Amp (Transformer)

Angel LaHash · #1 01-10-2013, 09:00 AM

Apart from shock going up my arms.. derrrr

Right i got a bigish AMP, the guy did think the Transformer wasnt working.. i hooked a Meter over each leg to see they are still linked and they are "continuity". So powered it up and tried to get a reading.. i could see the Power light was on
Well got a bit of a shock and the meter buzzed a bit but still alive..
I couldnt read any thing really on the Meter

Just thinking of it, i had it in DC!! ahh
but also when i went to do a resistance between 2 legs on the secondary side i got 1Ohm! do you think its shorted out some were to get such a low reading

B-string · #2 01-10-2013, 09:16 AM

If it was shorted the fuse would have blown, if the fuse is bypassed it would have smoked.
You need to to check for AC voltage at the secondary if your meter is not already damaged. Are you sure you are safe to be doing this?

Vostre Roy · #3 01-10-2013, 09:32 AM

Quote:

Originally Posted by B-string

Are you sure you are safe to be doing this?

This. Amp has enough voltage to be deadly, unless you know exactly what you are doing, never play inside an amp.

Angel LaHash · #4 01-10-2013, 09:50 AM

I only do Electrical Installations.. and used to be a Design Tech
but i normaly dont work with Transformers

also when its someone else i can think but when its my own i want to talk about it more to make sure for some reason like i dout myself

I just forgot the AC Voltage as I been in DC a lot of the time.. No Fuse was blown tho
and as for me getting shocks, i seem to live pass Direct Mains to the Heart.. Touching a buzz bar while on .. and been shocked in the Shower

wcriley · #5 01-10-2013, 10:02 AM

Quote:

Originally Posted by Angel LaHash

...as for me getting shocks, i seem to live pass Direct Mains to the Heart.. Touching a buzz bar while on .. and been shocked in the Shower

There's a big difference between getting bitten by 120v AC and getting hit by the 400v to 700v DC that is common in tube amps.

tom-g · #6 01-10-2013, 10:13 AM

+1

Take it to tech.

By the way, the secondary of transformer is basically a wire coil. Now you tell me what the reading of your ohm meter should read. You can't check if transformer is ok that way. Well, unless it's infinity, then it's broke.

B-string · #7 01-10-2013, 10:17 AM

Buzzing in a test meter is a bad thing, it usually means you have exceeded design values for arc-over. You meter needs to be rated for at least 1 KV AC.
Why are you starting at the transformer first if the fuse is not blowing?

Angel LaHash · #8 01-10-2013, 10:33 AM

Quote:

Originally Posted by wcriley

There's a big difference between getting bitten by 120v AC and getting hit by the 400v to 700v DC that is common in tube amps.

No Tube in it and its a bit from 240v 80mA as it was the buzz bar

Angel LaHash · #9 01-10-2013, 10:34 AM

Quote:

Originally Posted by tom-g

+1

Take it to tech.

By the way, the secondary of transformer is basically a wire coil. Now you tell me what the reading of your ohm meter should read. You can't check if transformer is ok that way. Well, unless it's infinity, then it's broke.

well a Pick up is a load of wires and it ranges from 4k-20kOHMS
so i would personal expect a bit more than that

Angel LaHash · #10 01-10-2013, 10:37 AM

Quote:

Originally Posted by B-string

Buzzing in a test meter is a bad thing, it usually means you have exceeded design values for arc-over. You meter needs to be rated for at least 1 KV AC.
Why are you starting at the transformer first if the fuse is not blowing?

i did check the wire from the Socket to the Transformer
Transformer to the board
and the Fuse ..

check the transformer than there is a flow going in the Prim
and a flow can be hand on the secondary

So as i see its all working.. BUT if there is a short in the transformer i guess it will skip some of the coils making the transfer rate highter

B-string · #11 01-10-2013, 10:39 AM

Quote:

Originally Posted by Angel LaHash

well a Pick up is a load of wires and it ranges from 4k-20kOHMS
so i would personal expect a bit more than that

The resistance of a power transformer is pretty low. The number of wire turns and gauge of wire is radically different from pickups.

wcriley · #12 01-10-2013, 10:44 AM

Quote:

Originally Posted by Angel LaHash

No Tube in it ...

