Altec Crossovers

[bowtie427ss]

Yikes! "break in" in audio.

This seems to be one of the more hotly and emotionally charged debates in audio, second only to the speaker wire/power cord debate, it also seems to suffer from a serious lack of scientific basis or analysis.

I agree with Marshall.............. completely.

When somebody finally shows me a measurable change that occurs in a new cap after a "break in" period, then i'll be a firm believer.

I'm a firm believer that "if it can be heard, it can be measured".

However, i also give merit to the idea that for a majority of folks "if you believe it, you will probably hear it". I think it's a caveat of being human.

I challenge the believers to "show me".

[bowtie427ss]

Maybe I should try to replicate the Heathkit AS 101 crossover for the Valencias-

All of the component values would need to be changed to accommodate the Valencia's 16 ohm components. At the end of the day the Valencia's are probably still not going to sound the "same" as the AS-101's on any given power source. That is not to say you wouldn't be making an improvement, rather that depending on your amplifier there still may be a significant difference in sound between the Valencia and AS-101.

There are others here who can explain the relationship between speaker impedance and amplifier output impedance far better than i can.

[voice of the theater]

Thanks for all the help on this everyone! I was really impressed with the improvement in the sound of the Heathkit/Altec AS 101s after byp***ing the 38 year old L Pads (since I was keeping the L pads turned all the way up anyways) and after replacing the old original leaky caps with Dayton 1% precision caps. I don't need the Valencias to sound exactly like the AS 101s current sound and I guess it's not realistic to expect that anyways even though they have the same drivers, they do have different impedance. I guess what I'm looking to do is a similar upgrade in sound for the Valencias--ideally I'd like to replace the caps and byp*** the old treble tone control pot on the back of the speaker but I'm told those aluminum cans (that are riveted shut) that hold the Valencia crossovers are filled with an asphalt-like material and that it's virtually impossible to break open the cans and get to the components inside without destroying them. So, now I'm wondering do I buy new crossovers, or maybe replicate the crossovers in the AS 101s (which is said to be superior to the Valencia crossover) but make adjustments so they'll work with 16 ohm drivers......

[bowtie427ss]

It's been a while since i messed with one of these "canned" crossovers, but if you're feeling adventurous i'll bet taking it apart without damage is well within your ability. You could then just do a basic re-capping like you did with the 846A's. I think you'll also find a big ceramic resistor in there that's part of the attenuator circuit, maybe replace that with a higher quality wirewound version.

There are a couple methods, but i think baking them in a ~150degree oven to melt the goo and then pour it off is probably the best method. I think we have/had at least a couple members here who have been very successful with this.

I've also heard of fellas freezing them and carefully chipping the stuff away, though i feel this method presents more potential for damage.

Another option would be to watch ebay for another reasonably priced pair of stock 846A Valencia crossovers, recap those and leave your originals in tact. To open them requires drilling out 2 or 4 rivets if memory serves, this will render them "tampered with" to the strictest purists. Doesn't offend me in the least, but it means much more to others.

Just some food for thought.

[westend9]

Thanks for all the help on this everyone! I was really impressed with the improvement in the sound of the Heathkit/Altec AS 101s after byp***ing the 38 year old L Pads (since I was keeping the L pads turned all the way up anyways) and after replacing the old original leaky caps with Dayton 1% precision caps. I don't need the Valencias to sound exactly like the AS 101s current sound and I guess it's not realistic to expect that anyways even though they have the same drivers, they do have different impedance. I guess what I'm looking to do is a similar upgrade in sound for the Valencias--ideally I'd like to replace the caps and byp*** the old treble tone control pot on the back of the speaker but I'm told those aluminum cans (that are riveted shut) that hold the Valencia crossovers are filled with an asphalt-like material and that it's virtually impossible to break open the cans and get to the components inside without destroying them. So, now I'm wondering do I buy new crossovers, or maybe replicate the crossovers in the AS 101s (which is said to be superior to the Valencia crossover) but make adjustments so they'll work with 16 ohm drivers......

If it was me and my thrifty ways, I'd build new crossovers to replace the old Valencia's potted networks. I would then compare the new vs. old. If the new ones sound better and I had made the decision to keep the Valencias to my demise, I'd sell the originals to recover costs and show a meager profit. Alternately, keep the originals to promote a sale to the Altec purist, should I decide to sell the Valencia's.