Hello,
I have a Focal iCub Pack sib 2.1 Actif jet black that doesn't work anymore but speakers are ok (Focal Pack sib 2.1 Actif jet black - Achat Pack d'enceintes Home-Cinéma sur Materiel.net)
I bought this board on ebay "Adjusted-Amplifier-Board-TDA7294-BTL"
Adjusted Amplifier Board TDA7294 BTL w/Sealed Dust Potentiometers & Dual Channel | eBay
It says it has to be powered with "Recommended power supply: 18V-0-18V to 26V-0-26V three-wire AC 250W or above power ring cattle is better."
Could you help me to find a power supply for this (cheap if possible)?
I'm quite noob in diy audio and lost in the power supply for amplifier but some advices should be fine 🙂
Thanks in advance for your help.
I have a Focal iCub Pack sib 2.1 Actif jet black that doesn't work anymore but speakers are ok (Focal Pack sib 2.1 Actif jet black - Achat Pack d'enceintes Home-Cinéma sur Materiel.net)
I bought this board on ebay "Adjusted-Amplifier-Board-TDA7294-BTL"
Adjusted Amplifier Board TDA7294 BTL w/Sealed Dust Potentiometers & Dual Channel | eBay
It says it has to be powered with "Recommended power supply: 18V-0-18V to 26V-0-26V three-wire AC 250W or above power ring cattle is better."
Could you help me to find a power supply for this (cheap if possible)?
I'm quite noob in diy audio and lost in the power supply for amplifier but some advices should be fine 🙂
Thanks in advance for your help.
It appears to already have the main power supply parts on the board. I see a bridge rectifier and reservoir caps.
The 18-0-18 to 26-0-26 would seem to refer the required transformer which needs to be a normal split or dual secondary type.
This sort of thing:
250VA TOROIDAL 2X18V - MULTICOMP | CPC
The 18-0-18 to 26-0-26 would seem to refer the required transformer which needs to be a normal split or dual secondary type.
This sort of thing:
250VA TOROIDAL 2X18V - MULTICOMP | CPC
Strange to say that doing an image search for
Go figure that one out... answers on a postcard 😀
actually brings up pictures of transformers.
Go figure that one out... answers on a postcard 😀
Hi guys,
Many thanks for your replies! Now I'm sure of what I need 🙂
I found this one:
VPT18-13800 Triad Magnetics | Mouser Luxembourg
I don't have shipping cost on this site.
Do you have some url to find cheapest ones?
I saw also some with dual circuits with 12V that can be insteresting for my build.
Thanks!
Many thanks for your replies! Now I'm sure of what I need 🙂
I found this one:
VPT18-13800 Triad Magnetics | Mouser Luxembourg
I don't have shipping cost on this site.
Do you have some url to find cheapest ones?
I saw also some with dual circuits with 12V that can be insteresting for my build.
Thanks!
The one in your link looks to be a 9-0-9 (18 volt total). You need an 18-0-18 (36 volt total). Also those look like the most expensive and classed as 'medical grade'.
I understood 115V in makes 9V out and 230V makes 18V...
I took this one RT300-2018 NORATEL - Transformer: toroidal | TME - Electronic components.
I hope it will be good...
thanks Mooly
I took this one RT300-2018 NORATEL - Transformer: toroidal | TME - Electronic components.
I hope it will be good...
thanks Mooly
The secondary voltage is always rated as a constant on the assumption that the primary winding/s are configured correctly.
A 230Vac primary/18 volt secondary would give 9 volts on 115Vac, but a 115Vac specified winding can not be run on 230Vac. The core would saturate, the magnetic field collapse and the primary would draw massive current.
That means that a 115/230 Vac transformer has to have the primary windings in series for use on 230Vac and in parallel for 115 Vac.
The latest one in your link looks OK 🙂
Make sure you understand the secondary connections and how to wire them. Although you series connect them, you have to get the phase correct which is very easy to do with an AC voltmeter.
A 230Vac primary/18 volt secondary would give 9 volts on 115Vac, but a 115Vac specified winding can not be run on 230Vac. The core would saturate, the magnetic field collapse and the primary would draw massive current.
That means that a 115/230 Vac transformer has to have the primary windings in series for use on 230Vac and in parallel for 115 Vac.
The latest one in your link looks OK 🙂
Make sure you understand the secondary connections and how to wire them. Although you series connect them, you have to get the phase correct which is very easy to do with an AC voltmeter.
Sorry, its not the post I intended.
For your transformer you need to phase the secondaries by using the DBT and connecting the two secondary windings in series.
You then measure the voltage between the two single free end wires. If you have little or no AC voltage then reverse the wires of one secondary winding only.
