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dynaco_dan

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About dynaco_dan

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  • Birthday 10/04/1946

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  1. Dynaco amp mods and tweeks

    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
  2. Dynaco amp mods and tweeks

  3. Dynaco amp mods and tweeks

  4. Dynaco A-50 cabinet salvage

    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.
  5. Dynaco amp mods and tweeks

    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.
  6. Dynaco A-50 cabinet salvage

    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.
  7. Dynacos stuffing replacement!

    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
  8. Dynaco amp mods and tweeks

    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.
  9. Dynaco amp mods and tweeks

    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.
  10. Should the AR-5 have been a 12" Speaker?

    Hi Frank It appears that you have all of the toy's and all in one room my friend. Vern
  11. Hi there Thank you for posting this information here. Vern
  12. AR Turntable Documents

    Hi there Thank you for posting this information here. Vern
  13. Dynaco A-25's & Subwoofer

    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
  14. HELP! Has anyone figured out KLH tweeters?

    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
  15. Dynaco A-50 cabinet salvage

    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
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