khendrik

Dynaco A-25's & Subwoofer

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I'm a complete newb to the Hifi world.  I just purchased a nice pair of Dynaco A-25's.  Hoping to set them up with a Sansui AU 7500 I have my eye on. Listen to a lot of 60, 70 rock, blues etc.  I'm simply looking to add a small subwoofer to fill out the sound a bit. 

  • what are a few basic subs anyone could recommend for a vintage setup. size etc.
  • what hookups on the sub should I be looking for (Someone mentioned a "Z hookup or connection"?*!") 

Thanks

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Hi khendrik, and welcome to the CSP forum. I am no expert with this famed speaker model, but the A-25 has that wonderful 10" woofer with rubber surround that gets such high praise - - how about first testing these "new" speakers out for awhile before deciding if they need any additional boost on the low end? Report back with impressions after listening to a variety of source material.

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On ‎29‎/‎01‎/‎2017 at 5:24 PM, khendrik said:

I'm a complete newb to the Hifi world.  I just purchased a nice pair of Dynaco A-25's.  Hoping to set them up with a Sansui AU 7500 I have my eye on. Listen to a lot of 60, 70 rock, blues etc.  I'm simply looking to add a small subwoofer to fill out the sound a bit. 

  • what are a few basic subs anyone could recommend for a vintage setup. size etc.
  • what hookups on the sub should I be looking for (Someone mentioned a "Z hookup or connection"?*!") 

Thanks

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

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Listen to both Vern & ra.ra's sensible comments and also consider Gordon Holt's comment about the A-25s rattling his windows at 29 Hz. before you add a subwoofer.

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Thanks, Jerry. I would have sworn the original article said it would rattle windows at 29 Hz, however optimistic that may actually be.

Also note all the typo's in this article, probably transcription errors, such as referring to AR5 when AR3 is intended and to AR5a when AR2a was most likely intended. 

I will go & look for the original article which is in a box somewhere in my closet.

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Here's the promised quote from Gordon Holt in Stereophile, Vol.9, Number 2. I think it was released in early 1970 although it is dated December, 1969. This quote comes from Dynaco's original literature packet and appears to be an exact copy of the original Stereophile review.

Careful readers will note that there is a big discrepency in the much more recently re-published Stereophile online article that has changed  35 Hz to 55 Hz and 30 Hz to 50 Hz in regard to the A25's limits.  

The online review also incorrectly mentions the AR5 as well as the non-existent AR5a, lending further support that the review was retyped by a non-Classic Speaker Pages reader who made a few too many typos. 

..... the A-25s tend to put out too much bottom in most rooms when placed on the floor or in the room corners. Best results were obtained in most instances with the speakers a couple of feet above floor level, which is convenient in view of the fact that these are, after all, supposed to be bookshelf systems. Both the AR-4x and the Seventeen have a noticeable amount of the midbass heaviness that seems almost to be an innate characteristic of ultra-compact systems, so whatever output they may have in the extreme low-bass range is rather effectively masked by the upper-range weight. By contrast, the A-25 seemed at first to be deficient through the entire low end, at least until some really deep stuff came along. When it did, what came out of the A-25 simply defied belief, for they went even deeper than two of our "standard" systems, the Z-600 and the KLH Nines. We knew that a single pair of Nines, with the panels separated, start to roll off below about 50 Hz, and that the Z-600s in most rooms start to dwindle below 40 Hz. But we were certainly not prepared to find these piddling little Dyna systems going flat down to 35 Hz and rattling windows at a hair below 30 Hz! And this with a degree of detail and tightness that rivaled the Nines and ran circles around the Z-60O. The AR3a, of course, is practically in a class by itself when it comes to low-end range. With virtually flat bottom down to around 25 Hz., nothing short of some monster systems can equal it in this respect. Certainly, the A-25 couldn't. But in the matter of transient response, particularly through the woofer's range, the AR-3a has left something to be desired, and it is here where the A-25 offer the AR-3a some real competition. ln test after test, the A-25s revealed more bass detail than the AR-3a and, in most cases, produced a more natural bass/treble balance than the larger ARs. Some listeners have complained about a certain "heavy" or "thick" quality about the AR-3a's sound, The A-25's had virtually none of this, and neither did they have any of the mildly distressing "crinkling-paper" sound that is so common in small acoustic-suspension-type systems. In other words, as ridiculous as this may sound in view of the price difference, we would opt for a pair of the A-25's over a pair of AR-3a's. 

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