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1969-74 Dynaco A-25 speakers compared to modern designs?

Blake Klondike

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#1
I was just given a pair of early seventies Dynaco A-25 speakers, and am wondering if folks have experience with them? How would they stack up vs newer designs in the past 50 years-- will they hold up? Thanks
 

Robin L

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#3
I was just given a pair of early seventies Dynaco A-25 speakers, and am wondering if folks have experience with them? How would they stack up vs newer designs in the past 50 years-- will they hold up? Thanks
Meh. I've owned them. Not much on top, not much on bottom, nothing particularly special about what's in-between. The "sleeper" of the era was the Large Advent, particularly stacked Advents.
 

sejarzo

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#4
They were one of the cheapest "serious" speakers of the day, popular with college students. If you had a decent receiver but couldn't swing a pair of Advents, they were the next best option.
 

sejarzo

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#5
Meh. I've owned them. Not much on top, not much on bottom, nothing particularly special about what's in-between. The "sleeper" of the era was the Large Advent, particularly stacked Advents.
LOL I was typing my reply above and saw yours as soon as I clicked the post button!
 

Dennis Murphy

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#7
I was just given a pair of early seventies Dynaco A-25 speakers, and am wondering if folks have experience with them? How would they stack up vs newer designs in the past 50 years-- will they hold up? Thanks
I owned a pair for several years, along with the large Advents, KLH5's, and several Acoustic Research speakers. Most speakers of that era were either 2-ways that ran the woofer too high, or 3-ways that had severe lobing problems and destructive driver interference due to poor driver positioning and poorly optimized crossovers. Of that group, my favorite was the KLH5. The A-25 sounded like the 5's with the very top and bottom ends chopped off. The Advents went much lower, but had less midrange presence and were colored on string sound. The AR's were pretty much a mess. A year or two ago I got hold of some KLH5's and was shocked at how poorly they did in the upper midrange, lower treble. Modern speakers have more presence and detail in that area, and I'm pretty sure the A25's would suffer in the same comparison. But considering the era, and the lack of any filter on the woofer and a minimal one on the tweeter, they did amazingly well. I would just enjoy them.
 
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#9
I owned a pair for several years, along with the large Advents, KLH5's, and several Acoustic Research speakers. Most speakers of that era were either 2-ways that ran the woofer too high, or 3-ways that had severe lobing problems and destructive driver interference due to poor driver positioning and poorly optimized crossovers. Of that group, my favorite was the KLH5. The A-25 sounded like the 5's with the very top and bottom ends chopped off. The Advents went much lower, but had less midrange presence and were colored on string sound. The AR's were pretty much a mess. A year or two ago I got hold of some KLH5's and was shocked at how poorly they did in the upper midrange, lower treble. Modern speakers have more presence and detail in that area, and I'm pretty sure the A25's would suffer in the same comparison. But considering the era, and the lack of any filter on the woofer and a minimal one on the tweeter, they did amazingly well. I would just enjoy them.
In '77, I started with the large Advents - my first "real" HiFi speakers to go with my first separates. Within about 6 months, I upgraded to higher end separates and a pair of AR10pi loudspeakers. I really liked the 10pi's. They had no personality and seemed, at the time, to be quite neutral. They were about $600.00 then, if I recall.
 

Dennis Murphy

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#10
In '77, I started with the large Advents - my first "real" HiFi speakers to go with my first separates. Within about 6 months, I upgraded to higher end separates and a pair of AR10pi loudspeakers. I really liked the 10pi's. They had no personality and seemed, at the time, to be quite neutral. They were about $600.00 then, if I recall.
In '77, I started with the large Advents - my first "real" HiFi speakers to go with my first separates. Within about 6 months, I upgraded to higher end separates and a pair of AR10pi loudspeakers. I really liked the 10pi's. They had no personality and seemed, at the time, to be quite neutral. They were about $600.00 then, if I recall.
I never got beyond the AR 4x in terms of ascending model numbers. I have measurements of the AR3a and AR4X on my murphyblaster.com site. I guess I should put some headless pink panthers up as well.
 

mhardy6647

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#11
For the year they had some pretty interesting driver technology.


