xerxes
Been here a while! 
Posts: 1,115
|
Post by xerxes on Sept 7, 2011 13:58:48 GMT
I've got pair of old, late 80's I'd guess, Goodmans Maxim 2 Speakers. I was wondering if there would be any point in upgrading and replacing the crossover capacitors and the internal wiring. Currently there are some Alcap axial electrolytic capacitors and the internal wire is essentially bell wire.  I was wondering whether replacing the caps with some axial polypropylene types might bring about any improvements. Has anyone else replaced/upgraded speaker crossover caps; what was your experience? |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Sept 7, 2011 15:01:09 GMT
Hi Owen,
I did this on an old pair of Tannoy Mercury M20s and reckon I had a marginal improvement. i.e. the bass seemed a tad cleaner as did vocals.
That's all from memory and many years ago.
The makers tend to throw in the cheapest stuff they can find so I don't see why ( without being silly on pricey ones ) you shouldn't get some, albeit small, improvement or just change.
|
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 7, 2011 15:23:42 GMT
I thought that might be the case. Even a set fairly low cost polypropylene caps are going to cost £20 or more, more than is really worth spending for a marginal improvement.
I think I'll save the cash and keep my eye open for a decent pair of used speakers.
|
|
XTRProf
Fully Modded
Pssst ! Got any spare capacitors ?
Posts: 5,689
|
Post by XTRProf on Sept 8, 2011 4:56:36 GMT
Oh, I used Solen MKPs on my Avance Alpha 44 and I was blown away. The mid and treble now less grain. However, these speakers are using famous high quality drivers which just slip my mind now.  |
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 8, 2011 10:13:48 GMT
OK, I've just ordered some 3.3uf and 4.7uf Solen MKP caps to replace the Alcaps of those values. The 450uf cap will have to remain unchanged as I can't find a polypropylene that big and if I could it would probably cost a fortune and be so large that it wouldn't fit in the cabinets.  I'll let you know how I get on.  |
|
XTRProf
Fully Modded
Pssst ! Got any spare capacitors ?
Posts: 5,689
|
Post by XTRProf on Sept 9, 2011 21:02:59 GMT
OK, I've just ordered some 3.3uf and 4.7uf Solen MKP caps to replace the Alcaps of those values. The 450uf cap will have to remain unchanged as I can't find a polypropylene that big and if I could it would probably cost a fortune and be so large that it wouldn't fit in the cabinets. That's really a bit unusual for crossover to use 450uf.  To improve things, just buy 4 good quality polar e-caps like Elna Cerafine to non polar them to equivalent series value and higher or same wattage.  |
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 10, 2011 13:15:22 GMT
Parts arrived this morning. I ordered the caps from www.falconacoustics.co.uk/ and paid the extra 50 pence per capacitor to have them matched +/- 2%. Before:  After:  I was originally going to replace the internal cabling, but when I looked in my parts box I didn't really have anything suitable. I do have some nice teflon insulated silver plated copper hook-up wire, but this was considerably thiner than the original cable, so I thought it best to leave it. I think there is some improvement, although it's difficult to say for certain because it took about half an hour to replace the caps, so no oportunity for a quick A-B test. But the overall clarity seems better and the imaging more precise; psycho-acoustics - who knows. Attachments:
|
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 10, 2011 17:03:56 GMT
I've been listening to these for several hours now and there's definately an improvement. Clarity and imaging are definately better and much more than before the sound doesn't seem to actually come from the speakers themselves, but between and around them.
All in all, for about £16 I'm quite pleased and I've ordered some cable to replace the crummy bell wire currently connecting the drivers, crossover and speaker terminals.
|
|
|
|
Post by southpaw on Sept 10, 2011 19:08:38 GMT
My technics speakers are nudging 30 years old - i'm going to take a look inside now |
|
|
|
Post by southpaw on Sept 10, 2011 20:48:58 GMT
my technics sb-f2 crossover  capacitors 1x6.8uf 1x3.3uf resistor 5w 2.7ohm 3x unknown inductor |
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 10, 2011 21:22:43 GMT
You could replace those electrolytic caps with some polypropylene caps similar to the ones I used. I wouldn't worry about the resistor and the inductors, resistors arent very expensive, but 6 inductors would cost a fair amount if you wanted to replace them with something significantly better. It might be worth doing with a speaker that has first class drive units, but the manufacturer has really scrimped on the hidden crossover components. Changing the crossover components might make an improvement, but it won't make a complete transformation so bear that in mind before spending a fortune, you can quicky get to the point where you could pick up another, better pair of speakers for the cost of the components. |
|
|
|
Post by southpaw on Sept 10, 2011 22:07:35 GMT
the speakers cost £10 so I'll be more out of pocket from the crossover bits I'll have a look at what it will cost first. |
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 11, 2011 8:56:36 GMT
With that as a start price, I think you might struggle to find upgrades that make economic sense.  Having said that, I see that Technics SB-F2 go for about £75 on Ebay, which is about 3 times what Goodmans Maxim 2s fetch. The cap values you need are similar to the ones I bought, so it's going to be around £15 to £20 for those alone. |
|
|
|
Post by PinkFloyd on Sept 11, 2011 9:28:48 GMT
|
|
|
|
Post by PinkFloyd on Sept 11, 2011 9:31:47 GMT
What I would also do Owen is to drill some holes at the sides of the caps so you can secure them to the board with cable ties.... you really don't want all those parts vibrating.... ideally, double sided sticky foam between board and cap and then secure down with cable ties.
