I guess I need to join this thread too... I recently (yesterday) acquired a pair of what appear to be very early version 1 Celestion 66 Studio Monitors, build numbers 00078 and 00082. They appear to be in beautiful shape! A minor scratch here and there except for the bottoms. The wife and I were blown away by the sound these produce, especially since they are probably almost 40 years old. We were switching back and forth between these and some Modula MT's I build last year... What a great open and detailed sound they make, they really make you want to keep turning the volume up. I'll have to look at the diffraction-fixing mods mentioned earlier in this thread as we both noticed a bit of smearing in the top end and this was confirmed when reading this thread.
I am noticing that the two 66's have different sound signatures though. I swapped them left for right and the difference followed the swap so it isn't placement related. One side has significantly stronger midrange than the other, confirmed by playing some pink noise through each of them. I'll have to open them up and see what's what.
Any suggestions on how to get the grills off? I can pry them forward a little bit, just enough to see the black baffles, but don't want to damage anything taking them off.
Thanks!
-Todd
I am noticing that the two 66's have different sound signatures though. I swapped them left for right and the difference followed the swap so it isn't placement related. One side has significantly stronger midrange than the other, confirmed by playing some pink noise through each of them. I'll have to open them up and see what's what.
Any suggestions on how to get the grills off? I can pry them forward a little bit, just enough to see the black baffles, but don't want to damage anything taking them off.
Thanks!
-Todd
Hi, a warm welcome to the thread, micagreenmachin!
In my experience the grills are normally secured as follows.
In the bottom of each speaker cabinet is a single screw in a recess. This screw goes up through the wooden cabinet base into a bracket fitted inside the bottom of the grill. So the first thing is to remove this screw.
Once you've done this, gently pull out the bottom of the grill until it is just clear of the wooden cabinet.
Next, you need to pull the grill downwards towards the floor. (This is much easier to do if the cabinet is lying flat on its back.) This is because the top of the grill slides behind two brackets fitted inside each side of the grill. If you pull downwards and at the same time perhaps ease the grill gently from side to side, the top of the grill should slide free of the brackets and you can then lift it off.
As they say in the instruction manuals, re-fitting is a reversal of this process!
Good luck...
In my experience the grills are normally secured as follows.
In the bottom of each speaker cabinet is a single screw in a recess. This screw goes up through the wooden cabinet base into a bracket fitted inside the bottom of the grill. So the first thing is to remove this screw.
Once you've done this, gently pull out the bottom of the grill until it is just clear of the wooden cabinet.
Next, you need to pull the grill downwards towards the floor. (This is much easier to do if the cabinet is lying flat on its back.) This is because the top of the grill slides behind two brackets fitted inside each side of the grill. If you pull downwards and at the same time perhaps ease the grill gently from side to side, the top of the grill should slide free of the brackets and you can then lift it off.
As they say in the instruction manuals, re-fitting is a reversal of this process!
Good luck...
More 66s
Hi - I have a pair of early, with the tagged circuit board. I recently had the caps replaced by Wilmslow Audio, using their poly caps apart from the pair of 72s in the bass circuit. They were replaced with electrolytics.
Previously, the treble output was way down and the mid could sound a little 'hard'. The bass, on the other hand was deep and 'solid'. Some drums really sounded like a drum being whacked, right there in front of me. Bass lines drove along, without sounding boomy, provided the speakers were at least 1/2 metre from the rear wall.
After the cap change I find that the mid clearer and the treble has extended and is very smooth. However, the bass has receded somewhat. I'm not sure if it's down in bandwidth or gain, but I have to place them close to the rear wall to get an approximation of what they were. Even so, there is still some of the 'whack' missing.
There seems to be a slightly higher gain to the mid and treble now. I noticed that I was listening at a lower volume to get the same mid and upper level I was used to. Perhaps this would account for the loss of bass.
May I ask for opinions please?
Hi - I have a pair of early, with the tagged circuit board. I recently had the caps replaced by Wilmslow Audio, using their poly caps apart from the pair of 72s in the bass circuit. They were replaced with electrolytics.
Previously, the treble output was way down and the mid could sound a little 'hard'. The bass, on the other hand was deep and 'solid'. Some drums really sounded like a drum being whacked, right there in front of me. Bass lines drove along, without sounding boomy, provided the speakers were at least 1/2 metre from the rear wall.
After the cap change I find that the mid clearer and the treble has extended and is very smooth. However, the bass has receded somewhat. I'm not sure if it's down in bandwidth or gain, but I have to place them close to the rear wall to get an approximation of what they were. Even so, there is still some of the 'whack' missing.