And aperiodic damping. :)

The SEAS (or were they ScanSpeak?! too lazy to check, sorry!*) rubber surround, AlNiCo magnet 10" woofer and dome tweeter were a good cut above the kind of thing one would find in most other sub-hundred buck loudspeakers of their era.
LRE Dynaco loudspeakers 1973 .jpg


source: https://worldradiohistory.com/Archive-Catalogs/Lafayette-Catalogs/Lafayette-1973.pdf

For their (very modest) cost when new, they were hard, perhaps impossible, to beat in their time.

Pointless, egocentric aside: I bought my parents a used pair in the early '80s (in as-new condition) for 75 bucks at Gramophone in Baltimore, MD after giving them a good listening-to. They're just -- nice. My aforementioned parents put a lot of miles on them over the years. They're now here. Cosmetically much rougher than nigh-on 40 years ago, but they still work fine.


At today's prices for a pair, though -- yeah, you can do better.

https://worldradiohistory.com/Archive-Catalogs/Lafayette-Catalogs/Lafayette-1973.pdf

_________________
* heh, both, apparently! :) https://www.cfuttrup.com/history/scan-speak.html
 

mhardy6647

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#12
And another pointless(ly) egocentric aside:
Pair of A-35s here, too -- come to think of it. :)

DSC_9644
by Mark Hardy, on Flickr

EDIT: FWIW, the OLA (Original Large Advent) never really "did it" for me. Sort of a reticent, ponderous-sounding, overdamped, heavy and thick sounding loudspeaker -- devoid of life in the treble part of the spectrum, although refreshing their hyper-simple XO with decent quality modern production capacitors helps them quite a bit.
 

Dennis Murphy

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#14
I attended a factory-sponsored promotion at the U of Michigan about 500 years ago. The rep demo'd the Advents against some of the competition, spending most of his time on bass response. At the end, he trotted about another pair and stacked them. The official factory line at the time was that it didn't make any doo dah difference and that one pair was just fine, which was kind of interesting given the temptation to double sales. The rep seemed genuinely bemused by the whole fad. I don't remember what I thought. I was probably preoccupied with an impending economic theory exam.
 
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#15
And aperiodic damping. :)

The SEAS (or were they ScanSpeak?! too lazy to check, sorry!*) rubber surround, AlNiCo magnet 10" woofer and dome tweeter were a good cut above the kind of thing one would find in most other sub-hundred buck loudspeakers of their era.
View attachment 105226

source: https://worldradiohistory.com/Archive-Catalogs/Lafayette-Catalogs/Lafayette-1973.pdf

For their (very modest) cost when new, they were hard, perhaps impossible, to beat in their time.

Pointless, egocentric aside: I bought my parents a used pair in the early '80s (in as-new condition) for 75 bucks at Gramophone in Baltimore, MD after giving them a good listening-to. They're just -- nice. My aforementioned parents put a lot of miles on them over the years. They're now here. Cosmetically much rougher than nigh-on 40 years ago, but they still work fine.


At today's prices for a pair, though -- yeah, you can do better.

https://worldradiohistory.com/Archive-Catalogs/Lafayette-Catalogs/Lafayette-1973.pdf

_________________
* heh, both, apparently! :)https://www.cfuttrup.com/history/scan-speak.html
Just to note that that $80 in 1973 would be almost $500 today. I assume the add is $80 for ONE not a pair (my recollection of speaker ads from that period and how thy priced is a bit, well, fuzzy). My dad had a pair of A25s with which he had replaced some smaller ARs. Being 17 at the time, they sounded pretty good to me - certainly much better than the cobbled together speakers I was using.
 

