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Old 14th January 2003, 03:50 PM   #11
Joel is offline Joel  United States
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I would...
a) get rid of the diodes.
b) use the 300V-0-300V@250mA hammond transformer.
c) use a 5U4GB rectifier tube, and a 10Hy choke immediately after it.
This will give you around 250V.
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Old 14th January 2003, 03:51 PM   #12
Colt45 is offline Colt45  Serbia
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Quote:
Originally posted by Joel
Ok, I see why you are confused. That's not "two secondaries", it's 220V, center-tapped.
440v CT if you want to get technical.
220v either side of the center tap

I would drop the SS power supply, and use tubes, but thats personal opinion.
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Old 14th January 2003, 04:28 PM   #13
Elkaid is offline Elkaid  Canada
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Thank you very much guys !

What do you think of that ?
Attached Images
File Type: jpg powersupply.jpg (14.4 KB, 1045 views)
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Old 14th January 2003, 04:59 PM   #14
Joel is offline Joel  United States
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Looks good to me. The Hammond 193M is 10H@300mA. Heavy too!
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Old 14th January 2003, 05:11 PM   #15
Elkaid is offline Elkaid  Canada
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OMG !!

Is there any way to avoid using that ?

(ouch....90$can + main power transformer (112$can) + output transformer (115$)).
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Old 14th January 2003, 05:21 PM   #16
Joel is offline Joel  United States
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Quote:
Originally posted by Elkaid
Is there any way to avoid using that?
Sure is - go with the original schematic instead.
But I don't think $200USD is that bad... how much do you think building a tube amp should cost???
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Old 14th January 2003, 05:23 PM   #17
Elkaid is offline Elkaid  Canada
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You're right ! Thank you very much !

Maybe I could buy a bigger Power transformer and a bigger choke and supply two amplifier from the same power supply.

Thanks again for your help !
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Old 14th January 2003, 05:29 PM   #18
Joel is offline Joel  United States
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Elkaid, I would just do this as a monoblock configuration. Otherwise it's just too much stuff on one chassis.
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Old 16th January 2003, 09:08 PM   #19
Elkaid is offline Elkaid  Canada
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Got another idea.

Why couldn't I use a standard transformer but connected "backward".

By example, this transformer :
Primary : 120V
Secondary : 60V

This transformer has a ration of 2/1
Connected backward (120V connected on the secondaries), we should mesure 240 volts on the primary right ?

Does that make sense ? I saw that once in an hybrid amp. From a low voltage transformer, the guy was able to drive output ICs + high voltage for the preamp tubes.

I'd like to get your impressions. Thanks !
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Old 16th January 2003, 09:17 PM   #20
dhaen is offline dhaen  Europe
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Elkaid,

You cannot run any winding at a higher than rated voltage. There are 2 reasons:
1) The core will probably saturate.
2) Even if it doesn't, there are breakdown of insulation issues.

Also, concerning running transformers backwards:
It will work, but there are safety issues to be considered before putting it into service.

Cheers,
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