Thanks guys for the help on my first question. I have read the spec sheet and studied the schematics by Peter Daniel.
http://www.diyaudio.com/forums/attachment.php?s=&postid=163274
What I cant figure out is why the power supply has 2 pairs of V+/-.
http://www.diyaudio.com/forums/atta...=&postid=164393
How that connects to the circuit. I thought all I would need is one - and one +. I am sure it's right in front of my face but I don't see it.
Also why is their three ground 2 connectioons and one ground 1 connection?
If I use a 120v outlet what plitron transformer should I use to max out the 3875 with quality in mind?
I think that is it for now 🙂
Thanks
Matt
http://www.diyaudio.com/forums/attachment.php?s=&postid=163274
What I cant figure out is why the power supply has 2 pairs of V+/-.
http://www.diyaudio.com/forums/atta...=&postid=164393
How that connects to the circuit. I thought all I would need is one - and one +. I am sure it's right in front of my face but I don't see it.
Also why is their three ground 2 connectioons and one ground 1 connection?
If I use a 120v outlet what plitron transformer should I use to max out the 3875 with quality in mind?
I think that is it for now 🙂
Thanks
Matt
tsnyder41 said:
All right I figured it out. The power supply design is for two channels not one.
But I still can't figure out how to determine what transformer I would need from plitron.
Thanks
Matt
What xformer spec do you want?
Tell me the following information and I will start you in the right direction:
How many VA? 320? 400?
What secondary voltage? 24? 18?
Mag Shield?
Screen?
Primary Voltage? 115?
The shield and screen options are generally reserved for orders of 5 or more. You can always ask when ordering though.
Tell me the following information and I will start you in the right direction:
How many VA? 320? 400?
What secondary voltage? 24? 18?
Mag Shield?
Screen?
Primary Voltage? 115?
The shield and screen options are generally reserved for orders of 5 or more. You can always ask when ordering though.
Honestly I don't know what I want. I can’t make sense of this transformer talk. From what I understand and I'm not sure, VAC is the input Voltage using Alternating Current, being in the US, 120? Now if I am making mono blocks wouldn't I only need a primary output?
Looking at the LM3875 spec sheet the max input voltage is 84v. But from what I read it can only handle around 40. I guess what I should have also asked is, what voltage should be put into the 3875 for the maximum quality stable output?
http://www.national.com/ds/LM/LM3875.pdf
I would be looking to order seven. If mag shields and screens would help than I would like to have them.
Very lost,
Matt
Looking at the LM3875 spec sheet the max input voltage is 84v. But from what I read it can only handle around 40. I guess what I should have also asked is, what voltage should be put into the 3875 for the maximum quality stable output?
http://www.national.com/ds/LM/LM3875.pdf
I would be looking to order seven. If mag shields and screens would help than I would like to have them.
Very lost,
Matt
Matt. I haven't got time for a full reply but try reading THIS for starters.
And seriously, before you build anything like this you need to do some homework rather than just ask questions. That way you will understand what you are doing rather than soldering bits together 'in the dark' and risking something going wrong.
And seriously, before you build anything like this you need to do some homework rather than just ask questions. That way you will understand what you are doing rather than soldering bits together 'in the dark' and risking something going wrong.
OK, you others make sure I'm not misleading anyone here!!
Primery means the electricity going into the transformer (mains supply) One cool thing is that many transformers have a wiring setup so you can wire the primery for 120 or 220 They have 4 wires in, you put them in series or parallel to use with 220 or 120
The secondaries are the "transformed" electricity
My understanding is that when you read about a transformer that says :
"40 volts center tapped"
It means that it has 3 secondary leads. You can use the outer two wires to get 40 volts positive and a ground.
OR:
you can use the center wire as the ground and the outer wires as plus and minus outputs of 20 volts.
The second ( +/- ) approach is a balanced supply and what you need for a gainclone or the Pass amps.
Not all transformers have the center tapped option
Primery means the electricity going into the transformer (mains supply) One cool thing is that many transformers have a wiring setup so you can wire the primery for 120 or 220 They have 4 wires in, you put them in series or parallel to use with 220 or 120
The secondaries are the "transformed" electricity
My understanding is that when you read about a transformer that says :
"40 volts center tapped"
It means that it has 3 secondary leads. You can use the outer two wires to get 40 volts positive and a ground.
OR:
you can use the center wire as the ground and the outer wires as plus and minus outputs of 20 volts.
The second ( +/- ) approach is a balanced supply and what you need for a gainclone or the Pass amps.
Not all transformers have the center tapped option
Variac said:
Sorry to but in Matt.....
..... so this 250VA, single 240v primary, 5 x 12v secondary tranformer i have in my hand is no good for a Pass or a gainclone because it doesn't have a centre tap ?
So any suggestions for a suitable first amp that can make use of this transformer ?
Cheers
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