This board shouldnt be doing to the amp what it is doing. An extremely cool operating amplifier, the sca80 will deliver a full 40 watts rms per channel from 20 hz to 20 khz with both channels driven simultaneously. Mint dynaco stereo 80 st80 amplifier woriginal manual. Congratulations on your purchase of the dynaco stereo 80 amplifier. The driver circuit had a single 7199 pentodetriode tube per channel, and. The downloadable schematic has been replaced with a high resolution pdf file as of 2007. Dynaco stereo 70 tube amplifier dyna st70 el34 amp dynakit good condition. Dynaco st70 7199el34pp valve amplifier, amplifier, electronic. Dynaco st 120 upgrade info techtalk speaker building, audio.
Dynaco mark 3 dynaco stereo 70 homebrew tube amp corner faqs and. It is a new design that is intended to look like the original dynaco, but with modern performance. For more information about jims build and his impressions of the st35 kit, see the dynaco st 35 tube amp kit thread on the message forum. Phono upgrade 23 pages amplifier dynaco pas2 assembly instructions manual. Please obtain the items outlined in the following list. Arc offered kits, to remake the st70, using only the chassis and transformers. The 6bq5 output stage is pushpull and the dynakit st35 amplifier is rated at 17. Worse, direct replacements are both expensive and offer no improvement in reliability. Dynaco continued to build both mono and stereo amplifiers until 1977. Dynaco st 35 schematic service manual dynaco st 70 ii schematic owners manual dynaco st70 schematic assembly manual dynakit sca 35 schematic assembly manual. Unfollow dynaco st 70 to stop getting updates on your ebay feed.
It is still rich in the midrange, but a lot less lush sounding than the original. Tools required before you begin you should have a few basic tools on hand to help you identify and repair the problem. I bought a stocklooking used dynaco st70 that was dirty and had one bad tube. Below you will found our manuals on the dynaco dynakit st70. Any vintage stereo repair or restoration involves cleaning. Jan 25, 2009 carl dynaco st 70, nice little amp in my opinion with a few judicious updatesmods not the last word in accuracy but a nice warm tube sound kinda in the mc30 sound neighborhood for a lot less cash. The most famous product was the st 70 amplifier of which over 300,000 units were manufactured factory wired and kit combined.
This a drop in replacement for the original dynaco st70 pc3 driver board but with modern epoxy fiberglass pcb. If you dont, will takes the stock dynaco chassis, strips everything off of it and has it sandblasted and. Sound systems circuit diagrams pa amplifiers technical pages, 2x80w 2x400w. Dynaco st70 6gh8 6gh8a ecf82 driver board pcb pc3 kit. Later during the 80 s sound valves columbus, ohio bought the entire remaining inventory of original dynaco parts.
Increases both the capacitance and voltage rating to 600 vdc. Dynaco st70 will vincent includes extra tubes for sale. Follow any comments here with the rss feed for this post. 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 st 70 tube stereo amplifier. The equipment was available as both factory wired and as kit form. Some of you have complained that you want more meat technical information on audio equipment. Below you will found our manuals on the dynaco st 80. Dynaco dynakit stereo 70 tube amplifier schematic and manual electronic. Dynaco amp schematics to assist you with your amplifier repairs and modifications. The dynaco stereo 80 amplifier uses special power supply buffering circuitry found in no other brand of amplifiers in this class. In addition, we offer an array of new select dynakit classic vacuum tube. 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.
Dynaco st 120 upgrade info the schematic shows one lm3886 chip amp per channel. The dynaco stereo 80 is an all silicon transistor basic power amplifier for use with. Another common problem with vacuum tube amplifiers is the value chosen for the interstage coupling capacitors. It is being included here to allow the owner to experiment, and. In use with varying program material, the unit justifies its design efforts to.
Download the dynaco dynakitst70 manuals for free hifi. Here at dynakit you will find the right parts to restore, repair or upgrade your original dynaco vacuum tube amplifier. Heres a scan of the serviceuser manual from my collection, stereo 80 manual 9 meg download pdf. Dynaco dynakit stereo 70 st70 tube amplifier schematic. The owners manual is used as an reference guide, instruction manual and instruction book.
