Hi folks,
I've got a pair of Truth 2030A monitors and one of them has what I believe to be a bad transformer (keeps blowing fuses). I've swapped in the transformer from the other monitor and that seems to work fine, so I don't believe it's a fault with the board.
There are no specifications on the transformer itself regarding VA rating etc, but I believe it's 24V secondaries with a center tap.
I'd appreciate if anyone could steer me in the right direction - given a board requirement of ±15v (after rectification, which is handled by 4 discrete diodes), and that the Truth 2030A provides 110w (75w+35w), would a 160VA toroid with 25V secondaries with centre tap be sufficient?
Cheers
I've got a pair of Truth 2030A monitors and one of them has what I believe to be a bad transformer (keeps blowing fuses). I've swapped in the transformer from the other monitor and that seems to work fine, so I don't believe it's a fault with the board.
There are no specifications on the transformer itself regarding VA rating etc, but I believe it's 24V secondaries with a center tap.
I'd appreciate if anyone could steer me in the right direction - given a board requirement of ±15v (after rectification, which is handled by 4 discrete diodes), and that the Truth 2030A provides 110w (75w+35w), would a 160VA toroid with 25V secondaries with centre tap be sufficient?
Cheers
18-0-18...36 V center tap. 30V DC after rectifiers.
110 W is about 3 Amps, so for safety and cool running go for 5 or higher. 180 VA.
Keeps blowing fuses...they do not blow immediately?
Check the circuit and transformer.
The working transformer output can be measured for better answering your voltage question.
But if changing the transformer only worked, do it.
A slightly higher rated unit will not get overloaded, and the price will not be much more.
110 W is about 3 Amps, so for safety and cool running go for 5 or higher. 180 VA.
Keeps blowing fuses...they do not blow immediately?
Check the circuit and transformer.
The working transformer output can be measured for better answering your voltage question.
But if changing the transformer only worked, do it.
A slightly higher rated unit will not get overloaded, and the price will not be much more.
Thank you!
The fuses are blowing instantly, but everything seems to work fine with the transformer from the other amp plugged in.
I'm glad I asked - guess I had the voltage/power rating all wrong.
This is what I've found through a local supplier:
M5518C - Powertran 18 + 18 300VA Toroidal Transformer - Altronics
They don't do anything smaller than 300va in 18-0-18, so I guess the only concern is whether it'll fit in the enclosure.
The fuses are blowing instantly, but everything seems to work fine with the transformer from the other amp plugged in.
I'm glad I asked - guess I had the voltage/power rating all wrong.
This is what I've found through a local supplier:
M5518C - Powertran 18 + 18 300VA Toroidal Transformer - Altronics
They don't do anything smaller than 300va in 18-0-18, so I guess the only concern is whether it'll fit in the enclosure.
A$145 is expensive. $20 US or so here, for a 30-0-30 5A unit. E-I style.
How is the transformer plugged in?
And what made you decide the transformer was faulty?
Please post a picture.
How is the transformer plugged in?
And what made you decide the transformer was faulty?
Please post a picture.
Find a 150 VA step down transformer, and connect your unit to 220 V through that.
Very common item, easy to find one near you.
Very common item, easy to find one near you.
Believe nothing 😄, MEASURE.
Tap voltage is measured directly, VA comes from size and weight.
There's your replacement specs.
See above.