As a complete novice I feel a little embarrassed joining here and asking for assistance but here goes..
Identification required please.
I’m in the process of attempting to renovating a pair of Griffin speakers I bought in 1980.
They have been stored for over 25 years.
As a trial I connected them to my equally aged Sugden Stemfoort amp. The result was ‘over bright’ in fact ‘extremely sharp’ when I removed the bass speaker I noticed that a Capacitor on the three way crossover had become detached from its circuit. On removal Maplin’s and R.S. were unable to identify this faulty component for replacement.
I have now ‘cut’ the crossovers out of their cabinets for closer further examination and found three other similar capacitors which have become separated from their circuits.
I enclose photos of the parts which I’d like to replace. I do not have a circuit diagram to aid identification and guess that the speakers may be: twin ported Aperiodic 27’s
Any help and guidance will be most appreciated, my electronic expertise is limited to the basic level of being able to solder. I understand that even if I’m able to replace what I believe is to be the problem that other factors may surface; but the fact that I was able to get some sound from them indicates that the speaker unit may be serviceable and can then be passed down the ‘food chain’ to my grandson along with my Sugden amp and Aura CD deck.
If all else fails, instead of repairing, is there an alternative replacement and affordable crossover I could obtain before biting the bullet taking them on a tear-stained journey to the tip?
Identification required please.
I’m in the process of attempting to renovating a pair of Griffin speakers I bought in 1980.
They have been stored for over 25 years.
An externally hosted image should be here but it was not working when we last tested it.
As a trial I connected them to my equally aged Sugden Stemfoort amp. The result was ‘over bright’ in fact ‘extremely sharp’ when I removed the bass speaker I noticed that a Capacitor on the three way crossover had become detached from its circuit. On removal Maplin’s and R.S. were unable to identify this faulty component for replacement.
An externally hosted image should be here but it was not working when we last tested it.
I have now ‘cut’ the crossovers out of their cabinets for closer further examination and found three other similar capacitors which have become separated from their circuits.
I enclose photos of the parts which I’d like to replace. I do not have a circuit diagram to aid identification and guess that the speakers may be: twin ported Aperiodic 27’s
An externally hosted image should be here but it was not working when we last tested it.
Any help and guidance will be most appreciated, my electronic expertise is limited to the basic level of being able to solder. I understand that even if I’m able to replace what I believe is to be the problem that other factors may surface; but the fact that I was able to get some sound from them indicates that the speaker unit may be serviceable and can then be passed down the ‘food chain’ to my grandson along with my Sugden amp and Aura CD deck.
If all else fails, instead of repairing, is there an alternative replacement and affordable crossover I could obtain before biting the bullet taking them on a tear-stained journey to the tip?
Welcome to diyAudio 
I believe your mystery part is a 2.2uF 250 volt capacitor (an old film type).
There also appears to be a resistor soldered to it which you would have to identify. There looks to be a bit of discolouration as if it has got hot at some point.
Can you measure a resistance reading across the pair ?
I believe your mystery part is a 2.2uF 250 volt capacitor (an old film type).
There also appears to be a resistor soldered to it which you would have to identify. There looks to be a bit of discolouration as if it has got hot at some point.
Can you measure a resistance reading across the pair ?
Goodness Me,
Mooly. Many thanks for your speedy reply.
Unfortunately I do not have testing equipment but suspect that the ‘cooked’ resistor may be within capabilities of Maplins to identify and replace I can make-out: R33.
I enclose other close up shots of the two other capacitors which I hope you may be able to identify their values.
Mooly. Many thanks for your speedy reply.
Unfortunately I do not have testing equipment but suspect that the ‘cooked’ resistor may be within capabilities of Maplins to identify and replace I can make-out: R33.
I enclose other close up shots of the two other capacitors which I hope you may be able to identify their values.
The top cap that is cut off in the image looks to be a 0.22uF. The two below that are 1uF and the one with a leg hanging off is also 0.22uF
R33 as marked on the resistor could be 33 ohm although these days you would take it to mean 0.33 ohm. 33R would normally be 33 ohm. However sticking a 2.2uF cap across 0.33 ohm sounds intuitively a little odd so I would go with 33 ohm at this point.
