Dynaco ST-70 kit or wired amp New with warranty | | Asking Price: | $625.00 | | Original Price: | $0.00 | | Condition: | NewItem Condition Descriptions- New
Brand new and factory sealed in the box. - Excellent
Perfect in every way. Indistinguishable from a new product but not factory sealed. - Very Good
Used but with no major damage anywhere. Item works as new and has no visible damage. - Good
Used with 1-2 minor scratches anywhere on the item. Item works as new. - Fair
Well used with minor scratches anywhere on the item. May have minor functional issues. - Parts Only
Does not work, use for parts only.
| | Location: | Sturbridge, MA | | Included Items: | |
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| Description: | Up for sale is an ALL NEW Dynaco Stereo 70 in KIT form. There are no "recycled parts" from an original Dynaco ST-70. Now you can BUILD YOUR OWN ST-70 on a new type 304 STAINLESS STEEL CHASSIS FRAME with stainless steel hardware. Although looking near stock, this ST-70 KIT has several upgrades which make it a more reliable and much better sounding amp.
1. The new STAINLESS STEEL chassis is identical in size, shape and markings to the older original nickel plated steel frame. This upgraded chassis is NON-MAGNETIC and removes any magnetic interference effects of a steel chassis on the audio circuitry. Stainless steel bottom cover with four hard rubber chassis supports also included.
2. The new power transformer has a 5/8 inch higher stack lamination and is rated for 120 volts instead of 115 like the old design. The two tube heater legs are rated for 5 amps each instead of 3 amps each like the old design. This beefed up transformer allows the use of 6L6, KT66, KT77, KT88 or 6550 output tubes in place of the standard EL34 tubes for a slightly different tonal presentation.The transformer sits on 4 neoprene isolation mounts to prevent any mechanically generated transformer noise from entering the chassis.
3. The A-470 output transformers are brand new USA made custom production transformers. They use the same interleaved/layer winding technique as the original cloth lead A-470's and incorporate high quality silicon steel M-6 grain oriented laminations. They are dimensionally accurate to the original design and have a durable heat resistant black finish.
4. The old stock 30, 20, 20, 20 electrolytic quad cap (90 Mfd total) which had marginal storage capacity for this amp has been replaced by a 80, 40, 30, 20 quad cap for almost double the power storage capacity. In conjunction with the 88 Mfd to power the driver board this amp has 258 Mfd of power storage - almost 3 times what the old amp had.
5. The upgraded VTA driver board uses three new 12AT7 triodes in place of the two mediocre sounding 7199 pentode/triode tubes. Dynaco saved money using a two tube 7199 board design but made some serious compromises in sound quality. The VTA triple triode board, however, features a long-tailed phase splitter/driver design with less feedback for noticeably better sound than the old design. No more soggy bass and rolled off top end. The older ST-70 design had one bias control for each channel whereas the VTA board has a separate bias control for each of the four output tubes. This design allows for individual adjustment of each output tube bias. Matched pairs or quads of output tubes are not necessary with this design. Quality Sprague 716P "orange drop" coupling caps are included with the board.
6. The input jacks are gold plated and have a wider spacing to allow for newer design thicker interconnects.
7. The output jacks are modern gold plated 5 way binding posts. They may be set up for 4, 8 or 16 ohm speakers.
8. The 7 octal tube sockets are modern high quality Micanol sockets with cadmium plated pins. These sockets are very durable and more reliable than the older stock phenolic tube sockets found in the original amps.
9. Also includes triode/pentode switches to allow a quick change between these two modes of operation. The switching may be done while the amp is running to instantly compare the two sonic presentations. See photo of the switches below ..
Triode mode - Power is reduced to about 22 watts per channel. The amp will have a little more mid range projection with a very slight roll off of the extreme upper and lower frequencies. Nice for acoustic jazz, vocals and systems with an aggressive top end.
Pentode mode – The normal mode of operation for the ST-70. Full power of 35 watts per channel. The amp will have more output at the frequency extremes. Nice for bass shy systems and systems that are a little “dark” in their top end.
The complete kit contains the following parts ...
1 - Assembly manual with pictorial
1 - Stainless Steel chassis frame with all original Dynaco markings
1 - VTA driver board with parts set
7 - Micanol octal tube sockets with cadmium plated pins
1 - PA-060 power transformer with bottom plate
4 - hard rubber isolation washers for power transformer
2 - A-470 output transformers
1 - C-354 choke
1 - multi section (80, 40, 30, 20) quadruple electrolytic capacitor
1 - three lug terminal strip
1 - one lug terminal strip
1 - pair of gold plated RCA input jack jacks with mounting board
2 - pair of gold plated output binding posts with mounting board
1 - rubber grommet
1 - fuse post with 3 amp SLO-BLO fuse
2 - SPST 16 amp rated slide switches
1 - 12 amp rated AC power cord
2 - .022 Mfd 600 volt capacitors
4 - 1000 ohm 1 watt resistors
4 - 10 ohm 1 % 1 watt bias resistors
1 - 2200 ohm 1 watt resistor for quad cap
1 - hardware kit for amp with all stainless steel screws
1 - 22 foot coil of 20 gauge tinned solid core copper wire
2 - Triode/pentode switches with associated parts
The KIT comes with an very easy to follow instruction manual and a clear pictorial specific to the VTA driver board. All you need is a soldering pencil, rosin core solder, a screwdriver, pliers and a wire stripper/cutter to build your own Dynaco ST-70. This very easy to build kit takes about 8-10 hours to complete depending on your skill level and any previous experience with kit building. . . Hundreds of thousands of amateur audiophiles built the original Dynaco ST-70 from 1959 through the mid '70's and now YOU can too! Even someone with NO kit building experience can successfully complete assembly of this kit. If you can use hand tools and you can follow instructions you CAN build this kit. Check the link below for a review of the amp by a FIRST TIME kit builder. Over 75 kit and wired amps sold in the past two years > many satisfied customers - check my feedback on Ebay and Audiogon on > Bob01605
$625 + shipping for the complete kit LESS TUBES
A complete tube set with 4 X EL34, 3 X 12AT7 and a GZ34 rectifier is available for + $70
Upgrades available for the kit > 4 X Russian PIO (Paper In Oil) coupling caps + $25, VTA driver board power supply upgrade caps > + $15
Unsolicited Email comments from customers ...
