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Classic Dynaco A25s: Am I imagining this?

jeeem

Active Member
I've accumulated a modest collection of vintage audio gear, mostly from the '60s and '70s: amps, receivers, turntables, tape decks. Vintage speakers tend to be bulky though, so while I have a few (Large Advents, Infinitys, Spica TC-50s, Magneplanar MG1s), they can be a hassle to place and swap. Over the last few years I've stacked up some new-ish bookshelf speakers connected to a six-way switch (Elac Debut Reference DBR62 & Uni-Fi UB5, Focal Chora 806, Triangle BR03...) and have enjoyed matching them to different amps/receivers and comparing their qualities.

But the other day, on a whim, I dug out a pair of old Dynaco A25s that were just sitting around in the basement accumulating their own collection of dust. I originally got them years ago to accompany my Marantz 2230, a match made in heaven.

Well, it's been a revelation. Playing through my Sansui AU-4900 (38 wpc) or Pioneer SA-708 (65 wpc) or Kenwood KA-8400 (55 wpc) or Sansui 5000X receiver (60 wpc) they make commercially produced music sound like I remember it when I first discovered "hi-fi" in the '70s -- and the way I imagine it was recorded and mixed to sound back then (even through a Roon/Mac/SOtM streaming setup running through an iFi Zen DAC, none of which I could even have conceived of in the '70s). Interestingly, my McIntosh separates (C28 and MC2505, 50 wpc), which sound great through most speakers, struck me as a tad anemic through the A25s.

I have them sitting on acoustic isolation feet on the floor a little more than a foot from the wall. The bass isn't boomy or bloomy; it's well-integrated into the music, which really breathes. The highs can border on harsh depending on the music, but I can play them all day without feeling any fatigue. So far, I've mostly been playing pop/rock from the '60s and '70s, which tends to be compressed and heavily mixed anyway: prime Stevie Wonder, Wilson Pickett, Al Green, Isaac Hayes... and today I threw in some early B-52's just to change things up a little. Best of all, they can pour out a lot of sound without straining. (I have a lot of jazz and classical music but haven't tried out Bill Evans or Miles Davis or Schubert or Mahler on them yet.)

I entertained the idea of hooking up a subwoofer, but after listening for a while that seemed like it might be overkill. I don't know quite how to explain it, but the cheap, antiquated Dynacos present this music in a cohesive way the newer speakers I have can't (or don't even try to) match. I guess speaker reviewers would say the A25s are "less analytical." The details are there, but the speakers don't pick them out and highlight them individually, bit by bit. Somehow they sounded to me both airier on the top and more substantial in the middle and bottom. Go figure.

Does that make any sense? I'm naturally compelled to try to explain in detail experiences that feel like they're beyond words, but I'm wondering if you've had similar encounters, perhaps with older equipment. I look forward to hearing any stories you may have...
 
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I have a pair of a50's as well as the a25. The a50 is warm and doesn't cause listener fatigue. The a25 is also very good in this respect though it has less bass being only one woofer instead of two like the a50. From articles I have read about the dynaco speakers, they don't put a strain on the amplifier being they maintain a 7 ohm impedance throughout the music spectrum. Amplifiers seem to be very happy playing through either. I also have a collection of speakers from KLH six, delphi, linaeum, rogers, audes, polk audio, kef etc. Each sounds different and each sounds different with different amplifiers. I find that there is a chemistry with certain speaker amplifier combinations as well as the room they are in. My a50 sound better in my carpeted basement setup with a luxman r-117 than in my family room with an arcam receiver and tiled floor. Love to play with combinations. enjoy!
 
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You're not imagining this - the Dynaco A-25s are one of the best-balanced speakers in audio history, and still hold their own in many ways. The A-35s are even better, but in a good setup - which it sounds like you have - the A-25s are awesome. I have both A-25s and A-35s. My main speakers cost many times the price, and they're better, but I still enjoy the Dynacos.
 
I'm coming at it from the other direction, always had bigger vintage speakers, love them. Recently started exploring smaller speakers and had a similar revelation in the detail of newer smaller speakers. I believe some if it is the cabinet itself. All my large vintage cabinets have a sound to them. They also have really wide motor boards and big lips at the edge of the baffle. All this has sound to it. I'm feeling these smaller speakers have naturally less resonant cabinets because of their size, really small baffles and smoothed off edges. You hear the driver more and the cabinet less. Leans towards the sterile side if you're coming from the vintage side. That's one aspect of it for me.
 
It is weird how good the A25 s can sound when their on axis response is so bad, there
are two 10 dB dips in the response. I once started a thread on the Stereophile forum
"When Bad is Good". The dips are in the range that has been described as the BBC
dip, though it is usually much less.

The response flattens out to close to perfect, 30 degrees below axis, or moving to the
left of on axis - the tweeter needs to be further back. Also, turning down the tweeter switch
a bit reducing the tweeter by a few dB should flatten it even more.
Interesting that if you tip them back 30 degrees which makes on axis like listening 30 deg
down from the original on axis. Then they have many similarities to the SPICA TC-50 but
with a much simpler crossover. This is speculation but the A-25 woofer does not have a
peak that requires a notch, and it probably has a natural 2nd to 4th order roll-off. The tweeter
has a first order roll-off as does the SPICA. They might even be roughly linear phase with
the tilt back. The issue with tilt back is that we move off axis from the large 1.5" tweeter
which rolls off the already limited top end. The modern SEAS 1" would help here as would
an adapter that tilts the tweeter more on axis even with the cabinet tilted back.