There seems to be a slightly higher gain to the mid and treble now. I noticed that I was listening at a lower volume to get the same mid and upper level I was used to. Perhaps this would account for the loss of bass.
May I ask for opinions please?
Ditton 66 problem solved.
I bought a pair of £8 L pads from Wilmslow. When they replaced my caps I also got them to bi-wire the crossovers. They were bi-wired with the bass and midrange together. A bit odd I thought, so I rejigged them to separate the bass from the mid and treble. I then put the L pads across the mid and treble part of the crossover, allowing me to attenuate just the mid and treble. I drilled through the back of the cabinets to mount the L pads externally, and sealed the hole with silicon goo when the leads were fed through.
What a difference! I now have as much bass as I want, and was used to. It gives me the freedom to move the speakers well away from the walls (without having to lose out on bass) to achieve a deep, open, wide and very clear sound. My 66s are now singing and I 've never heard them sound so good.
Once I've experimented with placement and attenuation, I'll hard wire a couple of resistors in place of the L pads. (I'd never heard the term before - I thought it was just a potentiometer).
I'm still curious as to why the bass output was affected by the cap change. Could it be down to 20-odd caps being replaced by only 6 or 7 new ones with different impedance characteristics?
I bought a pair of £8 L pads from Wilmslow. When they replaced my caps I also got them to bi-wire the crossovers. They were bi-wired with the bass and midrange together. A bit odd I thought, so I rejigged them to separate the bass from the mid and treble. I then put the L pads across the mid and treble part of the crossover, allowing me to attenuate just the mid and treble. I drilled through the back of the cabinets to mount the L pads externally, and sealed the hole with silicon goo when the leads were fed through.
What a difference! I now have as much bass as I want, and was used to. It gives me the freedom to move the speakers well away from the walls (without having to lose out on bass) to achieve a deep, open, wide and very clear sound. My 66s are now singing and I 've never heard them sound so good.
Once I've experimented with placement and attenuation, I'll hard wire a couple of resistors in place of the L pads. (I'd never heard the term before - I thought it was just a potentiometer).
I'm still curious as to why the bass output was affected by the cap change. Could it be down to 20-odd caps being replaced by only 6 or 7 new ones with different impedance characteristics?
Hello everyone ...
Unfortunately I have been caught up in a very time-consuming matter and have thus had no time to even look at this Forum, let alone Post anything.
I still have very little time spare, however I will Post a few comments now which I hope will be of assistance to the recently joined members.
Hello picpic - don't apologise ! It is good you have recalled an old thread, because that keeps it current for new searchers to find what they may need to restore their old Celestion 66s !!
Post again after you have your MD500s reconditioned and tell us the results.
Unfortunately I have been caught up in a very time-consuming matter and have thus had no time to even look at this Forum, let alone Post anything.
I still have very little time spare, however I will Post a few comments now which I hope will be of assistance to the recently joined members.
Hello picpic - don't apologise ! It is good you have recalled an old thread, because that keeps it current for new searchers to find what they may need to restore their old Celestion 66s !!
Post again after you have your MD500s reconditioned and tell us the results.
Read the Thread ...
Hello Mr G.O.A.T. - hey, please give us a short name to address you by in a Post !
(I like goats, however I suspect that you are not a goat ...)
Now for the time consuming part -
I strongly recommend you start at the bottom of Page 3 of this thread, at my Post #30, and read from there ALL the Posts about cross-overs and components for them.
You will find plenty of photos and diagrams, and much else, and hopefully everything that you will need.
Post again AFTER you have read through and thought carefully about it all, and yes it will take a long time, but given how long it took some of us to post all that information the first time we cannot be reasonably expected to post it again.
In the time I may have available later I want to Post about things that I have not addressed yet, or not completed addressing last year.
Both of rwtomkins' initial recommendations to you are good.
Hello Mr G.O.A.T. - hey, please give us a short name to address you by in a Post !
(I like goats, however I suspect that you are not a goat ...)
Now for the time consuming part -
I strongly recommend you start at the bottom of Page 3 of this thread, at my Post #30, and read from there ALL the Posts about cross-overs and components for them.
You will find plenty of photos and diagrams, and much else, and hopefully everything that you will need.
Post again AFTER you have read through and thought carefully about it all, and yes it will take a long time, but given how long it took some of us to post all that information the first time we cannot be reasonably expected to post it again.
