Hi,
I'm obviously chasing transformer ghosts! My tinnitus requires that I hunt and kill the buzzing of all amp transformers in my studio room. So I have new transformers for my OTS and C-lator currently shipping. But I also have found my trust old Event 20/20 BAS active studio monitors from the mid-1990s. These have awful transformer noise, obviously vibrating laminates, and are not usable in the current state due to the bothersome noise. So I have decided to try to refurbish these. Event Electronics are no longer in business, I think the brand is owned by RØDE. I probably wont find original replacement transformers, but I'm thinking of replacing them with toroidals. I have measured the secondaries at 2x 30 VAC with a center tap (60 VAC between both leads) @ 230 VAC primary. But I'm not sure how much current the PT needs to be speced at. On the back of the speaker it says "POWER REQUIREMENT 220-240V 50/60 Hz 200VA". Does that mean that I need a toroidal rated at 200VA (=3,33 A)? What happens if I choose a toroidal speced at 250VA?
I have found two toroidal I believe could be used as replacements:
200 VA:
https://www.tme.eu/en/details/tts200_z2 ... ufvassons/
and a cheaper one at 225 VA:
https://www.tme.eu/en/details/55164-p1s ... rs/talema/
Both should fit inside the chassis.
Any comments?
Thanks
Event monitors PT replacement
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Event monitors PT replacement
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- martin manning
- Posts: 13549
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- Location: 39°06' N 84°30' W
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Re: Event monitors PT replacement
Your logic is sound. A toroidal PT is more efficient than the E-I type, maybe as much as 5%, so you might even get away with a bit less than the stated VA. I would connect that device through a power monitor (an inexpensive and useful tool) and see what it is actually drawing.
Re: Event monitors PT replacement
Thanks Martin, againmartin manning wrote: ↑Mon Apr 01, 2024 11:45 am Your logic is sound. A toroidal PT is more efficient than the E-I type, maybe as much as 5%, so maybe you can even get away with a bit less than the stated VA. I would connect that device through a power monitor (an inexpensive and useful tool) and see what it is actually drawing.
I suppose its OK to choose the 225 VA as that is the cheapest of the alternatives? Can see if I can find a power monitor.
Toroidals are much less prone to vibration noises, am I correct?
- martin manning
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- Joined: Sun Jul 06, 2008 12:43 am
- Location: 39°06' N 84°30' W
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Re: Event monitors PT replacement
It won't hurt to oversize the PT a bit, and yes torroids are better behaved re core vibration.
Re: Event monitors PT replacement
Got those toroidals and installed them today. Works perfectly! No vibrations at all! Those 25 years old Events are rescued and sounds good!martin manning wrote: ↑Mon Apr 01, 2024 12:06 pm It won't hurt to oversize the PT a bit, and yes torroids are better behaved re core vibration.
Thank you once again, Martin, for your advice
- martin manning
- Posts: 13549
- Joined: Sun Jul 06, 2008 12:43 am
- Location: 39°06' N 84°30' W
2 others liked this
Re: Event monitors PT replacement
Nice, good to hear it worked out, and your monitors have a new lease on life!