Try measuring across it on your meter on a low ohms range and see what you get.
Tbh, it all looks very old and those large can type caps might be suspect.
R33 as marked on the resistor could be 33 ohm although these days you would take it to mean 0.33 ohm. 33R would normally be 33 ohm. However sticking a 2.2uF cap across 0.33 ohm sounds intuitively a little odd so I would go with 33 ohm at this point.
Try measuring across it on your meter on a low ohms range and see what you get.
Tbh, it all looks very old and those large can type caps might be suspect.
Mooly,
Again, thanks for the return.
Please confirm: the largest detached capacitor (red body,green and white stripe) 2.2uF 250v
Smallest capacitor shown ( brown body, red, black, yellow ,red.stripe) 0.22uF
Mid size capacitor. (Brown body, red, white , green black).. 1uF
The resistor could be 33ohm;what would the implecations be of fitting a 0.33 ohm resistor instead of 33 ohm and or visa versa?
Again, thanks for the return.
Please confirm: the largest detached capacitor (red body,green and white stripe) 2.2uF 250v
Smallest capacitor shown ( brown body, red, black, yellow ,red.stripe) 0.22uF
Mid size capacitor. (Brown body, red, white , green black).. 1uF
The resistor could be 33ohm;what would the implecations be of fitting a 0.33 ohm resistor instead of 33 ohm and or visa versa?
Getting the resistor wrong would totally alter the crossover characteristics. Try measuring the resistor you have first. Just because it is discoloured and burnt looking doesn't mean it has failed.
If you are just experimenting at the moment then I would be inclined to use standard parts and just tag them in place. No need to spend a fortune at this stage.
Check out 'CPC' which is part of Farnell.
http://cpc.farnell.com/vishay/bfc246828224/468-polyester-cap-400v-220nf/dp/CA05395
http://cpc.farnell.com/vishay/2222-468-16105/468-polyester-cap-250v-1uf/dp/CA01238
or,
http://cpc.farnell.com/ampohm-wound-products/fp-ca-1-au/capacitor-audio-1uf-630vdc/dp/CA05703
http://cpc.farnell.com/vishay/bfc246804225/468-polyester-cap-100v-2-2uf/dp/CA05387
or
http://cpc.farnell.com/ampohm-wound-products/fp-ca-2-2-au/capacitor-audio-2-2uf-630vdc/dp/CA05704
If you are just experimenting at the moment then I would be inclined to use standard parts and just tag them in place. No need to spend a fortune at this stage.
Check out 'CPC' which is part of Farnell.
http://cpc.farnell.com/vishay/bfc246828224/468-polyester-cap-400v-220nf/dp/CA05395
http://cpc.farnell.com/vishay/2222-468-16105/468-polyester-cap-250v-1uf/dp/CA01238
or,
http://cpc.farnell.com/ampohm-wound-products/fp-ca-1-au/capacitor-audio-1uf-630vdc/dp/CA05703
http://cpc.farnell.com/vishay/bfc246804225/468-polyester-cap-100v-2-2uf/dp/CA05387
or
http://cpc.farnell.com/ampohm-wound-products/fp-ca-2-2-au/capacitor-audio-2-2uf-630vdc/dp/CA05704
Attachments
Oddly Maplin used to sell those capacitors in the 1980's !
Polyester 2u2 250V.
RS do them:
Polyester Film Capacitors | RS Components
Polyester 2u2 250V.
RS do them:
Polyester Film Capacitors | RS Components
I’m not sure what the resistors wattage is.
Regarding the ventilation. Does that mean I should avoid packing the wadding in around the crossover?
Given that most domestic listening is under a couple of watts (yes, it really is that low) heat generation in normal use should not be an issue.
Sine wave testing generates far far more heat than music.
Also, if the speakers have been connected to an amplifier with either high frequency instability (oscillating) or a high DC offset then it is possible for overheating to occur.
