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Altec crossover upgrade

Now that's my kinda crossover. I figured it would sound good with all the time and care you took building it (and of course Paul C's knowledge that he so graciously shares). When I first built my horn speaker setup I was running them on some old Klipsch Type E crossovers that I had laying around. I thought they sounded pretty darn good too and considered just modding those. After I got my real crossover built and installed, I had one of those jaw dropping moments. I know exactly what you mean about the accuracy. I went from a PAT 4/Dynaco 70 on Heresies to Altecs and bass horns on 2A3s in about a years time of getting into the hobby. When I first sat down and really listened to the horns/triode setup, I actually had tears running down my face.:yes: That's pretty amazing considering I'm a big tough pipefitter. :D
 
Great job Fran and I'm sure glad you like them - would have been pretty crappy if you went to all this work on my prodding and you weren't happy!

I really like the way you used your day-job skillset (and resources!) to build something truly unique; this can make DIY audio just a little more satisfying in the end.

Keep us informed on how they work out sound-wise. Seems your initial impressions are similar to mine - better balance and detail - which I attribute to smoother midrange and more extended treble. I really think this improvement is all about the well designed and tweaked circuit (thank you Jeff Markwart!) but those oil caps might be playing a roll in this as well, I'm certainly in no rush to experiment there.

I initially thought the treble was a little soft as well but on further listening realized it's all there; just better balanced with the mids for a smoother, more extended, less 'in your face' presentation in upper-mids/lower treble region. The L-pad does have a very subtle adjustment range and I too ran it wide-open initially but started backing it down a touch over time to a point where I now never play with it. I'll probably do a little measuring when I get time (I prefer to just listen :) ) and will eventually replace the pad with higher-quality fixed resistors but to be honest, this crossover just hit the mark for me straight off and I put my system building focus elsewhere.

Let us know how it all finishes up for you.
 
jaymanaa said:
Now that's my kinda crossover. I figured it would sound good with all the time and care you took building it (and of course Paul C's knowledge that he so graciously shares). When I first built my horn speaker setup I was running them on some old Klipsch Type E crossovers that I had laying around. I thought they sounded pretty darn good too and considered just modding those. After I got my real crossover built and installed, I had one of those jaw dropping moments. I know exactly what you mean about the accuracy. I went from a PAT 4/Dynaco 70 on Heresies to Altecs and bass horns on 2A3s in about a years time of getting into the hobby. When I first sat down and really listened to the horns/triode setup, I actually had tears running down my face.:yes: That's pretty amazing considering I'm a big tough pipefitter. :D
Click to expand...

I hear ya, Jay!

It's really gratifying to came home after a shitty day and listen to something that can make me feel so much better. :music:
 
Billfort said:
Great job Fran and I'm sure glad you like them - would have been pretty crappy if you went to all this work on my prodding and you weren't happy!

I really like the way you used your day-job skillset (and resources!) to build something truly unique; this can make DIY audio just a little more satisfying in the end.

Keep us informed on how they work out sound-wise. Seems your initial impressions are similar to mine - better balance and detail - which I attribute to smoother midrange and more extended treble. I really think this improvement is all about the well designed and tweaked circuit (thank you Jeff Markwart!) but those oil caps might be playing a roll in this as well, I'm certainly in no rush to experiment there.

I initially thought the treble was a little soft as well but on further listening realized it's all there; just better balanced with the mids for a smoother, more extended, less 'in your face' presentation in upper-mids/lower treble region. The L-pad does have a very subtle adjustment range and I too ran it wide-open initially but started backing it down a touch over time to a point where I now never play with it. I'll probably do a little measuring when I get time (I prefer to just listen :) ) and will eventually replace the pad with higher-quality fixed resistors but to be honest, this crossover just hit the mark for me straight off and I put my system building focus elsewhere.

Let us know how it all finishes up for you.
Click to expand...

Hi Bill, thanks for the comments.

I was having a very difficult time trying to put my initial response into words. I guess that late last night, I began to realize that what I wasn't hearing was the "edginess" that the old crossovers had. :)

Of course, I had to fire up the stereo as soon as I got home, and I'm playing everything I can think of that I know the "sound" of.

Thanks again,

Fran
 
Paul C said:
Russell is using a 416C, so he can leave off the Zobel network (R3, C5).

The added parts for the horn compensation are R1, R2, C1.

If more top end is needed, he can add a 1, 1.5, or 2 uf cap between the L-pad terminals 2 and 3.

R1 and R2 don't have to be 40 w unless using with very high power amps. If using a low power tube amp like Jay, 10 w resistors will do just fine.

To make a 6 ohm 40 w resistor pack, wire four 6 ohm 10 w resistors in series-parallel. Ditto the 16 ohm 40 w, four 16 ohm 10 w resistors in series-parallel.
Click to expand...

See my post #76 for a "PS" where I added a pic of the doctored crossover, havent added the compensation yet, will be ordering thos parts along with the parts for my DIY JBL 4430 crossovers.

Russellc
 
Altec 604-8G crossover

Some great stuff in this thread. Has anyone used tuned amplifiers with the crossover built into the amp with R/C high and low pass for each amp in a bi-amplified setup?
I also have a pair of Altec N-1285-8A crossovers and I'm wondering if they could be adapted & modified for use with my 604-8G's in my Model 17's.
 
Excellent series of notes, thanks for posting them and can't wait to start planning and prototyping one for my 8g's and c models.
 
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