Preamp recommendation (or no preamp)?

[MattyW]

I'd be more inclined to put a 1:2 SUT between a source and passive pre if the source has insufficient drive. I've had pretty good success doing this though all SUT impart their own sound signature. I rather enjoy modern SUT using copper coils around an iron core such as Jensen or Boyuu Reisong make.

 

Then again,  I only like this with components which are missing that special magic on their own. A top notch source will not require it and will give better results anyway. Kind of like putting lipstick on a pig 

Edited June 14, 2020 by MattyW

[stereo coffee]

49 minutes ago, tripitaka said:

Apologies in advance for a silly question but can one have a 'reverse preamp'?

...by which I mean a step-down transformer used to reduce the dac output voltage without converting any of the precious current into heat which I presume all resistor-based attenuators do.

And if such a device even makes sense, can one easily purchase attentautors of this type?

I imagine that I could then put a 'normal' preamp immediately after this, to compensate for any loss in dynamics.

 

As I mentioned above, my dac vol is typically set at -40dB or so, which means that a single a unexpected auto zero-reset event within the dac will fry a quite expensive system (not really sure what type of amp protection I have, if any).

Thanks for any replies.

I believe you are referring to the need of attenuation, rather than unnecessary amplification of your DAC's audio signal.

 

A contact less passive attenuator does just this, it is positioned between your source component and power amp, to provide necessary volume adjustment of your audio signal. There is no heat as you describe with a contact less passive attenuator,

 

Your post hits on a interesting viewpoint of heat though, which is by product usually of amplification, and can be quite problematic where amplification parts dispersing heat, are co- located close to passive parts. Where parts are heated or indeed subject to any mechanical contact, the bathtub curve then can be seen, removing your enjoyment of audio in a much accelerated manner.    https://en.wikipedia.org/wiki/Bathtub_curve

Edited June 14, 2020 by stereo coffee

[Ittaku]

Most preamps have some gain, though there are many that come in configurable forms with more, less, or even zero gain. As SC has said, passives also provide only attenuation and no gain.

[Pops110]

22 minutes ago, stereo coffee said:

I believe you are referring to the need of attenuation, rather than unnecessary amplification of your DAC's audio signal.

 

A contact less passive attenuator does just this, it is positioned between your source component and power amp, to provide necessary volume adjustment of your audio signal. There is no heat as you describe with a contact less passive attenuator,

 

Your post hits on a interesting viewpoint of heat though, which is by product usually of amplification, and can be quite problematic where amplification parts dispersing heat, are co- located close to passive parts. Where parts are heated or indeed subject to any mechanical contact, the bathtub curve then can be seen, removing your enjoyment of audio in a much accelerated manner.    https://en.wikipedia.org/wiki/Bathtub_curve

Just tried out your pre and still had sound coming through even with the volume at zero. From what you’re saying above that shouldn’t have been the case.

[tripitaka]

2 hours ago, stereo coffee said:

I believe you are referring to the need of attenuation, rather than unnecessary amplification of your DAC's audio signal.

 

A contact less passive attenuator does just this, it is positioned between your source component and power amp, to provide necessary volume adjustment of your audio signal. There is no heat as you describe with a contact less passive attenuator.

Thanks for the reply!  If you will permit me to labour the point, yes I do wish to achieve what you have described (though without any particular interest in an adjustable device) and to this end I have collected a variety of fixed 5/10/20 dB L-pad attenuators (both RCA in-line & XLR in-line) but have had only mixed success with these. So, is there a system without any resistors and when you say 'contactless' are you referring to the lack of any mechanical attenuation adjustor, or is there actually an induction gap in the circuit?

 

 

Edited June 14, 2020 by tripitaka

[stereo coffee]

30 minutes ago, Pops110 said:

Just tried out your pre and still had sound coming through even with the volume at zero. From what you’re saying above that shouldn’t have been the case.

The start commencement point can be adjusted by the fixed resistance at the end of the LDR board.  Can you email me please,  and I can sort this for you.  If that is the unit from @robmid, Rob can do that adjustment when it gets back to Queensland - I will let him know so it is silent at zero volume for when it is on its travels next. .  

 

Edited June 14, 2020 by stereo coffee

[stereo coffee]

28 minutes ago, tripitaka said:

Thanks for the reply!  If you will permit me to labour the point, yes I do wish to achieve what you have described (though without any particular interest in an adjustable device) and to this end I have collected a variety of fixed 5/10/20 dB L-pad attenuators (both RCA in-line & XLR in-line) but have had only mixed success with these. So, is there a system without any resistors and when you say 'contactless' are you referring to the lack of any mechanical attenuation adjustor, or is there actually an induction gap in the circuit?

