(3) driverless Dynaco a25s acquired for free today

[wiredbecker]

Previous owner painted them black. Yellow_Light_Colorz_PDT_21 Then someone else stripped out and sold all the drivers. Fortunately for me, they still contain the dampening material and crossovers.

I found some woofers on eBay but I bet they'll go through the roof. Please keep your fingers crossed for me. As far as tweets are concerned, I found some replacement Seas at Madisound for $34 ea. But before I start filling up the holes, I need to make sure the crossovers are up to snuff.

Can anyone link me to some a25 crossover rehab directions?

[parabellum]

good luck man :)


I had a similar question about a25s and joeriz provided a link to to what he did with his own a25s.
http://diytube.com/phpBB2/viewtopic.php ... ght=#11372


I got a bit lazy and didn't do any of it yet Yellow_Light_Colorz_PDT_13

[wiredbecker]

oh yeah I totally forgot about that, thanks for the heads up

[erichayes]

A-25s don't have crossovers to speak of--just a 4.7µF electrolytic to keep the tweeter from getting fried by low frequencies and a simple voltage divider attenuator (10+2.2+2.2+2.2+2.2Ω) for tweeter level. The cap does provide a 6dB/octave turnover for the tweeter, but the physical characteristics of the woofer create the actual crossover "point".

I currently have 10 pairs of the original A-25s, and all I do to them is replace the cap with a Solen poly 4.7µF, clean the switch with anhydrous isopropanol, and replace the speaker leads with 16ga silver plate stranded wire.

Wear gloves.

[wiredbecker]

Eric,

You rock. Other sources suggest a Solen 5.1uF 400V cap. Should I consider getting replacement resistors as well? Will post pics of the recovery process.

[erichayes]

Just go across each resistor with an ohmmeter and check 'em for proper resistance. Wirewound resistors rarely change value--they're either good or open. I've never run across an open resistor in an A-25, but, with missing drivers, all bets are off.