Anyone familiar with these speakers?

Manticore

I have had these since 1980, purchased new at Crazy Eddies for around $500. Still have them but info is non existent besides the Roger Russell site, http://roger-russell.com/sonopg/micropg.htm#speakers that i found years ago. Does/has anyone owned them and would they be worth the investment of some new caps and resistors? Any thoughts?




From day one they had a really warm sound to them with great dispersion from that tweeter array.
They still work and sound decent but not like they did when new. They definitely show signs of moving around over the years. Any thoughts?

pitdogg2

Have you looked at the xo?

Schurkey

Caps and resistors can be had dirt-cheap. Even if all you do is put in FRESH electrolytic caps, you're likely to improve things over the nearly-40-year-old stuff that's in there now.

Dig out the crossovers, make a list of all the caps (and resistors, if you're inclined) and do some internet shopping.

Manticore

pitdogg2 wrote: »

Have you looked at the xo?

Yes and compared to lets say my 1C's...well there is no comparison.
Check these out!

And that's it!
I can read the two larger caps but, the smaller black one not so much. I have tried with a magnifying glass but it is very worn. I will have to check out the other speaker.

There was nothing in the tweeter housing... well except tweeters and wire.

pitdogg2

That is what i was afraid of. But look at the bright side it will be cheap to recap

Manticore

The second one was clear (RCL T5 1Ohm 5%) although a different brand from the first.

Now Knowing what the second one said it makes easier to interpret the first. The first one was TEL Labs 1ohm 5% with some other numbers (probably a part #).

Schurkey

One cap, two resistors per cabinet? Or the second resistor is from the other cabinet, making two caps, one resistor per cabinet.

Either way...wow.

pitdogg2

Not too unusual. I have seen a KLH pair that had 2 12"woofers a mid and a tweeter. I looked at that xo in amazement. One cap and a ferrite bar inductor.....
I didn't know where to start on the upgrade so i told the guy to buy a new set of speakers

mhardy6647

Thanks to this thread -- I feel this masochistic need to put in a good word for simple crossovers

While there have been myriad really terrible, cheap loudspeakers with ultra-simple XOs -- there have been some good ones, too. The good ones were those into which their designers put some thought and effort.

To me, the classic example -- the sine qua non -- are probably Winslow Burhoe's early EPI/Epicure loudspeakers. Burhoe & company did two things. Designed and built 'custom' 8 inch woofers that were designed to roll off naturally and very smoothly (obviating the need for a LP filter feeding the woofer) and a very smooth tweeter with well-behaved (especially for their time) dispersion characteristics -- the classic (and idiosyncratic, albeit in a good way) concave-dome "airspring" tweeter. The combination of those rather special drivers was well served by the simplest possible XO (edit: on most of their loudspeaker, at any rate) -- first order on the tweeter only (i.e., a capacitor). The woofer was allowed to free-range.


011 by Mark Hardy, on Flickr

Now, I won't defend the quality of the capacitor used on most of 'em... especially at this late date. Suffice it to say that a cost-effective upgrade is well-advised in 2018.

Some of the earlier/better EPI/Epicures also had variable tweeter level networks -- in the better cases, these were simply switchable resistors (sort of like the Dynaco A25), if memory serves.

As a final comment: it's also worth noting that, sort of like Polk Audio, Burhoe's legacy survived through several companies over the years, right down to the present day.

http://www.humanspeakers.com/
http://directacoustics.com/




Sorry for the fanboy diatribe.


102 by Mark Hardy, on Flickr


(Mr. B. with his rather outrageous EPI 1000 towers. Four "Burhoe modules" per loudspeaker -- and a force to be reckoned with)

Manticore

So it looks pretty simple. One 12uf, one 6uf and a 1ohm for each speaker. If i take the same route as the 1C upgrade the parts would be $88 from Sonic Craft.
Not to bad any thoughts?

pitdogg2

This would be the only speaker you will hear me mutter this......
Dayton and mills

Manticore

@pitdogg2 Your right. I think this is the first time i have read someone actually recommending the Daytons. I have read that folks used them, pulled them out for another and such. Is it just the price point or for what i am using them on they are more than suffice?

