Anyone using a commercial passive preamplifier?

Hari Iyer

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Are any FMs using a commercial passive preamplifier and if yes what's their opinion in comparison with an active counterpart?

Nowadays amplification in source is not required as the source itself provide around 2v RMS voltage and most power amplifiers can be easily driven by such voltages and what you require is just a matched input / output with an attenuator and a passive selector switch. This is better than using an active preamplifier which can add its own tone and signature and not to mention of power supply noise and ripple.

This weekend I built one such simple passive preamplifier and am happy with the outcome. What I immediately realised was it sounded very different than my active counterpart and it was more natural, open and uncompressed. This testing device is for keeps and I can't be more happy.
 

rikhav

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I did use a transformer based passive preamp many years ago.

It did sound decent but the b1 surely sounded fuller then the TVC
 

newlash09

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Are any FMs using a commercial passive preamplifier and if yes what's their opinion in comparison with an active counterpart?

Nowadays amplification in source is not required as the source itself provide around 2v RMS voltage and most power amplifiers can be easily driven by such voltages and what you require is just a matched input / output with an attenuator and a passive selector switch. This is better than using an active preamplifier which can add its own tone and signature and not to mention of power supply noise and ripple.

This weekend I built one such simple passive preamplifier and am happy with the outcome. What I immediately realised was it sounded very different than my active counterpart and it was more natural, open and uncompressed. This testing device is for keeps and I can't be more happy.
Hello sir :)

I got myself a passive music first audio magnetic tvc preamp. And it is the best I've ever heard by a very fair margin. This completely disappeares in the chain. Utter and awesome clarity and detail...stunning dynamics too. If someone likes the sound of their dac or digital source, then this is the best way to transfer it across. Absolutely no colouration what so ever.
 

bornfi

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Are any FMs using a commercial passive preamplifier and if yes what's their opinion in comparison with an active counterpart?

Nowadays amplification in source is not required as the source itself provide around 2v RMS voltage and most power amplifiers can be easily driven by such voltages and what you require is just a matched input / output with an attenuator and a passive selector switch. This is better than using an active preamplifier which can add its own tone and signature and not to mention of power supply noise and ripple.

This weekend I built one such simple passive preamplifier and am happy with the outcome. What I immediately realised was it sounded very different than my active counterpart and it was more natural, open and uncompressed. This testing device is for keeps and I can't be more happy.
I use Silvercore Preamp 324 that has all silver wiring including the transformer wound. After comparing this with some expensive preamps, all I can say that in my opinion, however expensive or well made an active preamp is, it always masks some details and of course changes the presentation of music. With actives I always feel that the rhythm and pace of the music change and deviates from the naturalness.
 

Miany

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Are any FMs using a commercial passive preamplifier and if yes what's their opinion in comparison with an active counterpart?

I have a fully balanced passive preamp, which i used with ATC actives some time back. I liked it more than ATC preamp itself. YMMV. Only problem is the absence of remote control and you have to get up every time to adjust the volume.

Also, if i remember correctly, there is some recommended ratio of output impedance of source to input impedance of power amp, which have to be taken care of.
 

Hari Iyer

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I have a fully balanced passive preamp, which i used with ATC actives some time back. I liked it more than ATC preamp itself. YMMV. Only problem is the absence of remote control and you have to get up every time to adjust the volume.

Also, if i remember correctly, there is some recommended ratio of output impedance of source to input impedance of power amp, which have to be taken care of.
Yes input and output impedance needs to be taken care off. My initial build results are quite encouraging though. I may take it to the next level shortly. If anyone interested in PCB can PM me.
Thanks to all FMs for their inputs.
 

kapvin

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Yes input and output impedance needs to be taken care off. My initial build results are quite encouraging though. I may take it to the next level shortly. If anyone interested in PCB can PM me.
Thanks to all FMs for their inputs.
That's great Hari, if you can keep it simple and keep costs down. count me among your first customers.
 