mhardy6647

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#16
Just to note that that $80 in 1973 would be almost $500 today. I assume the add is $80 for ONE not a pair (my recollection of speaker ads from that period and how thy priced is a bit, well, fuzzy). My dad had a pair of A25s with which he had replaced some smaller ARs. Being 17 at the time, they sounded pretty good to me - certainly much better than the cobbled together speakers I was using.
That is correct -- the price is each.
That said, and irrespective of inflation, see what else 80 smackers would've bought in 1973 in the way of loudspeakers in the US. The A25 was at the high end of the crop in terms of musical enjoyment.


1610381470457.png
 

YSC

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#17
despite it looks old (and some mould?) and very likely can't compete with modern speakers, maybe even desktop active monitors... but somehow this one looks great of the vintage feel and attracted me who wasn't even born back then
 

anmpr1

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#18
Dyna loudspeakers were not bad in context, and could be sourced as part of a 'package deal' from Dynaco dealers. That is, you could typically get a considerable MSRP discount if you bought their pre/amp/tuner kits plus speakers, together as a package. I think that fact alone sold a lot of them. Gordon Holt was a big fan, but realistically he didn't have much of an audience back then.

I owned Advents (almost everyone did back then) which I thought were 'smooth' sounding speakers, more open and less boxy than the competing AR and KLH. They didn't cost that much compared to a lot of speakers that sounded worse. Overall decent value. Nothing to get too excited about. Prim and proper.

I smiled at Andrew Pettit (not Petite for crying out loud) calling Pearson's rag a 'cultist' magazine. How right he was about that. And Harry thinking that the speaker could handle 100 watts of continuous power! Why would he put something that ignorant in print? Did he really think that? Who knows?

The fact that Harry experienced increasingly 'improved' sound going from 60 watts, to 150 watts, to 300 watts per channel when listening to music tells me that he was routinely clipping the lower powered amps, and that is what he was attributing to the different amplifier's sonic quality.
 
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#19
I smiled at Andrew Pettit (not Petite for crying out loud) calling Pearson's rag a 'cultist' magazine. How right he was about that. And Harry thinking that the speaker could handle 100 watts of continuous power! Why would he put something that ignorant in print? Did he really think that? Who knows?

The fact that Harry experienced increasingly 'improved' sound going from 60 watts, to 150 watts, to 300 watts per channel when listening to music tells me that he was routinely clipping the lower powered amps, and that is what he was attributing to the different amplifier's sonic quality.
And his "descendants" are only exponentially worse than he ever was...
 

MrPeabody

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#20
The "aperiodic" enclosure is an oddity, and there must be a reason why no one else thought it worth duplicating. The reason that no one else thought it worth duplicating is that it didn't do anything other than lower the Q for an enclosure that wasn't as big as it needed to be for the woofer. This sort of emulated a larger enclosure, taming the big response peak that would otherwise have been conspicuous, somewhere in the mid-bass. The tradeoff was that bass also leaked through the opening and cancelled with the front-radiating bass. The net effect was an overall reduction in bass which was stronger in effect at the mid-bass hump than elsewhere. There was no Helmholtz radiator effect, i.e., there was none of the familiar effect of a ported speaker. It is also worth noting that the use of damping material in the opening did not do anything different from simply making the opening smaller. To say it plainly, it was a kludgy design that didn't really make good sense.

I was a fan of Advent back in the day. I first heard the OLA speaker in the early '70s. It made a memorable impression on me because it was apparent that it was a good deal less colored than even good speakers from that era generally sounded. Sometime in the early '80s I walked into a hifi store one day and saw that they had a bunch of the last large Advent that was made before Jenson bought them. This supply of Advent speakers had evidently been liquidated by some distributor who wanted to get them out of the way, and the retailer had bought a big stack of them. I recall that I bought the pair for about what just one of them ordinarily sold for.