Dynaco stereo 80 manual stereo power amplifier hifi. Dynaco st70 capacitor board st70 power supply capacitor board this board replaces the large can capacitor in the power supply section of the dynaco st70 ampli. Service manuals, owners manuals, schematics, diagrams. Improve, renew, restore and repair your dynaco stereo 120, stereo 80, stereo 400, pat4, pat5, fm5 or af6. Ignored for years by many tube enthusiasts, due to modest power output, its become a hot item since the start of the new millennium, with new releases of complete amplifiers, clone boards, transformers, tubes and other parts. As shown in the photo on the previous page, i removed the original four section can capacitor, and replaced it with an input cap of 100 mfd its the large cap with two 50 mfd sections paralled, and two 470 mfd capacitors. The m60 mkiii c3 amp was a redesign of the dynaco mkiii. Scan of the dynaco dynakit stereo 70 st70 tube amplifier schematic from the instructions manual. If you are reading this you probably already know about his work. Output tube changes the original triode electronics board design manual included modifications to this board and to the amplifier to allow using other output tubes in a st70. Pa060s power transformer nearly twice the lamination stack size of the original, a470s output transformers, c354 choke. Lm3916n bar graph driver datasheet in pdf format, drives a 10 led bar. Ozren bilan room acoustics audio site links audiologs. This product was designed to provide the highest combination of quality and value available, which is the dynaco tradition.
It is a modified circuit, with custom wound transformers that are more than adequate. 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. Dynaco sca80 manual integrated amplifier hifi engine. As shown in the photo on the previous page, i removed the original four section can capacitor, and replaced it with an input cap of 100 mfd its the large cap with two 50 mfd. I selected the amp because i wanted to try tubes per the advice of this board and a friend of mine had restored about 8 dynaco st70s and said he would do one for me for the cost of the parts. Dynaco st 120 upgrade info techtalk speaker building. Some people would rather repair their stereo 120 without updating it, maintaining the original design. Another option is to build up the power supply from the various replacement capacitors making. It was, however, built on the exact same size chassis as the vacuum tube stereo 80, and so looked very similar to it. If the power supply doesnt work, then the amplifier certainly wont work. Our famous original dyna st70 rebuild plans by frank van. The sca 80 is a onepiece, transistorized integrated package combining the stereo 80 power amplifier with a preamplifier having all the quality and many of the features of the pat4.
This page has sca80 schematics, information about the stock sca80, and about kits. Scan of the dynaco dynakit stereo 35 st35 tube amplifier schematic from the instructions manual. 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. The unit contains two 40 watt amplifiers on one chassis with a common power supply. We hope this web page and the hints it offers could make it easier. Update 2002 test of dynaco st70 tube amplifier modifications by roy mottram note. The service manual functions as a repair guide for troubleshooting and sometimes contains tips for refurbishing and modifications. Exact replacements for the original can capacitors are difficult. All parts needed for a complete upgraded dynaco st70 type kit except for the tubes. An extremely cool operating amplifier, the sca 80 will deliver a full 40 watts rms per channel from 20 hz to 20 khz with both channels driven simultaneously. The most famous product was the st70 amplifier of which over 300,000 units were manufactured factory wired and kit combined. Dynaco stereo 80 manual stereo power amplifier hifi engine.
Plenty of dirt to clean on this dynaco st70 tube amplifier. Schematic diagram alternate ac line connections in case of difficulty service and warranty information 16 28 30 operating instructions installing your sca80q optional connections. Regretfully selling my dynaco st70 custom made by will vincent, in asnew condition. Dynaco 70speaker recommendations steve hoffman music forums. Exact replacements for the original can capacitors are dif. New dynakit st70 advice steve hoffman music forums. Later during the 80s sound valves columbus, ohio bought the. The sca80 is a onepiece, transistorized integrated package combining the stereo 80 power amplifier with a preamplifier having all the quality and many of the features of the pat4. Dynaco stereo 35 tube amplifier for sale us audio mart. Including our custom made transformers, which are made to original specs right here in the usa.
The el34 output stage is pushpull and the dynakit st70 amplifier is rated at 35 watts per channel. You can build a point to point 3886 amp for peanuts and have just as good an amp since that is where the power comes from. Triode, usa customer service mf 9am4pm ct 18007743201 email us anytime. To that great mix, dynaco added a version of their quadaptor, which allowed the recovery of 4channel ambience into rear speakers. If the dynaco st70 is great, then the heathkits are world class.
I then had the urge to try this schematic on a pair of heathkit w7s. The heart of the stereo 35 is the special dynaco z565. Our famous original dyna st70 rebuild plans by frank van alstine. 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. The kimmel design makes the st70 sound like a modern amp, much more extended highs and tight bass. Arc offered kits, to remake the st 70, using only the chassis and transformers. The dynaco sca80q was dynacos tremendously popular integrated amp. 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. Improve, renew, restore and repair your dynaco stereo 120, stereo 80, stereo 400, pat4, pat5, fm5 or af6 tuner, or. Select picture or schematic to display from thumbnails on the right and click for download.
The dynaco stereo 80 amplifier uses special power supply buffering circuitry. I have a st400 that i cannot find the trouble but it was a much more powerful amplifier. Due to coronavirus covid19 we have limited staff working on location. Modified updated dynaco st70 stereo tube power amp,repair,no tubes.