Have you actually tested the speaker drive units ? Are they all OK ?
Sine wave testing generates far far more heat than music.
Also, if the speakers have been connected to an amplifier with either high frequency instability (oscillating) or a high DC offset then it is possible for overheating to occur.
Have you actually tested the speaker drive units ? Are they all OK ?
“Have you actually tested the speaker drive units ? Are they all OK ?”
It was only after connecting them up after they had being stored away for 25 years that I realised how much better they were than the JPWs which I replaced them with.
However, as mentioned before after ‘listening’ for a short while as those of us on forum such as these really do I noticed how over bright and out of balance they were.
It was only after connecting them up after they had being stored away for 25 years that I realised how much better they were than the JPWs which I replaced them with.
However, as mentioned before after ‘listening’ for a short while as those of us on forum such as these really do I noticed how over bright and out of balance they were.
I know few people who have found joy after just willy-nilly replacing out components. More often they open a can of worms; or worse, they convince themselves that because they have done something, it has improved the sound, even when it hasn't.
I see no components that typically have aging problems in my experience, although I have none with those old can-type caps, but if they are paper-oil they aren't likely to be bad, AFAIK. The multi-color mylar caps don't go bad, but one of them is cracked.
More likely it is the crossover design rather than the components that are causing a problem. You can't fix it without understanding it. Trace out the circuit, put it in a circuit modeler and try to understand what changing component values does to the sound.
Measure the speakers (a useful measurement rig will cost you next to nothing) See if they are different from each other as a start.
Lang:
All resistors are rated in Ohms and Watts. Ohms is the resistance, but watts is about how hot they may be allowed to get before they deteriorate. Generally, physically larger resistors have higher power ratings.
Any resistor that turned brown/black over time was obviously overheating. That means the power was higher than it was built for. It also means that it gives off a lot of heat to nearby components. Think of it as an internal space heater.
So, yes, if you see this happening you should:
- increase the power rating of the resistor (Watts)
- Increase the space around the resistor (to give it more air to cool)
- Increase the distance from the resistor to other heat sensitive components like resistors and capacitors so they don't also overheat.
As may be assumed, power ratings for a resistor are based on more or less free-air mounting, which allows for convection cooling. If you pack them in thermal insulators, or squeeze them next to other components the power they can safely dissipate drops dramatically. Conversely, attaching a heat sink can dramatically increase the power rating.
Capacitors also have something similar, but for film caps what we worry more about is the temperature rating, in C. The longer they spend "hot" (near or above the temperature rating) the faster they deteriorate.
I see plenty of evidence in that crossover of overheating problems. Cracked capacitor bodies, loose connections, etc. so pay attention to what the crossover is telling you about heating issues so your rebuild lasts twice as long as the original.
Best,
E
All resistors are rated in Ohms and Watts. Ohms is the resistance, but watts is about how hot they may be allowed to get before they deteriorate. Generally, physically larger resistors have higher power ratings.
Any resistor that turned brown/black over time was obviously overheating. That means the power was higher than it was built for. It also means that it gives off a lot of heat to nearby components. Think of it as an internal space heater.
So, yes, if you see this happening you should:
- increase the power rating of the resistor (Watts)
- Increase the space around the resistor (to give it more air to cool)
- Increase the distance from the resistor to other heat sensitive components like resistors and capacitors so they don't also overheat.
As may be assumed, power ratings for a resistor are based on more or less free-air mounting, which allows for convection cooling. If you pack them in thermal insulators, or squeeze them next to other components the power they can safely dissipate drops dramatically. Conversely, attaching a heat sink can dramatically increase the power rating.
Capacitors also have something similar, but for film caps what we worry more about is the temperature rating, in C. The longer they spend "hot" (near or above the temperature rating) the faster they deteriorate.
I see plenty of evidence in that crossover of overheating problems. Cracked capacitor bodies, loose connections, etc. so pay attention to what the crossover is telling you about heating issues so your rebuild lasts twice as long as the original.
