Well you kinda did now didn't youI don't want to prejudice anybody's opinion, but 2425/6 has been conspicuously MIA in this analysis. I know better than to even go there..... If you didn't want to go there you should have not said it. As far as I am concerned they should be missing and with good reason. Running them to 800Hz is not the best application for them or any other 1' driver. They are much happier above 1K and they sound that way as well.
Rob
...and do a better job with what's left, too...Originally Posted by Robh3606
...snip...Running them to 800Hz is not the best application for them or any other 1' driver. They are much happier above 1K and they sound that way as well.
Rob
IM distortion lays low on pings and sweeps, but loves to party when there's a beat to dance to...
But I couldn't go get them because my driveway is being concreted, and I was etching the crossover boards and LCR network boards anyway. Tomorrow the drive will be walkable, so I will go to the company to pick up the drivers, drill and cut the PCB's, and package the Valencia grilles that were sold.
Here are pictures of the PCB's for two pair of crossovers (one at 1200 HZ and one at 3500 Hz) and for the LCR networks. The LCR board needs to be cut in half at the small line through the middle.
I can't wait to hear what the BMS drivers sound like. It seems like Christmas all over again.
Jack Gifford
Well, priorities at that company clearly need to be reordered!
Don't they know how many Valencias are at stake here?
[Geez, I sure hope they got there safely....]
Before the stock 846As go down in history as being seriously flawed, and in the interest of true objectivity, I'd like to point out that we've neglected to investigate them in the application they were designed for.
Knowing Zilch has exerted tremendous efforts on this project, (now on week 7) and has to be eager to move on to other things, I've hesitated to say what's been nagging at me. Therefore, I've come up with an idea that should be painless to all, will resolve my suspicions, and MIGHT be enlightening to all.
I'd like to see two more tests of the stock (uncompensated) 846A HF setup (806/811/N800F) performed under the conditions stipulated below. Zilch will be the final judge and jury in assessing the outcome. If he determines the results show no signifigant improvement over the previous tests of the same components, I will send a $100 donation to Zilchlab to compensate the extra effort. If, however, he notes a signifigant and improved difference, I think he'll agree the knowledge gained will offset the effort.
Conditions;
The DUT must be driven in stock configuration by a period-typical tube amp of the type likely used by an original owner of an 846A. No SETs, no exotics, merely a garden variety, push-pull, multi-tapped xfmr-coupled tube amp with negative feedback. Tests from both the 8 and 16 ohm taps required. If the amp happens to have adjustable feedback (damping), the control should be varied to note any effects. Other controls to be set to obtain the nearest to flat response with a resistive load and said response noted. If a reasonably-similar substitute for the 416A isn't available, the network LF out should be loaded with the appropriate resistance.
This is NOT a tube/SS war, merely further investigation of a design under the conditions it was designed for.
Not a challenge,
Not a bet,
Not even a request
Merely an offer for consideration.
The only tube amp I have here is an EICO I built in high school, which has not been powered up in 20 years. I've been meaning to do that, actually, and have the requisite Variac to make it happen, but it could fail.
Jack has plenty of tube amps, of course, and can probably provide the answer toot sweet, using fully stock Valencias. He's setting up the comparative listening right now, and can easily add that as an option, I would guess, if a subjective result would be sufficient.
From past hints on the subject, he may be setting up to do some measurements himself, as well....
Yer right, y'need to dig out the EICO. Send me the values, and I'll give you new electrolytics (maybe even tubes) for it.
I've plenty of amp candidates, but after spending LOTS of time and $ fixing the shipping damage they incurred coming to me...well...you know.
If I had a good N800F and some 16 ohm 'frams, I'd do it myself. I do prefer all comparative tests to be done under identical conditions though, hence the suggestion (and unbiased review) for ZilchLab Inc. (And I've jerked so many chains nobody'd believe me anyway).
While this HAS been on my mind, I happened to have the opportunity for some hands-on (subjective) A/B'ing in KC yesterday on 2 pr of Vals...so the $ offer was made with that fresh in mind.
I have a glimmering of what's going on, but no way could I explain it correctly. Probably take someone like Earl for that.
Give it 24 hrs, I'll bet the local tubeheads will be beating a path to your door, amps in hand.
And I ain't gonna delete the offer....you'll hafta decline....
C'mon, would it be sufficient for you?....He's setting up the comparative listening right now, and can easily add that as an option, I would guess, if a subjective result would be sufficient.
You don't have any financial holdings in BMS, do ya?
I'm only thinking of the (potentially numerous) Val owners already using tubes that (might) rush to fix a problem they (might) not have. Your fix is likely the most cost effective for the rest.
O.K., I'll dig in the dungeon and see if I can find this masterpiece of early Zilchdom here.
I built several of these for local teen dance clubs back then, the most memorable among them being Toby Clair's "Rockin' Robbin."
The police were CERTAIN I was up to no good with all that gear in the back seat....
- It's a great idea to explore the tube amp / current source angle . Good for you moldoldy !
- I know that on my part, last fall I explored on Tom Loiseauxs' initiative, just what happens when the 2 resistors in a "fixed Lpad", have their "stock" positions reversed . There was also coupled with this swap, an "appropriate misplacing" of the circuit order, of a first-order cap ( ie ; driver side of the reverse pad ) . FWIW to this discussion ; I believe I was able to get a couple extra db of HF gain out of the tweeter using this arrangement / calculating the turnover Freq. was a bit of nightmare . I didn't document or publish the findings since it represents just the thin edge of designing circuits that are working more current source than voltage source.
- At this time I need to let the Nelson Pass(es) of the world explain the current source approach while I get a better grip on the math behind voltage sources .
Good diversion. Keep 'em from looking under the front....The police were CERTAIN I was up to no good with all that gear in the back seat....
Whoaa Nellie!
Jack don't have no tube amps. None. All of my stuff is solid state. Burn't my fingers on them glowing muthers too many times in school. Didn't want any more when I finished.
Sorry
Jack Gifford
Don't forget to load the output before power-up. 60/120 hum from old 'lytics constitutes driven input...
I've learned to avoid those "unit powered up but no other testing done" ads...good output iron's too hard to come by.
Probably a redundant warning, but easy to forget after 20+ yrs of flipping SS switches.
I didn't ask him to say that, Zilch...
Don't be hatin' me now.
There's still the ($100) chance I'm wrong.
(Anyone else notice the recent glut of 806/811s on eBay?)
*sigh*
O.K., puttin' on my shoes, then.
I THINK it's got all the tubes, still.
[And the matching preamp....
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