Dynaco diagrams, schematics and service manuals download for free. Instead they found a short stay in my second system coupled with an upgraded dynaco st80. Replacement cap for c11 in the driver power supply. All connections to the board are marked with the original number markings on the top and bottom silkscreen layers. Stereo 120 had an electronically regulated power supply and larger power transformer.
The dynaco driver board is the weakest part of the st70 design, and after 20 or 30 years it is due to be tossed out and replaced. It was arguably the best selling power amplifier of all time, and is arguably the most maligned such device as well. This dynaco st70 driver board pc3 has been developed and designed to be a dropin replacement for dynaco 7199 board. Dynaco st70 6gh8 6gh8a ecf82 driver board pcb pc3 kit dyna. David hafler and ed laurent founded the dyna company later dynaco with the intention of not only producing transformers, but highquality audio circuitry. High performance power supply modifications to an st35. One of the most frequent failures in the dynaco st70 is the original quad. Ce manufacturing replacement capacitor is the most common solution, but it is hard to find and expensive. Dynaco st70 repair and restoration vacuum tube power.
View and download dynaco sca 80 assembly manual online. Below you will found our manuals on the dynaco st 150. The layout was changed to use the contemporary components and 6gh8a tubes. These amps smoked the dynaco from the beginning of the bandwith to the last and final note. Download the dynaco st80 manuals for free hifi manuals. Dynaco dynakit stereo 35 st35 tube amplifier schematic and. The tubes4hifi version was done in a similar manner to this. Using classa pushpull stereo topography, versions of this amplifier in the past have been characterized as a robust, with a reliable design of exceptional value.
The dynaco st 70 surely must represent the greatest amplification paradox of all time. David hafler released the dynaco st35 twochannel power tube amplifier nearly 50 years ago as a lower cost alternative to the popular st70. Stereo headphone box takes input from one audio power amplifier and drives. Ive designed a replacement capacitor board for the st70. Bass control treble control cio 50,000 ohms special. Imagine what wed have had, back then, if hafler and johnson had formed a company. Dammig och saknar tva av fyra fotter men det ska ordnas. This entry was written by admin, posted on may 29, 20 at 3. Below you will found our manuals on the dynaco st80. Dynaco dynakit stereo 70 st70 tube amplifier schematic and. But, hey over 350,000 stock st 70s were sold, making it the most popular tube amp ever.
Dynaco st70 series 3 stereo integrated tube amplifier. One of the most frequent failures in the dynaco st70 is the original quad electrolytic capacitor. Modifications for the dynaco st70 basic amplifier stock amplifier shown. Output tube changes the original triode electronics board design manual included modifications to this board and to the amplifier to allow using other output tubes in a st 70. Hard to find parts including dynakit original dropin replacement components typically ship within 24 hours of ordering. Comments are closed, but you can leave a trackback. This introduces another large low frequency rolloff within the feedback loop. This dynaco st70 is in pretty rough shape and is in need of some repair and restoration work. The energy storage capability of the filter capacitors of the original dynaco st35 is 8. Later ones i modified but they were never part of my serious system.
Photos of a dynaco st35 tube amplifier kit from dynakitparts which was put together by jim wisconsin, usa. Dynacos st70 series 3 stereo tube amplifier produces 35 watts per channel stereo and switchable between both 4 and 8 ohm outputs. Vta driver board kit rebuild pages amplifier dynaco pat4 assembly manual. Mine has tungsol 6u8as and black plate rcas in the driver board, with gold lion kt77s and mullard rectifier. Dynaco vintage hifi service manuals available youtube. This board replaces the large can capacitor in the power supply section of the dynaco st70 amplifier. Unfollow dynaco st70 to stop getting updates on your ebay feed. Download the dynaco st150 manuals for free hifi manuals. The dynaco st70 surely must represent the greatest amplification paradox of all time. The stereo 80 was the little brother of the stereo 120. The magazine ad from 1994 below introduces the modernized vacuum tube dynaco stereo 80 and the upgrade to the pas3 preamplifier, the modernized pas4 vacuum tube preamplifier. The company was incorporated in october 1955, with business premises located at 617 n.
But, hey over 350,000 stock st70s were sold, making it the most popular tube amp ever. Dynaco stereo 120 repair information update my dynaco. Find the right dynaco parts to restore, repair or upgrade your original dynaco vacuum tube amplifier. I wrote that 6th street bridge blog post above and as a fun fixitupper, a dynaco pat is. Dec 14, 2016 david hafler released the dynaco st35 twochannel power tube amplifier nearly 50 years ago as a lower cost alternative to the popular st70. If the page is blank click here original dynaco st70 manual.
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