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Everything posted by dynaco_dan

  1. Hi there Try solder-wick, available in several small gauges. It may be what the manufacturers used in the old days. Vern
  2. Hi there Just recently I came across more old paperwork. The TIP mod for the ST-120 amp is an 8 pages instruction and parts list. Gregg Dunn site has that TIP mod with a short list of parts with no instructions, which is all that he may have been given. My comment is not negative for Gregg's site which is very beautifully done, but without a forum. Also another 8 page mod to increase the ST-400 to a ST-416 watt amplifier output, referred to as "The Double Dyna", substantially doubling a ST-400's wattage output. Stereo Cost Cutters (SCC) Dec 1983 catalog of most of 13 pages of 24 pages 8 1/2 x 11 paper size remaining Dynaco inventory they had purchased on Dyna's closing, 40,000 pounds worth. The parts list of only 5 pages was done in such a small font, it may not even be scanable. US and Canadian Dynaco wholesale and retail price lists. The MBI-400 mod changes around parts, wires, etc to turn a 400, 410 and 416 into a 600 watt mono amps and this is to be considered non-reversible and very prone to hurt the user (hernia). This project is extensive and the possibility of expensive damage to the amp, if an error is made or serious personal injury, also 8 pages long, not for the rookie. The danger is so great that maybe that is why it was pulled from Greg Dunn's site. I will scan and post some as soon as I can. Errata: There was 60,000 pounds of parts and inventory. There is also 2 follow-up SCC hot sheets which mentions that they had a flyer, 20 pages, of just Dynaco. I'm only mentioning that fact, I don't have it, date unknown. Vern
  3. Hi there This is the earliest 2 speed motor set. There doesn't appear to be the platter drive belt in the photo, oh well, less than $5.00. Vern
  4. Hi there I just read this topic a few weeks ago, thank you very much. Most all Audio magazines are complete and in downloadable condition, from 1950 - 1990+, thanks to the website owner. I could only imagine if they were presently being newly sold including coupons on every other page, lot's of missing sections. LOL Edgar Villchur was a very knowledgeable contributing author prior to AR. Vern
  5. Hi there I thought I would jump in here. I have both speaker systems, AR-3A's first and LST's later. When the opportunity to demo a pair of LST's in my house came up in the mid '70's, I jumped at it. I had the 3A's for several years of ownership and almost constant usage, so I had in intimate opinion of their capabilities. To add another point here is that I also had a Crown DC-300A amp and IC-150 preamp on another weekend loaner and after only a few minutes of listening again, the 3A's were outstanding reproducers on their own. In this case the electronics made all the difference, and they also were returned. My feeling after only a few minutes of usage with an AR amp was that the LST's were at least double the 3A's or at least considerably better. This was a weekend test setup and I returned them after the weekend, no WAF. I am sure I pouted for many, many weeks until in the mid 1990's when I bought a used and abused pair of LST's. Still not having the money or brains to turn down yet another used pair, I bought another used pair a few years later. No, I haven't stacked them, or placed Microstatic array tweeters on top of them. If you keep your eyes open, try to find an original pair of LST's as mint as possible. In my opinion, if you were to build your own cabinets, and be given brand new drivers and use the AR-3A crossover you would likely be happy with them, even with them being audibly less than real LST's. The LST's are great reproducers but they are only speakers. Vern
  6. Hi there I would suggest using small brass double nuts, bolts and lock washers, rather than those steel ones. If you have a source for FNM fuses I would suggest a 1 1/2 amp rating maximum rather than 2 amp. Great speakers with top end electronics. That stool looks just the right height and strength to use as a speaker stand, just not as pretty as a dedicated stand. Sure would be a lot less expensive though. Vern Hi Frank
  7. Hi there You mentioned the fuse clips. On a pair of LST's I found that AR had soldered them to the circuit board, rather they heated up the clips which made them fragile later on. I had extra regular fuseholders and drilled the rivet off of those clips and used very small brass hardware to remount to the circuit board. I did not solder any of the new mounting so that the clips should not break off in the future from being over heated. Just a thought for today, unless you can find just the original bare FNM fuse clips somewhere. Just do not attempt to solder them to the board. Vern
  8. Hi again Here I am with some more trivia about the Dynaco 400, 410 and 416 amps. Today I found an article which I will write about another day and perhaps scan and post here. It is a more detailed story about the coil/resistor which I discussed earlier. The colours were correct but they used a black plastic sleeve over the coil. I also came across a copy of the MBI-400 super-charge mod which can increase the mono output to 600 watts This is one of several links that has disappeared from, home.indy.net/~gregdunn/dynaco/components. That site does not have a forum, sadly, because Gregg has done a beautiful job setting it up. Also I came across price lists both retail and wholesale which I need to scan first. To change the subject here, I see lot's of viewers but only a few get involved with this site. If everyone visiting could post an answer or a question it would be great, even if no one here can answer it. Especially me. Also if everyone could post a photo of an article or ad they have of old Dynaco. Vern
  9. Hi Martin I feel that those tiny felt pads are definitely not enough to really isolate them from the wall. You would need to locate them at least with the tweeter at head height and equally spread along the wall. It is worth a try at least with maybe a piece of carpet between the cabinet and wall. Please report back here with your comments.
