hello guys,
this is the Schematic of the amp.
according to the sheet this amp has 2x70W output to 8Ohm speakers.
the amp is in good and orignal condition, only the trafo misses.
i think i should purchase a trafo with 2x42V secondary voltage and around 210VA((2x70W)x150%). or you guys have better ideas?
this is the Schematic of the amp.
according to the sheet this amp has 2x70W output to 8Ohm speakers.
the amp is in good and orignal condition, only the trafo misses.
i think i should purchase a trafo with 2x42V secondary voltage and around 210VA((2x70W)x150%). or you guys have better ideas?
You're on the right road...
Dual 42v secondaries should do it. I suspect that the original transformers on the P140, P170, P270, A370 had 45v secondaries (and consequently a rail voltage too high for those 63v rated caps that saw full rail voltage).
In terms of transformer size - I personally use the 'as big as possible' approach.
That said, if you want the original transformer, I have a pair of A100 transformers - which I suspect are the same item used in the P140. (More knowledgeable members will appear shortly to confirm, or otherwise).
Dual 42v secondaries should do it. I suspect that the original transformers on the P140, P170, P270, A370 had 45v secondaries (and consequently a rail voltage too high for those 63v rated caps that saw full rail voltage).
In terms of transformer size - I personally use the 'as big as possible' approach.
That said, if you want the original transformer, I have a pair of A100 transformers - which I suspect are the same item used in the P140. (More knowledgeable members will appear shortly to confirm, or otherwise).
still waiting for the answer from someone that knows.
will be happy if someone tells me the secondary voltage and watt from the orignal transformator.
will be happy if someone tells me the secondary voltage and watt from the orignal transformator.
I got +-58.5Vdc from my 230:40+40Vac transfomer running on 240Vac.
Your estimate of 42+42Vac for +-60Vdc looks OK to me.
Your VA estimate is out by a mile.
I got 170W (36.9Vac, ~52.2Vpk) into 8r0 from a 3pair BJT stage running on that +-58.5Vdc.
I would expect a FET output stage to achieve between 150W and 170W from your +-60Vdc.
I would use a 250VA to 500VA transformer for a mono block and double that to 500VA to 1kVA for a two channel amplifier powering 8ohms speakers.
I don't know your country, nor your maximum mains voltage, but take heed of that capacitor warning given by Lenin.
Your estimate of 42+42Vac for +-60Vdc looks OK to me.
Your VA estimate is out by a mile.
I got 170W (36.9Vac, ~52.2Vpk) into 8r0 from a 3pair BJT stage running on that +-58.5Vdc.
I would expect a FET output stage to achieve between 150W and 170W from your +-60Vdc.
I would use a 250VA to 500VA transformer for a mono block and double that to 500VA to 1kVA for a two channel amplifier powering 8ohms speakers.
I don't know your country, nor your maximum mains voltage, but take heed of that capacitor warning given by Lenin.
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To avoid excess power dissipation for the 12V regulators, the transformer should also have a pair of 15V windings. Few conventional regulators can cope with 45VDC over them.
But ofcourse, with a good designed supply for the IC, it would be possible to tap the +60V and -60V rails without too much problems.
Any idea what the consumption of the IC is?
But ofcourse, with a good designed supply for the IC, it would be possible to tap the +60V and -60V rails without too much problems.
Any idea what the consumption of the IC is?
thanks for the reply but i really dont think that little trafo(no more than Ø100mm) can be 1kVA, this ist a photo from an orignal P140x
Then the schematic showing a 5pair mosFET output stage on +-60Vdc is not correct.
Which amplifier do you have?
Feed the wrong data to the Forum and the Forum will feed nonsensical answers back.
Maybe everyone realised you had posted the wrong schematic and that is why you had only one reply in the past year and a bit.
Which amplifier do you have?
Feed the wrong data to the Forum and the Forum will feed nonsensical answers back.
Maybe everyone realised you had posted the wrong schematic and that is why you had only one reply in the past year and a bit.
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Do you want me to guess at what is under that cooling strip?
I'll guess that there is 1pr for each channel. To ensure that this 1pr is not overloaded, the supplies run @ <+-40Vdc.
The transformer to meet that specification is very much different.
I'll guess that there is 1pr for each channel. To ensure that this 1pr is not overloaded, the supplies run @ <+-40Vdc.
The transformer to meet that specification is very much different.
If anybody is still wondering, I have just acquired the amplifier in mention including the original transformer. I measure 2x48.8VAC on the secondaries. Bear in mind that the measurement has been performed with the transformer connected to the amplifier during idle load. So it might be 2x49 VAC or 2x50 VAC secondaries nominal.
You can see a picture of my transformer and it's label here, however it does not include any information on the secondaries:
https://i.imgur.com/EHFsrGa.jpg
You can see a picture of my transformer and it's label here, however it does not include any information on the secondaries:
https://i.imgur.com/EHFsrGa.jpg
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