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upgrading speaker crossovers & tuning

I recently picked up a pair of Snell type A's (orginals) in near perfect condition. The foams were recently upgraded.

I have them hooked up to 60 watts of tube power while I search for the preamp & power that will drive them for real.

At this point the speakers sound fine (barring the lack of the right power), but I'm considering having the crossovers upgraded. I found a gent out on the east coast that has redone one pair of Type A crossovers with apparently very good results. (see bottom of webpage --> http://classicloudspeakerservices.com/gallery.html#crossover)

There is one point I'm sticking on & I hope someone here can help me out. It's said that Peter Snell 'tuned' each set of speakers prior to them being available for sale. I hear this is still the practice today.

One description of the tuning I've run across is: "A highly specialised set up process, which matches the crossover to the drivers in a way that not only aligns the drivers in the frequency and time domain, but also affects the dispersion."

My question is whether the crossover upgrades will basically negate the tuning that Snell did. Is this 'tuning' marketing hype or something real that shouldn't be lost? As I said, the speakers currently sound very nice, but I have to believe the capacitors and resistors might be weak just from age alone on top of being obsolete in design.

If the tuning is lost by the upgrade, can I get it back? I'm told there are variable resistors in the crossover that may be the tuning mechanism & that the upgrade doesn't touch these. Would this maintain the tuning in spite of the upgrade?

Lots of questions I know...

thanks
fishboat
7 responses Add your response
unsound
7,313 posts
 
The old Snell's claim to fame was the degree to which everything was matched. Unless you are aware of a problem my suggestion would be to leave well enough alone. Tampering with the crossover might devalue them for resale. Of course one could also argue that there are better parts and applications available now. I'd leave them alone.
jeffreybehr's avatar
jeffreybehr
805 posts
 
I disagree with Unsound. I agree with Fischboat in that the quality of the caps and resistors probably leave a LOT to be desired.

I certainly don't disbelieve that Richard Snell personally tuned each system. I THINK you can retain that by matching the replacement resistor and cap values to within 1%. I'd sure take out any variable resistors and replace with good fixed resistors. The Mills 12W. NI WWs sold by Percy and Sonic Craft are great for crossovers, and probably I'd use SoniCap-1s to replace all caps*. If there are inductors in series with the signal (other than in the bass section), as in a MR low-pass filter, I'd use the AlphaCores, here http://www.soniccraft.com/alphacore_inductors.htm .

Good luck.

* except any shunt cap in the woofer section.
.
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rauliruegas
12,823 posts
 
Dear Fishboat: I agree almost with Jeff.

Where you can hear an improvement is when you change the inductors and capacitors ( less with the resistors, but you can try. ).

The Alphacore inductores are the best that I know, I'm using the silver wire version, better than the cooper one.

About the capacitors: I already try almost every cap out there, including the Sonicaps that are very good, and I think that the best are the ones from V-caps: hands down any other cap in the market for a speaker crossovers.

For the resistors, nothing come close like Mills resistors.

Where I disagree with Jeff is about the variable resistors, because this ones are used to " tame " some internally design parameters and maybe you could use it for align something in the speaker crossover.
Now, if after you change the caps and inductors you think that everything is Ok, then you can follow to change that variable resistors for good fixed ones ( Caddock ).

Regards and enjoy the music.
Raul.
jeffreybehr's avatar
jeffreybehr
805 posts
 
Raul's comments make sense to me. I'm no GEA but I've heard differences in caps and resistors, the latter between the cheapest sand-type and the Mills NI WWs. I've replaced the usual 16g. inductors in series with the MR drivers of my Eminent Tech. 8s with Solo copperfoils, and the whole topend sounds better, but I did other things too.

Tuning with and later replacing variable resistors is a good idea.
.
theaudiotweak
2,772 posts
 
Peter Snell made his own multi-caps that were composed of many small value electrolytic caps. He did this so he could add more or less value to flatten the curve. He also weighted the woofer so as to lower the resonance and to better balance the woofer piston movement. I have in my own experience found that resistors make much more of a difference in a speaker than a designer would ever admit. Using Vishay metal film types in a ladder bridge configuration works out to be about sixty dollars per replacement, lotsa locations add up to lotsa money and lotsa difference in sound quality. Totally black and quiet backround nothing but music minus any noise. If you remove each and every value in your speakers and measure and record each value you will be okay to replace with newer more modern material types.. 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. I have also used various inductor types flat 12 ga. six nines copper from Solo.. sounded very good however the latest and best sound came from inductors sourced from North Creek which were 8ga. round or oval wire also copper.Tom
fishboat OP
245 posts
 
Thanks to all for your specific advice. Since I won't be doing the upgrade personally, I'll pass your thoughts on to the gent with the soldering iron.

If anyone else has any thoughts please chime in. I haven't contacted anyone at Snell Acoustics yet, but will do so before pushing the button on this.

thanks..
blblues68
68 posts
 
Contact Dave at The Upgrade Company 269-665-7433. I just had my Consonance Eric 3 speakers done, I also picked up a upgraded Pioneer A-71 amp and a CEC TL5100Z CD player from him. I am simply amazed, my speakers sounded as if they were covered with a blanket before.
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