If anyone's appetite's been whetted by this thread, have a look here:
http://cgi.ebay.co.uk/ws/eBayISAPI.d...tchlink:top:en
http://contact.ebay.co.uk/ws/eBayISA...lerQuestion_VI
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If anyone's appetite's been whetted by this thread, have a look here:
http://cgi.ebay.co.uk/ws/eBayISAPI.d...tchlink:top:en
http://contact.ebay.co.uk/ws/eBayISA...lerQuestion_VI
Here is my redesigned crossover. I think I'm going to get new air-cored inductors and build new crossovers complete.
http://farm8.staticflickr.com/7292/8...2c68e809_b.jpg
I thought you would Martin that rats nest would have me loosing sleep for a month, i suspect your the same? :D
As the outsides of the terminal plates look a bit rough & that your omitting the fuses. maybe you could kindly ask Mark (YNWaN) if he could make you some replacements to your design out of Acrylic!
You're right, Andr'e. I prefer the idea of starting it over and laying everything out nicely.
Greetings, Martin. You're schematic is badly wrong. so is the original:
http://i26.photobucket.com/albums/c1...ps0ee9e0d5.jpg
Those capacitors at the input to the midrange filter make a dead short at high frequency.
My best guess is the 6.8uF goes AFTER the 0.3mH coil. It would probably be very good to put a 2.2 R resistor in front of the whole midrange filter, since it dips dangerously low near 3 ohms even in the original. The Gale was known as an amp killer anyway.
The treble filter is a straight lift from the Celestion Ditton 44, as it goes. Hope that helps, I like the Gales. :)
Thanks, Steve. Now that you point it out, it does look wrong. I shall trace the real one when I remove it.
Thanks again to Steve, I've revised my crossover diagram and replaced the original in post #52 for fear of anyone seeing and making use of it. The circuits in the Gale refurbishing website are incorrect except for the GS402, which shows the capacitor in the correct position (thanks to Andr'e for sending me the link).
I don't know which would have lasted longer, the caps or the Chord. My money would be on the Chord, but I wouldn't like to try it for real :lol:
Looking at the GS402 crossover here, I'm intrigued by the resistor choices in this non-variable design. The mid has 6R4 resistors (10 in parallel with 18) giving a little more mid output than mine, and the tweeter has a fixed 1R2 giving some more treble energy.
I would expect the 402 to sound brighter as a result.
Do the US ones have the same bass units in them as the UK examples?
They seem to Dave, they look like the AR bass units and have a square magnet assembly.
There was an equivalent Peerless 8" as used in later Gale 301's but it also had a foam surround so any left alive will need re-foaming now too.
The crossover board was a right bugger to remove; those staples were designed for permanent fixture. That and the amount of glue used makes the board effectively unmodifiable. I doubt that I could rescue the inductors without destroying them; as it is, the coils are quite loose and only held in place by the cable ties. You can see at the top that one capacitor has exploded meaning that this crossover was already inoperative.
The pot tracks are in a bad way and I had to exercise them a lot in order to take measurements in their nominal centre positions. Interestingly, the mid adjuster is almost at max level while the tweeter is closer to centre position. This has helped me to finalise the circuit shown in post #52.
http://farm8.staticflickr.com/7364/8...609ea796_b.jpg
Crossover Shopping List
Resistors (all Mills MRA12)
0R82 x 2
3R9 x 2
6R2 x 2
Capacitors (all Supersound polypropylene)
4uF x 4
5.6uF x 2
6.8uF x 2
30uF x 2
Inductors (all Wilmslow air cored)
0.15mH x 2
0.3mH x 2
1.8mH x 2
3.3mH x 2
Speaker terminals x 2
Thin ply board 220 x 160mm x 2
Id be tempted to try find some long thread terminals & use at least 1/2'' ply board.
