Dynaco A25 Speakers still getting attention.

...so others can enjoy.

I like this. ^^^^

May good karma come your way & may the new owner be tickled pink!


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What a great thread! So fun to read all the praise for this humble old speaker. Dynaco sure did a lot of things well. I just recently bought a pair of A25s and they will arrive tomorrow. I have a pair of Klipsch Heresy III now, and I like them very much with the right music, but I wanted to try something a bit softer and more tolerant of material that is not perfectly recorded. I am looking forward to auditioning the A25s as an alternative. I am using a VTA ST-70 power amp and PAS 3x or SP12 preamp.

I notice a lot of folks are replacing the capacitor in the A25s. Are most just swamping in a new NP electrolytic?
 
^^^^ Welcome to the thread and Congratulations!

Post a few pics when you get everything setup. :thumbsup:
 
I had theA25 and A40XL at the same time before selling the A25. The Dynaco A40XL is a larger sealed box but with the same stuffed port across the INSIDE of the box about half way from top to bottom. The sound was similar. However the performance differs in three distanced ways. One the actual extension on both ends is better. Two the bass is more defined. Three it's much more sensitive AND can take much more power.
These improvements make for a completely different speaker than the A25 when put into use. Although they sound generally the same most of the time, and look the same. I could not tell the difference in a direct a/b at moderate sound level on most music. The difference came to light when attempting to play much louder and with wider range in the music from bottom to top.
The one thing it won't do is put the rock drum solo snap in the house as well as my Realistic MachOne. I suspect due to the lack of top bass bump and bottom mid bump.
I have experience with only these two Dynaco.
 
Is it easy to remove the crossover for recap or do you have to work on it while in the cabinet? (My Bozaks the crossover could be unscrewed from the cabinet and pulled out to work on)... That may determine if I go through the process of removing the woofer to tackle the recap job... thanks
 
The past few days I mate my A 25s to my new (to me) Yamaha CL 1040 80wpc receiver. Coming from the KLH6s it took a few days to get used to the Dynacos. But I have come to really like the combination. The ice cold Yamaha sound is tamed just a touch with the A25s honey. It makes the speakers disappear after a while.
 
My A25s arrived yesterday and they are in excellent condition. Beautiful wood veneer and grills and badges all intact. Here is a pic of them on top of my Klipsch Heresy IIIs. First impression is they have a very nice natural sound. I'll be doing much more critical listening over the coming weeks for sure. I have a switch wired up so I can switch between speakers instantly from my listening position, but the Klipsch are so much louder it is difficult to compare because I need to adjust the volume each time I flip the switch. I'll measure the relative efficiencies later. For now, it's off to the workshop to take a peek inside.

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I opened one of the A25s this morning to have a look inside. The grills were stuck on pretty well and I had the impression they may never have been opened before, but it's hard to say. I was careful to unscrew the Dynaco badge and carefully pried off the grill. The typical SEAS drivers were inside. Port on bottom. The enclosure was packed pretty full with heavy glass/wool insulation cut into very neat strips that fit perfectly to the inside dimensions. I was going to change the crossover cap (or at least measure the old one) when I noticed it is this big yellow cap in the pic below. I assume this is not original, so someone must have recapped these I guess. I see no name on the cap, just the numbers. It is labeled 4.7uf, but it measures 5.032uf and ESR is 0.15. I assume that someone hand picked from a supply of 4.7uf caps to find one that was as close to 5.0uf as possible. Has anyone seen one of thes caps before? The ESR is too high for a poly cap. It seems to be closest to some very high quality NP electrolytics that I have (Nichicon UDB, ESR = 0.20). In any event, this cap and all the resistors measure perfectly dead on and I see no reason to mess with them. Here are a few shots of the crossover and the drivers.

Also, is that insulation original, and also the green plastic bag like shield that is apparently there to keep the insulation off of the switch contacts? If these were reworked, it looks like someone who really cared about their workmanship was in there. Great soldering too. And even that yellow cap is glued down.

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I think, that while you're in there, you may want to dab/spray the contacts with some Fader Lube or D5 just to clean them up a little. I'm sure the cap switch has been rotated often (?).

Nice work on finding the that yellow cap, too. Your link says 'High End Audio' (whatever that means, LOL) but sounds like you're headed in the right direction. :thumbsup:
 
Yes, Deoxit D5 is the best! Here are a few more pics. I have heard the phrase "Scan Dina" used to describe some of these components but until yesterday I had no idea it was short for Scandinavia. See "Made in Scandinavia" in the woofer pic. Duh!

Also, look at this capacitor. Out of the circuit it measures even better. How ever did they get exactly 5uf?

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I’ve owned lots of great vintage speakers: AR2AX, Advents, KLH 6, 23, 17, Bozak 302a, Bostons, Allison Acoustics, etc. There are lots of speakers that do one thing or another better than the Dynaco A25s, but I’ve found none that are any more satisfying to listen to. The Dynacos simply have a magical quality to them, especially with a tube amp
 
I have the chance to pickup a cosmetically ugly pair for $150. Any chance my small 9w tube amp will drive these to moderate levels?
 
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