In the time I may have available later I want to Post about things that I have not addressed yet, or not completed addressing last year.
Both of rwtomkins' initial recommendations to you are good.
Important !
Hi Todd,
I strongly recommmend you read my Post #38 on Page 4 of this thread, and then read through the remainder of what I have posted about old and new capacitors.
I think it is highly likely that the differences you are hearing are result of significant DIFFERENT degree changes in each of the old 24uF capacitors,
AND, both may be partly leaking to different degrees,
as also may be the capacitors that are parallelled in the tweeter circuit that combine for the 4uF and 6uF if these are the old large cylindrical types -
look at the pictures in early posts to see what yours have.
Do replace the 24uF, and the effective 4uF and 6uF if they are the type I described above, before you continue playing your speakers loudly,
because if those caps are leaking then low frequencies will be reaching the mid-domes and/or tweeters and will damage them.
The 4uF cap in parallel with the mid-dome is less critical, because leakage there cannot damage the dome, but if complete leakage there it may cause excess current to flow from your amplifier and overheat its output stage.
This could occur if the large caps in the bass circuit are completely leaking also, though the series resistance of the two inductors there will limit the current flow to some degree.
Those caps in the bass circuit will be leaking to some degree, but probably not complete short circuit yet, because if they were completely shorted I think you would hear peculiarities in the lower midrange.
What brand and model number amplifier are you using ?
As you are in the USA you can buy Sonicaps directly from the manufacturer via Mail Order.
Or, buy Clarity Caps, the 250 volt series will be sufficient, from Madisound.
Buy 22uF for the 24uF, or 27uF if you have 30uF there in your speakers.
Buy 3.9uF for the 4uF, and to use instead of parallel small caps in the tweeter circuit, and similarly buy 6uF or 6.2uF for tweeter circuit.
You can parallel 2 or 3 medium value caps to sum to near 70uF if you want to replace the bass circuit caps, BUT chose those in the manner I described in early posts to get equal length caps otherwise you will get peculiar Timbre.
Or, buy 75uF Solens, if they will fit on your board. The 250 volt Solens will be sufficient, and their 400 volt caps are physically too large to fit easily.
Any of the other brand names I listed in earlier posts are OK for use in the bass circuit as the critical sound locations for caps are in the mid and treble circuits, thus the more expensive Sonicaps and Clarity Caps may not be worth spending the money on there, particually if you are price limited.
With any new caps do use the ESR simulating resistors I wrote about in several posts, because without those you will get the unbalanced tonal result described by dloper on Page 29.
The 5 watt Mills sold by Sonicap will be fine for the resistors.
Hi Todd,
I strongly recommmend you read my Post #38 on Page 4 of this thread, and then read through the remainder of what I have posted about old and new capacitors.
I think it is highly likely that the differences you are hearing are result of significant DIFFERENT degree changes in each of the old 24uF capacitors,
AND, both may be partly leaking to different degrees,
as also may be the capacitors that are parallelled in the tweeter circuit that combine for the 4uF and 6uF if these are the old large cylindrical types -
look at the pictures in early posts to see what yours have.
Do replace the 24uF, and the effective 4uF and 6uF if they are the type I described above, before you continue playing your speakers loudly,
because if those caps are leaking then low frequencies will be reaching the mid-domes and/or tweeters and will damage them.
The 4uF cap in parallel with the mid-dome is less critical, because leakage there cannot damage the dome, but if complete leakage there it may cause excess current to flow from your amplifier and overheat its output stage.
This could occur if the large caps in the bass circuit are completely leaking also, though the series resistance of the two inductors there will limit the current flow to some degree.
Those caps in the bass circuit will be leaking to some degree, but probably not complete short circuit yet, because if they were completely shorted I think you would hear peculiarities in the lower midrange.
What brand and model number amplifier are you using ?
As you are in the USA you can buy Sonicaps directly from the manufacturer via Mail Order.
Or, buy Clarity Caps, the 250 volt series will be sufficient, from Madisound.
Buy 22uF for the 24uF, or 27uF if you have 30uF there in your speakers.
Buy 3.9uF for the 4uF, and to use instead of parallel small caps in the tweeter circuit, and similarly buy 6uF or 6.2uF for tweeter circuit.
You can parallel 2 or 3 medium value caps to sum to near 70uF if you want to replace the bass circuit caps, BUT chose those in the manner I described in early posts to get equal length caps otherwise you will get peculiar Timbre.
