Capacitor Help - Dahlquist M905

[bitterpirate]

Hello,
I am trying to replace the caps in a pair of Dahlquist M905s. I opened them up and found 2- T1 capacitors. I wasn't sure how to interpret the value. Might someone know the value of these and what would be the best replacement? Thanks,
gb

 

[ericj]

I would guess that those are 10uf and 6uf. The "K" marking on larger caps is less common.

Those also look like film caps so chances are good that they are in good condition and there is no compelling reason to replace them.

Component testers that can tell you the capacitance and ESR of a cap are pretty affordable these days:

https://www.amazon.com/Longruner-Po...Backlight-Transistor/dp/B07C5LC486/ref=sr_1_5

 

[bitterpirate]

Thanks ericj! I think that is a good guess. Funny, I can't seem to find anyone that knows for sure exactly the type and value or the caps.

 

[teal'c]

Interesting. Same caps as in my AT-15s.

 

[bitterpirate]

Interesting. Same caps as in my AT-15s.

Hey there. Might you know the type and value?

 

[teal'c]

No more than ericj posted. No need to replace unless you want to roll them.

 

[rogerfederer]

6 and 10 uF must be correct. take a look at this:
http://www.alltronics.com/cgi-bin/item/28P244/AD/Tecate-5.6uF,-100v-Polyester-Capacitor#

 

[RTally]

Thanks ericj! I think that is a good guess. Funny, I can't seem to find anyone that knows for sure exactly the type and value or the caps.

No mystery here. The markings on those caps are standard for that type of cap. The first two digits are the capacitance value in microfarads, the letter is the tolerance of the capacitance value, the final part is the voltage rating or dielectric breakdown voltage. For example, "10 K 100 V" means 10 uF +/- 10 % tolerance with 100 V maximum voltage.

A google search will show how to interpret capacitor markings, for example:
http://www.robotoid.com/appnotes/electronics-capacitor-markings.html

PS: Those Mexico caps are common. I have seen them used in crossovers for various speakers.

 

[ericj]

No more than ericj posted. No need to replace unless you want to roll them.

On occasion, a film cap does get damaged. But those look like they had had easy lives.

ESR meters have become so cheap that everyone who tinkers with speakers should have one.

 

[F1nut]

Those are mylar, easily bested.

 

[Blue Shadow]

I am trying to replace the caps in a pair of Dahlquist M905s

Why? Now that you are inside looking at the goods and find out they are good, by looks not measurement but not 'lytics that change over time, you can probably leave them alone and go attack some other chunk of gear in your stable. But as stated you can get into some fancy caps, audyn, clarity or some such brands, not the common stuff and improve things. You already have good, common stuff.

Enjoy the journey and let us know what you slap in there and how it sounds.

 

[homebrew]

Replacing the cheap mylar film caps with Audyn A4's (10uF @4.57 ea. and parallel 3.9 & 2.2 uFd (yeah, it.s 6.1 but that's no big deal) 4.59 for both. That's $18.32 for both speakers. A very worthwhile investment. I'd probably replace the 5W sand cast resistors with 10W non-inductive resistors (less than $1.50 each). Total damages: $25.00. Leave the inductors alone.

 

[bitterpirate]

Thanks everyone. Thanks for the spot on cap interpretation!! Joe at Regnar (Dahlquist) returned my call readily. He said while the caps could very likely check out within tolerance, they have found a marked sonic degradation. He didn't push a replacemtn but predicted a noticable improvement with replacement. A friend also recommended replacing the tweeter ferrofluid while I am at it. All told, about $35 in parts for the refresh.