Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plexi50 on January 29, 2012, 05:31:52 pm

Title: 220 Volt Main Transformer
Post by: plexi50 on January 29, 2012, 05:31:52 pm
This is a weird question that i already know the answer to but im getting this info from the seller of a Greek amp:
It goes like this: The PT requires a 220 volt main. He put a 110 power cord on the amp and plugged it into a 120 outlet
He says the amp has been running for 2 years but sounds like something is wrong with the sound

I said well of course. The secondary voltage needed to run the amp is virtually non exhistant. Like trying to run an 8 cylinder car on 1 cylinder

Anyway i was also thinking that there could be damage to the amp if the transistors are trying to draw current they cant get

What a weird call this was. I cant believe anyone that can change a power cord would not know this. I told my friend to stay away from it and keep his $400 dollars.
Title: Re: 220 Volt Main Transformer
Post by: stingray_65 on January 29, 2012, 05:57:38 pm
I'd shy away from a SS amp any how :icon_biggrin:

But a SS amp the owner claims "sounds funny" well that just not a good thing.

Maybe you're loosing some information in translation.

my best info is Greece has 230V 50Hz mains

http://en.wikipedia.org/wiki/Mains_electricity_by_country (http://en.wikipedia.org/wiki/Mains_electricity_by_country)

where did he get his 120 from?
Title: Re: 220 Volt Main Transformer
Post by: Jack1962 on January 29, 2012, 05:59:05 pm
It's starving for volyage that's why it sounds wierd and yes it will damage the Solid State components.
Title: Re: 220 Volt Main Transformer
Post by: plexi50 on January 29, 2012, 07:35:34 pm
I'd shy away from a SS amp any how :icon_biggrin:

But a SS amp the owner claims "sounds funny" well that just not a good thing.

Maybe you're loosing some information in translation.

my best info is Greece has 230V 50Hz mains

http://en.wikipedia.org/wiki/Mains_electricity_by_country (http://en.wikipedia.org/wiki/Mains_electricity_by_country)

where did he get his 120 from?


Yes i miss typed. It is a 230V main. The amp is in Los Angeles. I suspected it would harm the components
Title: Re: 220 Volt Main Transformer
Post by: PRR on January 29, 2012, 08:22:32 pm
> trying to run an 8 cylinder car on 1 cylinder

Closer to two cylinders.

We had a 2-cyl Miata and it sure ran bad.

115V on 230V amp is not sure to do damage. I can think of a few designs would run "OK" at 1/4 power. Many more which would "sound funny".

Title: Re: 220 Volt Main Transformer
Post by: plexi50 on January 29, 2012, 08:39:00 pm
> trying to run an 8 cylinder car on 1 cylinder

Closer to two cylinders.

We had a 2-cyl Miata and it sure ran bad.

115V on 230V amp is not sure to do damage. I can think of a few designs would run "OK" at 1/4 power. Many more which would "sound funny".



What bothers me is why he did the 120 cord change when he has a step down transformer from 230 to 120.  It is a really rare amp and im stuck wondering if i should tell my friend to take the chance. Again there is no schematic or info to know what the secondary voltages would be for the rectifier bridge even if i changed out the transformer to a 120V Mains PT

I could quess and maybe safely be in the ballpark with 34-52VAC but quessing could be trouble . Not how i like to run my life or work