perfect power supply

nomad100 · Post by **nomad100** » Sat 04/21/07 9:27 am

what would the perfect power supply look like if part count and cost wasn't an issue.

My mesa so noisy i'd almost risk modding the power supply! I did smell something start to burn when i turned it few weeks ago. Then I turned it off and checked my cables and turned it back on, No problem. Except i think it's noisier now.

It's noisy clean with no guitar, or cable attached.

Michael · Post by **Michael** » Sat 04/21/07 9:47 am

Sounds like you may have lost a cap (open circuit), although I believe they normally fail shorted.

The perfect power supply would have no noise. It may still have variable voltage versus load, as you may like sag.

For tube amps, "perfect" may even have a bit of noise, as some recognize it as classic tube amp sound.

Are you looking for a specific design? If so, what characteristics are desirable to you?

octal · Post by **octal** » Sat 04/21/07 9:57 am

Take about 33 car batterys and series them together.

Mooreamps · Post by **Mooreamps** » Sat 04/21/07 10:01 am

Take about 33 car batteries, and series them together.

-g

morcey2 · Post by **morcey2** » Sat 04/21/07 10:16 am

Queen w/ david bowie:

octal wrote:Take about 33 car batterys and series them together.

Vanilla Ice:

Mooreamps wrote:Take about 33 car batteries, and series them together.

'nuff said.

otterpop · Post by **otterpop** » Sat 04/21/07 10:37 am

.. and that's why it's called B+.

nomad100 · Post by **nomad100** » Sat 04/21/07 10:42 am

well i like a good punchy amp, but the perfect power supply would have no diode noise, and be able to supply power for a good punch. I'm thinking more for SE amps. I'm not opposed to having a switch to weaken the bass a bit.

I'll look for a bad cap, something broken because the whole chassis is shaking. It's been doing that for a long time. About 2 months ago i replaced the power supply choke. Seemed to make a difference, though the amp still vibrated a little. About 3 weeks ago i plugged in at church smelt like something burnt. It's been noisier ever since. The vibration feels like it's coming inside the chassis. It's bad enough my power tubes are vibrating. I'm trying to avoid paying someone 60 an hr to fix it not to mention the 1.5 hr drive, and at least a 2 week wait.

The amp is a nomad 100 HD, you can find a schematic for the nomad 55 on schematic heaven. I'd post the link but i don't know if that can get the 18watt in trouble.

bradleyt · Post by **bradleyt** » Sat 04/21/07 10:59 am

morcey2 wrote:Queen w/ david bowie:
octal wrote:Take about 33 car batterys and series them together.
Vanilla Ice:
Mooreamps wrote:Take about 33 car batteries, and series them together.
'nuff said.

I get it, LOL

Spankenstrat · Post by **Spankenstrat** » Sat 04/21/07 3:03 pm

Check to see if your amp has any molex connectors and check their condition. I had a 295 that fried the connection to the board from the PS Transformer. Not made verry well if you ask me..

Post by **zaphod_phil** » Sat 04/21/07 6:08 pm

What the "perfect PSU" would be depends on if you want punch, smoothness or compression. Each would be done differently. Also it differs between SE and PP amps. In the case of a Meza it's probably more in the punch category.

I've come across other reports of Mezas being pretty noisy, and some of that may be due to their generally high gain levels.

However, if you've blown something in your amp, let's look at that first and then figure out how to improve the power supply. Do you get the same noise levels in the clean and dirt channels? Also is it more like a buzzzz or a hummmm?

nomad100 · Post by **nomad100** » Mon 04/23/07 6:55 pm

well in the same amp how would you make a power supply switcable between: punch, smoothness, or compression.

Thanks for the tips on work on the mesa, but i don't want to get to on that track. I'm moving this week and probably wont be able to work on it anyways.

Mooreamps · Post by **Mooreamps** » Tue 04/24/07 4:46 am

zaphod_phil wrote: I've come across other reports of Mezas being pretty noisy, and some of that may be due to their generally high gain levels.

Really. Gee, that's too bad about their noise problem. Maybe they will figure out how to fix that someday.

-g

ur12 · Post by **ur12** » Tue 04/24/07 10:35 am

The last amp I built had a power supply that had 6 mosfet adjustable regulators, SS diodes and bias supply all on one board. The regulators allowed me to dial in the voltages on each of the preamp tubes independently. You could actually set up the gain structure of the amp by adjusting the voltages on each tube. Add in some oversized caps and it came out very nice. I would call this my ultimate power supply. A little pricey but it worked great if money is no object.

morcey2 · Post by **morcey2** » Tue 04/24/07 10:43 am

nomad100 wrote:well in the same amp how would you make a power supply switcable between: punch, smoothness, or compression.

Thanks for the tips on work on the mesa, but i don't want to get to on that track. I'm moving this week and probably wont be able to work on it anyways.

This is just my amateur guess, but to go between punchiness and compression(sag), use a SS rectifier switchable between a sag resistor and voltage dropping zeners to keep the idle voltage the same. There will still be a little sag from the PT resistance, so maybe switching in a larger first filter cap with the zeners would help.

mooreamps wrote:
mumblemumblemumble

Thanks for the comment gary. I hope we're not taking too much time away from your business.

Matt

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