qls1 xo work

[InAp]

Hi, Thinking about upgrading the xo's in my qls-1, I have 2 sets of these speakers, the xo on the right is from a set I bought brand new in 1978, the one on the left are from an older set I bought second hand 20 yrs ago , which has the front full cover. I would like to build them external in a box and eliminate a lot of the crap and make it half way between settings on midrange and up. What are your thoughts on this, external makes it simple to try different caps and components with ease.
Thanks Al

 

[tubed]

Why not.
Especially when you can rid them of those ridiculously difficult speaker terminals.

 

[Bucky Badger]

I need to work on my X-overs as well.
GLWYoverhaul.

 

[InAp]

Has anyone seen the early xo , did it have caps and resistors on the v1 and v2 coils?

 

[pauljh]

Absolutely go ahead and make the crossovers external. That's what the PS Audio folks did when they rebuilt their IRS V system.

 

[tubed]

Has anyone seen the early xo , did it have caps and resistors on the v1 and v2 coils?

???

 

[pauljh]

Has anyone seen the early xo , did it have caps and resistors on the v1 and v2 coils?

If the woofer has two voice coils, it is a Watkins woofer and it certainly will have capacitors and inductors in series with both voice coils.

 

[InAp]

What I should have said is, did the early xo have all the black caps? as in the pic above on first post. I know the tin can caps are stock on the later as I bought them new, just curious if the early ones were upgraded before I got them.
Thanks Al

 

[tubed]

What I should have said is, did the early xo have all the black caps? as in the pic above on first post. I know the tin can caps are stock on the later as I bought them new, just curious if the early ones were upgraded before I got them.
Thanks Al

Both early and later QLS-1 probably used the black caps. It's believed the caps were not of the highest quality.
I have a pair of "later" ones with the black caps which I quickly replaced with some Bennics.
Perhaps I bit too quickly as I could have made the crossover a bit prettier.

 

[slimpikkins]

My pair of xo looked like yours. My black/red caps measured ok but still replaced them with bennics. I have a pair of Quantum 2 which had the black caps and were split and a sticky mess...fell apart when I removed them.

Looks like yours (one on left) have a value of 1600uf on the 4ohm coil. Mine did and my woofers would bottom out. Infinity changed that value to 1100uf and also change the coil on the newer models. When I removed my old caps I replaced the 1600 value for 1100 and the woofers no longer bottom out at high playback levels.

 

[InAp]

Tubed, What are the values of the blue caps? and are they electrolytic as well?

 

[tubed]

Tubed, What are the values of the blue caps? and are they electrolytic as well?

Electrolytics.
1400uf to vc #2
1100uf to vc #1

 

[cdfac]

My advice: make the crossovers match official schematics. That represented the upgraded crossover version, and in my experience that sounded fantastic rebuilt. Use all new capacitors and resistors, including bypass caps on any electrolytics. I reused used all of the larger inductors, though, only replacing the smallest one or two.

I think you're pretty safe choosing a median range value for the resistance of the pots, instead of keeping the pots operational.

 

[tubed]

I did bypass the pots, completely, as I preferred the highest setting anyway.
Also, I went a single larger value capacitor for the tweeters, as I used the highest setting.

 

[chef free]

Don't lose the pots, what resistance values work for one room will sound weird in a different room. The pots come apart without tools for easy cleaning.

 

[tubed]

Don't lose the pots, what resistance values work for one room will sound weird in a different room. The pots come apart without tools for easy cleaning.

Pots are still there, simply bypassed.