"Eerie," a weird word. Alternatively spelled "Eery." Never saw that.
Shut up and eat your dinner, Zilch. CLIO awaits....
I see I spelled Blk wrong. Gotta fix that, too....
"Eerie," a weird word. Alternatively spelled "Eery." Never saw that.
Shut up and eat your dinner, Zilch. CLIO awaits....
I see I spelled Blk wrong. Gotta fix that, too....
My boss, Jeff, had model 19's at his last nightclub back in the late 80's.
I told him we could get some. He was all a-gog! He has really enjoyed listening to the L200b's with the new double 18 subs Lisa and I built.
I am sitting here waitng for the cabaret show to start. Performers are late. Costume malfunctions. You know.
Thank you for all that you and Clio are doing!!!
I really appreciate it!
Scott.
One step above: "Two Tin Cans and a String!"
Longtime Alaskan Low-Fi Guy - E=MC˛ ±3db
Thats Zilch for you, he's half way towards Project April by now. Most guys would have just pushed in a loudness button.Originally Posted by moldyoldy
My 802-8gs supposedly had a good charge, and have new diaphragms, so it will be interesting to see if Zilch's measurments somewhat match mine.
O.K., full N-800-F attenuation plots up at #457, now
Pick yer poison....
http://audioheritage.org/vbulletin/s...180#post160180
Now what? Any remaining crossover issues? Voltage drives?
I'll build a breadboard to Jack's schematic and see if it replicates the transfer function, using a conventional L-Pad. If it's close enough, maybe replace Scott's busted one, if he says O.K. based on the results.
Wow, it seems like the ELPAC's values must be the same in all N800F's. I only have one Val running with the APT tweeter and breadboard crossover, but it seems to want the mid (800 Hz to 3.5 Khz) turned down a little more than with the standard crossover. Guess that makes sense now. Maybe the tweeter fix would be better with the standard crossover instead of rebuilding the entire thing. Would be more economical too. I will try the second Val later today, and see it that is better.Well, ain't THAT an unanticipated kick in the patootie....
No wonder the schematic's "Not available...."
Who said those Altec engineers didn't know what they were doing?
Jack Gifford
Zilch, I will end up with a pair of N800F's after building the 1200 Hz crossovers for the second pair. Scott is more than welcome to one of them, if he wants it. It is wired the same as his, not backwards like the one you have.
After trying the crossover replication, I'll fine tune the compensation for the BMS drivers and send them to you. That seems the best solution to me thus far, but it's your A/B listening that'll make the final determination for you.
As of now, from the curves, the LE85 looks the best, but I can easily get the BMS performing equal to or better than that. LE85 sounds very good; it's got a bunch of "logistical" problems, tho:
1) I don't think it will fit in the Valencia cabinet without modification to the hole in the rear panel. It's about 1" deeper than the Altec 806A mounted on the horn.
2) New mounting holes must be drilled in the horn flange; the pattern is different.
3) Finding good vintage LE85s with original tangential-surround aluminum diaphragms is a crapshoot. In my experience, 30 - 50% of them are FUBAR, and require refurbishing, and the only way to know is to measure them. They should all be opened and refurbished, which knocks half the resale value off them with loss of the red seals. Chances are good the foam damping pad inside the rear cover has deteriorated in virtually all of them.
4) They are expensive.
5) Performance of the JBL diamond-surround aluminum replacement diaphragms is indeterminate. They SHOULD be better in the VHF, but the one pair I have is not fitting well in older LE85 motors. They, too, are expensive, currently $244 apiece. Aquaplassed titanium ($136 for the raw diaphragm) is a possibility, but that also requires verification. In my experience, different diaphragms perform differently, even among factory offerings, let alone aftermarkets.
6) 2425/6 is another option, but it's the diaphragm thing with them, too, and they're actually deeper than LE85s. Some may be happy with the stock titanium diaphragms, but LE85's vintage aluminum with its inherent damping is certainly sweeter listening....
OTOH, if I was a JBL person with some known good LE85s sittin' around, and wasn't dealing with Valencias, I'd be hunting down some 811s or 511s and an analog active crossover with dialable delay for the woofers like Behringer CX3400 ($130 at PE,) maybe....
Very nice to see we are getting some great knowledge from all of this.
Just so you know Zilch, the model 19 XO I sent is an orphan and untested but probably fine. You are welcome to do what ever you would like with it as far as experimental changes you think might be of value. Sorry I am not technical enough to follow some of this but in the name of science, my donor is at your mercy so have at it and send it back when you are done.
I will ofcourse pay the costs of any upgrades you make in this process because the knowledge we learn from it will be invaluable.
Gary
Per Jack's schematic, using standard Dayton 16-Ohm L-Pad from PE:
1) Per the factory stock L-Pad connections, "Attenuation," CW decreases output. Disconnects at MAX attenuation.
2) Reversed legs per Jack's sample, "Level," CW increases output.
3) Standard L-Pad connection, "Normal," wiper is output, CW increases level. Disconnects at MIN level.
I'm calling #1 "functionally equivalent" to factory, but with about 2 dB wider adjustment range, which might be adjusted, if desired, via R1.
Well, one pair of Vals is now playing with a totally new crossover on one side, and the original N800F on the other. These two units have the APT-80 tweeter fix, making them three ways. The crossover points are at 800 Hz and 3.5 KHz. The new crossover is balanced versus the strange imbalance in capacitor values noted in the N800F's. The N800F has some compensation for the large midrange ( roughly 5-8 db from 800 to 3.0 Khz) hump in the 806A as Zilch discovered. I was convinced building new crossovers would be best, since the N800F's are aproaching 40 years old, but didn't realize their built in compensation. Once Zilch discovered that, it seemed they may be the better choice for the tweeter fix.