Oops. I saw "biggish amp" and "transformer" and automatically read "tube". Sorry 'bout that.

B-string · #13 01-10-2013, 10:46 AM

Quote:

Originally Posted by Angel LaHash

i did check the wire from the Socket to the Transformer
Transformer to the board
and the Fuse ..

check the transformer than there is a flow going in the Prim
and a flow can be hand on the secondary

So as i see its all working.. BUT if there is a short in the transformer i guess it will skip some of the coils making the transfer rate highter

What? Shorts in a transformer usually will burn through the separating insulator and cause over-current.

Bassmec · #14 01-10-2013, 10:49 AM

The only way to test the performance of an output transformer that isn't obviously open circuit and therefore obviously dead is to use a heater transformer powered by a Variac to supply a very small voltage to the secondary and measure the primary voltage at the tube sockets.
Take this amp to a good tech as its probably a case of a little knowledge being a very dangerous thing.
You got a shock from the AC you won't be doing anything but smoking ever so slightly if you get across the DC ht if its got any working diodes in it.

Sorry just read its a transistor amp of some as yet un ascertained description

best put it in the garbage then, as they are not worth messing with, when you can buy one that works and weighs nothing for about 30pence and a half chewed mars bar these days.

B-string · #15 01-10-2013, 11:04 AM

We are apparently talking about a SS amp.
IF the secondary had inter-wind shorts (isolated from chassis or primary) the secondary voltage would be lower, resistance still means very little unless it is a complete open. You need to measure AC voltage at the secondary and compare to the spec on the schematic.
DON'T GET SHOCKED AGAIN.

BassmanPaul · #16 01-10-2013, 03:14 PM

This whole thread has filled me with alarm. OP PLEASE take the amp to a tech. His bill will be much less than your life is worth!!!!

BawanaRik · #17 01-10-2013, 03:22 PM

Quote:

Originally Posted by Vostre Roy

This. Amp has enough voltage to be deadly, unless you know exactly what you are doing, never play inside an amp.

+1 I would buy a Aspen Pittmann Tube Amp Book or Gerald Weber's, Handbook.

And Keep your left hand in your pocket. When and trust me it's when, you do get that potential life ending jolt you don't want your heart in line.

I got hit with a TV high voltage and survived.

Angel LaHash · #18 01-10-2013, 04:22 PM

well i was told i would die by 17 of CF and lived pass that
Had Strange Heart Flutters as 12 due to a Mains
Sent to a Hospital with a Child Killer
Touched the Buzz bar..
Touched a Transformer in a PVR at work one time (smelt funny all day)
and just got a little Jolt off off a AMP what just made my arm feel funny

Why else am i called Angel.. also seem to have a Low Resistance and a High Salt level

Angel LaHash · #19 01-10-2013, 04:26 PM

Quote:

Originally Posted by wcriley

Oops. I saw "biggish amp" and "transformer" and automatically read "tube". Sorry 'bout that.

Is a Tube Amp but just one ECC83 (think its 83) i got to buy one but i kind of hoped that i could get it running before spending money on a Tube .. them dam things cost £10 a pop 12AX7

Bassmec · #20 01-10-2013, 05:04 PM

Quote:

Originally Posted by Angel LaHash

Is a Tube Amp but just one ECC83 (think its 83) i got to buy one but i kind of hoped that i could get it running before spending money on a Tube .. them dam things cost £10 a pop 12AX7

That's about par for the course around here, I have Aspergers and dyslexia, can't you just borrow a known good ecc83 for test purposes.
Is there any information on the amplifier, like make or type, or anything else us amplifier OCD junkies can get our teeth into.