Passive Magnetic Preamp!

Matthewong · 2nd September 2007, 03:19 PM

Does anyone listen before the passive magnetic preamp? How is the sound quaity? I would lke to build one and I don't know how. Can anyone give me sme idea and also the schematic as well, thanks.

sawreyrw · 2nd September 2007, 03:28 PM

If you are talking about a classical mag amp, I don't think it will be at all satisfactory for audio signals.

Brett · 2nd September 2007, 03:42 PM

If you mean a moving magnet cartridge / RIAA pre, then build Allen Wright's FVP5A from www.vacuumstate.com

planet10 · 3rd September 2007, 07:00 AM

Passive magnetic preamp = TVC = Transformer Volume Control

There is at least 1 really good thread here.

You will need a pair of transformers (major expense) some switches to select taps, a switch for sources, some jacks for I/O and a box.

HNere is a good place to start http://www.intactaudio.com/atten.html

dave

Steve Eddy · 3rd September 2007, 07:20 AM

Quote:

Originally posted by planet10
Passive magnetic preamp = TVC = Transformer Volume Control

Could also = this: http://www.electra-print.com/pva.php

se

Brett · 3rd September 2007, 11:55 AM

I've got some S&B TX102 laying about. Wanna buy them?

kevinkr · 3rd September 2007, 10:42 PM

I've heard a number of passive magnetic line stages over the years, and they all sounded very good.

I heard a transformer based line stage from hificollective and thought it sounded pretty good. (Andy Grove)

http://www.hificollective.co.uk/kits..._pictures.html

One thing to keep in mind if you use this approach is that the source impedance of the driving components should be pretty low for best results. Most solid state sources shouldn't have any problem driving one of these and sources like dacs using current tube designs with high transconductance, high current triodes like the 5842, triode connected 6688 or D3A should not have problems either.

stoolpigeon · 4th September 2007, 10:23 AM

Hi Brett, which version of the TX102 and how much?

dejanm · 4th September 2007, 05:12 PM

I have TVC based on S&B T102 MK3, silver wiring, WBT connectors, Shallco switches, ... Most of these parts I bought at:

http://www.bentaudio.com/

I recommend it highly. It is very natural sounding pre-amp. But what astonishes the most when compared to EAR 864 or Pass Labs X2.5 (to name only a couple that I tested and compared in last 6 months) is the reproduction in the bass area. TVC is so superior in that respect that I was really tremendously surprised. I used different power amps there SS (Pass Labs X150.5) or tube (DIY SET 6C33, or let's say Jadis JA30).

I do not think you will be sorry if you proceed with this idea ...

By the way, on the Bent Audio site you have all necessary schematics for connecting S&B 102 trainnies ...

2nd September 2007, 03:19 PM	#1
Matthewong diyAudio Member Join Date: Jun 2005 Location: KL	Passive Magnetic Preamp! Does anyone listen before the passive magnetic preamp? How is the sound quaity? I would lke to build one and I don't know how. Can anyone give me sme idea and also the schematic as well, thanks.

3rd September 2007, 07:00 AM	#4
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	Passive magnetic preamp = TVC = Transformer Volume Control There is at least 1 really good thread here. You will need a pair of transformers (major expense) some switches to select taps, a switch for sources, some jacks for I/O and a box. HNere is a good place to start http://www.intactaudio.com/atten.html dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

3rd September 2007, 10:42 PM	#7
kevinkr diyAudio Moderator Join Date: Sep 2004 Location: Boston, Massachusetts Blog Entries: 6	I've heard a number of passive magnetic line stages over the years, and they all sounded very good. I heard a transformer based line stage from hificollective and thought it sounded pretty good. (Andy Grove) http://www.hificollective.co.uk/kits..._pictures.html One thing to keep in mind if you use this approach is that the source impedance of the driving components should be pretty low for best results. Most solid state sources shouldn't have any problem driving one of these and sources like dacs using current tube designs with high transconductance, high current triodes like the 5842, triode connected 6688 or D3A should not have problems either. __________________ www.kta-hifi.net

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2nd September 2007, 03:28 PM	#2
sawreyrw diyAudio Member Join Date: Apr 2006 Location: Minnesota	If you are talking about a classical mag amp, I don't think it will be at all satisfactory for audio signals.

2nd September 2007, 03:42 PM	#3
Brett diyAudio Member Join Date: Jan 2002	If you mean a moving magnet cartridge / RIAA pre, then build Allen Wright's FVP5A from www.vacuumstate.com

3rd September 2007, 11:55 AM	#6
Brett diyAudio Member Join Date: Jan 2002	I've got some S&B TX102 laying about. Wanna buy them?

4th September 2007, 10:23 AM	#8
stoolpigeon diyAudio Member Join Date: Feb 2007 Location: Laputa	Hi Brett, which version of the TX102 and how much?

4th September 2007, 05:12 PM	#9
dejanm diyAudio Member Join Date: Jul 2005 Location: Vienna	I have TVC based on S&B T102 MK3, silver wiring, WBT connectors, Shallco switches, ... Most of these parts I bought at: http://www.bentaudio.com/ I recommend it highly. It is very natural sounding pre-amp. But what astonishes the most when compared to EAR 864 or Pass Labs X2.5 (to name only a couple that I tested and compared in last 6 months) is the reproduction in the bass area. TVC is so superior in that respect that I was really tremendously surprised. I used different power amps there SS (Pass Labs X150.5) or tube (DIY SET 6C33, or let's say Jadis JA30). I do not think you will be sorry if you proceed with this idea ... By the way, on the Bent Audio site you have all necessary schematics for connecting S&B 102 trainnies ...

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