I haven't spent a lot of time listening to them, but had the wife listen as well as myself, and both of us agree the one with the N800F has more depth, and just sounds smoother. Using the N800F would also be the most economical method to add some HF to the Vals. Storm is convinced his Vals sound better with an EV T-35 and simple capacitor coupling to aid the 806A, and he is probably correct, but a true crossover at 3.5 KHz to a tweeter which has essentially flat response out to 20 KHz (at least compared to the 806A) seems so much better.
At any rate, for about $125 a pair of Vals can be adapted to generate some HF if the tweeter is mounted inside the cabinet. There are still issues of time alignment, but I can't hear any time problems with the tweeter mounted in the horn. But of course, I don't play any tap dancing cd's. If the time alignment is a problem, a simple move of the tweeter into a separate cabinet atop the Valencia, as done by S1A and others can be adapted to solve these problems, but at the expense of imaging. You pays your money and takes your chances.
I will leave this pair as configured using the N800F's and the tweeters mounted in the horns, and wait to see how the BMS fix sounds. That will be more expensive, but may be the best way to go, until a new horn hits the market. They sound so much different than Vals have ever sounded, it will take the Giffords some time to adapt to them. I love them.
Jack Gifford
O.K., here's my best effort tonight at compensating the BMS 4550. The peak at 19 kHz can be knocked down flat with -6 dB of active EQ at 20 kHz, but I don't know how to squelch it more than the -2 dB I already have passively. I sure can't hear it. Perhaps Earl K or others will have an idea; I'll talk to BMS for more information, since it appears on their entire line of drivers.
You can see I'm fighting the variation in output impedance of N-800-F at higher attenuation levels. Switching to a conventional L-Pad from Altec's divider, or simply adding one after it, produces a family of the red curve, if that is desired. Otherwise, it's "Plug 'n' play" with a simple compensaton network:
Dear All,
I am getting a little confused at this point.
Thank you very much for the offers to repair the l-pad, and/or the option of aquiring another N800-f xover to replace the broken off l-pad shaft. I never knew the level of committment of the some of the members until now. Thank you!
In keeping with the original theory of the Valencia, as a whole, I believe in the 2-way passive cab. And to that point, can see where the BMS 4550 driver update is warranted.
1. It is a simple bolt-on.
2. It does not break the bank.
3. It extends the uhf out to a frequency that is desired in all genres of music listening.
4. It holds the engineer's plans for a smaller VOTT, but did not have a better driver to use in its inception.
Mr. Z, and Jack Gifford,
1. Is it your recommendation to add tweeters to the Vals, or not?
2. Is it more advantageous to add the BMS 4550 with a new crossover from Zilchlabs, and what will be the price for the two drivers and xovers?
3. Maybe we can get the Foilcal thread guy to make us some Altec Valencia hotrod labels! Obviously, the more l-pad holes, the better!
Scott.
ps. Happy April Fool's Day.
One step above: "Two Tin Cans and a String!"
Longtime Alaskan Low-Fi Guy - E=MC˛ ±3db
We're trying two options. Jack has multiple pairs of 846A (16-Ohm) Valencias. He has installed tweeters in one of them, and built a complete new crossover. He likes the stock crossover better, now that we understand it more, so he's building a network just for the tweeter part, as add-on.
I worked out a way to get the requisite VHF response using an updated driver, the BMS 4550. It also works with the stock crossover, requiring only a simple four-component additional compensation filter for optimization. The 16-Ohm BMS drivers go to Jack tomorrow, along with the compensation filter specs. He'll have to buy some metric bolts and build the filters, is all, and he'll be in business. He's going to load them into a second pair of Valencias and do an A/B/C listening evaluation.
I'm going to continue testing drivers and diaphragms, and work out the "fix" for the 8-Ohm 846B Valencias, like Storm has now. If Jack likes the BMS two-way results, that's what it'll be. I have a perfectly matched pair of the 8-Ohm version of the BMS driver here for the development work. In detail, they behave a little differently from Jack's 16-Ohm ones, which has to be worked through; I just need the specifics of the factory crossovers in 846Bs to move ahead with that. I'm getting some apparently good input from other resources, now, too, as interest in this project has expanded to other sites....
That is what I did.............. Did we forget? Worked very well, and blended nice might be a little high but we can always bring it down.
http://www.audioheritage.org/vbullet...9&postcount=21
http://www.audioheritage.org/vbullet...4&postcount=22
Zilch,
Are you thinking 5k on a perfect point to x-over?
J/S-S1A
Jeff-S1A
5 - 8 kHz looks like the region with the best of the drivers I've measured here.
Jack seems to like a little lower, 3.5 kHz.
I don't think we've forgotten your approach, but a primary objective in my mind from the start has been to get the fix in the cabinet, behind the grille, if possible....
[There's also the technical stuff....]
Copy that!!!!!!!!!! Have a great Sunday night.5 - 8 kHz looks like the region with the best of the drivers I've measured here.
Jack seems to like a little lower, 3.5 kHz.
I don't think we've forgotten your approach, but a primary objective in my mind has been to get the fix in the cabinet, behind the grille, if possible....
J/S-S1A
Jeff-S1A
There are currently 2 users browsing this thread. (0 members and 2 guests)
Posting Permissions
Reply With Quote
