Dynaco Speaker design

[Guest fetzenpeter]

>Hi again Christian;

>

>My last write-up should have suggested disconnecting the amp

>from the rear connections.

>

>With the woofer and tweeter out of the cabinet.

>

>Cut one lead to each or both.

>

>Separately, test with a single 1 1/2 volt, maximum, battery

>and see if there is a forward movement of the woofer and a

>click on the tweeter.

>>>>> CD: I did it with a fresh 1,5 V AA battery. But on the woofer i just got a little click and no movement, and on the tweeter nothing at all. Funerals now ? Thanks, Christian

>That is all I can think of, Christian.

>

>This was the very last thing that I wanted you to do, remove

>both drivers and cut wires.

[dynaco_dan]

Hi Christian;

If you have lots of time and patience you can disect them to see what the problem might be.

There may be a chance that a wire from the tweeter connection to it's voice coil may just have break in the lead.

The woofer would require that you unsolder the leads from the solder clips.

Gently peeling off the rubber surround from the frame.

Carefully, with a small paint brush, outdooors of course, brush a small amount of lacquor thinner or Acetone along the outer perimeter of the spider only and the glue should soften and release the cone.

If you have gone this far, please take a photo or two.

[craig]

Hi Vern

I was surprised to read about A-25 systems having woofer burnout issues. You are right about some people not knowing when their amps are clipping and going dc.

I recently purchased a MINT pair of A25's (in the original cartons) from my local vintage stereo shop. They sounded beautiful with the exception of the somewhat lacking high end. The Seas tweeters were working, but they sounded more like midranges to me. I replaced them with Vifa 1" silk domes, and now they sound terrific. I do prefer my AR3A's, but for the remote speakers in the den the A25's can't be beat.

Do you think the Vifa's are okay with the existing crossover? They sure sound ok!! I'm driving with a Pioneer SX-850 (65 watts rms?)

Also you mentioned fuses. Do these units have fuses in the cabinets?

Lastly, they have beautiful brownish-pumpkin colored grills. Have you ever seen those before? I remember the older Scan Speak and the newer Seas units having white grill cloth. I also noticed that they moved the aperiodic vent from under the tweeter to under the woofer. Was this due to the Seas drivers having a different dynamic?

strange i own 2 pairs of A25s and one pair seems to have brilliant highs the other not as much so

[dynaco_dan]

strange i own 2 pairs of A25s and one pair seems to have brilliant highs the other not as much so

Hi Craig

Are the 2 pairs identical?

By that have you checked the serial numbers?

Have you checked the drivers through the grille cloths, with a flashlight, or removed the grilles yet?

Are your switches in the same, such as, identical 1 of 5 positions?

Are the switches both the same on the rear, such as, screwdriver versus knob and both have 5 positions, not 3?

It may be that you have a pair of A-25XL's which are about 3 dB more efficient, as in slightly louder.

Have you switched left and right speakers in your present setup?

Have you interchanged with the different sounding speakers?

It is possible that at this moment you may have Scan drivers in one pair and Seas drivers in the other, by fluke.

Or even Scan and Seas in each pair.

I've not listened to my Scan and Seas sets to see what the differences, if any, there are.

My confidence in Dynaco is that they sound remarkably similar, hopefully, not blind trust.

As you reply to this writeup we can hold your hand and troubleshoot the difference, Craig.

As the world turns.