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Well packed, well sent and arrived just so. Many thanks, Jim Bass excellent to deal with.

My advice would be fix it. The construction makes this easy - large components, widely spaced and big wide pcb tracks. You can keep this amp going forever. It is also a relatively simple amp in terms of design so fault finding is straightforward. I had one, extremely loud and no annoying fan is a big plus. As Icastle states, do make sure you get the capacitors wired with correct polarity. The results of getting it wrong are quite spectacular. The BW in mine failed in a surprising way - like yours it was about 30 years old. A buzzing noise started on some low notes. The glue holding the cone to the frame had given up. If you catch this early before too much damage it should be an easy repair.

[quote name='brensabre79' timestamp='1363020853' post='2007041'] I'd say the caps are blown! But like iCastle says, might not be all... Another thing the Combo 300 is rather prone to that makes a crackle is the soldering of the inductor coil. Its easy to spot this, its a coil of copper wrapped in cardboard. These can work a bit loose with the internal vibrations and very small cracks can appear in the solder - which supports the entire weight of the coil! It should just need resoldering - it happened to mine and it took me ages to figure it out. Simple test is to turn the thing on with the amp open and, with something non-conductive (plastic pen), you can give the coil a light tap. [/quote] A good point, I had forgotten that little issue that they develop. I have just looked at the photos. Looking at the photo with the transformer (real iron lol) you will see to the right and front of the blue capacitors another pair of capacitors - black and grey with polarity arrows. These are also electrolytic and if I had the soldering iron to hand I would replace these as well. They will be cheap and available from any good electronics supplier.

Since I do not use fb I was unable to access sound clip. Several possible causes. First thing to try would be rotating the controls a lot when switched off. Rotate each control back and forward several times. If this helps then spraying contact cleaning spray (e.g. Servisol) into the pots may fix the issue. Next areas I would explore - [size=4]If you can de solder / solder it is diy and not expensive - [/size][size=4] [/size][size=4]replace the smoothing capacitors, they are 20? years old. If that does not remedy, then replace diodes in bridge rectifier. All of these can be done for small expense and worth a try unless you have access to an oscilloscope. With a scope and the circuit diagram (easily available on web) you should readily find the problem.[/size]

Thank you, gives a sense of what was what for those of a long way away from the big city.

One of my major musical influences for so many years. Wilko's music has been with me for most of my life and will continue to so.

If it is the walls of the cab you may need to glue some bracing inside the cab. Fairly simple to do.

[quote name='ahpook' timestamp='1362351142' post='1998907'] if there's any articles you can't get hold of, and would like to see, do let me know. about time i annoyed them at the British Library again [/quote] Thanks, offer well received since my current employment provides lab rats but no access to journals etc Essential Tension.... be careful what you start

[quote name='Beer of the Bass' timestamp='1362349870' post='1998876'] It'd be very cool if your experiment was documented with audio files. You could perhaps coat a cheap piezo disc in epoxy to stop it from shorting and attach it to your plank... [/quote] Piezo is where I was going, but am also interested in magnetic pu, ie how does the (potential viscous) drag affect the magnetic response? showing a total lack of knowledge I also wonder about what frequency is propagated in the medium (water). Will it be the same as the string vibration? This is not my branch of Physics so I may be asking very simplistic uniformed questions about well understood effects. Time for a lit survey I think. I had not thought of audio files, however that would be straightforward since the data would be voltage - time to obtain frequencies. The fun bit is it is a simple experiment to execute and provides good data to answer the question. Before anyone asks, I can access a swimming pool so boundary reflections can be negated lol.

[url="http://basschat.co.uk/user/1234-ahpook/"]ahpook[/url] [color=#222222]It Is a long time since I have been called a star [/color] [color=#222222] It is a phrase I use on my students, showing my age.[/color] [size=4]The initial question is a really good one, and not readily soluble to mere mortals ( ie sub Einstein abilty) or me without experimental data. It is the sort of practical real world Physics I enjoy. Let's build a test rig and find out... Will there be a significant difference between E and G string due to mass/unit length and diameter? etc, etc[/size] [size=4]Lastly I also have a beard ! They are essential for all sorts of reasons [/size]

A tough call in life but you have your reasons. Life will move on, other music opportunities will appear that can fit your circumstances. Keep in touch with lads in band, give support as best you can. What goes round comes round.

Speaking as an engineer and physicist I think I will have to get some students (lab rats) building the test rig. The problem is complex and of interest. Plywood, old strings, machine head and bath to be pressed into service. Watch this space.

[quote name='BigRedX' timestamp='1362236360' post='1997374'] It could just as easily be on the inside 10 turns. [/quote] Agree, that what was I was trying to say with which end to remove turns from. You said it more clearly - inside or outside windings. Ask the guy can he rewind without original coil - he will have some originals to work from. If he has, you now have nothing to lose and £20 to gain (other than time, faff and possibly varnish everywhere). If he can rewind try the DIY first. Nothing to lose, beer money to save...

Very unlucky by the sound of it, probably a short. However it can't be far in, say 6K ohms and 7500 turns for whole pickup. This gives about 1 ohm per turn. Are you brave? You might get lucky by removing say 10 turns - problem is which end to remove 5 turns from. The danger of this approach is that you may destroy it forever and it may not fix the issue. It depends on how the pickup coil was wound. It may not be possible to remove the offending wire to remove the short. Another desperate measures method - am not sure if this will work. Polyurethane varnish (spirit based), dilute until incredibly thin. Immerse pickup coil, leave several days. Remove, allow to dry. You might get lucky and varnish gets into the 'short'. Good luck

If the main body of the coil is still in its paper / plastic wrap (I forget what, was 1975 or so when I took mine apart to look inside) then the coil should be ok. You might have a short against the metal case. Take it apart, remove the coil from the magnets (it is very simple construction if an original one). Try measuring resistance. If in the K ohm range (as mentioned above) the coil is ok. If the coil is ok when outside the case, coat the wires in something like varnish or nail varnish. This will hopefully sort it.

Play it, see what you think, is it worth the money. I would also suggest look at Yamaha pacificas, seriously good value for the money.