|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
162.232.122.153
In Reply to: RE: Electro-Voice Regal lll posted by CraigI on January 07, 2017 at 08:49:23
If your goal was to change the capacitors, now you have the values.
I'm having a hard time trying to figure out the 5.7 uf for the mid horn but there it is from the factory and EV choose that value for a reason.
When they got more into the bookshelf speaker market they did have different drivers that were not a part of their normal driver offering so it does get confusing unless the full specs of all the drivers are known.
A friend had a pair of EV bookshelves, EV Two's I think and the mid horn looked liked yours but I don't think they were T25's because the output was so low and I think the magnet structure was smaller.
I wouldn't replace the inductors (coils) but that's up to you.
Without a schematic or way to check their values it's not possible anyway.
Don't go nuts trying to find those exact cap values because they probably never were those exact values due to the manufacturing tolerance factor of either plus or minus 10 or 20%.
I found a Clarity ESA cap from Madisound that was close enough to the 2.84 but never had to locate a 5.7uf.
If you parallel two caps they sum, so a 3 and 2.7 would be 5.7. The voltage rating isn't a problem because most of what your going to find today will have a voltage rating that exceeds 50 volts.
If you end up using two caps in parallel to make the needed value, I'd use the same type of cap.
If the speakers sound good to you now, save the old caps because new and better isn't always better sounding. They aren't electrolytic caps so they may be old but not bad.
I find that changing caps can indeed alter the "voicing" of speakers and amps and those old caps can sound pretty darn good compared to some new ones that have better specs on paper but ultimately it's personal sonic preference.
Your not dealing with a high voltage electronic circuit where an old coupling cap is a time bomb in the output section and can damage the output tubes if one fails.
About 6 months ago I hooked up some 1950's EV drivers and their associated crossovers that are 100% original and they sounded fine to me without the urge for "better."
If your going to be working on "vintage speakers" then find a copy of Hi-Fi Loudspeakers and Enclosures by A Cohen. That book taught me a lot back in the day. There's a copy on E-Bay now for $22 and change.
You can get a new speaker design book but it will most likely be dealing with zobel networks, EQ networks,new driver design/technology and other things that don't apply to most speakers before 1968.
Follow Ups:
Thanks for the book recommendation. I am doing one speaker at a time just so I could compare the sound. I was told the caps would be electrolytic and would be bad after this many years. You said "They aren't electrolytic caps so they may be old but not bad." So that I can learn; how did you discern that? Would the following new caps be a good choice?
https://www.parts-express.com/dayton-audio-dmpc-27-27uf-250v-polypropylene-capacitor--027-416
https://www.parts-express.com/dayton-audio-dmpc-56-56uf-250v-polypropylene-capacitor--027-425
Electrolytic caps were and still are pretty common in xovers.
They are non polar and don't have a plus or minus side like an electrolytic in say a power supply circuit of an amp so they can be installed without regard to "polarity."The non polar lytic for a speaker xover has to pass an AC signal, not filter it or block it.
"Conventional wisdom" says that if can use a film and foil cap, like the Daytons or a paper in oil cap in place of a lytic, it's a good thing.
But when your talking about higher values, the size and cost is a consideration and the lytics are smaller and less expensive.
When your talking about a 2.8 uf and 5.7 uf, that isn't an issue and even back when those speakers were made the 2.7 UF and 5.7 UF values weren't large enough so that a lytic was the only practical choice in size or price.
Lytics are usually obvious because they are in a sealed metal package sometimes with a plastic like wrapping on them that has the data printed on it.
The cap values in your xover didn't need to be lytics because of cost or size and they appear to be some kind of film and foil not of the lytic variety due to the way they are packaged.
My EV Esquire 200's has two lytics in the xover but those values are much higher, 40 uf and 140 uf I think. At the time a film and foil cap of those values would have probably been unavailable or just too nuts to think about and the use of paper in oil caps like motor run caps with those higher values wasn't by any means common place due to size and price so they were non polar lytics and still are, but new ones.
Unfortunately I didn't save the old 2.84 caps to compare to any new cap in the tweeter. That was before I discovered that new caps can change the sonics for some known and some still debated reasons.
The Daytons of 2.7 uf 250V and 5.6 uf 250 V should be fine. They would most likely be lots closer to the stated values of the caps in there now.
I've never read anything bad about the Daytons so give them a try. Not to say that another brand wouldn't sound different but that's where mind set over price and specs and sonic taste come into play.
A friend bugged me to replace the caps in his Warfedale W70 speakers because he was convinced new caps would sound better.
I choose the Daytons because of price and the fact that I had never read anything bad about them.We did one speaker and couldn't hear any difference between the two. He listened for a couple of days and concluded that we should do the other speaker so that the caps were new in both. Net gain zero other than having new caps so draw your own conclusions because I have no answer other than the old caps were good and the new Daytons provided the same sonic signature.
Yes, like Paul says, it's generally advisable to think about new caps for a couple of reasons but that can open a can of worms with sonics. Just because the new cap is the same value as the old one it may not automatically sound better to you than the good old cap.
Designing xovers isn't rocket science but you have to know all the parameters of each driver and that's still an unknown here.
Then there's the actual listening test to hear what you designed using those parameters.Speakers like the EV 200, 300 and 3000111, were at the time, sort of budget speakers or speakers for those that wanted decent and almost full range sound at a good price or that just didn't want BIG speakers.
And of course marketing came into play because other companies were offering bookshelf speakers and EV's mainstay had been the larger systems.That meant sticking to a price point and using some tricks in design to achieve a result that was satisfactory. It's hard to second guess those designs as to why they were done that way.
The same holds true today with price points versus design and performance.
Edits: 01/07/17 01/07/17
Dave V,
Thanks for the education. I'm with you on preserving the the original sound. Since this is my first project it still interests me to try to "improve" the original. I know these speakers were lower end; good first project.
Your welcome CraigThose speakers aren't that low end. I've heard new speakers that cost over $2000 a pair that don't sound as good to me as my Esquire 200's.
What I meant was that EV's lineup of larger systems were more straight forward in design for the day and used their standard drivers and crossovers.
Those systems are more efficient, better balanced overall, have a more extended low end due to the driver and cabinet size/venting and they didn't need to use what I call tricks to do that.The cap thing is your call. I just cautioned you not to toss out the original caps just in case.
I remember when I got my Altec Model 19's and I searched around the Internet to see what people were doing about the caps.
There was the camp that said to put better caps in and the camp that said they still have the originals and they sound fine to them and were afraid to change the original voicing in this classic speaker.The camp that changed caps had different favorites from metallized and non metallized film and foil to paper in oil so it's very doubtful they all sounded the same in the end.
Some changed the inductors too because the originals aren't air core and they have a higher DC resistance than air cores made with a heavier gauge wire.
I did a quick survey of Model 19 owners and asked them if they had measured the values of the original inductors. The responses I got showed exactly what I found. The actual inductance of all three inductors was different than what was shown on the schematic so the people that changed the caps and inductors were listening to three changes,not just the caps.
So when people offer their opinion there can be more involved too.
If we're not talking about replacing a truly faulty part with a good part then "better" is in the ear of the listener.
Edits: 01/08/17
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: