for dollar paid. Yamaha B-4 Stereo Power Amplifier Used Japan 100v Gt-2000 Yal Phono Vintage Mc. Dynaco ST-70 mystery hot power transformer - triode3 12:57:17 01/17/18 Mark Read; RE: Dynaco ST-70 mystery hot power transformer - coffee-phil 09:13:00 11/09/18 (0) RE: Dynaco ST-70 mystery hot power transformer - Audio Pete 08:56:00 11/09/18 (0) There are at least three different OEM power transformers for the ST70 - viridian 13:11:52 01/26/18. David Hafler released the Dynaco ST-35 two-channel power tube amplifier nearly 50 years ago as a lower cost alternative to the popular ST-70. We now have a Killer Mic Preamp Project with our new ST70 EF86 board. We use the original power transformer. I used some of the original parts and fabricated a new chassis and cabinet. They rearranged the pins, gave the audio companies an ultra cheap price for OEM use, then guaranteed themselves an exclusive market for replacements. Our Famous Original Dyna St-70 Rebuild Plans From Audio Basics, July, 1982 Article By Frank Van Alstine www. Dynaco Panor Pas-3 Series 2 Ii Phono Mc Mm Tube Preamp W/ External Power Supply. JUST REBUILT FOR You Dynaco St-70 Stereo Tube Amplifier - NEW Chassis! - $850. Any vintage stereo repair or restoration involves cleaning. The HIGH END show 2016 in Munich marks the re-launch and advanced design of the newest iteration of the Dynaco Stereo 70 (ST-70). Dynaco ST-70 , rentegnet Dynaco dynakit Mark IV Tube Amplifier Schematic and Instructions Manual for Assembly and Operation. This particular PAT-5 is annoying my neighbors happily via a pair of JBL L-166s and an SAE 2200 power amplifier, with a total system cost of around 500 bucks, including the cost of the Technics SL-1200 table I picked up at a garage sale. The Dynaco Dynakit Mark III amplifier is rated at 60 Watts. The results that you state are pretty much what most would get after a change. ) The preamp used the amp's power supply. This Dynaco ST-70 is in pretty rough shape and is in need of some repair and restoration work. Also known as "Supply B" on the original Dynaco power supply schematic. It uses Class-A push-pull stereo topography that has long been characterized as a robust, reliable design of exceptional value. Ignored for years by many tube enthusiasts, due to modest power output, it’s become a hot item since the start of the new millennium, with new releases of complete amplifiers, clone boards, transformers, tubes and other parts. Företaget grundades 1954 av David Hafler (1919–2003). It has an internal 1kHz generator. The VTA ST-120 uses three custom wound USA made transformers and is available as a KIT amp or completely WIRED and TESTED. Modifying an Original ST-70 the K&K Audio Upgrade Mk II Circuitry. Amount of DC storage on the amp > This, in my opinion, was the major limiting factor on power output for the Dynaco ST-70. Original circuit board with upgrades to power supply with sheldon stokes circuit board for increased capacitance and solid state rectifier up-grade. Of couse we also sell the replacement aluminum can capacitors as well. Price-wise and power-wise, the Stereo 120 is the equivalent of a pair of Dyna Mark IIIs, but there the comparison ends. The Dynaco PAS2/3 preamp upgrade kits we offer are the best available on the market! Developed over many years, Erhard Audio is the ONLY and OFFICIAL seller of all these great upgrade kits, spare parts and more. The Dynaco Mk III monoblock was introduced by Dynaco was back in 1957, just after the Mk II and the PAM-1 pre-amp and two years before the famous ST-70. A separate rectifying system is used to provide direct current to heat the filaments of the tubes. Recently, I got bitten by the nostalgia bug and picked up a pair of old factory-wired Dynaco ST70s in pretty nice condition. It can now be wired for 220 volt / 50 Hz operation. The MV 50 was one of Conrad-Johnson’s earliest vacuum-tube power amplifiers, utilizing EL34/6CA7 output tubes, with a modest power output of 45 watts per channel. It also survived three teenaged boys. Electrolytic power supply caps likely constitute the single worst liability in old audio, radio and test equipment. Both are reproduced equally by the output stage.