When correctly phased you should measure the full 36 volts AC between the two free end wires.
The junction of the two windings is the common centre tap which is the 0 in the 18-0-18
Hope that clarifies it 🙂
> I understood 115V in makes 9V out and 230V makes 18V...
If it is a _115V_ primary: 115V in makes 9V out and 230V makes smoke.
Do not exceed the rated voltage! Or just a little, like 125V on "115V" winding. If you go much over rated voltage, the core saturates, the transformer sucks huge current, and burns-up.
If it is a _115V_ primary: 115V in makes 9V out and 230V makes smoke.
Do not exceed the rated voltage! Or just a little, like 125V on "115V" winding. If you go much over rated voltage, the core saturates, the transformer sucks huge current, and burns-up.
Hi guys,
I received my toroidal transformer today and it works fine.
I made a quick test with non soldered input (ruban glue 🙂 ) and I remark that I have a lot of noise.
Do I have to connect the transformer or the input to a mass (ground? Sorry for my english) or is there something else to so ?
Maybe the issue will be fixed when I will complete the soldering.
Next step, I need a fan because heatsink was quite hot or maybe it's normal ?
Once again thank you
I received my toroidal transformer today and it works fine.
I made a quick test with non soldered input (ruban glue 🙂 ) and I remark that I have a lot of noise.
Do I have to connect the transformer or the input to a mass (ground? Sorry for my english) or is there something else to so ?
Maybe the issue will be fixed when I will complete the soldering.
Next step, I need a fan because heatsink was quite hot or maybe it's normal ?
Once again thank you
The amplifier heatsink should only get really warm/hot as you play music. Just sat idling and it should be fairly cool.
Do you mean you have noise (buzzing) from the transformer itself, or noise on the speaker outputs ?
Do you mean you have noise (buzzing) from the transformer itself, or noise on the speaker outputs ?
Hi Mooly,
The temp increased when I put the volume up but I was still able to put my fingers on it without burn 🙂
The noise comes from the speakers
The temp increased when I put the volume up but I was still able to put my fingers on it without burn 🙂
The noise comes from the speakers
That sounds normal for the temperatures.
What sort of noise is it ? Buzz, hiss, or something else... although the procedure is basically the same to check it.
You need to run just the amp board and speakers and have the inputs shorted at the PCB (no wires connected to sockets etc). That will eliminate any grounding or wiring issues on your part. If its silent after doing this then the problem would seem to be down to the way you have wired it all up. If the noise is still there then it is an issue with the board layout/design.
What sort of noise is it ? Buzz, hiss, or something else... although the procedure is basically the same to check it.
You need to run just the amp board and speakers and have the inputs shorted at the PCB (no wires connected to sockets etc). That will eliminate any grounding or wiring issues on your part. If its silent after doing this then the problem would seem to be down to the way you have wired it all up. If the noise is still there then it is an issue with the board layout/design.
Hi there,
So I finished my "build".
I have 2 issues:
- buzz noise when the input device is off. I didn't test again but normally no noise when the socket is unplugged from the board so easy to guess from where come the issue, the jack socket or cabling. I will change it or I will see when I will receive my bluetooth board that will be powered in continious.
- vibration in the bass case.... :/ I tried to find it and was able to reduce it a bit but I still have too much vibration when I put the bass to too high level. The solution will be to put the board and transformer in an external box... If you have some link for cheap box I'm interested as usual 🙂
Thanks 😉
So I finished my "build".
I have 2 issues:
- buzz noise when the input device is off. I didn't test again but normally no noise when the socket is unplugged from the board so easy to guess from where come the issue, the jack socket or cabling. I will change it or I will see when I will receive my bluetooth board that will be powered in continious.
- vibration in the bass case.... :/ I tried to find it and was able to reduce it a bit but I still have too much vibration when I put the bass to too high level. The solution will be to put the board and transformer in an external box... If you have some link for cheap box I'm interested as usual 🙂
Thanks 😉
2 pics in case someone is interested....
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
The buzz just might be down to the 'input device' (assume you mean the source playing the music) having an output that floats when it is off. You could try a resistor in parallel with the input socket. Value would depend on the source component... no lower than say 2k for a line level but if you are driving it from a headphone feed then you could go as low as 100 ohm or so.
I finally solved this buzz issue. I don't know exactly how but it seems I got a bad contact with the plate beside the sub. For the vibration, I added parallel bar for the board, now it's
a bit better. I also added the bluetooth board so I'm happy with this for now, it's enough powerfull for my needs. Later I will buy a case and put everything inside to free the sub.
Thanks !
a bit better. I also added the bluetooth board so I'm happy with this for now, it's enough powerfull for my needs. Later I will buy a case and put everything inside to free the sub.
Thanks !
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