DIY phono preamp - cheap and simple! - Page 43

rjm · 27th September 2010, 07:06 AM

400V 6A will be just fine.

/R

Jezza56 · 27th September 2010, 08:44 AM

Hi RJW, just wondering if your single side board download file VSPS 45G is complete, I down loaded the file and all It shows is the black traces and pads is there another version I am new to electronics so please bear with me
Jezza

rjm · 28th September 2010, 01:08 AM

answered elsewhere, but for future reference: In Eagle, press the ratsnest button to fill the polygonal traces.

rjm · 26th January 2012, 03:26 AM

Eagle .brd file attached.

Changelog:

Added thermal isolation of power and ground planes.
Added optional C8, C9, 0.1 uF ceramic bypass caps for decoupling high-bandwidth op amps.
Removed the alternate C3 cap mounting position to fit Black Gate NX. These caps were discontinued many years ago and are essentially no longer available.

dimkasta · 16th March 2012, 12:49 AM

Richard I was browsing today around the DCB1 sections and I found this topology diagram.

Since the cartridge output is inherently balanced, you think something similar could be done with 4 boards of VSPS or Phonoclone?

The reason I am asking is that I plan on replacing my pre with a passive one, but since my amp is balanced only, I will have to use a 1:1+1 transformer to get hot and cold signals and perhaps a buffer if the attenuated signal is not enough to drive the transformer.

So making the phono balanced will solve the transformer issue for me (athough it will make phono and pre construction a lot more complicated)

rjm · 16th March 2012, 08:27 AM

It's electrically feasible, but unlikely to be worth the expense and complexity.

Incidentally the noise for a balanced phono pre is 3dB higher than an unbalanced one. That's because each phase sees an input signal that is half the total cartridge output voltage.

dimkasta · 16th March 2012, 09:58 AM

I know...

Sometimes I want to change my amp just for his lack of SE inputs...

At least it has a huge input impedance (200k), so I hope it can be easily driven with the passive pre and the transformers.

27th September 2010, 07:06 AM	#421
rjm Richard Murdey diyAudio Member Join Date: May 2004 Location: Kyoto Blog Entries: 46	400V 6A will be just fine. /R __________________ RJM Audio (phonoclone.com / G+)

27th September 2010, 08:44 AM	#422
Jezza56 diyAudio Member Join Date: Sep 2010	PCB board Hi RJW, just wondering if your single side board download file VSPS 45G is complete, I down loaded the file and all It shows is the black traces and pads is there another version I am new to electronics so please bear with me Jezza

28th September 2010, 01:08 AM	#423
rjm Richard Murdey diyAudio Member Join Date: May 2004 Location: Kyoto Blog Entries: 46	answered elsewhere, but for future reference: In Eagle, press the ratsnest button to fill the polygonal traces. __________________ RJM Audio (phonoclone.com / G+)

16th March 2012, 08:27 AM	#426
rjm Richard Murdey diyAudio Member Join Date: May 2004 Location: Kyoto Blog Entries: 46	It's electrically feasible, but unlikely to be worth the expense and complexity. Incidentally the noise for a balanced phono pre is 3dB higher than an unbalanced one. That's because each phase sees an input signal that is half the total cartridge output voltage. __________________ RJM Audio (phonoclone.com / G+)

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16th March 2012, 12:49 AM	#425
dimkasta diyAudio Member Join Date: May 2010 Location: Athens	Richard I was browsing today around the DCB1 sections and I found this topology diagram. Since the cartridge output is inherently balanced, you think something similar could be done with 4 boards of VSPS or Phonoclone? The reason I am asking is that I plan on replacing my pre with a passive one, but since my amp is balanced only, I will have to use a 1:1+1 transformer to get hot and cold signals and perhaps a buffer if the attenuated signal is not enough to drive the transformer. So making the phono balanced will solve the transformer issue for me (athough it will make phono and pre construction a lot more complicated)

16th March 2012, 09:58 AM	#427
dimkasta diyAudio Member Join Date: May 2010 Location: Athens	I know... Sometimes I want to change my amp just for his lack of SE inputs... At least it has a huge input impedance (200k), so I hope it can be easily driven with the passive pre and the transformers.

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