Best,
E
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I've dropped a few solder joints to heat from resistors, I'm sure some must have been speaker related.
Clearly the resistor in the photos was too close to the capacitor - by lead connection and by convection. Capacitors don't like heat.
Well, I’m now back up and running and sincerely thank everyone on the forum that has contributed posts to my amateur repair project, particular thanks to Mooly who was able to specify the values of the faulty components without such help and guidance I wouldn’t have been able to started at all.
I was able to obtain the 8 capacitors I needed to replace over the counter at Maplins this morning and have taken on-board the recommendations made with regard to the separation between caps and resistors. In the end, I took a chance and re used the original resistors. The crossovers were reposition in the cabinets and resealed all round and then over taped with Gorilla tape.
Over the last few days whilst sorting out my plan of action for the crossovers refurbishment; I’ve stripped down the walnut veneered enclosures using 80, 120 and 240 grit on an orbital sander. I’m waiting for some 400 grit disks to finish it off before they will be Tong oiled.
Tonight, while I clear up my workshop after this project I shall be accompanied by the wonderful sound that I last enjoyed many, many years ago before I stepped off the HiFi treadmill due to domestic compromises from ‘her in doors’ who didn’t possess the same hearing finesse that so few of us enjoy 😉
What a smashing bunch of members you are.
Thank You.
I was able to obtain the 8 capacitors I needed to replace over the counter at Maplins this morning and have taken on-board the recommendations made with regard to the separation between caps and resistors. In the end, I took a chance and re used the original resistors. The crossovers were reposition in the cabinets and resealed all round and then over taped with Gorilla tape.
Over the last few days whilst sorting out my plan of action for the crossovers refurbishment; I’ve stripped down the walnut veneered enclosures using 80, 120 and 240 grit on an orbital sander. I’m waiting for some 400 grit disks to finish it off before they will be Tong oiled.
Tonight, while I clear up my workshop after this project I shall be accompanied by the wonderful sound that I last enjoyed many, many years ago before I stepped off the HiFi treadmill due to domestic compromises from ‘her in doors’ who didn’t possess the same hearing finesse that so few of us enjoy 😉
What a smashing bunch of members you are.
Thank You.
Just when you thought you’d seen the last of me.
I now have another question for you.
As stated previously I have an old Sugden Amp I think it’s about 50 watts per channel.
With your help I now have a working pair of Griffin Speakers (could be Aperiodic 27s)
Now to the crux of the matter.
Speaker cables.
Sorting through my oddment box of electrical stuff I’ve collected over the years I came across a pair of cables I remember I once paid a fortune for back in the 1970s. I’ve used these to connect the amp and speakers.
They are flat and braided green and copper coloured wire. I did a google search and believe they may be a Litz or Polk type.The search describes them as the very best but then confusingly also warns of the danger of using them.
Your thoughts please on their usage.
I understand that if I were to cut the present two cables into 4 I could then safely use two cables per speaker and avoid the possibility of them shorting out and blowing the amp. Alternatively I also have conventional twin core which I could use.
I now have another question for you.
As stated previously I have an old Sugden Amp I think it’s about 50 watts per channel.
With your help I now have a working pair of Griffin Speakers (could be Aperiodic 27s)
Now to the crux of the matter.
Speaker cables.
Sorting through my oddment box of electrical stuff I’ve collected over the years I came across a pair of cables I remember I once paid a fortune for back in the 1970s. I’ve used these to connect the amp and speakers.
They are flat and braided green and copper coloured wire. I did a google search and believe they may be a Litz or Polk type.The search describes them as the very best but then confusingly also warns of the danger of using them.
Your thoughts please on their usage.
I understand that if I were to cut the present two cables into 4 I could then safely use two cables per speaker and avoid the possibility of them shorting out and blowing the amp. Alternatively I also have conventional twin core which I could use.
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This stuff:
Audio Asylum Thread Printer
Lets just say I wouldn't want to use my amp with that
Go conventional.
Audio Asylum Thread Printer
Lets just say I wouldn't want to use my amp with that
Go conventional.
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