Or, buy 75uF Solens, if they will fit on your board. The 250 volt Solens will be sufficient, and their 400 volt caps are physically too large to fit easily.
Any of the other brand names I listed in earlier posts are OK for use in the bass circuit as the critical sound locations for caps are in the mid and treble circuits, thus the more expensive Sonicaps and Clarity Caps may not be worth spending the money on there, particually if you are price limited.
With any new caps do use the ESR simulating resistors I wrote about in several posts, because without those you will get the unbalanced tonal result described by dloper on Page 29.
The 5 watt Mills sold by Sonicap will be fine for the resistors.
Exactly as I described !
Anyone of earlier Posters in this thread who are wondering why I emphasized to such degree to install ESR simulating resistors to use with new caps, do note the audible results that dloper has described !!
Hi dloper,
the tonal changes you have heard are result of what I described in several posts earlier in this thread.
I don't remember exactly how many nor where I started about that, but start reading from Page 4 and through till you find them all.
In short, part of it is owing to the less signal loss through the new capacitors, however another part is owing to the change of the Transient Response of the speakers as result of less internal series resistance inside the new polycaps than was in the old caps.
The new electrolytics in the bass circuit will have sufficient ESR to produce similar sound to the original bass circuit caps.
If you are very happy with the sound now with the L-pads, then stay with that, or fit fixed resistors of suitable values after measuring the L-pads' settings you decided.
That will address the signal gain part,
however, if you want to obtain a Transient Response similar to the original 66 sound you will have to fit individual resistors in the manner I described in early posts, to simulate the ESR of the original caps.
These ESR simulating resistors will also shift the actual cross-over frequencies back to close to those chosen by Celestion originally, and also restore the original slopes of the filters.
With modern low ESR caps in that circuit the crossover frequencies will have shifted a little, and the filter slopes will have steepened a little, but no crossover frequency changes to a degree that will cause any damage to the drivers,
thus if you like the Transient Response as it is now, then no need to install individual ESR simulating resistors.
Anyone of earlier Posters in this thread who are wondering why I emphasized to such degree to install ESR simulating resistors to use with new caps, do note the audible results that dloper has described !!
Hi dloper,
the tonal changes you have heard are result of what I described in several posts earlier in this thread.
I don't remember exactly how many nor where I started about that, but start reading from Page 4 and through till you find them all.
In short, part of it is owing to the less signal loss through the new capacitors, however another part is owing to the change of the Transient Response of the speakers as result of less internal series resistance inside the new polycaps than was in the old caps.
The new electrolytics in the bass circuit will have sufficient ESR to produce similar sound to the original bass circuit caps.
If you are very happy with the sound now with the L-pads, then stay with that, or fit fixed resistors of suitable values after measuring the L-pads' settings you decided.
That will address the signal gain part,
however, if you want to obtain a Transient Response similar to the original 66 sound you will have to fit individual resistors in the manner I described in early posts, to simulate the ESR of the original caps.
These ESR simulating resistors will also shift the actual cross-over frequencies back to close to those chosen by Celestion originally, and also restore the original slopes of the filters.
With modern low ESR caps in that circuit the crossover frequencies will have shifted a little, and the filter slopes will have steepened a little, but no crossover frequency changes to a degree that will cause any damage to the drivers,
thus if you like the Transient Response as it is now, then no need to install individual ESR simulating resistors.
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Experts ?
Hello rwtomkins !
Well, I'm not an Expert, but merely somewhat experienced in some audible phenomena to know reasons for SOME results of components' change,
{but to no degree all, yet ... if ever ...}.
Please, any genuine Experts reading this entire Thread, do post comments !
It's very good that you have kept this discussion alive rw,
and I hope to return to it when I have time available.
Hello rwtomkins !
Well, I'm not an Expert, but merely somewhat experienced in some audible phenomena to know reasons for SOME results of components' change,
{but to no degree all, yet ... if ever ...}.
Please, any genuine Experts reading this entire Thread, do post comments !
It's very good that you have kept this discussion alive rw,
and I hope to return to it when I have time available.
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Thanks for that alan-1-b, at least my mods have proved your ideas! As I said, I think my 66s sound better than before, but extended listening leaves me feeling the 'wallop' is diminished. Had I only ever heard them with the new caps I think I'd still be delighted with them, not knowing what was missing. I'm in no way tempted to set up my Kef 104s, Dynaudio Countour 1.8mk1s or Acoustic Energy 509s except as poor seconds while the 66s are off line for mods.
