dynaco A25 super bright

[Brad Muller]

The Zillchster speakes!:yes: You're always there for us Zilch! It's a bird....... a plane....., no, just the Zilchster.:thmbsp: Brad

 

[markus]

just for shits and giggles, have you tried different preamp and/or amp ?

not bashing your gear by any means, but I run my A-25's off a magnavox PP 6BQ5 amp, and a Marantz 2226B as a pre, and I actually have to turn the bass down a couple clicks. . . (its the Marantz . . . .)

 

[dagray3]

Ok, here are some pics (I think);

The close up of the center of the driver shows the glue around the center felt(?) is delaminating from the cone itself.

I also included one showing the vent port, and you can see the start of the SEAS H3 part number coming off of it. Both also have the SEAS rubber surround (SR 231).

I put in a pic of the setup of the speaker (left side) relative to the wall and to the amp.

Finally, there is a pic of one of the full speakers.

 

[dagray3]

Markus, I haven't tried any other gear yet. My stuff is all vintage dynaco, recapped but still not really top of the line. I ahve tried other speakers on my amp, but I haven't tried the A25s on different amps. I have some crappy surround sound theater thingy I use for TV that I can try and see if they sound different. I'll let you know.

 

[Doug G.]

The reason for the misunderstanding when Zilch first said they need subs is that many younger people actually call the woofers in a normal pair of speakers "subs". So the OP thought he was saying his A25s needed new woofers.

What he really meant was the A25s need to be used with external sub-woofers to get deeper bass.

Back in the day, we never referred to the woofers in a normal pair of speakers as "subs" and now we see why. It leads to confusion.

The low frequency driver(s) in a speaker are "woofers" and the high frequency drivers are "tweeters". Subs are an external speaker for even lower frequencies than the main speakers can provide.

EDIT: Oh, and dagray, repair or get that woofer repaired now as it will only get worse.

Doug

 

[avguytx]

I have 2 pairs of them and needing a sub is all personal preference as the charts say one thing and our ears say another. Go with your ears. I think they sound very good on stands and fairly close to the wall. Even better stacked but of course, in the Forum, that's personal preference. Just my $.02 and YMMV.

Try some contact cement for repairing the felt back to the cone.

 

[dagray3]

Thanks for the advice on the contact cement.

What does stacked mean? I have seen that before, but I don't really know what it means.

Doug was right, I thought Zilch meant I needed new woofers.

It really does sound like the brightness is coming from my ears and their expectations. Any advice on how to repair my ears? Should I drop some of the contact cement in there? I suppose I'll just spend some more time listening with the A25s and see what turns up. I need to refinish them anyways (they look like they've ben through a carwash). So, I'll decommision them and glue, refinish and then try to give them ample experience.

I think my taste in low end has been changing, but I am new to real audio -- I mean listening to how the music is supposed to sound rather than pumping the bass until the house shakes. It's a difficult adjustment, since I have always listened on crappy, superbassy systems. I am getting there.

Thanks again everyone.

 

[jgmacv]

I recapped my A-25s about a month ago. I originally didn't notice a real difference, but after listening for some time, I can tell an improvement in the high end. I never noticed a difference in bass. I'd give them more time to "mellow", and then see what you think. I'd also read another post about using longer screws to secure the woofers to the cab.

 

[jnoyes4]

Its good that you are trying to learn to appreciate a system that can produce distinctive bass notes rather than the one note bass produced by many vintage speakers. Give then ample time, may a few months, maybe less. But in the end, its what you like that makes a difference. Don't think you are supposed to like something because someone else says so. There are many members here with speakers that produce what is called "one note bass". Many of them like it that way. What's wrong with that? In the end you are the one listening, make yourself happy!

Jon Noyes

 

[Gary Francks]

Just a quick thought on this.
If you remove the drivers on A25's don't you need to re-seal them into the cabs?

I thought the driver/cab seal was part of the tuning for the bass in combination with the vent, each speaker being individualy tuned at manufacture by varying the vent filling.

 

[dagray3]

So, how about it? When I recapped, I just unscrewed the drivers, pulled them out, recapped, dropped the drivers back in and rescrewed. I didn't scrape the goo or replace it with new goo. Should I have? Would that make any difference?

