Today, dynaco is best remembered for its highly regarded vacuum tube stereo amplifier, the stereo 70 st 70. Said to be the most popular tube amplifier ever made, the dynaco stereo 70 has been around for over thirtyfive years. Dont get me wrong, the mcintosh 240 is a wonderful amp with a superior build quality and measures better than the dynaco at the frequency extremes. Dynaco st70 6gh8 6gh8a ecf82 driver board pcb pc3 kit. In fact, the stereo 70 has gone on to have a life of its own long after the. We have 3 dynaco stereo 70 manuals available for free pdf download. The underside of the dynaco st70 chassis with all parts now removed. 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. One of the most frequent failures in the dynaco st70 is the original quad electrolytic capacitor. The money would be better spent in another amp altogether.
We like to think of the st70 series 3 as the update that david hafler would have made if he were alive today. The venerable dynaco stereo 70 by dan schmalle from valve issue 3, march 1994 said to be the most popular tube amplifier ever made, the dynaco stereo 70 has been around for over thirtyfive years. The original stereo 120 crossover distortion harmonics are down 6070 db. Its early popularity was due to a reasonable price coupled with good quality iron and a sound seemingly liked by all. This kit will replace the original dynaco driver circuit and printed circuit board, using the excellent sounding 6sn7 triode. Dynaco st70 6gh8 6gh8a ecf82 driver board pcb pc3 kit dyna. Dynaco stereo 70 series ii amplifier manual keywords. Why start with an amp you have to mod, when ours comes fully loaded.
Apr 17, 2012 but the original sound had more character. Stereo 120 had an electronically regulated power supply and larger power transformer. Its mounting holes and connections points are identical to the dynaco pc3 making installation and wiring a snap. The dynakit stereo 70 is a complete dual 35 watt power amplifier kit which offers the highest possible fidelity, at low cost and in a compact arrangement.
A custom dynaco st70 kit diy audio electronics from. I plan on doing some of the necessary upgrades, but keep it as original as realistically possible. I dunno if i was to buy a stereo 70 these days, i may just keep the circuit stock, but just change the electrolytics out and upgrade the bias supply. Later versions, especially with the black cage had a fancy dynaco logo on the chassis and cage. Dynaco stereo 70 series ii amplifier manual created date. Go a bit furtherimproved power supplies and better inputdriver stagesand a modified stereo 70 can embarrass most of whats out there in the subthou solidstate world. The easiest way to repair and restore these amps is start from the bare chassis and rewire the whole thing using new stranded wire. Here at dynakit you will find the right parts to restore, repair or upgrade your original dynaco vacuum tube amplifier. Dynaco stereo 80 manual stereo power amplifier hifi engine. One of the reasons for its popularity has been the wide array of modifications offered for the 70. This entry was written by admin, posted on may 29, 20 at 3.
Introduced in 1959, the st 70 was available as a kit dynakit intended for assembly by the purchaser or as a complete factorywired unit dynaco. Dynaco stereo 80 manual stereo power amplifier hifi. Worse, direct replacements are both expensive and offer no improvement. The original dynaco stereo 70 is a true classic that is still regarded with awe by audio enthusiasts worldwide. Below you will found our manuals on the dynaco st 70. Dynaco stereo 70 ii power amplifier manufacturers comment. Dynaco stereo 70 manual stereo power amplifier kit. Pa060s power transformer nearly twice the lamination stack size of the original, a470s output transformers, c354 choke. The tubes4hifi recreates the chassis exactly as it was aside. This board is a must for any serious restoration of the dynaco stereo70 to full stock condition. Restoration module this is an exact replacement for the original dynaco pc3 board fabricated from milspec materials.
They sounded great, to my amazement though, my dynaco stereo 70 produced a deeper soundstage and had a bit more midrange clarity. The price is 30x its original retail, but we think this is a steal for someone that wants to put a cherry on their audio collection by. You could built it yourself or buy one complete but this 35 watt per channel amp changed audio forever. It doesnt get more classic than a dynaco stereo 70. First is our stereo70 upgrade system on board sob a complete amplifier on pc board. In 1959, dynaco embraced the stereo revolution with the stereo 70. Find the right dynaco parts to restore, repair or upgrade your original dynaco vacuum tube amplifier. The unit contains two 40 watt amplifiers on one chassis with a common power supply. Improve, renew, restore and repair your dynaco stereo 120, stereo 80, stereo 400, pat4, pat5, fm5 or af6 tuner, or sca80q highend sound on a budget. The schematic is a technical drawing or diagram of your system, a perfect supplement to the service manual.