"Bob, Great manual and pictorial. I couldn't believe how easy it was to put together and it worked great the first time I turned it on. The amp is dead quiet and the sound quality just blows away the old original ST-70 I still have here. Cleaner, tighter bass. Better top end extension and just a greater overall sense of clarity. Norah Jones sounds like she's in the room here with me." C. L., Florida
"Bob,
Started up the ST-70 this weekend. Amazing sound, I'm very satisfied with everything. Superb instructions, easy to follow. No hum whatsoever and great warm sound. It started up right away after your instructions on upstart and bias adjustment .... I am very pleased with this kit which gave me a lot of building pleasure and I'm sure I'll have many hours of listening pleasure in the future." J. L., Sweden
"Bob ....WOW, I am sitting here listening to some vintage Emerson, Lake and Palmer and Steely Dan AJA .. If this thing is going to sound better after some burn in -- I can hardly wait. The other two tube amps I have are supposed to be around 35 watts/channel -- they don't even come close to the dynamics I am getting out of this ST-70 right after initial start up. The imaging is holographic with vocals pinpoint where they should be near the center and specific instruments with pinpoint locations outside the speakers with some forward and some behind the speakers--truely a 3D image of what the music should sound like - and very S-M-O-O-T-H overall sounding. That said, the Bass is full, articulate and powerful like it should be. My 12 year old son even came in to hear the initial fireup and was so impressed with the sound he actually sat down and listened for a good half hour before returning to his video game (quite an accomplishment)." B. H., Nebraska
"Hey Bob, just a quick note to let you know that I got the amp all finished this weekend. I worked on it for a couple of hours once or twice a week for the last few weeks and finally got it done. It sounds great! I was really impressed! This is actually the first kit (out of about 20 that I have built) that the instructions were in such detail, that you didn't have to Guess where things went or what to do "if" somthing didn't fit. I didn't have one single problem. Excellent , Excellent, Excellent!! I have it outfitted with some JJ KT88's. I got it going, set the bias, let it run for about 10 minutes or so, rechecked, dialed them in a little more and had it on for about 3 hours. I checked them again and it was right where i had it! I was up last night until about 2:30 AM this morning listening to it. It sounds wonderful. The sound quality is much better than the Velleman kit that I put together. Thanks again! Glad I found you! Hope you have a great Holiday!" R. B., Florida
"Hi Bob, I purchased the ST-70 and PIO caps a few months ago. I have to tell you I love it! The caps made a huge improvement in texture and detail. Added EH tubes and they (after breakin) made drums and bass have a punch that I never heard before. Great kit! Thanks for selling something so good and so affordable .." T. H. New Jersey
"Hi Bob,
Just wanted to let you know that I finished the amp last night. I plugged in the tubes, made the bias adjustments and it worked first shot. The instructions were great. I really enjoyed building this amp. Now I'm looking to pickup a Dynaco pre-amp and maybe updating it with new parts to go along with my power amp." B. B., New Hampshire
"Bob: Just a note to let you know that the assembly of the amplifier went smoothly and it’s working great. The sound is excellent. Even some CD’s that sounded sterile and harsh on my NAD solid state amp now sound quite listenable. Setting the bias was a snap, got the bias for all tubes adjusted close to each other in just a few minutes. And I haven’t even moved it from triode to pentode; the triode mode provides plenty of power to drive my Epos ELS-3 speakers. Great kit. I’m very happy with it." L. G., South Carolina
"Bob, The kit went together very well. Great directions ... The amp's sound quality, i.e. timbral accuracy, imaging and sound stage, depth, etc. are all absolutely wonderful." J. M., Oregon
"Hey Bob ... I built a number of Heathkit, Eico and Dynakits back in the 1960's and 1970's but your kit far and away had the best assembly manual and the highest quality parts I have ever seen in an amp kit. A 16 amp rated power switch! Hey - the fuse blows at 3 amps! Beautiful stainless steel chassis. I love the triode/pentode switches. I haven't really decided which way sounds best because they both sound great .. Your amp sounds so much better than my old ST-70 .." C. W., Texas
"Bob, I just finished a weekend listening to the Dynaco ST70 I purchase from you and which arrived on time last week. Having been an owner of two original Dynaco ST70's, I was not prepared for how much better your version is. It has the sweetness of the original but with sold lows, foot tapping rythm an much more accurate highs. I was so impressed that I am writing to you to inquire about availability of another unit, assembled and with the Russian caps ..." D. S., Puerto Rico (Note - Second amp was purchased on 2/25/08)
"Bob, What I am really surprised about is that this amp is so clear and lively.... it makes my solid state monos sound dull... the detail is fascinating and it does have that liquidy tube sound without being overly liquid. I very much like it so far and presume it will keep getting better for a while! I am impressed, really." J. C., Quebec, Canada
The kit amp is also available COMPLETELY WIRED AND TESTED with all tubes and a one year parts and labor warranty (90 days on the tubes) - for $845 + shipping. Wired and tested amp WITHOUT tubes > $775 + shipping.
NOTE - I have no AudioXsell feedback but check my Audiogon and Ebay feedback under Bob01605
Payment Terms: Paypal, Money Order
Shipping Terms: United States, Canada
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