Mike.
|
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 11, 2011 10:36:33 GMT
|
|
|
|
Post by PinkFloyd on Sept 11, 2011 11:05:14 GMT
Hot melt glue is ideal owen.... what they used to do with high quality crossovers was to pot them in wax.... you can still do that.... put a frame around the X-over and pour melted candle wax into it. X-over damping is very important. Had a look around and I have 1 x 4r7 Mundorf which is yours if you want it.... that way two of them will only cost you £8.50  |
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 11, 2011 11:19:20 GMT
Thanks Mike, that's very generous of you, as long as you're sure you won't be needing it?
|
|
|
|
Post by PinkFloyd on Sept 11, 2011 11:24:45 GMT
Thanks Mike, that's very generous of you, as long as you're sure you won't be needing it? I won't be needing it Owen, no worries..... I can also make you up a nice 450uF non polar "multicap" to replace that 'orrible ALCAP thing.... let me put one together and see what you think, I'll upload pics later. Will match both caps to a perfect 450uF, they will be physically BIGGER than the solitary ALCAP but will sound a LOT better Let me see what I can come up with. Mike. |
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 11, 2011 11:37:55 GMT
What can I say, thank you very much. I must admit I didn't really get that bit about making up a 450uF cap that Chong mentioned and I didn't realise that you could make a NP cap from polarised caps until I just Googled it. |
|
|
|
Post by PinkFloyd on Sept 11, 2011 11:54:17 GMT
What can I say, thank you very much. I must admit I didn't really get that bit about making up a 450uF cap that Chong mentioned and I didn't realise that you could make a NP cap from polarised caps until I just Googled it. I am putting together two high quality Nichicon non polars (220uF x 2 / 100V caps) and 1 x 4.7uF polyprop film cap (250V) The Nichicons are extremely close tolerance (+/- 1%) so I will be able to match both pairs to an almost PERFECT 450uF (I have a good few Nichicons to work with) The ESR will be about 0.03 ohm... watch this space! Mike. |
|
|
|
Post by PinkFloyd on Sept 11, 2011 13:34:36 GMT
The Nichicon VP are very nice non polar caps and I slapped an ICW polyprop on just to get them as close as poss to a perfect 450uF... the polyprop will also be beneficial to the SQ Basically take the three caps....  Glue the two non polars together.....  Solder thus.....  Glue the polyprop on....  Wrap the leads of the non polars arond the polyprops and solder thus....  More glue around the cap assembly for good damping...  A bit of yello heatshrink on the legs.....  More heatshrink around the non polars.... this provides even more damping......  Test them.....  Trim the excess heatshring tubing and mark the values on the multicaps.....  Fit them onto the board this way up Owen and drizzle some hot melt under and around to support them.....  Ugly looking things but very "precise" multicaps, these will shite all over that Alcap thing  Have fun! |
|
|
|
Post by PinkFloyd on Sept 11, 2011 13:45:46 GMT
Taller than an Alcap but the way I have put it together should mean it will fit on the board perfectly... just flood some holt melt under and around it to support it.... should sound great!  |
|
xerxes
Been here a while!
Posts: 1,115
|
Post by xerxes on Sept 11, 2011 14:47:31 GMT
That's fantastic! Thanks Mike. I ordered some better cable the other day and just ordered the other resistor. When I have all the bits, I'll perform upgrade stage 2 and post up some pictures and impressions. I'm looking forward to this. You've sent me things before, do you still have my address? I reckon I've got just about enought glue sticks for the job.  |
|
|
|
Post by PinkFloyd on Sept 11, 2011 14:50:20 GMT
That's fantastic! Thanks Mike. I ordered some better cable the other day and just ordered the other resistor. When I have all the bits, I'll perform upgrade stage 2 and post up some pictures and impressions. I'm looking forward to this. You've sent me things before, do you still have my address? Ho Owen, no.... please PM it |
|
To improve things, just buy 4 good quality polar e-caps like Elna Cerafine to non polar them to equivalent series value and higher or same wattage. 
