Amp making filter sweep effect?

[Dharmajester]

I'm having an issue with a couple of amps at present where when playing with a bass heavy neck pickup tone ( old school woman tone ) and the amp cranked the notes phase like they are going through a filter sweep effect. Being predominantly a neck pickup guy it's f'in annoying.
Local tech can't find anything obviously wrong and blames our rural mains supply. However I'm unconvinced as I have other amps which are performing fine in the same capacity.

Any of you amp tweekers out there have any ideas? Happy to email sound clips to anyone with diagnostic ears.

[Molly]

Could the tech not be right and it's maybe just something that that particular amp is susceptible to? My amps all pick up a 'ticking' noise from time to time and I've no idea what's causing it but it's pretty quiet. Next time I should also check what guitar I'm playing just in case the pickups etc. are a factor.

Hope you get it sorted.

[AiRdAd]

My amps were making a funny noise one day, and it turned out to be my phone in my pocket, interfering with my pick ups .

[Reg18]

Might be an excuse to buy a power conditioner?

[kwhelan]

agreed if its happening to more than one its not the amp, could be a freezer or anything, get a UPS $100 well spent PBtech or suchlike ,you'd be surprised how much dirty power is on the grid.
Ive got a mutlieffects power brick that does the same thing when plugged into one socket in house, fine in another circuit so it can happen to pedals too

[Dharmajester]

Could the tech not be right and it's maybe just something that that particular amp is susceptible to? My amps all pick up a 'ticking' noise from time to time and I've no idea what's causing it but it's pretty quiet. Next time I should also check what guitar I'm playing just in case the pickups etc. are a factor.

Hope you get it sorted.

The ticking noise could be a nearby farmer's electric fence. Also often caused by pedals which have a charge pump inside.( 9 to 15/18v internally)

I've tried all the usual running from different outlets in different rooms etc and sure we do have horrible dirty mains however those kind of artifacts usually vary throughout a 24 hour period being affected by current fluctuating according to demand etc...

I have been reliably informed that unless you fork out several k's on a really serious international touring style mains supply unit all the lesser power conditioners are pretty much toy town.
Would a domestic UPS be grunty enough for a 50 watt valve head?

[Molly]

Would a domestic UPS be grunty enough for a 50 watt valve head?

Dunno...

I bought a surge protector / four-way the other day. They asked me if I wanted one that 'cleans' the power. I declined as it was quite spendy. As you say, it's probably not that great anyway.

[sizzlingbadger]

Take the amp into town and test it on another supply, that will rule out your power issues. Also... are they heads ? if so try a different cab to rule that out too.

A proper mains filter/cleaner is expensive, the ones in the shops generally just have a surge protecter and HF filter, not much use really.

[philly]

I'm having an issue with a couple of amps at present where when playing with a bass heavy neck pickup tone ( old school woman tone ) and the amp cranked the notes phase like they are going through a filter sweep effect. Being predominantly a neck pickup guy it's f'in annoying.
Local tech can't find anything obviously wrong and blames our rural mains supply. However I'm unconvinced as I have other amps which are performing fine in the same capacity.

Any of you amp tweekers out there have any ideas? Happy to email sound clips to anyone with diagnostic ears.

I've just started looking at the power supply in my studio... mainly because i feel the noise from mics, pre's etc. seems a bit high
(there is also an occasional electric fence on the same circuit)
no fridges etc tho... it's on a different loop to the house
how far from Dunedin are you Dharmajester?
does the expression "technical earth" mean anything to anyone here?

[sizzlingbadger]

Its usually a central ground where all equipment is grounded, often in labs they have a central copper bus bar that all equipment is earthed to. Most of the "sensitive" equipment used in the lab will have a dedicated earth connection on the rear panel and this is connected to the central earth bus bar.

[philly]

i was hoping to get away with a fence picket!

[Dharmajester]

Yeah, I'm taking them in to the Albany Street uni studio with the tech at some point to test his mains theory. We are away out of town with our own transformer ( from which lunatic thieves occasionally steel the copper neutral and earth wires) on a pole outside. I have five amps here at present, three are perfectly fine but two, once the volume is over half way start this phasey malarky. Didn't have it with any previously owned kit ( Twin, Matchless Hc, Reinhardt, Goodsell, Vox, Blankenship )

[Molly]

Yeah, I'm taking them in to the Albany Street uni studio with the tech at some point to test his mains theory. We are away out of town with our own transformer ( from which lunatic thieves occasionally steel the copper neutral and earth wires) on a pole outside. I have five amps here at present, three are perfectly fine but two, once the volume is over half way start this phasey malarky. Didn't have it with any previously owned kit ( Twin, Matchless Hc, Reinhardt, Goodsell, Vox, Blankenship )

Ah, that's your problem right there. Need to get back to decent gear...

[Dharmajester]

Yeah, I'm taking them in to the Albany Street uni studio with the tech at some point to test his mains theory. We are away out of town with our own transformer ( from which lunatic thieves occasionally steel the copper neutral and earth wires) on a pole outside. I have five amps here at present, three are perfectly fine but two, once the volume is over half way start this phasey malarky. Didn't have it with any previously owned kit ( Twin, Matchless Hc, Reinhardt, Goodsell, Vox, Blankenship )

Ah, that's your problem right there. Need to get back to decent gear...

Ok whaddya wanna sell now

[Molly]

Yeah, I'm taking them in to the Albany Street uni studio with the tech at some point to test his mains theory. We are away out of town with our own transformer ( from which lunatic thieves occasionally steel the copper neutral and earth wires) on a pole outside. I have five amps here at present, three are perfectly fine but two, once the volume is over half way start this phasey malarky. Didn't have it with any previously owned kit ( Twin, Matchless Hc, Reinhardt, Goodsell, Vox, Blankenship )

Ah, that's your problem right there. Need to get back to decent gear...

Ok whaddya wanna sell now

Step this way, Sir. We have much to discuss...