Dynaco stereo 70 manual stereo power amplifier kit hifi. He is heading to a retirement village and cant take it along. The dynaco st70 surely must represent the greatest amplification paradox of all time. Youll get one pcb, all resistors and capacitors, two ceramic tube sockets and one matched pair two tubes of nos 6gh8a. This dynaco st 70 driver board pc3 has been developed and designed to be a dropin replacement for dynaco 7199 board. Hard to find parts including dynakit original dropin replacement components typically ship within 24 hours of ordering. Dec 06, 2014 the st 70 is a great relatively inexpensive introduction to what tubes can do and it gets you about 75% to true audio nirvana that last 25% is quite a slog, cant say ive completely made it there. The easiest way to repair and restore these amps is start from the bare chassis and rewire the. The pc board has been carefully routed and optimized with advanced circuit. Unfollow dynaco st70 to stop getting updates on your ebay feed. Legendary dynaco st70 has been relaunched the absolute. Arc offered kits, to remake the st70, using only the chassis and transformers. The heathkits have solid state rectification where the dynaco is tube rectified. Follow any comments here with the rss feed for this post.
You can get seriously highend sound out of your dynaco stereo 120 power amp, pat4 preamp, or sca80 integrated amp. These shipped complete so everythings in there including the original mullard el34s. Our st70 kit is one of the best stereo tube amps of all time. The st70 used four el34 output tubes, one gz345ar4 rectifier tube, two 7199 input driver. The owners manual is used as an reference guide, instruction manual and instruction book. For a generation who adored it, there have been those in following generations who are quite vocal about it, to the point that the only.
Most were kits and 90% of the ones i have seen were assembled by amateurs that did a terrible job of wiring and soldering. With production starting in 1959, by the late 1960s hundreds of thousands of dynaco stereo 70 power amplifiers were in use worldwide, more than any other stereo power amplifier. The st 70 used four el34 output tubes, one gz345ar4 rectifier tube, two 7199 input driver. Dynaco pas 3 stereo tube preamp wphono new 12ax7 tubes tested 1910. Tube replacement for dynaco st 70 audiogon discussion forum. Legendary dynaco st70 has been relaunched the absolute sound. Unfollow dynaco st 70 to stop getting updates on your ebay feed. Download the dynaco st 70 manuals for free hifi manuals.
You also requested a simple and reliable power supply module. Unfollow dynaco stereo 70 to stop getting updates on your ebay feed. Dynaco st 120 upgrade info techtalk speaker building. The st70 series 3 marks the introduction of a third generation of vacuum tube products bearing the dynaco name. Btw, one of my clients is the owner to all the acrosound dynaco iron tooling, papers, patents magnequests mike lafevre who i have talk with. To add confusion to all of this, over the years the power transformer also changed. Overall i am in love with the new sound of my st70.
And in the 1990s, about 25 years after their heyday, there were still many thousands in use internationally. Over 300,000 of the st70s were produced, and more continue to be built as kits from companies like tubes4hifi and triode electronics. These amps smoked the dynaco from the beginning of the bandwith to the last and final note. The dynaco st 70 surely must represent the greatest amplification paradox of all time. After all, every major audiophile publication in the world has rated the st. The m60 mkiii c3 amp was a redesign of the dynaco mkiii. You could built it yourself or buy one complete but this 35 watt per channel amp changed audio. The dynaco stereo 120 was the first powerful 60 wattschannel transistorized stereo power amplifier in wide production. Imagine what wed have had, back then, if hafler and johnson had formed a company. If the dynaco st 70 is great, then the heathkits are world class. If one wants good high frequency performance then one must have very small output. I built one of these about 4 years ago and foolishly sold it.
The stereo 80 was the little brother of the stereo 120. Stereo 70 owners manual full stereo 70 repair guide. In the case of the dynaco st70 for example see attached schematic. I am really just talking about the feasibility of throwing another whole run of upgrades into the dynaco stereo st 70, which he just upgraded. It just does not put out enough punch and power for the klf 30s. Download the dynaco st70 manuals for free hifi manuals. Dynaco st70 tube amp, upgraded, improved, restored, ex sound, usa, fresh tubes. Dynaco stereo 70 completed rebuild classic tube audio. Dynaco st70 series 3 advanced classic tube amplifier ruckkehr. Well known as the bestselling 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. Everything driver, bias supply, quad cap, filters is included. Soi will, one way or another, keep this little legacy going. If, as you say, you want to find the bestsounding affordable tube gear, the new stereo 70ii should have lit your fire. Arc offered kits, to remake the st 70, using only the chassis and transformers.
