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Dynaco A25 repair help

lpnewguy

lpnewguy

New Member
Hey AKer's!
I have some A25's that I picked up, cabinets in great condition. I noticed that the right channel was not as bright as the left. After months of use, I drove them pretty hard one day (SX-780 so maybe not too hard) and the right started to sound blown, some crackling. Switched the inputs to make sure it was not the Pioneer and same thing. I didn't use them for about a month and just ran them moderately last night and it sounded ok, same as before, right side not as bright as the other channel. I live in Placerville, CA about 30 min west of Sacramento. I'd like to have them checked out and recapped or what not but want someone who can do it and keep true to their original sound. Anyone know of anyone/place in my area that can help? I'm afraid to take the covers off because they don't seem to want to come off too easy. Can you tell the build by the S/N's? Any help or input would be greatly appreciated. I really like them!
 
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lpnewguy said:
Hey AKer's!
I have some A25's that I picked up, cabinets in great condition. I noticed that the right channel was not as bright as the left. After months of use, I drove them pretty hard one day (SX-780 so maybe not too hard) and the right started to sound blown, some crackling. Switched the inputs to make sure it was not the Pioneer and same thing. I didn't use them for about a month and just ran them moderately last night and it sounded ok, same as before, right side not as bright as the other channel. I live in Placerville, CA about 30 min west of Sacramento. I'd like to have them checked out and recapped or what not but want someone who can do it and keep true to their original sound. Anyone know of anyone/place in my area that can help? I'm afraid to take the covers off because they don't seem to want to come off too easy. Can you tell the build by the S/N's? Any help or input would be greatly appreciated. I really like them!
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You can find the schematics for your speaker on line I can't find mine so I posted the closest think that I had to give you an idea. The speaker is a full range woofer with no crossover of any king it runs wide open and the tweeter is rolled on with a simple crossover not much to check easier to just replace with new better quality parts a grate little loudspeaker even today it can be made to sing sweetly. Keep them they will never let you down or get blown away by anything that you would willing to pay for. You can modify the crap out of them if you want and make them better. I just rebuilt a pair and I replaced the fiberglass damping with new and reconfigured the orientation of the fiberglass so the surface facing the woofer is open. Run on a fin quality system you will be astounded by the nuance and subtleties they can bring forth in a very well balanced manner. Some brace work will tighten them up not a transformation but worth while.
 

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Thank you for the reply moray james. I'm really hoping to find someone within a few hours of me who is an expert on these speakers I can take them too. I have no experience with repair myself.
Question, are you suggesting that the A26 drivers and components are a good replacement to drop right into these a25 boxes?
Thanks again!
 
The A25 is a simple speaker and if you don't want to mess with them someone, not necessarily an expert on the A25, would probably do a great job making the speakers correct to their original sound.

woofers easy enough to replace (one has ears for the mounting screws, one does not, a round basket like most woofers) replace like with like
tweeters, Seas or Scanspeak, replace like with like
crossover with a single cap and a switch that puts an additional resistor in line as the tweeter level is decrease. Replace the cap.

but oh those pesky grilles. Hot glued in place, just use a 90° pick to go in between the grille and speaker and pry it up, move to a putty knife if needed. Remove the hot melt glue replace with Velcro and install Velcro on the speaker for easy grille removal next time.

soldering required,

Not hard at all but not for everyone. Maybe someone in your area is a hands on type working with the gear and can get this done for you. The cord from my soldering iron is not long enough to reach from the base to your speakers or I could help you out.
 
@Blue Shadow great advice on the grills, thank you! I think I can attempt that. But I have never soldered before. If I can get the correct speakers and electrical components, I do know I guy who could probably wire it up for me. Anyone have links to OEM type drivers?
Thank you!
 
lpnewguy said:
@Blue Shadow great advice on the grills, thank you! I think I can attempt that. But I have never soldered before. If I can get the correct speakers and electrical components, I do know I guy who could probably wire it up for me. Anyone have links to OEM type drivers?
Thank you!
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Gotta see the guts but there are only 4 drivers really, two woofers and two tweeters depending on when the speaker were made. Then there is the cap. Replace with same value, look inside to see what you have, Dayton or Solen from Parts Express
 
The A-25's are considered vintage speakers. Being that, they are a nice bookshelf speaker that shouldn't be driven too hard. Don't know off hand the wattage specs, but suspect they aren't very high.
 