Hari Iyer

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That's great Hari, if you can keep it simple and keep costs down. count me among your first customers.
Thanks Kapvin, the cost is only for the volume potentiometer, input selector, RCA input/ output and chassis. I don't think all will cost more than 5k. I have made the volume pot as ladder type control. This keeps the input and output impedance always the same.
 

Hari Iyer

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Images of my WIP passive pre-amplifier built for a FM. It uses a pair of dual ALPS blue potentiometer arranged in a ladder network. This keeps the input impedance always at 47Kohm irrespective of the volume knob. The output gain is continously variable attenuation type.

Passive Preamp.jpg

Thanks for looking.
 
D

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Since passive preamps don’t add any color to the sound, the DAC becomes all the more important in terms of sound signature. I don’t like the sound when I bypass the active pre of my integrated amp (by employing a Schitt Sys passive) while I am using the Cambridge CXN’s DAC - because the sound becomes too analytical and dry. However when I use the Sys with the Schitt Bifrost DAC, I find the sound to my liking (warm enough). The passive pre improves bass resolution - more nuances in the tabla for example and better voice texture. So, as long as the musicality is ensured by other components (primarily the DAC), passive pre works out.
 

Hari Iyer

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Ok, IME even adding a simple interconnect in-between is a degrade in audio. Let alone an active device. Like @prem says, it's in the balance of the setup that's important.
 

Ramanuj

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I toggle between a passive pre from Creek and a Tube Pre from Cayin. Both has its own charm. Passive pre is very dependent on a good front end and a great power amp is what I opine.

IMG20180815192015_copy_784x1046.jpg
 
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Hari Iyer

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I toggle between a passive pre from Creek and a Tube Pre from Cayin. Both has its own charm. Passive pre is very dependent on a good front end and great power amp or else sounds too limp and unexciting.
Ok, you can't blame the passive pre for that if something else in the chain is not up to the mark. Using a tube preamplifier/ buffer would be like a band-aid to address issue. The passive preamp is like a mirror showing the source directly to the power amplifier. Using an active preamp is like a processed image to the power amplifier.
 

Ramanuj

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Ok, you can't blame the passive pre for that if something else in the chain is not up to the mark. Using a tube preamplifier/ buffer would be like a band-aid to address issue. The passive preamp is like a mirror showing the source directly to the power amplifier. Using an active preamp is like a processed image to the power amplifier.
Exactly that's what I said. Since you can't hide you better have great upstream and downstream equipments. What ever is coming from the source is already processed so that processor better be good!
 
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Since passive preamps don’t add any color to the sound, the DAC becomes all the more important in terms of sound signature. I don’t like the sound when I bypass the active pre of my integrated amp (by employing a Schitt Sys passive) while I am using the Cambridge CXN’s DAC - because the sound becomes too analytical and dry. However when I use the Sys with the Schitt Bifrost DAC, I find the sound to my liking (warm enough). The passive pre improves bass resolution - more nuances in the tabla for example and better voice texture. So, as long as the musicality is ensured by other components (primarily the DAC), passive pre works out.
I’ve been playing around with these two DACs in both active and passive combos. And also optimising my speakers positions. And my perceptions have drastically changed from above. As I got the speakers into a better position (which is about a metre from the rear wall which is allowing me to appreciate the higher fidelity (nuances) it adds to the listening), it’s the CXN’s DAC that’s giving more likeable result than the Schitt DAC. But that’s just an update and not relevant to this thread (it is elaborated at length in my CXN thread if anyone’s interested). What’s relevant to this thread is that I have decided to keep the Sys passive pre in my chain and use only the power section of my Audiolab 8200A integrated amp. So, there’s a case for passive pre in my opinion; try and see if it works for you.
 

greenhorn

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I have one of these
yes it's a passive preamp, but for me it was just an added feature. it works fine, and haven't really evaluated critically.
 
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