I've gone for thinner ply, Andr'e, on the basis that it's thicker than the hardboard used. Long thread terminals already ordered ;)
Just for fun, Martin, here's my opinion of the Gale GS401A:
http://www.diyaudio.com/forums/multi...ml#post2886588Quote:
Originally Posted by system7
Flippin' great speaker. :)
Well Steve, you've just whetted my appetite even more. I certainly remember them the first time around, when they were just unobtainium to an enthusiastic teenager. I remember those early ARs too (like the 3a) and they certainly had clout.
Amusing that people lust after the chrome ones; I'm quite happy I found a pair in the wood finish. They don't need to show off, let the sound do the talking!
I'm currently doing the layout for the new crossovers. All parts received so I'll template everything in order to produce a matching pair.
I wasn't happy with my idea of using brass panel pins as uprights/supports. I've therefore ordered some proper silver turret tags from Hi-Fi Collective and am waiting for them to arrive. Otherwise, I'm all ready for the crossover build and re-foam sections of my project. I just need more free time!
Redesigned crossover ready to attach speaker driver cables. All components hot-glued into place. I designed it to keep the four chokes as far away from each other as possible, and to isolate the sensitive midrange section on the left (treble top-right, bass bottom-right). Silver turret tags used for anchor points. 4mm sockets protrude on the other side, ready for fitment to the rear cabinet access hole.
I'm going to try to rescue the Gale label complete with serial number from the old crossovers.
http://farm4.staticflickr.com/3815/8...6ce38a72_b.jpg
That is a very neat job Martin... :clapclapclap:
The label was almost impossible to get off the old crossover (by cutting around the opening) and what actually peeled off was the top film layer of the original label, impossibly thin and wanting to just disintegrate in my hand. I did the best I could with it but this was about the fourth attempt using Aleen's Tacky Glue.
It looks better in real life than in the photo, but to be honest I was only trying to preserve the serial number to keep them honest. This is what will be viewable through the rear cabinet access hole when it's all been assembled in place.
http://farm3.staticflickr.com/2894/8...79369751_b.jpg
I've just noticed something: my two speakers are serial nos. 2284 and 2556, quite a difference. They are also constructed differently internally (though not externally). The chap I bought them from says he had them since new. Why the discrepancy? Could he have had one replaced under warranty?
Fascinating, as the cabinets definitely look like they were built by different people, even to the internal brace from rear to baffle being angled differently in the two speakers.
Great job so far Martin - I always wanted to try 401s but they have always been expensive s/h even 20 years ago. What is the situation with the tweeters? Are they working okay after all? If not it may be worth sourcing an original pair, evne though it is pricey the re-sale value of the speakers once finished would seem to warrant it.
Delicate. One looks fine, the other has suffered from the top fibre mounting having warped. I've tried gluing it down and weighting it with an egg cup, to limited success. They both read fine resistance-wise (about 5.5 Ohms). I'm going to test fire the tweeters through the crossover over the weekend and have a listen. If they sound good, I'll leave them alone.Quote:
Originally Posted by Macca
If I have to replace them, I'll probably go with the Seas direct replacement (H0737) since sourcing a couple of decent HF2000 tweeters will cost more than I've paid for the whole project so far.
Sounds like they could be okay, which is good. :)
Looking good Martin, just one thing on the crossovers. Seeing those bare wires crossing over without insulation makes me feel uncomfortable. I'd definitely have put sleeving on those.
Id get that redesigned omitting what you've removed get some screen printed on thick acrylic or formica, as long as it looks on the simular lines as the original.. You ought to have really done that before building the new board as to get the binding posts in a suitable uniform area.Quote:
Originally Posted by MartinT
I thought of that, Geoff, but the choke wires are enamel insulated and there is a height gap between them that you cannot see in the photo.Quote:
Originally Posted by walpurgis
I thought of omitting them altogether, Andr'e, but as I said I wanted to preserve the labels for authenticity and for the serial numbers. The appearance doesn't bother me as they're for the rear panel and I won't be looking at them every day!Quote:
Originally Posted by Rare Bird
Good news. I've just tested the tweeters on a lash-up with a crossover and they both work fine!