I shall read the earlier posts carefully. It would only be polite after the effort people have made to assist the less technically able. My technical knowledge doesn't go much further than v/ir, which is why I used the lazy option of L-pads but I'll install ESR simulating resistors and let you know how I get on.
After my memory loaded !
It has been a while since I looked at what I researched last year, thus a few errors in my Post:-
Corrections :-
www.soniccraft.com for the Sonicaps - get their Gen I, 200volt series,
available in 3.9uF; 6.2uF; 24uF or use two x 12uF in parallel if the 24uF is too long to fit neatly on your board,
and I recommend using their 27uF instead of 30uF if your 66s have the 30uF fitted, because 27uF will roll-off that older mid-dome a little higher in frequency and thus allow a little higher power handling.
"ClarityCap" is the actual name - use their PX series, available in 3.9uF; 6uF; two x 12uF in //, or 25uF single if it fits neatly.
The 250 volt rated Solen 75uF are only available from www.solen.ca ,
or use two x 36uF in // , or 33uF // 39uF, if the 75s are too long for your board.
www.percyaudio.com have 250volt/75uF AEON {Axon} capacitors which are very similar to the Solens, and AEON also in 33uF and 39uF in suitable lengths for a parallel pair.
{in the above, // = parallel}.
soniccraft.com and partsconneXion.com both sell the Mills MRA-5 non-inductive wirewound resistors.
It has been a while since I looked at what I researched last year, thus a few errors in my Post:-
Corrections :-
www.soniccraft.com for the Sonicaps - get their Gen I, 200volt series,
available in 3.9uF; 6.2uF; 24uF or use two x 12uF in parallel if the 24uF is too long to fit neatly on your board,
and I recommend using their 27uF instead of 30uF if your 66s have the 30uF fitted, because 27uF will roll-off that older mid-dome a little higher in frequency and thus allow a little higher power handling.
"ClarityCap" is the actual name - use their PX series, available in 3.9uF; 6uF; two x 12uF in //, or 25uF single if it fits neatly.
The 250 volt rated Solen 75uF are only available from www.solen.ca ,
or use two x 36uF in // , or 33uF // 39uF, if the 75s are too long for your board.
www.percyaudio.com have 250volt/75uF AEON {Axon} capacitors which are very similar to the Solens, and AEON also in 33uF and 39uF in suitable lengths for a parallel pair.
{in the above, // = parallel}.
soniccraft.com and partsconneXion.com both sell the Mills MRA-5 non-inductive wirewound resistors.
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Simultaneous - a mental connection or merely coincidence .?.
Hi dloper !
and there you were typing whilst I was correcting mine from 2 days ago !!
Before you remove the L-pads, carefully measure the DC resistance in each arm of each L-pad.
The Series arm will probably be a low value resistance in each, and the Parallel arm will probably be a higher value.
Post the two pairs of values here, and if they seem a bit strange I'll re-think what might be the optimum ESR simulating resistors for your particular sample,
but still do read all my earlier ESR sim. resistors' posts so that you will understand what this is about and why I recommended specific types, etc ...
If you want to query any, then please quote the Post number and the Page number it is on,
or use the Quote function and edit out all the unnecessary parts to leave only the part you are querying.
I don't remember exactly where I posted exactly what after all this time, and it will take a lot of time to find it all - time I'd prefer to put to answering queries !
What individual values of new capacitors are now installed in the treble and mid circuits ?
Are your KEF 104s the originals or the later 104ab ?
Hi dloper !
and there you were typing whilst I was correcting mine from 2 days ago !!
Before you remove the L-pads, carefully measure the DC resistance in each arm of each L-pad.
The Series arm will probably be a low value resistance in each, and the Parallel arm will probably be a higher value.
Post the two pairs of values here, and if they seem a bit strange I'll re-think what might be the optimum ESR simulating resistors for your particular sample,
but still do read all my earlier ESR sim. resistors' posts so that you will understand what this is about and why I recommended specific types, etc ...
If you want to query any, then please quote the Post number and the Page number it is on,
or use the Quote function and edit out all the unnecessary parts to leave only the part you are querying.
I don't remember exactly where I posted exactly what after all this time, and it will take a lot of time to find it all - time I'd prefer to put to answering queries !
What individual values of new capacitors are now installed in the treble and mid circuits ?
Are your KEF 104s the originals or the later 104ab ?