 

[jnoyes4]

It's certainly important for acoustic suspension designs (sealed box) to be pretty much air tight. The air spring effect controls bass response. The Dynacos are aperiodic meaning a stuffed vent. I think there would have to be a pretty big leak to cause a problem such as you describe. I doubt it's that significant. The bass response would be impacted if the stuffing in the vent is not as originally designed, but I think you already checked that right?

Jon

 

[dagray3]

as far as I can tell the stuffing in the vent is Kosher.

 

[Urizen]

I didn't scrape the goo or replace it with new goo.

After I recapped my A25s, I noticed an air leak around one of the woofers. I could feel it with my hand. Some speaker caulk took care of it. Dynaco put that goo there for a reason. There should be no air leaking around the drivers.

 

[Dadbar]

Take a picture of the cabinet stuffing and post it

The Dynaco's are sensitive to the quantity of stuffing in the cabinet for bass response. It's possible that the previous owner decided to ditch the original fiberglass stuffing and put in new polyester stuffing without realizing what he was doing.

My A25's had a few sheets of fiberglass stuffing on them that came out pretty easily when I recapped...and they didn't take up the entire cabinet.. Maybe yours are vastly different?

 

[fazman]

Hey, I recently picked up some A25s off ebay. I recapped them (5.1uF from Angela.com) and the high end sounds spectacular. The problem I am having is that the bass seems lacking. I feel that it's just not all the way there. If I adjust the crossover, the highs seem to get muddled (which is bad) but, of course, the bass stays weak.

I thought I had read that replacing the screws on the bass drivers could tighten up the bass?? Anyone have any advice on kicking my bass in a little?

I am running a Dynaco PAS3 and an ST70 to drive these speakers. My setup sounds good with other speakers (although the highs are veiled), so I don't feel I need to do any adjustments on the amp/preamp end of things.

I would appreciate any advice anyone has.

Thanks

dagray.... You may have fixed your issue already, but incase you didn't... You used 5.1 uf caps for the tweeter. This WILL make a difference. You are allowing the tweeter to go lower in frequency albeit not by that much. The proper value from what I've seen is 4.7uf. I've tried a 5uf cap with a .1uf bypass cap and I didn't like the results. I felt the same way you did about the sound. So I put in 4.7uf caps and....
Try it... I think you'll be happy with the results. The lower treble is not as blaring when you use the 4.7 thus making the bass seem more apparent.

Caps are cheap... try it.

 

[hypertone]

Are they in phase?

 

[wiredbecker]

Just for kicks try flipping them over so the tweeters are on bottom and the woofers are on top. How does that change the sound for you? Are they still bright?

 

[avguytx]

dagray.... You may have fixed your issue already, but incase you didn't... You used 5.1 uf caps for the tweeter. This WILL make a difference. You are allowing the tweeter to go lower in frequency albeit not by that much. The proper value from what I've seen is 4.7uf. I've tried a 5uf cap with a .1uf bypass cap and I didn't like the results. I felt the same way you did about the sound. So I put in 4.7uf caps and....
Try it... I think you'll be happy with the results. The lower treble is not as blaring when you use the 4.7 thus making the bass seem more apparent.

Caps are cheap... try it.

The original cap is 5uf and, within a 10% tolerance, 5.1uf and will NOT make a difference. 5.1 is closer to the original than the 4.7 anyway. Mine have been in there for 2+ years with no problems. If your ears can hear a .4uf swing in a cap, then you are a better man than us in here. But, go with what works for you.

Bypass caps add in their own oddities and are personal preference. Most times they were used in conjunction with cheaper electrolytics to add in some sonic characteristics of the poly cap. Used with good quality poly caps, though, is a waste. I've always removed them and not used them again with better caps. Just my $.02 and YMMV.

 

[JohnVF]

My A25s can sound very bright depending on what I drive them with, and they haven't been recapped or modified in anyway. They sound full and tight on a Fisher x202b, but with my ARC sp3/Dynaco 70 combo they sound bright and the punchy bass they had with the Fisher is a bit lacking. I have heard A25s with another Stereo 70 that didn't sound bright, so maybe it was my ARC.

Not sure this helps..just a similar observation. They sound great on the Fisher, though.