Capacitor values, which one to use?

I can’t help myself, saw a pair of Goodmans Mezzo SL speakers for £20, cabinet tatty but all drivers spot on, so I bought them.
The crossovers are all original with 48 year old Erie caps, these need replacing, the top end is very shouty and uneven and not the ‘British version of the Dynaco A25’ I would expect to have heard.
Problem, two caps, one inductor and one resistor in the crossover, x/over frequency 2000hz, both caps are 63 volt and I can only get (from Falcon) 1x 50v and 1x100v of the correct uf value. Would substituting the 4.7uf 63 volt cap with a 5uf 100 volt cap at 10% tolerance throw the circuit out of alignment or should a 4.7uf 50 volt be ok and not fail prematurely ?
X/over component values 1x 4.7uf 63v cap, 1x 2.2uf 63v cap, 1x 10R resistor and an unmeasured small inductor. Help/opinions will be greatly appreciated.

I’m reluctant to substitute components with lower-rated ones, but you might well get away with it - 50 volts peak into 8 ohms is 150 watts, and the peaks in music don’t occur very often.

Falcon probably have access to a capacitance meter. You could ask them how much they’d charge to select a couple from their 5uF/100V stock which are as near to 4.7uF as they can get.

To be honest though I’d be surprised if you could hear the difference between 4.7uF and 5uF.


Thanks Graeme, I’m glad my uneducated thought process was heading in the right direction, but didn’t know why :roll_eyes:. I shall take your welcome advice, I may even splurge the cash and buy one of each just to listen and compare, no expense spared eh, and I’ve 'nowt else to do at the moment.

Thanks for the link, but I’m replacing like with like and they are electrolytics . Replaced the caps in my jr149’s with poly’s, what a disaster, sucked all the life out of them, popped electrolytics back in and they sang.

that’s some going as JR149 are lifeless to start with :stuck_out_tongue_winking_eye:


Why not just shop somewhere else?

Agree with Graeme tho’ - for this application the slight difference in capacitance is irrelevant.

As it happens I have some 10uF 100V electrolytics if needed. You would back-to-back them (- to -) which will give you a ~5uF bipolar/non-polar cap.

I’d always look to use bipolar caps if I have to put electrolytics (yuk!) into a speaker crossover.

Thanks for the offer Paul, I’ve already put my order in to Falcon and as suggested the 0.3uf difference should make little if any audible change. I’m just a sucker for the mid 70’s era of hi fi and usually buy after a few scoops of intoxicating liquid, recently a Quad 34/306/Fm4 and now the Goodmans Mezzo Sl. The Goodmans because they mimic closely the Dynaco A25, always liked them. If they come up to the mark I’ll re-veneer them and put some less tired speaker grill fabric on them in due coarse. I’ve got a good feeling about them.