The Phonoclone and VSPS PCB Help Desk - Page 160

kaban · 10th September 2011, 10:48 AM

Well, after a year or so rest, my phonoclone fired up pretty well this afternoon!

I've attached some pics of my turntable, phonoclone preamp and power supply.

Can I ask you a dumb question - why should the preamp powersupply have a large Va?

Wirehead.be · 10th September 2011, 11:40 AM

Quote:

Originally Posted by kaban

Can I ask you a dumb question - why should the preamp powersupply have a large Va?

I don't think that changes anything, having large VA. You just need an adequate power supply, with decent filtering.

kaban · 11th September 2011, 03:57 AM

Thanks for the reply. I really love the phonoclone. I want to build a decent tube amp as well... I have built a pair of E.J. Jordan full frequency TL speakers. At the moment, I have a NAD 3121 which is pretty good for its age.
As an experiment I just plugged my phonoclone into the Blueray player surround system's AUX input. It sounds great.

rjm · 11th September 2011, 06:41 AM

Quote:

Originally Posted by kaban

Can I ask you a dumb question - why should the preamp powersupply have a large Va?

Simple answer is larger transformers tend to sound more "solid" and "powerful".

Anything over 25 VA should be sufficient, but 160VA-225VA can be considered an optional upgrade path. Depending on the supplier, there isn't always a lot of different in price vs. VA, so one larger transformer might be more cost effective than two smaller ones.

CognitiveDiscord · 12th September 2011, 11:03 PM

Where exactly can I order the Talema transformer products?

rjm · 13th September 2011, 08:01 AM

Digikey for example,

Digi-Key - TE62062-ND (Manufacturer - 62062-P2S02)

Wirehead.be · 13th September 2011, 10:11 AM

If you want a PCB-mountable version,Bürklin in Germany stocks them. Exceptionally fast shipping (2-day max in Europe). http://www.buerklin.com

Wirehead.be · 22nd September 2011, 08:13 PM

I measured the Noise Level on my VSPS stage. Pretty good, as there's nothing too exotic component-wise.

This was measured using an E-MU 0404 USB (s/n ratio 113dB - sampled at 24-bit / 92kHz). After setting the sensitivity of the Line-In's to the maximum (without clipping) for a line signal, I came up with the following graph:

First of all - the resonant frequency of my cartridge & tonearm seems to be 7Hz, but overall, it's great. Only a little 50Hz and 100Hz noise left, coming from the PSU. But it's at -89.2dB, so no biggie

rjm · 24th September 2011, 12:21 AM

Since the y-axis is not referenced, I can't say for sure, but whatever hum you are picking up here is most likely through the cartridge. The "true" output noise of the VSPS300 can be estimated by replacing unplugging the phono cable and putting 1 kohm across the input instead.

To calibrate your y-axis, adjust until an input signal of 1 kHz sine wave / 1 V rms returns a peak of 0 dB in the FFT.

Wirehead.be · 24th September 2011, 09:18 AM

Allright, thanks for the info for taking measurements! I disconnected the turntable, put 1Kohm 1 percent tolerance resistors across the inputs, and I've adjusted the input with a 1Khz sinewave to 0dB.

This is what I get:

Noise Level - 1kOhm - Calibrated @ 0dB @ 1kHz
50Hz peaks at -91.6dB; I guess it's OK, but I'll be looking at some additional filtering of the power supply. Using 7815/7915 now in separate housing. It's not bad at all, but there's always room for improvement

13th September 2011, 08:01 AM	#1596
rjm Richard Murdey diyAudio Member Join Date: May 2004 Location: Kyoto Blog Entries: 72	Digikey for example, Digi-Key - TE62062-ND (Manufacturer - 62062-P2S02) __________________ RJM Audio (phonoclone.com / G+)

24th September 2011, 12:21 AM	#1599
rjm Richard Murdey diyAudio Member Join Date: May 2004 Location: Kyoto Blog Entries: 72	Since the y-axis is not referenced, I can't say for sure, but whatever hum you are picking up here is most likely through the cartridge. The "true" output noise of the VSPS300 can be estimated by replacing unplugging the phono cable and putting 1 kohm across the input instead. To calibrate your y-axis, adjust until an input signal of 1 kHz sine wave / 1 V rms returns a peak of 0 dB in the FFT. __________________ RJM Audio (phonoclone.com / G+)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

11th September 2011, 03:57 AM	#1593
kaban diyAudio Member Join Date: May 2006	Thanks for the reply. I really love the phonoclone. I want to build a decent tube amp as well... I have built a pair of E.J. Jordan full frequency TL speakers. At the moment, I have a NAD 3121 which is pretty good for its age. As an experiment I just plugged my phonoclone into the Blueray player surround system's AUX input. It sounds great.

12th September 2011, 11:03 PM	#1595
CognitiveDiscord diyAudio Member Join Date: Nov 2010	Where exactly can I order the Talema transformer products?

13th September 2011, 10:11 AM	#1597
Wirehead.be diyAudio Member Join Date: Nov 2006	If you want a PCB-mountable version,Bürklin in Germany stocks them. Exceptionally fast shipping (2-day max in Europe). http://www.buerklin.com

22nd September 2011, 08:13 PM	#1598
Wirehead.be diyAudio Member Join Date: Nov 2006	I measured the Noise Level on my VSPS stage. Pretty good, as there's nothing too exotic component-wise. This was measured using an E-MU 0404 USB (s/n ratio 113dB - sampled at 24-bit / 92kHz). After setting the sensitivity of the Line-In's to the maximum (without clipping) for a line signal, I came up with the following graph: First of all - the resonant frequency of my cartridge & tonearm seems to be 7Hz, but overall, it's great. Only a little 50Hz and 100Hz noise left, coming from the PSU. But it's at -89.2dB, so no biggie

24th September 2011, 09:18 AM	#1600
Wirehead.be diyAudio Member Join Date: Nov 2006	Allright, thanks for the info for taking measurements! I disconnected the turntable, put 1Kohm 1 percent tolerance resistors across the inputs, and I've adjusted the input with a 1Khz sinewave to 0dB. This is what I get: Noise Level - 1kOhm - Calibrated @ 0dB @ 1kHz 50Hz peaks at -91.6dB; I guess it's OK, but I'll be looking at some additional filtering of the power supply. Using 7815/7915 now in separate housing. It's not bad at all, but there's always room for improvement