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spkrdtr said:
The A-25's are considered vintage speakers. Being that, they are a nice bookshelf speaker that shouldn't be driven too hard. Don't know off hand the wattage specs, but don't suspect they aren't very high.
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20-60 watts. I have em hooked up to a Citation 22 at 200 per but I sure don't see the top LEDs lighting in that bedroom system.
 
The SX-780 is rated at 45 watts (some say underrated) so I feel it's a good match watts-wise. I LOVE they way the A25's sound with it and from all I read they could sound better with recap at the very least I guess. I'm gonna carefully take the grills off and see if I see any damage to the speakers. I don't know why the one would sound blown and then seem to be OK after sitting a while.
Thank you for the replies!
 
OK, I carefully used a 90 pick and got those pesky grills off. I still need to clean up the muck and velcro them or something. Anyway, I have pics of them with the grills off. Tweeter left and port on bottom. Does this tell you anything?
What do you use to reseal the drivers after you remove them? There is blue sealant there now.
I guess the next step is to get in there, recap them, clean them up and see if that fixes the sound problem. If so great! If not, then I need to look into replacement tweets. Any suggestions on what to use for drop in replacement true to the original sound?
This is my first project and I have decided to go for it myself. I will just have a friend help me wire in the caps. I appreciate any and all feedback and suggestions!
A25 1.jpg A25 2.jpg
 
Great speakers -well worth the effort. There is a reasonably good chance that the multi-position switch on the back just needs to be cleaned or replaced. I replaced the caps in my one really ugly pair with the cheapest Solen film caps -nice improvement without changing their character in any negative way. When you go to screw the woofers back in - suggest you do it by hand -placing your off hands fingers between the screws and the speakers surround - that way if the screwdriver slips you'll stab yourself rather than punch a hole in the rubber surround. Hand tightening also allows you to feel when you've got them tight -this is probably the easiest screw up -there isn't a lot of particle board for the screws to bite into -don't over-tighten. You might want to replace the speaker connections with something a little more rugged while you're in there. The bad news is that if you need replacement drivers - they'll be a bit rare -'cause they can only come from pull outs from existing salvaged A25's. There are no new exact replacements.
 
My repaired pair are really butt ugly -got them thatway (grey porch paint??)-no grills -so I just used ductseal since I was using them as bench speakers and figured I might want to get inside again. You can look at Madisounds site for what they sell to seal speakers into cabinets (foam tape with a adhesive back) or just look for a equvalent product at a good hardware store. I wouldn't use RTV for this since the routed out area of the cabinet is a little weak and you'd probably end up breaking it up getting a RTV's woofer out of it.
 
Might want to glue a block of wood behind the screw holes if you want to use those holes again.
The foam tape is a Parts-express offering, didn't see it at Madis but didn't look at everything.

The foam would be good as these ported speakers don't have to be so tightly sealed like an acoustic suspension speaker must be. The pressure will want to go to the port not through the foam.

The ears on your woofers will tell someone in the know whether they are seas or scanspeak, I gotta look it up each time.
 
Soldering question: What type would you use to replace the caps? I'm new to this and seems easy enough to do but there are so many options! What temp gun? What type solder (lead-leadfree-60/40 etc) to use on these Dynaco crossover caps? Suggestions?
 
Regular leaded 60/40 rosin flux solder is what they were made with. Dayton film caps from Parts Express are what I used to recap my Mission 737R's. Hello Ipnewguy, Welcome to AK. Just replace the cap with same value in a film cap. You can solder it across the original cap then cut out the old cap. Had to do the same thing to recap my Missions.
 
I've cut gaskets for KLH woofers out of Harbor Freight toolbox drawer liner (the solid stuff) if you don't want to use e.g. RTV or 3M rope caulk. Neat and clean and seems to work well.
 
Thanks PJ! That is thread I had not found before. Look forward to reading through it. I really appreciate it.
 
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