Want to bi-amp 604-8K.

[dooey263]

Gentlemen...

I'm attempting to biamp a pair of 604-8k's, in 620 cabs, with the stock,604-8K dual attenuator crossovers.They seem to be the same as the 604-8H crossovers on Jeff Markwart's site. The reason for the attempt.... I'm currently driving them with either a pseudo triode el84 SE amp, or a regular pentode el84 SE amp. Both amps sound great, but have particular strengths... The pseudo triode has an unbelievably firm bottom end, while the pentode SE has speed, articulation, and detail in the top, that the triode just can't quite match. I want the strengths of both.

I've tried a couple of active electronic crossovers, with less than satisfactory results.After studying the 6048H crossover schematic at Jeff Markwart's site, I can't quite figure out how to seperate it, to be able to split it into two sections.The C5 16 uf capacitor seems to do dual duty to both sections.( Zobel?)I was thinking of driving the woofer section with a separate unit, similar to the dual attenuator, and also JM's 604-8h simplified, just a 1.7 mh inductor in series, with a 16 uf cap paralleled.

So, I think my questions are.....

Can I mechanically/electrically split a 604-8k dual band crossover into 2 seperate sections to biamp it?

Will the crossover perform correctly if I was to use only the HF outputs, and not the LF ?

Can I assemble a separate crossover using the woofer section of JM's 604-8h simplified, using a 1.7 mh inducter in series, and a 16 uf Cap paralleled? Even though the inductor seems to do dual duty into the HF section?

I split a Hiraga crossover for my A5's, using 845's for the 288's, and Bryston SS for the 515B, and it has worked flawlessly for me. But, it was very simple to do, for an electrically challenged wonk like myself....

I have attempted to include the pdf's from JM's site, but they are too large, and I don't have the brain cells left to figure out how to do it. So, I'm attempting to include some links....Any help with this is mucho appreciated....

Cheers.... Scott (Altec Slappy)

Jeff Markwarts fabulous site..... Jeff Markwart's Corner - Phase Corrected Crossovers

Altec 604-8H vintage crossover pdf.... http://home.earthlink.net/~jmarkwart...les/604-8h.pdf

604-8H simplified..... http://home.earthlink.net/~jmarkwart...4-8h_gsmpl.pdf

[Altec Best]

I have attempted to include the pdf's from JM's site, but they are too large, and I don't have the brain cells left to figure out how to do it. So, I'm attempting to include some links....Any help with this is mucho appreciated....

Hey Scott, It's not that the file is too large it is that the board doesn't support .pdf file format's unfortunately.You have to post as link's as you did.

As I encountered the same issue before. You may want to PM Donald Patten as I think he specializes in the 604-605 circuit.I'm not 100% certain though.

BTW - He is a very nice gentleman so shoot him a PM see if he can help out!! :2thumbsup:

[RonSSS]

If you look at the simplified schematic, it's easy.

Pull the 2 wires that go to the woofer (input to the 1.7mH choke and gnd)

Connect these to your bass amp.

Connect the originals to the HF amp.

i did it, even added jumpers for when I wanted to use a single amp.

Ron

[Cal Weldon]

Hi there,

For the cost of dinner for two you can buy a Behringer 2310 XO. So much control for so few $, it's hard to beat. It's what I am doing for my 604-8H's

[dooey263]

Thanks Guys for the advice so far.....

AB.... I'll attempt to PM Donald Patten

Ron.... I know splitting the "Simplified" crossover is quite "simple",he he, but I really want to split the stock dual attenuator Altec unit. I will build and use the woofer section of the "Simplified" if I must, but it would be a last resort.

Cal... I've owned and used a number of electronic crossovers, but always seem to go back to the passive ones. I'm not sure if they add or subtract something, but I always get the impression they change the sound, and not always for the better. Could be just me and my prejudices though. This is my home vinyl rig, and purity and simplicity seem to = more natural sound.

I'm including a pic of my shop rig in this post....Sorry to have to show it with it's JBL parts.I'll repent and try and be more Altec in the future! It is my experimenting setup....I built the 828 cabs with a lot of help from this board a few years ago, I don't think I ever posted a pic of it, so here it is.

828 cabs..... Dual layer 3/4" mdf inner walls, 2"x2" hard maple stringers, 3/4" oak ply outer wall, solid 3/4" white oak trim, solid horn flares.Weigh in at about 400 lbs a piece.Virtually no resonances, The detail from the 515B's is amazing..... The rest...

288B with 1005 Horns

JBL 2405 slots phase aligned on aluminum brackets above the horns

Jbl 2245H 18's... stereo sub cabs, Greg Timbers design.

At this particular moment, (and it changes almost daily)

845 triodes into Hiraga crossover for 288B-515B's

845's also power the slots through JBL 8000 khz crossover with L pad

Bryston 4B into Reckhorn crossovers for subs.

This is about the simplest electronics I use, and also sounds the best... I have quad amplified at times. A bugger to set.

Sorry for the mess, but its a working shop... I listen to this rig basically all day every day, needed something to compete with the db's from the power tools, and this setup wins every time!

Cheers.... Scott

[Panomaniac]

Those are truly beautiful. Nice work!