The only review with frequency response measurements is provided in this .pdf on page 6
with the tweeter control full up:
https://www.updatemydynaco.com/documents/DynacoReviews.pdf

Stereophile review from 1969:
https://www.stereophile.com/content/dynaco-25-loudspeaker

A serious weakness of all of the early Dynaco speakers is that the voice coils are wound on
paper and easily overheat with big modern amps. The A25XL uses a later version of the
woofer with the voice coil wound on an aluminum former as was also the tweeter.

There never was an A-50XL, what would be interesting would be to rebuild an A-50 with a
pair of XL woofers, this would vastly improve the power handling and make the system 4 ohm.
 
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I have had A35's for 25 years and have yet to hear any speaker I enjoy as much. I recently recapped them as well as rearranged my music room and I keep falling in love with them all over again. I looked to describe the sound as "cohesive" -- everything melds together wonderfully with no over exaggeration or "color added." Incredibly smooth, low, low bass and great clarity but won't fatigue you in either direction
 
I have had A35's for 25 years and have yet to hear any speaker I enjoy as much. I recently recapped them as well as rearranged my music room and I keep falling in love with them all over again. I looked to describe the sound as "cohesive" -- everything melds together wonderfully with no over exaggeration or "color added." Incredibly smooth, low, low bass and great clarity but won't fatigue you in either direction
I feel the same about the A35, I had them for many years. The A25 is close to that magical sound.
 
.....The highs can border on harsh depending on the music, but I can play them all day without feeling any fatigue.

I don't know quite how to explain it, but the cheap, antiquated Dynacos present this music in a cohesive way the newer speakers I have can't (or don't even try to) match.


In my experience, my Dynaco A25 are about the very last speakers I own that I'd associate the term "harsh" to. For me they always seem buttery smooth. If anything for me the high is so smooth that I can sometimes feel like I'm missing some high end sparkle.

Also, regarding 'cheap,antiquated'. I'd describe them as...... inexpensive. Not cheap as SEAS drivers are anything but cheap. And antiquated? Mmm.... good design is never antiquated.

If you want to have some real fun, try stacking various pairs of your speakers. At one point I stacked some EPI M90 on top of Dynaco A25, and the combination was very nice. Each speaker seemed to fill in for the shortcomings of the other.
 
They are really good.

I just sold a pair, and spent a few days prior to the sale listening to them with some very good electronics and sources. I was amazed by what this built-to-a-pricepoint speaker could do.
 
I am driving my a50's with a luxman r117 which is 160 per channel. Never played loud enough to over heat the woofer coil. I have a built-in volume limiter. (my wife who says turn it down) They are sitting on top of other speakers with klh six on top of them in my basement which is carpeted and wood paneled. They play alternatively with khl six. They both fight for which sounds better to me. To be fair, I resealed the klh six surrounds and replaced the caps. The a50s are original condition with no cap updates. Maybe I should replace the caps and see if there is an improvement?
 
I am driving my a50's with a luxman r117 which is 160 per channel. Never played loud enough to over heat the woofer coil. I have a built-in volume limiter. (my wife who says turn it down) They are sitting on top of other speakers with klh six on top of them in my basement which is carpeted and wood paneled. They play alternatively with khl six. They both fight for which sounds better to me. To be fair, I resealed the klh six surrounds and replaced the caps. The a50s are original condition with no cap updates. Maybe I should replace the caps and see if there is an improvement?
A50s stacked with Model Sixes? That's about as good as it gets.
 
My first speakers were A50s, from Illinois Audio. Wish I still had them. I currently have A10s, A25s, slightly modded A35s, and I like all of them. Also a pair of Seas by Sennheiser SE2'S. These are sort of A45s, similar to A50s, a bit smaller. Two 8 inch 16 ohm woofers in series and the usual H87 tweeters...

IMG_20211227_150603_1.jpg

IMG_20211227_150630_1.jpg

All of these speakers are keepers.
 
Maybe I should replace the caps and see if there is an improvemen

FWIW just did my A35's and it really made a difference, evidenced by the fact I had to totally redo my EQ settings. I didn't realize how much high end I had lost over the years, but after recapping I wound up turning down the mids/treble a good amount. I found that I had to actually turn up the low end a little to compete.
 
I had them back in the day and liked their voice and presentation but was bugged by their poor dynamics. I bought another pair (from Musicraft) and doubled them up but they were still frustrating. I moved on to significantly more dynamic speakers.

Now I'd probably find their dynamics more than adequate. Once in awhile I consider the modern version of the speaker sold by Madisound.

https://www.madisoundspeakerstore.c...6-10-2-way-kit-pair-based-on-the-classic-a25/
 
I have the A40xl. A seal box with an internal aperiodic port. Yes, it's a very good speaker. I use them mostly for casual, conversation and dinner music when there are several people in the house. Non-intrusive, but still enough detail. Good female contralto to mezzo-soprano voices play REALLY well. Very good with most acoustic instruments.
Loves 4-piece acoustic jazz band with a single voice. They take an admirable shot at getting a live performance sound in your home. Go to the jazz bar, go home, turn on the Dynaco's. But you will need some watts.
Not good for hard hitting rock, won't do organ justice, and lots of big orchestra stuff goes missing.
It's not a cheap outdated speaker. It's very good at what it does.
I purchased spare used drivers. I will need them eventually. Very economical speaker to have over time.
 
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