• Content count

  • Joined

  • Last visited

Community Reputation

0 Neutral

About dynaco_dan

  • Rank
  • Birthday 10/04/1946

Contact Methods

  • Website URL
  • ICQ

Profile Information

  • Gender

Recent Profile Visitors

17,521 profile views
  1. 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
  2. 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
  3. 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
  4. Hi Kent Thank you very much for your posting of photo. Vern
  5. Hi there Is there a speaker review or schematic of this speaker system available?.
  6. Well, it's been a while, but one of my two amps died. My first thought, because I saw something glow red how in the case when I turned the unit on, was the unit suffered a cascade failure. AKA not cost effective to repair.

    Fall is here, my depression over the event has abated a bit and I decided to open the unit to see how bad the damage was before trashing. No burn marks, no scorched wires or melted or loose connections to be found. Checking further, both 5 amp fuses were blown in the right channel, the channel that failed.

    I decided to check the TO-3 transistors first, and found two that are a dead short between B-C-E. Each was part of a pair, it's matched transistor was good, er, acceptable given it's age.

    Checking further, I noticed whatever repair facility replaced 2 of the 4 NPN transistors in the channel, and used the wrong part number.

    The original part numbers are now obsolete (MJ15024 and MJ15025) but two substitutions are available. The better choices for the TO-3 NPN and PNP transistors is MJ21193G and MJ21196G. Mouses strongly recommended replacing all eight if going with these options. They have a slightly higher gain than the originals, supposedly better linearity and a high SOA.


    If this fixes the amp, this plus the new electrolytic caps should be a minor upgrade in performance and perhaps extend this old Heathkit AA-1800's life a few more decades.