You can achieve a fixed level attenuation or for ease of use make it adjustable to find the point that suits and leave there. This can be done with these

https://lunainc.com/product/optocouplers/

 

To do so, for a stereo arrangement arrange 4 matched devices in a L pad configuration, or if you need more inputs, as many as you need can be configured as seen below 

 

[Pops110]

That’s good to know that’s it’s an easy fix. I tried it out for a bit in my system but I think I prefer a valve pre. Very good pre for a stupidly small amount of money.

[tripitaka]

3 hours ago, MattyW said:

I'd be more inclined to put a 1:2 SUT between a source and passive pre if the source has insufficient drive. I've had pretty good success doing this though all SUT impart their own sound signature. I rather enjoy modern SUT using copper coils around an iron core such as Jensen or Boyuu Reisong make.

 

Then again,  I only like this with components which are missing that special magic on their own. A top notch source will not require it and will give better results anyway. Kind of like putting lipstick on a pig 

Hi! I wasn't sure if you were replying to my query, but I might give this a go anyway as it seems quite interesting... and what else am I going to do  to pass time during this time of plague

Cheers

Edited June 14, 2020 by tripitaka

[tripitaka]

Having thought a little bit more, I have another question, Team Stereonet, which directly relates to the title of this thread.

 

Say a power amp isnt able to suck as much instantaneous input current as it might wish for from a not-so-special dac (ruining the dynamics), I gather that one might improve the situation by putting a good preamp in between.

So far so good, BUT, wouldnt the preamp then face exactly the same difficulty when sucking current out of the dac, so has anything really changed?

And if the situation actually has improved, how does the gain setting on the preamp affect that level of improvement?

 

There, hopefully that's a sensible question!

[Ittaku]

2 minutes ago, tripitaka said:

Having thought a little bit more, I have another question, Team Stereonet, which directly relates to the title of this thread.

 

Say a power amp isnt able to suck as much instantaneous input current as it might wish for from a not-so-special dac (ruining the dynamics), I gather that one might improve the situation by putting a good preamp in between.

So far so good, BUT, wouldnt the preamp then face exactly the same difficulty when sucking current out of the dac, so has anything really changed?

And if the situation actually has improved, how does the gain setting on the preamp affect that level of improvement?

 

There, hopefully that's a sensible question!

Nope, that's precisely one of the main jobs of an active preamp - a so-called buffer. You can buy just a buffer (no volume control or selector or anything else) that makes the DAC match the power amp better too, but most buffer-only jobs are pretty low quality offerings.

[tripitaka]

4 minutes ago, Ittaku said:

Nope, that's precisely one of the main jobs of an active preamp - a so-called buffer. You can buy just a buffer (no volume control or selector or anything else) that makes the DAC match the power amp better too, but most buffer-only jobs are pretty low quality offerings.

Thanks!!

so, based on all of this, I think I'm in the market for an active preamp after all!   which is perhaps not a million miles from MattyW's idea of a SUT/PassivePre combo anyway

 

 

[Mat-with-one-t]

For a further spanner in the works, I use (what I feel is great) a Wyred4Sound STP-SE preamp, which is kinda sorta a passive preamp, but adds gain only if required as you turn up the (very good) volume control.  Best of both worlds, and a super-practical unit to boot!

 

https://6moons.com/audioreviews/wyred2/preamp.html

Edited June 14, 2020 by Mat-with-one-t

[MattyW]

A SUT is interesting as it provides gain though is in fact itself a passive component. 

 

https://www.ebay.com/itm/273124304630

 

Works very well indeed in front of any number of passive preamps with some DAC's I've tried it with.... Also the little Realistic 42-2101 phono stage which isn't that high output.

Edited June 14, 2020 by MattyW

[stereo coffee]

8 hours ago, tripitaka said:

Having thought a little bit more, I have another question, Team Stereonet, which directly relates to the title of this thread.

 

Say a power amp isnt able to suck as much instantaneous input current as it might wish for from a not-so-special dac (ruining the dynamics), I gather that one might improve the situation by putting a good preamp in between.

So far so good, BUT, wouldnt the preamp then face exactly the same difficulty when sucking current out of the dac, so has anything really changed?

And if the situation actually has improved, how does the gain setting on the preamp affect that level of improvement?

 

There, hopefully that's a sensible question!

 

Your earlier post referred to high sensitivity of your speakers, and cautions you had with levels, the answer if that still matters, then the answer is to attenuate your audio signal, with as little signal degradation, as is humanely possible.  

 

A contact less  passive represents simple resistance.   A active represents input capacitance, resistance, gain devices, many phase anomalies leading to tonal coloration, from simply not being able to depart from being a vast series circuit to the incoming audio signal.   The circuit attempts to correct with feedback and proximity etc. A study of feedback shows it is a cat and mouse affair at best  https://en.wikipedia.org/wiki/Feedback#Electronic_engineering

 

If audio quality is important to you, and if you  can, ...then compare all methods of attenuation. 

