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Dynaco A-25 mods

I don't know the answer to that.... I suppose it might.

It would be interesting to hear from someone who has tried this both ways.
 
hpsenicka said:
I don't know the answer to that.... I suppose it might.

It would be interesting to hear from someone who has tried this both ways.
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I have heard it both ways, with my Seas tweeters. I preferred the sound without them, even off-axis.

My KLH Six and Seventeen tweets use metal grills, as do the tweeters in my Fried Q/3. Older Advents, too. All of them are a pleasure to listen to, but IMHO, they all lack in smooth extended highs.
 
So far I'm disappointed...

I replaced the electrolytic caps in one of my A-25s with the Dayton 5.1 uF 250v caps that Urizen used. My wife and I both did an A/B comparison and both chose the speaker with the old cap as sounding better. More dynamic and clear. What am I doing wrong? More importantly, what can I do besides solder the old one in to improve it?
 
jallenbass said:
I replaced the electrolytic caps in one of my A-25s with the Dayton 5.1 uF 250v caps that Urizen used. My wife and I both did an A/B comparison and both chose the speaker with the old cap as sounding better. More dynamic and clear. What am I doing wrong? More importantly, what can I do besides solder the old one in to improve it?
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I'm not sure of the background to the the old thread, but perhaps the new caps were meant to be used with the "replacement" tweeters; whereas, the original speaker had different cap values???? Just a guess, hopefully the original posters will chime in.
 
jallenbass said:
I replaced the electrolytic caps in one of my A-25s with the Dayton 5.1 uF 250v caps that Urizen used. My wife and I both did an A/B comparison and both chose the speaker with the old cap as sounding better. More dynamic and clear. What am I doing wrong? More importantly, what can I do besides solder the old one in to improve it?
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See a doctor...tell him there's something wrong with your hearing.

(just kidding)

Those old, original electrloytic caps are wayyyyyyyy past their 'due date'. They should be replaced regardless of what tweeter you're using.

Solder the oldy-moldy electrolytic cap back in? Good Lord no...:no: Maybe you've grown accoustomed to the 'built-in' filter that the worn-out cap has provided for you, but whether you like the results of replacing it with a new film cap or not (and if you do not, you're in a minority of your own here) that isn't the way Dynaco meant for those speakers to sound.
 
The filter that I hear is with the new cap. The old one sounds open.

I know some are wondering about our hearing but we're both classical musicians with multiple degrees, professional experience and such.
 
jallenbass said:
The filter that I hear is with the new cap. The old one sounds open.
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Every vintage speaker I've recapped sounded as if a blanket were lifted from it, bringing the crossover point to where the original designer meant it to be.

I'm with winters860, perhaps you have a defective cap, or possibly it may have been damaged during the soldering process. Also, check the polarity on the tweeter. You may have wired it out of phase.
 
Just to clarify, I only changed out one speaker's cap. I have yet to replace the tweeters.

Urizen - I will check the caps with a multi-meter. I hope it's as simple as that. Thanks.
 
Urizen said:
I am truly interested as to how a metal grate can help a tweeter sound better. Perhaps someone else will chime in,
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Have you ever done the solar eclipse shadowbox thing? If not, you take a box and put a small hole in one end. Stand it up with the hole on top and the (former) top of the box open so that the sunlight will come through the hole and project onto the (current) bottom. As the eclipse progresses you will be able to see the amount of the sun covered by the earth in the projection on the bottom of the box. Now the important part, the projection is much bigger than the hole. The same principle applies to the metal grate.

It is diffraction, just like EW said. You can look it up on wikipedia if you're mathmatically inclined. It's a little dry.

One of the major issues in the commercial sound world is dispersion. Contractors are happy if you can increase the dispersion of the speakers so they can use less of them for covereage of a given area. We played around and found that by using a baffle type plate in front of the speaker that had a hole about 70% of the speaker's radiating area that the disperion angle was increased something like 20%. That's basically what the metal grate is doing.

As to killing off the direct sound...the same amount of energy will come out of the speaker. What the grate does is change the ratio of direct to reflected sound. It will change the sound directly in front by sending more of the energy out to the sides to be reflected/refracted by the room. Typically this will even up the power response and create a bigger soundstage.

Ray
 
Eee gaads! change out the original tweeter for a better one?! :scratch2:
Try to improve the sound with better drivers? :scratch2:

Just being facetious :banana:

I thought A-25's had some vintage value and were worth restoring. Perhaps not?

I developed a great sounding upgrade to the classic AR3a using new Seas mids, tweeters & crossover with bi-wiring capability. The details are available on my web site. However, not much interest has been shown. Perhaps there is more interest in restoring the AR's than Dynaco's?

Any opinions on this viewers?
 
I thought A-25's had some vintage value and were worth restoring. Perhaps not?
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Tweets were changed on mine due to an intermittent fault in one of the originals, otherwise I'd probably have simply changed the cap and called it a day. As far as I'm concerned, the end result is an improvement over the stock tweeter, who's dispersion pattern is nothing to write home about.
 
I have seen it, and posted it in another thread.

The "Air" it adds is constant, independent of the HF attenuation setting.

I considered using something similar on AR4x, but found it unnecessary with them, as the VHF is already extended, as I recall....
 
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