They don't seem to make a 6uf, so would the 6.2uf be just fine?

pitdogg2

Personally i can't believe I actually said Daytons. While i love my sonicaps, are you going to use these as your main rig speakers? If so by all means jump in with the sonicaps. If not then give the daytons a whirl. Check to see if they have any 1% for your needs and try them out. Heck you will not be out much and yes i think the 6.2 will be fine. You could put the daytons in the low pass and sonicaps in the high pass.

It's hard to believe they were 500.00 new I never heard them so i could be way off base.

Let the flogging begin.

Manticore

No, these will not be used as my main rig. They might go in what would be considered a formal living room for ambience. If you look at the photo below there is a double connection from the pos & neg terminal. The woofer gets a direct wire connection ( single blue & single black wire ) from the inputs with no caps or resistor in line. The caps & resistors are on the other lines only going to the tweeter array.


I dont mind using the Daytons but, they dont make a 6uf. The caps needed are 12uf & 6uf with one resistor. Even that connection looks weird. The 12uf goes to a purple wire and the 6uf goes to the brown wire and the resistor goes to both. So it would be from the spade to the resistor, one end of the res goes to a 6uf to brown wire to array and the other end of the res goes to the 12uf to the purple to the array.

I cant question as to why but, it seems to have worked from day one. Just thought a refresh would be in order after almost 40 years. So your thoughts are the 6.2 would be ok? Of course PE is out of stock of those til mid March.

mhardy6647

See if Madisound has the Bennics Same capacitors (AFAIK).

IMO (and FWIW): Horses for courses - if one is rehabbing, say, a $20 KLH 32 or a Jensen-era Advent Legacy, the Dayton/Bennic will absolutely-no-two-ways-about-it represent a cost effective (cost-appropriate!) improvement. I kid you not (as Jack Paar woulda said).

Is 6.2 uF close enough? Probably -- depends upon the XO topology. Assuming it's first order, let's see:

6 uF (@ nominal 8 ohm) = 3.32 kHz (rounded to 10 Hz)
6.2 uF (@ nominal 8 ohm) = 3.21 kHz (rounded to 10 Hz)

for a nominal 4 ohm load, of course, the nominal values would be 6.64 vs. 6.42 kHz.

For second order (or other aligmnents), you can use a calculator! Here's a handy collection of crossover calculators from Erse (despite the weird URL!), or you can plug the equations into an Excel spreadsheet & make your own

http://shopping.na3.netsuite.com/s.nl/c.650256/n.1/sc.14/.f

Manticore

Thanks @mhardy6647 for the reply. Sorry your explanation is above my pay scale. It is appreciated though!
You would have to dumb this down a little for me. OK a lot more! I do get the (cost-appropriate) part of it and i do not want to put more into these than necessary but, i would like them to be done correctly. No hello kitty style for me. The speakers are rated @ 8ohms. I don't remember the sensitivity. They are easy to drive.

I will check out Madisound when i get back from the grocery store.

pitdogg2

The caps in there are more than likely +/- 10% and that 6.2 would be far closer to value. or look for two 3uf and parallel them to 6uf . don't get all twisted over the .2 new caps are still going to be +/- 3% more than likely sooo.

mhardy6647

pitdogg2 wrote: »

The caps in there are more than likely +/- 10% and that 6.2 would be far closer to value. or look for two 3uf and parallel them to 6uf . don't get all twisted over the .2 new caps are still going to be +/- 3% more than likely sooo.

That's absolutely true and a very good point -- I thought about going there, but I thought it might've been too esoteric! I shoulda just gone there & skipped the other stuff!

So, yeah, 6.2 uF is most likely close enough. The old NP caps in the speakers now may have been 5.5 uF or 6.6 uF and still have been in spec -- and who knows what they are now?!