The Phonoclone and VSPS PCB Help Desk - Page 219

dimkasta · 3rd March 2013, 10:06 PM

Quote:

Originally Posted by troystg

Agreed, transformers can't but secondaries can.

If he parallels the secondaries of the transformers he doubles the current in a safe manner.

You can only parallel secondaries of the same transformer, of course if the transformer allows that... The leaflet that comes with it should give you what you need to do it

troystg · 3rd March 2013, 11:07 PM

Quote:

Originally Posted by dimkasta

You can only parallel secondaries of the same transformer, of course if the transformer allows that... The leaflet that comes with it should give you what you need to do it

+1

A better, more thorough explanation...

rjm · 3rd March 2013, 11:20 PM

Well, okay, okay: technically if you make sure the windings are the in phase and the output voltages and impedances and current ratings equal, secondaries sharing a core and secondaries on separate cores can be treated equivalently. You can connect them in parallel to increase the total output current. Probably. Haven't tried it but I see no reason in principle that it wouldn't work.

However, that diagram in proximity to the words "i'll admit from the start i know nothing about electronics" is reason enough for alarm.

If you need more current, buy a bigger transformer.

vulejov · 4th March 2013, 04:17 AM

Quote:

Originally Posted by rjm

If you need more current, buy a bigger transformer.

How big transformer for phonoclone?
I think 1.9 VA is enough..

rjm · 4th March 2013, 05:01 AM

1.9 VA is only 80 mA @ 24VAC. It will work, but peak current draw in the phonoclone rectifiers can easily exceed that. A 25-50 VA transformer provides a good practical compromise in cost, size and sound quality.

(I think we've been here before. Many times...)

vulejov · 4th March 2013, 08:02 AM

4 LT 1028.. 4x7=28 mA
4 LM 7812/7912.. 4 x1= 4 mA

Wht is enough?!

Bibio · 4th March 2013, 07:52 PM

thanks guys thought it was a silly idea.. lol

i'm looking forward to the phonoclone kit coming from Richard and should be good fun putting it together and if i can manage to do it then there is hope for everyone as i'm completely clueless but want to learn.

btw. i have not heard vinyl for over 15 years and i have been subjected to MP3's in the meantime so my ears will be fresh as a daisy. busy putting my LPT back into service and i'm like a kid with a new toy :-)

rjm · 4th March 2013, 08:54 PM

Quote:

Originally Posted by vulejov

4 LT 1028.. 4x7=28 mA
4 LM 7812/7912.. 4 x1= 4 mA

Wht is enough?!

See here.

vulejov · 4th March 2013, 09:49 PM

Quote:

Originally Posted by rjm

See here.

Thanx.. but this is irrelevant.. LM78/7912 works or doesn't works, after stabilisators voltage is always 12V..

1.9VA transformator works very smooth, believe me or not..

Bibio · 4th March 2013, 09:49 PM

another question.

i take it the rectifiers are dependant on what current the transformer can put out?

so the 200v 3amp rectifier would be for a transformer capable of outputting 3 amps.

if i got larger transformers lets say of putting out 6amp would i keep the 200v the same but up the current handling of the rectifier to 6amp?

3rd March 2013, 11:20 PM	#2183
rjm Richard Murdey diyAudio Member Join Date: May 2004 Location: Kyoto Blog Entries: 72	Well, okay, okay: technically if you make sure the windings are the in phase and the output voltages and impedances and current ratings equal, secondaries sharing a core and secondaries on separate cores can be treated equivalently. You can connect them in parallel to increase the total output current. Probably. Haven't tried it but I see no reason in principle that it wouldn't work. However, that diagram in proximity to the words "i'll admit from the start i know nothing about electronics" is reason enough for alarm. If you need more current, buy a bigger transformer. __________________ RJM Audio (phonoclone.com / G+)

4th March 2013, 05:01 AM	#2185
rjm Richard Murdey diyAudio Member Join Date: May 2004 Location: Kyoto Blog Entries: 72	1.9 VA is only 80 mA @ 24VAC. It will work, but peak current draw in the phonoclone rectifiers can easily exceed that. A 25-50 VA transformer provides a good practical compromise in cost, size and sound quality. (I think we've been here before. Many times...) __________________ RJM Audio (phonoclone.com / G+)

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4th March 2013, 08:02 AM	#2186
vulejov diyAudio Member Join Date: Aug 2010	4 LT 1028.. 4x7=28 mA 4 LM 7812/7912.. 4 x1= 4 mA Wht is enough?!

4th March 2013, 07:52 PM	#2187
Bibio diyAudio Member Join Date: Mar 2009	thanks guys thought it was a silly idea.. lol i'm looking forward to the phonoclone kit coming from Richard and should be good fun putting it together and if i can manage to do it then there is hope for everyone as i'm completely clueless but want to learn. btw. i have not heard vinyl for over 15 years and i have been subjected to MP3's in the meantime so my ears will be fresh as a daisy. busy putting my LPT back into service and i'm like a kid with a new toy :-)

4th March 2013, 09:49 PM	#2190
Bibio diyAudio Member Join Date: Mar 2009	another question. i take it the rectifiers are dependant on what current the transformer can put out? so the 200v 3amp rectifier would be for a transformer capable of outputting 3 amps. if i got larger transformers lets say of putting out 6amp would i keep the 200v the same but up the current handling of the rectifier to 6amp?