Dynaco a25 questions (should I service or not)!?

[mique]

I bought a beautiful pair of Dynacos on Ebay. After discussing on "solid state" forums... I bought a Luxman amp.

I'm a rookie I had a KRK powered speakers before that, but I wanted to dig into vintage audio to get a better and warmer sound for my living room (and not paying a fortune for it).

The system sounds good. I had to turn up the treble for 6 db and lows for 3 db to get the sound I liked. But after a couple of days I was begining to hear the differences between the two speakers. So I turned on the "mono" and was listening the songs on left and right. What I found out is that left speaker has stronger bass and mids, while the right one has more open highs, but is much weaker on lows.

What could it be, should I service them? Or considering this are original speakers and older than 40 years - this is normal and should just accept it. what are your thoughts?

 

[Oozure]

You should have them looked at if you do not feel comfortable doing it yourself. They shouldn't be left to function improperly. It could lead to a damaged receiver/amplifier or further damage the speakers.

 

[trinhsman]

Speakers that old may need the crossovers re-worked. There are a couple of people I know that can do this very well. Once is Carl's Speakers, the other is an AK member GordonW. They both are masters of crossovers. I can't tell you for sure if that is your problem, but it very well could be and the crossover re-work won't hurt.

 

[Crestwood23]

That's a sweet little setup you have going on. The A25's are all time classics and deserve to be restored. It's most likely just an out of spec capacitor causing the issue, do a search on AK for recapping A25's, there's a lot of info. If you can solder, it's a pretty easy repair. If you can't, there are some you tube videos that can teach you. If the issue still persists after the recap you have a driver issue, then it's time to test the individual drivers or seek pro help.

 

[elitopus]

The hardest part would be getting the woofers out. They used a black goo to seal them.

Once inside you just change out a single 5uf cap and clean the pot. Then make sure and reseal the speaker as well as it was.

I would also take a look at the woofer terminals while you are in there. They have been known to fall apart and short out or go open.

 

[N8Nagel]

weak treble = crossover caps or dirty pots

weak bass = not sure, but definitely check out woofer terminals per above. Might as well reflow all solder joints while you're in there, and if there are any Fastons (I'm not sure what Dyna used, not ever having had any) hit them with Deoxit and disconnect/reconnect a few times.

 

[WaynerN]

Seas woofers in Dynaco speakers have a history of the input terminals falling apart. When this happens, there is a possibility of the woofer shorting out.

Of all the many A25 and A25XL speakers that I have worked on, the cap was usually within tolerance. Weak point is the selector switch on the back. That needs to be really cleaned up with Deoxit-5. Some folks have bypassed the control and have hard-wired it in the position they favor.

 

[sax6]

Seized voice coil on the weak woofer ?

Push gently and evenly on the cone of the bad woofer.

Hear some scrapping ?

If so, woofer is finished.

 

[mique]

Thanks everybody! I found a guy who will check them and see what to do. I'll forward him this topic for a reference.