  10. Hi Joel Yes the original composition resistors were slightly under-rated and that chap, Kevin, takes us through the steps to get to and replace them. After completing those replacements we get a helping hand to reset the bias. Only listed tools, parts and a VOM are needed. Which caps did you replace and were the new ones 85' or 105'? Did you strip the amp right down to it's basic components? Great job for someone here to do, you must be highly skilled. I picked up a Dyna 400 with meters here because one channel was dead. It is really ugly as it was tinkered with and likely stored in a damp carport. Less than $50.00 though, another of my rescues. I went to the directory here and see over 80 viewers have seen some or all of this topic. I wish some of those viewers would leave a comment or? Nice to see this amount of interest in this topic.
  11. Here it is a little late, sorry. It is now 210kb in size rather than the several mb of the original photos. Vern Dynaco A-50.pdf This photo was the most interesting one of all the ones I took. The underlying walnut veneer is beautiful and it was worth all the effort to remove the paint. My comment earlier was because Dynaco was not going to be using the metal corner hanging bracket plates on the A-50's at least. You would need to really isolate the back of the enclosures from the wall or the wall would now become part of that enclosure thereby over exaggerating the bass. Yes, you can place rubber or felt pads on the rear of the cabinet.
  12. Hi there Here is my 2 cents worth of advice for this evening. With the classic Dynaco A-25's etc unless the cap is defective, such as is open, leave it alone. Some folks replace the caps with new ones and are happy. With the resistors unless you see one or more cracked or burnt up, which I've never seen, leave alone as well. Some folks replace the resistors and are happy. The cabinets fiberglass insulation was particularly fine material and without question should be left intact. There is much synthetic material which might do as good a job but without test equipment you will likely end up with less than you started with. The vent opening was covered with a particular piece of fiberglass which was determined by lab equipment. The switches were of good quality and very reliable. Wire was adequate for the job. Overall the Dynaco A-25 and family are well designed at a dollar compromise. No foam rot is a big plus issue. When a replacement driver is needed there was so many sold that there is a flood of used OEM drivers available. Vern
  13. Hi Joel The site referral is a site without an active forum. The repair was written by Kevin Boales for PC-28 circuit boards. I can print out the St-400, etc, mod for my use but I do not know how to just save it. This mod is for usually one dead channel and it covers replacing a common cause of the one dead channel. I do not feel it is ok for me to print out that file and re-scan it and post it here.
  14. I have a few mods or tweeks information on Dynaco's ST-150, ST-400, ST-410, ST-416 amps also series 80 amps and ST-120. If there is sufficient interest I will follow up here in the near future. If I remember correctly there was a phase 2 Dynaco ST-400, I have no information on why there was this added model designation. It may have been an internal doc. Please post here if you are interested in following up on these issues. Remember there is a serious risk of shock if you are not experienced. There was a TIP mod well known for the ST-120 but there was also a similar TIP mod for the 80 series. The mod for the ST150 - ST-416 amps is on Greg Dunn's web site. It was posted there around 2002. You can print out the article. A set of 8 pages has been deleted there that would have created a 600 watt mono amplifier. No explanation posted. Perhaps liability issue. Vern I do not have an email address yet.
  15. Hi Frank It appears that you have all of the toy's and all in one room my friend. Vern
  16. Hi there Thank you for posting this information here. Vern
  17. Hi there Thank you for posting this information here. Vern
  18. Hi there Just a small comment here. The original Dynaco A-25's were very well liked in their day. J. Gordon Holt of the original Stereophile Magazine fame went gaga over them in his first review. Very smooth and wide range, within their limits. I like them very much. Use caution with any bass boost, loudness controls or loud volume levels. You might download Dynacophil's "Dynaco Dynamax" paper from this site. It show's several options for multiple Dynaco speakers of the same brand and model. There is no reason the same cannot be used with most all 8 ohm speakers, at least to experiment with. For more bass, maybe if you have a friend with another pair of A-25's, try paralleling them together. Fusing them with a 3/4 or 1 amp fast blow fuse in an open style fuse-holder will help protect your investment at least. Just a thought. Vern
  19. Hi Kent I am certainly not an expert but the tweeter must have a totally enclosed metal frame so that the woofer back pressure does not pop out the tweeters cone material. I have seen some tweeters with holes stamped into the frames, but the correct version will not have any holes. The same with the mids. They had intentionally installed special sealed sub enclosures to prevent that type of accident. The satellite speakers with a single mid/fullrange driver would not have any issues in this regard. Vern
  20. Sorry for not posting photos. I took a lot of photos, but at too high a resolution to post here. Here it is 5 years later and I have still not posted them. There is photo editing software that I am trying to locate to allow me to post them. The photos of the work are too nice to not complete this article. The work that was done can be done to any walnut or other wood veneers. I may remove a woofer to photograph the inside of the enclosure and crossover network and even take some measurements. Originally I commented that the rear cabinets corners had the metal brackets for hanging on a wall and this wall not as Dynaco had advertised them, despite their light weight. Dynaco had several times advertised artists conceptions of their products and then altered the final product appearance, sometimes several times. Till next time. Vern
  21. Hi Kent Thank you very much for your posting of photo. Vern
  22. Hi there Is there a speaker review or schematic of this speaker system available?.
  23. Hi there Check out Ebuy for a used pair. The original tweeter was well regarded, not only in the Fives.
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