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 st70 is a great relatively inexpensive introduction to what tubes can do and it gets you about 75% to true audio nirvana that last 25% is quite a slog, cant say ive completely made it there. In fact, there are tens of thousands of the original dynaco tube amplifiers still in use around the world. Dynaco stereo 70 manuals manuals and user guides for dynaco stereo 70. It uses a patented circuit of outstanding performance characteristics, along with top quality parts, including the new dynaco superfidelity a470 transformers the finest available. The dynaco st 70 series 3 tube amplifier is 35 watts per channel and switchable between both 4 and 8 ohm outputs, with classa pushpull stereo topography, that has long been characterized as a robust, reliable design of exceptional value. Restoration manual, owners manual dynaco stereo 70 restoration manual 20 pages. If the dynaco st70 is great, then the heathkits are world class. The phono preamp upgrade kit increases signal to noise ratio by between 4 and 8. Dynaco st 120 upgrade info ive got a question in to them, for some details but after spending some time on the site, im pretty sure ill go ahead w updating my dead stereo 120 as well. I compared it to a scott lk150 in the past before the upgrade the lk150 stock sounded much clearer and more transparent. May 09, 2016 dynaco senior engineer dan fraser explains. The dynaco st70 series 3 tube amplifier is now finally.
The dynaco stereo 80 is an all silicon transistor basic power amplifier for use with separate preamplifiers such as the dynaco pat4 or pat5 or for use with tape recorders or tuners such as the dynaco fm5 which have their own volume controls. On another note it wasnt until the upgrades that i started to notice the limitations of the dynaco 70. It uses the 7199 circuit from the original it is not a redesign using the inferior 6gh8. This board is a must for any serious restoration of the dynaco stereo 70 to full stock condition.
Introduced in 1959, the st70 was available as a kit dynakit intended for assembly by the purchaser or as a complete factorywired unit dynaco. The early dynaco logo said dynakit stereo 70 on the chassis and cage. Dynaco stereo 70 kit your eyes are not deceiving you. My uncle had the stereo 120, pat4 preamp, fm3 tuner, and a25 loudspeakers. The venerable dynaco stereo 70 by dan schmalle from valve issue 3, march 1994. The amplifier modules are built on high quality 2layer fr4 pc boards. The kit seems well thought out and seems to be a bargain to me.
Which dynaco st 70 mod 2channel home audio the klipsch. There is a difference between the two amps besides the transformers. Below you will found our manuals on the dynaco st70. View and download dynaco stereo 70 owners manual online. All parts needed for a complete upgraded dynaco st 70 type kit except for the tubes. Comments are closed, but you can leave a trackback. All parts needed for a complete upgraded dynaco st70 type kit except for the tubes. The dynaco or dynakit stereo 70 also known as the st70 vacuum tube amplifier was one of the most popular tube amps of its time. Including our custom made transformers, which are made to original specs right here in the usa. The dynaco st70 amps were available in either factory built or in kit form. Id imagine that the venerable dynaco st70 is the most well recognized tube amp in the world.
I have to say i enjoyed the upgraded sound more than the stock sound, which i found a bit too warm and fuzzy along the edges. The ava enhanced pure vacuum tube amplifier for your original dyna st70 chassis. It was introduced in 1959 and was sold until mid1990. We also offer an array of new select dynakit classic vacuum tube amplifier kits based on the. In addition, we offer an array of new select dynakit classic vacuum tube. Updatemydynaco makes audiophile kits that make your dynaco stereo 120 power. Introduced in 1959, the st 70 was available as a kit dynakit intended for assembly by the purchaser or as a complete factorywired unit. Dynaco is best remembered for its highly regarded vacuum tube stereo amplifier, the stereo 70 st70. They also manufactured other tube and solid state amplifiers, preamplifiers, radio tuners and. Dynaco st70 series 3 advanced classic tube aplifier. We have a new in box, unopened dynaco stereo 70 kit from 1963.
Many of you have requested that we develop modules to upgrade the existing dynaco design as opposed to our complete modification package. Following is the frequency response of a professionally upgraded st70 with the. Our offerings have the most requested upgrades we sell, built right in. Our famous original dyna st70 rebuild plans by frank van alstine. Founded by david hafler and ed laurent in philadelphia, pennsylvania in 1955, dynaco was an american hifi audio system manufacturer popular in the 1960s and 1970s for its wide range of affordable, yet high quality audio components its best known product was the st70 tube stereo amplifier. All the parts are through hole no surface mount parts, and the pc card is. It was arguably the best selling power amplifier of all time, and is arguably the most maligned such device as well.
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