The big Advent woofer was unusual in several respects but was a much better woofer than Jensen's cheap commodity woofer. It may not be widely understood that in order to get deep bass from a woofer in a sealed enclosure the driver Q actually needs to be rather high (in relation to Fs), and that this was achieved by using a magnet that wasn't very strong such that the electrical part of the damping was weak. One of the downsides to this is that the suspension stiffness (the spring effect not to be co-mingled with damping) has to be unusually low, lest the enclosure will end up being inconveniently large.

In the last large Advent speaker that was produced prior to the Jensen takeover, Advent engineers had already switched from the "fried egg" paper tweeter to a true dome tweeter. By the early '80s it was no longer necessary for Advent to manufacture their own custom paper tweeter in order to have a tweeter that they deemed superior to the small cone tweeters that were common in the '60s and '70s. Kloss' fried egg tweeter wasn't ever a great tweeter. It might have been better than most cone tweeters from the early '70s, but not even this is certain. It sounded different, and many people liked it and some still do, but the obvious question is whether this may have been due in major part to low-order harmonic distortion. I suspect so.

Once I had that pair of big Advents in my possession, it was probably only a matter of an hour or two before I realized that while they sounded pretty good, they didn't compare favorably to any number of better speakers that were then available. They continued to hold their own in terms of value. I doubt if there was anything else you could buy in 1980 that sounded quite as good and that didn't cost a lot more. At one point I paired them up with a pair of EPI-100s, wired in parallel of course. This combination actually did sound pretty good, for a while anyway. The dullness of the Advents was made up for by the brightness of the EPI with that inverted dome tweeter, and the excessive brightness of the EPI was made up for by the stronger bass of the Advent. I quickly grew tired of the mismatched look and eventually decided that the EPI colored the sound so much that the Advent sounded better by itself notwithstanding the dullness. I occasionally contemplated ways to improve the Advent, but it would have been a lot of work that I didn't think would have been worth doing unless it was converted to a 3-way, and at that time I would have expected to encounter difficulty with the crossover design. I would have ended up with a Frankenstein speaker that would only serve as a constant reminder that I had expended a lot of effort on something that would have made other people ask why I didn't just buy some new speakers. I kept the Advents for a period of time vastly greater than I would have imagined when I bought them. Roughly twenty-five years. Sometimes I wish that I had not sold them, but the way this kind of thing works is that if you still own them you are wanting to sell them. All in all a pretty good speaker and a great value speaker, but not a great speaker when value isn't a strong consideration.

The double Advent thing was also curious and never really made sense, for reasons that are well understand by anyone who has ever dabbled in speaker design. The pair of tweeters are further apart than the operating wavelength at even the low end of the tweeter range. As soon as you get a little bit vertically away from the horizontal plane passing between the two speakers, you start getting interference/cancellation, and the familiar comb filtering effect applies in upper treble if you are as little as a foot or so above or below that horizontal plane (unless you are very far away from the speakers). In fact the vertical separation between the two woofers, together with the fact that the crossover point was fairly high, meant that the same thing occurred in the upper part of the woofer operating range. The only true benefit was the improvement in bass, which was significant and which would have included pushing the F3 point a little bit lower. There can be little question that the enhanced emphasis in bass was the reason that people liked this arrangement. A better result would have been obtained by stacking them without inverting the upper one and with the tweeter disconnected in the lower one and with a simple modification to the low-pass filter in the lower woofer to limit the upper end of its range to some very low frequency, below the frequency where the mid-bass peak was found (which was due to the moderately high Q and which accounted for the "warm" sound that was widely appreciated). The lower woofer would then be essentially a passive, sealed subwoofer without much deep bass extension, but beneficial nonetheless. This would be better than the stacked arrangement that was a very peculiar fad back then, but would still be a kludge that wouldn't make much sense unless maybe you already had a spare pair of big Advents sitting in a closet and otherwise not being put to good use.
 
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