Search found 10547 matches
- Fri Mar 29, 2024 10:35 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
… the fading away thumping noise on switch off suggests low frequency oscillation. But not sure how. Could have been the PSU doing weird things, and amplified by the o/p stages. Just guessing. Aye it’s been a saga but I’m enjoying the fault finding and the general argy-bargy involved in wrestling r...
- Fri Mar 29, 2024 8:44 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
…I don't think I'd be able to resist trying the 80uF after the stacked lytics, to see if it sounds better than the electrolytics as the last cap in the audio circuit. :D Or I could just bung another blue LCR motor run in as the final cap and remove the electros altogether. Look…you’ve set me off ag...
- Fri Mar 29, 2024 7:58 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
Was getting more weirdness yesterday: a series of soft thumps at warmup and again on power-down. The thumps faded out as the HT drained away. I've finished up simplifying the power supply to a single channel but with an extra choke. Changed the rectifier to a GZ34 to keep the same voltages as before...
- Wed Mar 27, 2024 7:52 pm
- Forum: Assorted Stuff
- Topic: Nothing In Particular
- Replies: 16446
- Views: 4677821
Re: Nothing In Particular
Hope everything works out Phil.
- Wed Mar 27, 2024 11:31 am
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
Thanks for that Paul. I’ve started to realise that inadequately rated components and choke-input supplies don’t mix. It seems self-evident from the wobbler throwing telly, that the iron I have is not up to the job. A cap-input supply is perfectly adequate for my needs. The amp sounds great with the ...
- Tue Mar 26, 2024 8:51 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
So here are the mods: RC filters after the first cap now have 270R resistors as opposed to the previous 470R, which have been shifted onto the cathodes of the EL34s. EL34CinputPSU.png Because of the higher HT voltage, the OPT is now on the 5K tap, cathode resistor on the output valve has been change...
- Tue Mar 26, 2024 7:24 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
I don't know what the hell has been going on with this amp, but it was putting out some kind of electromagnetic pulse every time it was powered down. It has been doing this ever since I built it with the choke input supply. It got that bad on two occasions, that on power down, accompanied by a crack...
- Thu Mar 21, 2024 8:14 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
There's a lot more room in the chassis than in the Mk1 version of the amp, so, copying Paul, I purged the power supply of electrolytic caps by installing a nice pair of LCR motor run caps in place of the electrolytics that decoupled the input stages. Didn't think it would make a lot of difference, b...
- Mon Mar 18, 2024 10:48 am
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
It’s back in the system after the cosmetic facelift and power supply upgrade.
Sounds great with the LCRCRC supply. Glad I searched out the 450V transformer, despite the head scratching over the primary phasing.
Sounds great with the LCRCRC supply. Glad I searched out the 450V transformer, despite the head scratching over the primary phasing.
- Sun Mar 17, 2024 7:41 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
Circuits:
1. Audio Circuit with measured voltages:
2. Choke input power supply:
1. Audio Circuit with measured voltages:
2. Choke input power supply:
- Sun Mar 17, 2024 7:38 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
Amp undergoing soak testing in the system.
- Sun Mar 17, 2024 7:37 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
Thanks chaps.
Amp is finished. Last two jobs were to cable the input sockets to the selector switch and to put a reinforcing piece of anodised aluminium L section along the bottom edge of the rear panel, to match the one at the front:
Amp is finished. Last two jobs were to cable the input sockets to the selector switch and to put a reinforcing piece of anodised aluminium L section along the bottom edge of the rear panel, to match the one at the front:
- Sat Mar 16, 2024 8:22 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
All the circuitry is done. Just the four inputs to cable to the selector switch.
It all works and biases up correctly:
It all works and biases up correctly:
- Sat Mar 16, 2024 1:02 pm
- Forum: Everyones Projects
- Topic: OK…so I’m on wi’ summat
- Replies: 156
- Views: 33294
Re: OK…so I’m on wi’ summat
Cheers Ray.
Should be finished by Sunday.
Should be finished by Sunday.
- Fri Mar 15, 2024 9:17 pm
- Forum: Everyones Projects
- Topic: 6550 SE Amplifier
- Replies: 110
- Views: 9608