  7. Hi there Check out Ebuy for a used pair. The original tweeter was well regarded, not only in the Fives.
  8. Hi there Check your woofers cones for the black felt marked 25+/- or other numbers. This is the cone weight and depending how low the number was determined which model it was installed in. The opposite is also the the same.
  9. Hi there Put back the original piece of fiberglass.
  10. Hi there I need to scan and post the Audio Magazine review I have found of the A-25XL speaker system. I read it 3 or 4 times to try to digest it's contents. Will try to post it soon. The owner that gave them to me also found one broken coil wire. Strange!
  11. Hi there Dynaco used both Scan and Seas drivers. B&O used some drivers that were made by Seas also. European speakers tended to be 4 ohms and North American 8 ohms. The original A-25 prototype was 4 ohms and Dynaco insisted that they be made in 8 ohms. You need to check the paper label for model numbers and if missing use a VOM to verify impedance. Whether swapping out both drivers in a Dynaco speaker with 4 ohm drivers or visa versa with B&O's would be up to experimenters to try. There may be an improvement or not in each case. I was recently given a pair of Dynaco A-25 XL's and the tweeters had been replaced with a brand of other manufacture. My hearing is poor so I cannot say if there is any difference in output between Seas and Scan drivers. Dynaco A-25's tweeter had a commented peak at about 9 - 11 kh in many reviews. I cannot comment on the A-25XL's tweeter reviews.. Even the Dynaco's woofer either had horned baskets or round baskets and were both were from Seas. These may or may not have performed exactly the same. I have not read the complete story of Dynaco's relationship with Seas and B&O, and the A-25 birth. While Scan drivers were used early on there was a switch to Seas. There was no fanfare or announcement to that fact that I've seen. There was tweeter on the right and left of center versions. Different grille cloth frames. There is no Dynaco internal information of any of their speaker systems. They may have experimented with a mirror image pair but found it difficult to keep paired in distribution. The A-25XL came out when I was transitioning and never saw them for sale. I own AR-LST's which are 4 ohm. Their tweeters tend to have a disintegration of the tweeter cavity padding. I bought 4 ohm versions of the Seas Dynaco/B&O tweeters for future replacement. They won't perform the same but will last longer than me. As long as you are happy with the xL's, enjoy.
  12. Hi there It is possible the switches stop is bent or broken. Only opening up the cabinet and inspecting the switch is there a possible solution available. A used switch is not much of a gamble in my experience. When I didn't have an original switch I bought a 5 position MBB or make before break stepped switch and have not had a problem with it. You may be able to buy a cheap used pair on Ebuy and if shipping is cheap go for it. Be carefull not to buy a BBM or break before make switch, as you lose the signal each break in the contact. Some surplus switches have adjustable adapters so that you can have 1 up to 10 positions (limit of some switches). Do check the stop post first.
  13. Hi there I believe the AR1X schematic is one of the many thousands of documents I downloaded here over the years. In my many postings due for the library additions, I also included the original handwritten note regarding the AR-1 tweeter discontinuation. It was I believe, either a phone call from AR or a personal conversation with the A C Simmonds rep that the Altex tweeter was discontinued and the replacement was the cone 2 1/2" tweeter. My memory is bad but if you say Altec's as plural it sounds like Altex, that is why I am guessing the source rather that a printed sheet from AR. If you said that over a phone call you might write down the incorrect spelling accidently. The local warrantee depot did not have computers, fax or emails so personal conversation or phone call is my best guess at this time. I could ask my friend who managed the warrantee depot but I do not like to bother him. He may have had other sheets mailed from AR regarding this AR1-X conversion but I may have not photocopied it when I had the chance in the mid '90's. Obviously AR would have shipped out conversion kits, which I never saw, to warantee depots with the attached round hardboard or plywood adapter. The replacement would have been exceptionally well packaged, in a well designed cardboard box with instruction sheet (s) and lots of putty At the local warrantee depot you would have needed a very large van to haul all the parts that AR shipped, at absolutely no charge, including lot's of new cartons. From my perspective a company totally dedicated to the public, dealers and warrantee depots, without equal. We need not mention discounting.
  14. Hi there I am not here much any more but here is my nickels worth of advice. Absolutely do not allow anyone not experienced with AR speakers to touch your speakers. When working they are gems. When not they are not for the inexperienced service person to service. My advice is to NOT advertise on EBUY . When I was actively buying on EBUY a disgruntled seller wrote that with using Paypal and the cost of EBUY advertising, 25% was deducted from the sale price, for one issue. Tom is correct with his advice as usual, but they may also be the earlier 4 watt pots which I have seen totally burnt out. I will look at the photos again and will comment further. Vern Just returned and from the photos I believe they are the 25 watt pots with the black plastic shafts, not the 4 watters. Do not spray or drip any kind of fluid into the pot via the pot shaft. Do not attempt to remove the grille cloth even. The subject of removing and cleaning pots has been much discussed over the years here. To be absolutely correct, there is no long term repair to the pots irregardless as to the person or their efforts. The wiper and wire coil is usually scored and the original surface is scarred and pitted. Every effort is temporary at best, irregardless to who does the cleanup. Buying a used or reconditioned one is, in my opinion, a waste of money. A new old stock (NOS) original pot is the best replacement. It is made of unobtainium, as it has not been made for decades. There may be some out there in surplus companies but I have not come across any. A suitable equivalent replacement is the Ohmite surplus or Chinese new, equal in wattage, the Chinese version is slightly larger in diameter. Both are built like tanks, with their coil and wiper exposed at the back. The Ohmite pot has replaceable parts, also, if available as surplus from ?. I believe that I have a solution to the pots rear protection. A member here developed a stepped switch and the owners manual may still be in the library. It was ingenius and I do hope he was successful with his venture. This may be an quality alternative to pots, but I do not have any experience with them. Hopefully the pots are the only bad parts, but the caps may also be open and finally the tweeter may be open. A terrific AR specialist can diagnose and service them. Good luck. Try Craigslist maybe? No fees. They also will require very special packaging to limit potential damage. .
  15. Hi there I posted the actual original A-25 and A-35 capacitor information on May 17th 2011 which was the start of this topic. I am holding my original crossover board with the 2 different caps and a switch attached to it. I had tried using a pot instead of a stepped switch with the resistors. This was my attempt to be able to switch between A-25 and A-35 crossover frequencies. Also included was an inline open style fuse holder with a 1 amp glass fast blow fuse. Maybe someone here can check out the cap model number to see what level of cap this was. Likely it was a lower level but suitable product. As far as I can see 5uf and 8uf are not made anymore, but a slight value difference above and below these values is not going to be of a significant audible difference. I bought these from the local Dynaco warrantee depot here in Vancouver. There is no reason that Dynaco did not have to sub the caps due to a shortage for a brief period. This is only my guess as I have never seen or heard of this incident happening. Sadly there is little information here of Dynaco classic products other than positive magazine reviews, no engineering drawings or such. They seemed to stay with the same resistor and switch suppliers as well. Thank you Phil for the Dynamax information.