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Need help choosing capacitor upgrades in crossover

I'm in the process of rebuilding a pair of Dahlquist DQ-20i's. For those that have heard the 20i's, you know they have a warm, detailed sound. Some consider them a best buy in the under $600 vintage market. I like their sound, but I want to see if I can improve on a good thing. I plan to rebuild the crossovers with:

- Mills wire wound resistors 12 watt
- 10 AWG inductors (custom made)
- 10 AWG oxygen free wire

I'm looking for advice in choosing capacitors. The stock caps are Solen PB metallized polypro 400 VDC. There are four caps I'm looking at replacing (3, 5.1, 13 and 24 µF). I understand that Solen's are a great value and widely used in the mid-priced speaker market. As you know, high-end caps are very expensive. If I need to spend $450 to hear an improvement, it's just not worth it to me.

After price shopping, I've narrowed down my choices to: Sonicap, Kimber and Auricap. I've heard good things about Kimber and Auricap, but will they be a significant improvement over the stock Solen's? I know very little about Sonicap. If you have other suggestions, please let me know.

If you had to choose between Solen, Kimber and Auricap which would give the best bang for the buck?

Here are my total costs for each brand:

Sonicap $144.60 @ Sonic Craft
Kimber $237.22 @ Sonic Craft
Auricap $250.50 @ Parts Connexion
AudioCap Theta $442.92 @ Sonic Craft
Mundorf Silver/Oil $1186.30 @ Parts Connexion
Solen (exact replacements) $37.60 @ Parts Connexion

I hesitate to mix brands, even though North Creek thinks it's okay:

"We feel that most film-and-foil capacitors and many metallized film caps have a sonic signature that is a little inhomogeneous and with an over-emphasized or ragged treble. For most of these caps, bypassing with a 600 Volt Crescendo cap will do wonders for the combination's harmonic balance. Capacitors with an overly soft treble (such as polyester film or low frequency polypropylene film caps) will benefit from a 1µF Harmony bypass cap, and can be further upgraded with the addition of a 0.10µF Crescendo cap."

http://www.northcreekmusic.com/CapacitorFAQ.html

A conflicting opinion from an AGon member says:

Make sure you use the same type of caps thruout. I would not mix and match these different films as they have different speed and respective signatures.

http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1126890142&openflup&5&4#5

FWIW, my electronics:

Anthem Pre2-L
Parasound HCA-1500A
Rega Planet 2000

Thank you in advance for any advice and thoughts you might have.
mingles
9 responses Add your response
mingles OP
791 posts
 
Hi Opalchip, I agree the DQ grills are a ridiculous cosmetic affair that do more harm to the sound than anything. The Dynamat suggestion is interesting. I like the idea of controlling vibrations, but I haven't noticed any noise coming from the grills. I have noticed an air-flow "wheeze" coming from the seal around the binding post area in the back. I wonder if others have had this problem. I'll definitely use rope putty to seal everything tightly. I'll also use felt tape to completely cover the midrange/tweeter baffle to reduce diffractions.

This current project is a precursor to a larger project I have in mind. I'd like to build a DQ-20i/Alon IV hybrid with an attractive wood enclosure and a minimal grill. For the time being, I need to stay focused on getting my crossover back together! Thanks again for all the feedback! -Mark
opalchip
355 posts
 
I have done a fair bit of experimenting with DQ's, which are IMO still very competitive with many current designs from an overall "listenability" perspective. I've found their main weaknesses to be somewhat "soft" highs and a bit of a suckout in the low mids.

If your budget is fairly limited, my recommendation would be to spend the money on addressing those issues with better mid/tweeter section caps and skip, for now, any changes to the woofer side.

The low end exhibits a bit of rolloff in comparison to many newer speakers simply by virtue of it's sealed enclosure vs. the trend toward ported "boom boxes", but it IS tight and melodic - as long as you're giving them plenty of power. So I don't think you'll see much improvement there by replacing caps - and it's certainly not where the bang for the buck is on a budget. If you're happy with the mid/high upgrades you could later contemplate replacing the old Advent woofers with something more state of the art.

One additional tweak to consider if you're running them with grills on is to damp them by placing a "quasi-triangular" strip of Dynamat along each side of the grill (on the expanded mesh inside) from the top down to just above the woofer enclosure. You want to keep the Dynamat's shape as wide as possible without "interfering" with the tweeter and midrange drivers' normal horizontal dispersion patterns.
Then place another strip across the grill near the bottom (well below the woofer). Then glue thick felt onto the dynamat to prevent acoustic reflection.

The DQ grill was a cosmetic nod to the Quad's design, which was a favorite of Jon Dahlquist, but it's a sonic problem that serves little purpose other than look cool (although it does protect the speaker really well from toddlers). Doing this mod will significantly reduce coloration in the mids and highs, and allow more bass energy to propagate rather than be absorbed.
mingles OP
791 posts
 
Thank you for your feedback. I realize this is a subjective question to ask. Some have suggested North Creek Crescendos. I've heard good things about them, but the cost is $430 for my project, hence putting it out of my price range. The Obbligato's look interesting, but there isn't much information aside from their website. I'm leaning toward Kimber caps. I think they're a safe choice and reasonably priced. Thanks again! -Mark
vman71
218 posts
 
IMHO, I like Kimber Kaps and Auricaps. The price vs. performance is great. As somebody mentioned earlier, they are basically the same cap. They come out of the same production factory.
gmood1
1,251 posts
 
Have you seen the Obbligato Premium Capacitors? I haven't heard them. But I do agree it is a preference so no real wrong or right here.
Solen are fine for bass. I wouldn't use them for midrange or highs in the crossovers. The Mundorfs are terrific as mentioned above.I like the Sonic Caps also. I found their sound slightly cool but open. The North Creeks have a good sound both the Crescendo(warm) and Harmony caps. The Crescendo is tweakable just by reversing the inputs.

None of these caps are bad. Unfortunetly the only way to know if they work for you...is to experiment.
tweakmenow
35 posts
 
Typo in above post.... Caps I used are SA. (no such thing as PA)
tweakmenow
35 posts
 
I just replaced caps in my RBH Signature speakers. They came with 250v Solen's. I replaced them with 630v Clarity PA's. (their best) I was surprised how smooth the Clarity were. Also the Clarity are a real bargain. I purchased them at e-speakers.com

Read this amazing page to help you decide which cap to purchase: http://www.humblehomemadehifi.com/Cap.html
loontoon
301 posts
 
Garlic no garlic, this is a case of personal opinion, I can say that I've heard some of the bunch, and I don't like Sonic caps, hard and etched. Kimbers I liked, Solens are good low priced but then you already have that, Auricaps not heard, Theta's too long ago and the Mundorfs I've heard, not Silver Oil are good.

jeff
merganser
216 posts
 
The Auricap and Kimber caps are essentially the same, both are good. The Mundorf's are excellent, but probably far more than you want to spend. I think the Sonicap's are very good to excellent and if you bypass the high frequency caps with their .1uF Platinum caps I believe you may find yourself in heaven. All of the above sound better than Solen's to my ears.
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