[sir sanders zingmore]

16 minutes ago, stereo coffee said:

then the answer is to attenuate your audio signal, with as little signal degradation, as is humanely possible.  

Signal degradation is easily measured. Do you have any measurements to show that the device you sell degrades the signal less than active designs?

[tripitaka]

20 minutes ago, stereo coffee said:

 

A contact less  passive represents simple resistance.   A active represents input capacitance, resistance, gain devices, many phase anomalies leading to tonal coloration, from simply not being able to depart from being a vast series circuit to the incoming audio signal.   The circuit attempts to correct with feedback and proximity etc. A study of feedback shows it is a cat and mouse affair at best  https://en.wikipedia.org/wiki/Feedback#Electronic_engineering

Thanks and I don't doubt this, indeed fear of all the above is why I currently have no preamp at all.  And it's also true that questions of attenuation are fundamental to my situation.   However, the technology for achieving attenuation is of less interest to me (and in any case I love my dac vol control so, if anything, I like the idea of introducing fixed attenuation).  Anyway, my over-riding interest really, is the effect which a given level of attenuation at different points along the signal chain might have on dynamics, which you can see I've been clumsily grappling with above!

Edited June 14, 2020 by tripitaka

[Lochawe]

10 hours ago, Pops110 said:

That’s good to know that’s it’s an easy fix. I tried it out for a bit in my system but I think I prefer a valve pre. Very good pre for a stupidly small amount of money.

After trying many passive preamps in my system I arrived at the same conclusion – I prefer a valve preamp.

[stereo coffee]

33 minutes ago, sir sanders zingmore said:

Signal degradation is easily measured. Do you have any measurements to show that the device you sell degrades the signal less than active designs?

Measured with the best measuring devices available. 

 

 

[sir sanders zingmore]

[Red MacKay]

After 30 years of experimenting with solid state pres, valve pres, Lightspeed LDR, WarpspeedLDR, Truth LDR, Dave Slagle TVC, Promethius TVC and just plain passive pots.

 

I am now back at a valve pre.  It definitely gives the music the best chance.  You need your pre to have very low output capability though - or it won't drive anything and you will be disappointed.  Especially low impedance to drive your Bryston.

Edited June 23, 2020 by Red MacKay

[Auracle]

17 minutes ago, Red MacKay said:

 a valve pre.  It definitely gives the music the best chance.  You need your pre to have very low output capability though - or it won't drive anything and you will be disappointed.  Especially low impedance to drive your Bryston.

What he said!

[MattyW]

I'm absolutely blown away by my new DACGEAR LDR Pre Mk2. I think my setup had too many different tube component signatures before (source,  pre and power amp).

 

The LTA MZ3 was spectacular when I had the darTZeel NHB108B copy, though has never seemed to pair with my Wavebourn Edelweiss-3 power amp as well. 

 

I notice sound is more open sounding,  music flows more naturally and has greater presence or immediacy. Imaging is improved and I'm noticing detail I've never heard before. I found myself bobbing my head to music while eating dinner,  never mind toe tapping.

 

That's not to say that it is better than the MZ3. Simply that the LDR is superior in my current system configuration. As I said earlier I believe I had too many different tube components in my system before and they sort of cancelled each other out which isn't something I want with the great sources I currently possess.

 

Anyway,  I'll be selling my LTA MZ3 shortly.  Good thing I kept the boxes.

Edited June 23, 2020 by MattyW

[tripitaka]

On 06/06/2020 at 2:05 PM, astonmartinv8 said:

 

I've got a PS Audio Directstream with Bridge 2 running straight into a pair of Bryston 7B SST's and B&W 802 diamonds.

 

I've been thinking about a preamp (looking at PS Audio BHK Signature), and of course their literature tells me how much more musical everything is with it (bringing out the magic that the $9500 DAC forgot to ).

 

Any update on whether you tried anything?

 

I ran a dac direct to poweramp and then added a preamp resulting in significant improvement, very noticeable better imaging, but the scientist in me says I was merely compensating for deficiencies in the dac output stage by buffering it and letting it operate at lower output (preamp is wound up to max output).

 

I'd be confident (or at least very hopeful) that a dac as expensive as yours wouldn't see any imaging improvements from introducing a more complex signal path (leaving 'voicing' preferences to one side of course).

 

[AussieMick]

Townshend Allegri+
No remote, but it sounds bloody amazing. I’m a believer preamps make a difference, too. I’m running a two source system (DAC and phonostage) and I am very happy. Buying from their eBay store saved me a lot of money. 
not affiliated with them, just love the device.