That is excellent news Martin :)
All driver holes now opened up with 6mm drill and M5 Tee nuts fitted so that I can use dome headed hex bolts. I'm also adding four holes to each bass driver to mount them with eight bolts each. I like well fastened drivers :)
Taken before the further holes for the bass drivers were drilled, cabinets with one coat of Danish Oil applied with fine wire wool, driver holes opened up and Tee nuts inserted.
There are a couple of small repairs I have yet to sort out with a little matching stain.
http://farm8.staticflickr.com/7377/8...2f52088d_b.jpg
i don't mean to sound a pain in the arse Martin but i would have sourced some veneer edging strip for down the front edges cover up the chipboard showing! they look like American black walnut finish which is pretty easy to get hold of.
You can also buy that velco strip that's stapled to the baffle board if you fancy replacing it, or for a neater look you can get round velco..
looking good tho buddy.
There's no chipboard showing any more, Andr'e, that's wood filler. I'll stain it to match when I get around to the finishing touches.
I take your point about the Velcro strips, in fact I have to remove them if I'm going to give the baffle a coat of black.
Looking good Martin - while you have the oil out, that chair could do with a lick ;)
Ah yes, the garden furniture, indeed. I bloody *hate* teak oiling them and have left it a couple of years. I did the table last week, chairs still to be done...
Coming along nicely Martin. I bet you'll be delighted with them once they're up and running. They are a nice sounding speaker.
I've 'faked' wood grain on filler in the past using a very fine art brush and black and brown paint.
Ah, good man, I was hoping someone would tell me it can be done.Quote:
Originally Posted by walpurgis
Getting very close to refoaming the drivers out in the garden (you don't want all that tar-like mess in the house). Good weather for it now.
What the heck are you going to use Martin?Quote:
Originally Posted by MartinT
As I've said (often) 'Aleene's Tacky Glue' is the best!
Aye don't drop a ballerk like i did, i changed the gooey idler wheels & pinch roller in my Ferrograph Reel + Reel machine, i only went & dropped the pinch roller on the carpet whilst cleaning the dinner table off. Absolutly destroyed the carpet. That little job cost me £100.00 for the new wheels + £500.00 for a new carpet :steam:Quote:
Originally Posted by MartinT
The idler wheels of my Ferrograph 632 machine have also gone 'gooey'. I have a new set, but can't see how to change them. Do you know of a web site that can provide instructions on how to do this?
PM
Yes, I'll be using the Aleene's alright. Have you ever done a refoam? The crap that the old foam surrounds turns into over the years is so horrible, rubbery and sticky that it behaves like tar and you do NOT want to get it on your carpet!Quote:
Originally Posted by walpurgis
Yes, I've done a number of surround replacements, using contact adhesives sometimes, particularly when it's a plastic cone bonding to a rubber surround. But Aleene's seems best for paper/pulp cones. The sticky old surround residue just takes a lot of patient scraping to remove. And yes, I did get a couple of little bits on the carpet. I just plucked them off and cleaned up with paint brush cleaner, followed by soapy water.Quote:
Originally Posted by MartinT
A quick update as I've been away for a while so not a great deal of progress to report, however all four bass drivers are pretty much prepared and ready to take the replacement roll surrounds. All your warnings were heeded and the work was done in the garden, which was wise as the nasty tar-like stuff that came off really did stick to everything, as well as continually fouling my chisel.
http://farm6.staticflickr.com/5522/9...1e94f79c_b.jpg
I'll be mounting the surrounds shortly and completing the second crossover soon. Not long to go now before firing them up. I'm getting pretty excited!
You must have been busy ! I'd have died of anticipation by now :D
How did you clean the old foam off ? I find nail varnish remover brings the baskets up like new.
I used pure acetone, but even with that it was pretty hard. Will give them a final going over before the new surrounds go on.
Ah even better :thumbsup:
Having sat there & done 4, one after the other myself I can sympathise ! First one's interesting, second one's fun, third one's boring & the fourth is tedious :D ...Aching fingers just make it harder :(
2nd crossover completed and both tested fine. Just the four bass drivers to re-foam now and a repair to one tweeter. Should be about a day's work left.