mikeydee

Listed on gumtree for £s with full description and pics but free to collector from Bristol bs6. Available most evenings

Hi there folks, I wonder if anyone has the same bass guitar as me and can comment on the pickup output level. It the P Bass American Deluxe with a N3 (noiseless?) bridge pickup and 3 band active circuit. The pick ups are set to about 6-7mm below the string and have a limited range of adjustment that does not help much. For me the passive next pick up is rounded, fat and loud (as I would expect) but the jazz bass output is a bit weedy. If you switch the guitar to the active setting then the jazz bass output is about as loud as the precision pickup in passive mode and of course the neck pickup goes up in proportion too. It's not a massive deal but it means messing with my amp in between songs. Just wondering if this was normal behaviour. I don't have another Jazz bass to compare which is a pity.

Nice easy fix. Well done!

Any warranty left? If I follow correctly then the power amp seems to be ok because you connect the bass to the FX return and all seems fine - even when the fault is present. So if the pre amp is cutting out then that could be: dodgy FX connectors or other external loop connectors like pre amp out etc OR flaky internal cable connections - both of these faults usually respond to a little tapping so you should give each connector a little tap say with a wooden spoon tip. If you are able to venture inside safely it could be valve that is not well seated in its base - would also respond to tapping externally in all likelihood. One thing additional is that the clicks you mentioned: is this tiny clicks that you hear from valves as they warm up or is it relay clicks (assuming you know what I am getting at). If the latter then, it could be an internal fault around the amps power supply delivering inconsistent voltage usually due to bad connections, joints etc. Mike

Yep UK mains hum is 50hz and will occur from pickup on previous amp valve heaters. This minimised through twisted pair wiring. 100hz noise is what is left on the power supply after rectification and smoothing. In a push pull or class ab amp which is most amps with multiple valves this imperfection is cancelled out by the push pull circuit. In a class a it is left there. The cathode bypass caps job is to filter it out and on the first preamp too. Replacing that cap is inexpensive and worth doing

Sounds like a great project by the way. Inn terms of sounds we could do with some reference tones but my take is that. . . . hum is 50 - 120hz and sounds like hmmmmmm Buzz is a mixture of frequencies and sounds like buzzzzzzzz often picked up from airborne sources like fluorescent tubes, dimmers and fridges but also picked up on mains like my dimmer light at home Hiss is high and sounds like hisssssssss And then there is Clicks Pops Crackle That's enough

If it is the amp I am thinking of it is a class a output stage with two valves. I would expect that if one of the valves is red plating then so would the other as they are connected to the same cathode bias resistor. Reasons why this wouldn't be the case are the valves are not will matched or perhaps if the input coupling caps are leaking. Worth checking for dc on the grids? Lot of strain on the cathode resistor and cap. If that is dried up then the amp will hum. By the way hum and buzz are different sounds and mean different fault conditions. Sound clips can really help.

I tried to find the schamtic for this but its not on the Fender site. If you have it post a link. If the buzz is a bit like when you have guitar lead not plugged in then my bet is that either the pot/switch is damaged internally, or the component that the pull knob bypasses/includes is damaged or has a bad joint. Try wiggling the knob side to side to see if it is the pot and give it a bit of a tap around the cabinet area to see if a bit of vibration triggers it. Control pots often get damaged by handling in and out of cars etc.

I Don't know about that particular mixer but I regularly contact yamaha for spares and they are very helpful and their parts and shipping prices are reasonable. I have done this as trade and none trade so unless something has changed in their policies it sounds like your repair man doesn't want the work. You can reach them on the phone at 08448111116 I think you should ask them a. About other repair places, b. If they will repair and c. Cost of new board.

Sounds like a good plan. I would expect it to be up to £120 shipped so your second hand one seems reasonable. Good luck with the fix.

Did hartke quote for the new tranny? Just curious like

Excellent stuff such a relief when you get it nailed

I use hot glue pen on caps and similar components I am sure there is better stuff too. But hot glue has the advantage of not messing up every thing else in the room.

Ah ok sounds there are different transformer depending on year. Mine is a square one that construction is known as an EI transformer. Yours is torroidal or doughnut style. Usually a transformer fails it is with a short on the winding. I doubt that is the problem in your case as it sounds like it working for a while and then shutting down due to thermal protection. Not sure if korg do repairs but they are excellent with parts like the little LED pots etc. A transformer is expensive stuff est £80-100 so best to get someone qualified to verify the fault before spending.

Hi, The cutting out is a good sign. It means the amp's protect circuit is working. The hot thing - if it is the biggest square thing in there just behind the centre fan then that is the power transformer . It should get warm but it will get very hot when there is a fault somewhere as it is delivering all the electricity to the different parts of the circuit including the part with a fault. It might be bad itself but hopefully the fault is elsewhere. Few questions: [indent=1]What's the amp's history - is this a recent purchase or have you had it for a while.[/indent] [indent=1]During the ten minutes when it is on, are you playing or is it just idle. If you did play, would it work. Also, if possible connect the line out or FX send to another amplifier's input and see if signal is coming out of the Hartke and whether it sounds ok - this would give an indicator that the pre-amp is good.[/indent] Ideas: There are two fans on this amp and both should be spinning. The rear centre one blows air in and the little one on the power amp module (left hand side) blows warm air out. Maybe the little fan on the power amp module isn't working? Fault Possibilities are:[list] [*]power amp module (left hand side) [*]Pre Amp inc valve (front) [*]Power Supply (transformer, big capacitor cans and associated parts) [/list] Either way it will need to go to a tech and probably a bit of a repair bill I am afraid. Depending on where you are located I may be able to help you find a tech. Sorry not better news.

Sounds like it is a dry join opening up with temperature and responding to vibration (coupled from the speaker), Agree, freezer spray might help identify be careful with lid off tho.

I guess if it is associated with the shoes then I guess you or it are getting charged with static. Are you wearing a fleece per chance? If the fault can only be repeated with those shoes, then unlikely it is the amp in my view.

Textbook pre amp valve fault. Rustke, rumble and whistles. New tube is about a tenner from hotrox if you fancy a diy fix.