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Dolpers technical gap
Hi Alan - thanks for the reply. I'll sort out those figures in the next few days. I've had a bit of upheaval in the house and I've mislaid the circuit diagrams with my l-pads included. I don't have a note of the new cap values, but I can quickly pull the bass driver and look. By the way, the Kefs are the earlier 104s, with the treble roll off slope switch, 7metres by 4.5metres room, Classe electronics.
I'll post the numbers in the next few days. Much obliged
Hi Alan - thanks for the reply. I'll sort out those figures in the next few days. I've had a bit of upheaval in the house and I've mislaid the circuit diagrams with my l-pads included. I don't have a note of the new cap values, but I can quickly pull the bass driver and look. By the way, the Kefs are the earlier 104s, with the treble roll off slope switch, 7metres by 4.5metres room, Classe electronics.
I'll post the numbers in the next few days. Much obliged
Hi there, I am also the owner of a set of 66 studio monitors, mine are early 'blackies' (?) , with a hand wired pcb for cross over, during my 22 years of ownership, they have almost become members of the family.
Like anything over that length of time,things break! in the late 80's , i had to replace the tweeters and at some point had Celestion rebuild the midranges, sadly one went again in the mid 90's and Celestion know longer offered a rebuild service! (please bear in mind this was before the internet was the resource it is today) , and as i couldn't find anyone to rebuild them, they were replaced with a similar dome style midrange from Dynaudio. (And I can't find the old midranges now to have them rebuilt!) Please don't send hate mail
I am only new to the forum and have been trying to absorb the wealth of information in this thread, so please bear with me if I ask anything that was previously covered!
I have recently started to restore the speakers, starting with replacing the internal wiring with some heavy 'monster' speaker cable and intend to replace the caps on the crossover, alan - 1 - b, could you recommend any UK based companies to supply me replacement caps? as opposed to the US?
Also, one of the speakers has always (at least for the last 7-10 years) sounded 'louder' than the other ,but when i was replacing the internal wiring, I'm sure there was a different number of caps on one of the crossovers? and also the bass 'reflex' type driver is different (plastic housing in black on one, compared to aluminium housing on the other ) between the two units?
Can anyone shed any light on why that may be?
Anyway thanks to all those who have previously posted, and thanks in advance to anyone who can help me!
jwt.
Like anything over that length of time,things break! in the late 80's , i had to replace the tweeters and at some point had Celestion rebuild the midranges, sadly one went again in the mid 90's and Celestion know longer offered a rebuild service! (please bear in mind this was before the internet was the resource it is today) , and as i couldn't find anyone to rebuild them, they were replaced with a similar dome style midrange from Dynaudio. (And I can't find the old midranges now to have them rebuilt!) Please don't send hate mail
I am only new to the forum and have been trying to absorb the wealth of information in this thread, so please bear with me if I ask anything that was previously covered!
I have recently started to restore the speakers, starting with replacing the internal wiring with some heavy 'monster' speaker cable and intend to replace the caps on the crossover, alan - 1 - b, could you recommend any UK based companies to supply me replacement caps? as opposed to the US?
Also, one of the speakers has always (at least for the last 7-10 years) sounded 'louder' than the other ,but when i was replacing the internal wiring, I'm sure there was a different number of caps on one of the crossovers? and also the bass 'reflex' type driver is different (plastic housing in black on one, compared to aluminium housing on the other ) between the two units?
Can anyone shed any light on why that may be?
Anyway thanks to all those who have previously posted, and thanks in advance to anyone who can help me!
jwt.
Using the Ditton 66 TBC diagram.
Checked the L-pads today. Pin 1 goes to the -ve rail, at the same point as L1. Pin 3 and Pin 2 go to the +ve rail, between L3 and C4.
At the clockwise extent of the wiper, I get 6 ohms between pins 1 and 2, and 6 ohms between pins 1 and 3. Zero ohms between Pins 2 and 3
At the anti-clockwise extent of the wiper I get Zero ohms between pins 1 and 2. The meter fluctuates between 3 and 4 ohms on pins 1 and 3 and Pins 2and 3 A similar result with both speakers, except one reads 3 ohms steady rather than fluctuating between 3 and 4 ohms.
The capacitor values are as follows:
C1 80u
C2 80u
C3 4u
C4 is marked CPA 2u2 J400
C5 25u
C6,7,8 are now one 4u cap
C9,10,11, 12 are now 2 caps in parallel, marked CPA 0U68 J450 and CPA 5U6 J400
I'm afraid the numbering system on C4 and C9,10,11 and 12 has me baffled, but it doesn't look right to me...
I hope this information suffices and thanks again for your help alan-1-b