DIY tube amp power supply

SgtWookie

Joined Jul 17, 2007
22,201
Where is the schematic?

It is not clear from the Ebay listing exactly what is required - except they recommend a 150W transformer. I don't know why they show 18v-0v-18v and 24v-0v-24v and 9v-0v as well. It may be due to the heater requirements. The schematic will tell the tale.
 

Thread Starter

frenchie29

Joined Nov 28, 2008
134
I just posted it Might gonna have to save it and use the magnifier glass it's at the top right
 

SgtWookie

Joined Jul 17, 2007
22,201
The 1st image is just too fuzzy to see. Can you scan it at a higher resolution, and post it in .png format instead of .jpg?
 

Wendy

Joined Mar 24, 2008
21,839
From the eBay ad. I'm still not sure what it needs.

power supply :AC 18V-0V 0V-18V ,(main power:AC 24V -0V 0V-24V) , AC 9V -0V transformer > 150 VA (W) is recommend
 

SgtWookie

Joined Jul 17, 2007
22,201
Well, the 18VAC in seems to be feeding the plate voltage supply for the tube/valve, while the 24v supply is being used for + and - rails for the IC.

I can't make out what the transistor is doing; the schematic is just too fuzzy. I guess you scanned it into .jpg format and then converted it to .png format? That doesn't work, I'm afraid.

If you have to scan it in .jpg format, you're going to have to use a much higher resolution; like perhaps 150 DPI.
 

Thread Starter

frenchie29

Joined Nov 28, 2008
134
I scanned at 300dpi but I am not sure what the original format of my scanner is So how could I manage to split all that voltage accross? Do I have to build a power supply for it or I can buy one and modufy it? I'll try to re-scan it again


EDIT; The file is fine on my computer, I think photobucket compress the file when I upload it. can we send files here to PM??

I scanned the file at 1000dpi
PNJ is about 82MB
JPEG around 21MB

Ièll post it tomorrow I think it will take a while to upload.
 
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SgtWookie

Joined Jul 17, 2007
22,201
It looks like it has the supply built in; but you need to connect a transformer (or transformers) that have the correct voltage and power rating in order to get it to work properly.

It looks like they're adding the 18vac to the 24vac to get the plate voltage. That would give you in the neighborhood of roughly 52v. I don't know what your tube needs, though. I have an old RCA Receiving Tube Manual that I bought in 1970, but it doesn't have a listing for any of those tubes.
 

Thread Starter

frenchie29

Joined Nov 28, 2008
134
Could I just use one tranformer and split to the 3 locations?

The way I see it is 24V power supply step down to 18 and step down to 9v

Have they make a mistake? I think it should be DC and not AC
 
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SgtWookie

Joined Jul 17, 2007
22,201
OK, those image files are WAY too large to be uploaded here.

See if you can scan at a lower resolution. Somewhere between 100DPI and 150DPI should be ok.
 

Thread Starter

frenchie29

Joined Nov 28, 2008
134
Photobucket really compressed the files it went from 22mb to 175kb you guys know of a hosting site wheer they don't compress files after uploading?
 

SgtWookie

Joined Jul 17, 2007
22,201
You can use the "Go Advanced" button under the message text box, and then "Manage Attachments" to attach your images, right to the forum.

Note that there is a size limit; it varies depending on the type of file.

.png and .jpg files can be up to 293kb.
 

kubeek

Joined Sep 20, 2005
5,587
you can try some free webhosting and post it there. The picture needs to have at least double size, so that we can see the details. Also try to save it as a .png to get the best quality.
 

Wendy

Joined Mar 24, 2008
21,839
We have a web hosting as part of the AAC site, it's called Albums. It will automatically adjust the size of the picture, unlike attachments.

You can find it looking at your profile.
 

SgtWookie

Joined Jul 17, 2007
22,201
Well, we don't want it to be resized. That's what the problem has been so far.

Too much detail is getting lost.

The last scan (lastscan.jpg) was 34kb in size. You can go up to about 290kb in size.
 

Audioguru

Joined Dec 20, 2007
11,251
The LM4780 Amplifier IC is an excellent stereo amplifier.
The vacuum tube will just add even harmonics distortion and heat anything nearby.
 
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