Analog Attenuator?

[bbosler]

I was triamping my horns with Naim gear so I had him make me one with 6 channels of SE. Relays switch the resistors in/out so one controller can control multiple channels

 

I have since reconfigured it with a single balanced amp so I have 2 channels of balanced using 4 of the 6. So think of it as individual pairs of volume controls. A pair can either be a stereo SE preamp or one channel of a balanced preamp. Keep adding pairs until you get as many balanced channels as you want. At $1295 a pair you are looking at $10K+ for an eight channel balanced control. Guy is a very good person to deal with so maybe a well know reviewer might get a price break ?? You can ask

 

I assume the controller can handle as many channels as you want?

[sphinxsix]

2 hours ago, The Computer Audiophile said:

I have an HPA4 here that I'm testing as well. 

 

 

 

Something tells me this will not be DROK 

 

BTW I think that preamps group test would be great, there aren't many of these.

[Kal Rubinson]

29 minutes ago, bbosler said:

............................... Keep adding pairs until you get as many balanced channels as you want. At $1295 a pair you are looking at $10K+ for an eight channel balanced control. Guy is a very good person to deal with so maybe a well know reviewer might get a price break ?? You can ask

That is not appealing to me because 4 Benchmark LA4s come price out at $10K and they would include multiple inputs and active circuitry.  A big bite, though.

[bbosler]

 

To your points

1. they would include multiple inputs... most people don't have multiple sources with 5.1 or 7.1 outputs. Those that do use receivers or surround preamps with HDMI or discreet multichannel inputs. I don't see why Placette couldn't do that though assuming Guy is still willing to build one-off units like he did for me. 
2. active circuitry.. if your source is capable of driving a power amp directly why would you want to add another layer of circuitry to the signal? My goal was specifically not to have it, which I was thinking is the point of the OP

however, assuming you are interested in resale at some point, 3-4 stereo preamps would probably be easier to sell than a single 6-8 channel preamp. Then again, there are quite a few people who have multi-channel DACs like yours  and Pro Audio interfaces with multiple  outputs so there must be some demand.. at least you are interested in one. 

 

 

[Kal Rubinson]

17 minutes ago, bbosler said:

they would include multiple inputs... most people don't have multiple sources with 5.1 or 7.1 outputs. Those that do use receivers or surround preamps with HDMI or discreet multichannel inputs. I don't see why Placette couldn't do that though assuming Guy is still willing to build one-off units like he did for me. 

I do have more than one and there are no suitable AVRs or prepros.  

 

19 minutes ago, bbosler said:

active circuitry.. if your source is capable of driving a power amp directly why would you want to add another layer of circuitry to the signal? My goal was specifically not to have it, which I was thinking is the point of the OP

Good point but I cannot be sure that any source I might use in the future might not need some amplification.  In addition, even with balanced lines, it is not a sure-thing that a passive will drive my 30' cables.

 

22 minutes ago, bbosler said:

however, assuming you are interested in resale at some point, 3-4 stereo preamps would probably be easier to sell than a single 6-8 channel preamp.

Granted.

[sandyk]

32 minutes ago, bbosler said:

active circuitry.. if your source is capable of driving a power amp directly why would you want to add another layer of circuitry to the signal? My goal was specifically not to have it, which I was thinking is the point of the OP

 

Why indeed ?

[The Computer Audiophile]

32 minutes ago, Kal Rubinson said:

Good point but I cannot be sure that any source I might use in the future might not need some amplification.  In addition, even with balanced lines, it is not a sure-thing that a passive will drive my 30' cables.

This is something that has me hesitant. I exchanged emails today with an engineer, who everybody knows, and he said that under strict conditions passive attenuators can be magical. But, those conditions have to be perfect and unchanged. 
 

He also mentioned very short cables are needed most of the time. 
 

This makes it difficult for those of us with new equipment once in a while. 

[tmkirst]

From the professional world....

 

 https://www.tcelectronic.com/Categories/Tcelectronic/Computer-Audio/Accessories/LEVEL-PILOT/p/P0D71#googtrans(en|en) 

[bbosler]

2 hours ago, The Computer Audiophile said:

passive attenuators can be magical. But, those conditions have to be perfect and unchanged. 

 

I think that is a bit of an overstatement. 

 

"Perfect conditions" implies that the uses are very limited. I disagree,,, and what  does "perfect" even mean? Relatively low output impedance from the source and relatively high input impedance at the amp is the general consensus. Most equipment meets that pretty easily. Short cables? Again, what does that mean? Thirty feet is probably a bit too long but even then it depends on the 2 impedance factors already mentioned as well as the impedance of the cable, and if you think about it, microphones which output very low level signals are often used with long cables and sound just fine. AND, those 30 foot cables are probably going to surround channels where super high fidelity isn't needed in the first place. 

 

Then you factor in the unavoidable coloration of the active stage which leaves you with which is the worst evil even if you don't meet the "perfect"criteria, whatever that is. A presumed loss of something with the passive or the definite added coloration of the active? I would argue that often times when somebody claims a passive is losing something what it is losing is the coloration of the active preamp, which for whatever reason that listener prefers.

 

2 hours ago, The Computer Audiophile said:

 

This makes it difficult for those of us with new equipment once in a while. 

 

isn't that the same situation you face every time you try something new? Is this preamp a good match with this amp with this speaker with this cable with this DAC with this whatever. It is all about synergy no matter what you are changing.

 

 

[Summit]

10 hours ago, Kal Rubinson said:

OK but there are very few of them with more than 2 channels.

 

Yes and for a good reason.

[Summit]

3 hours ago, The Computer Audiophile said:

This is something that has me hesitant. I exchanged emails today with an engineer, who everybody knows, and he said that under strict conditions passive attenuators can be magical. But, those conditions have to be perfect and unchanged. 
 

He also mentioned very short cables are needed most of the time. 
 

This makes it difficult for those of us with new equipment once in a while. 

 

An engineer, who everybody knows, and that have recipes for magical things – It must be Frank .

[Kal Rubinson]

9 hours ago, tmkirst said:

From the professional world....

 https://www.tcelectronic.com/Categories/Tcelectronic/Computer-Audio/Accessories/LEVEL-PILOT/p/P0D71#googtrans(en|en) 

Two channels only.

 

6 hours ago, bbosler said:

AND, those 30 foot cables are probably going to surround channels where super high fidelity isn't needed in the first place. 

In my setup, they go to the front L/C/R amps and speakers.

 

6 hours ago, bbosler said:

Then you factor in the unavoidable coloration of the active stage which leaves you with which is the worst evil even if you don't meet the "perfect"criteria, whatever that is.

The Benchmarks come close enough for me.

[sphinxsix]

9 hours ago, The Computer Audiophile said:

This is something that has me hesitant. I exchanged emails today with an engineer, who everybody knows, and he said that under strict conditions passive attenuators can be magical.

Many tears have been shed by megabuck active preamps owners who heard a 10x cheaper passive one performing better 

[sphinxsix]

@sandyk I'm not claiming that every passive preamp is better than every much more expensive one. 

[Summit]

21 minutes ago, sphinxsix said:

Many tears have been shed by megabuck active preamps owners who heard a 10x cheaper passive one performing better 

 

I don’t know anyone who have compared a top active preamp to a cheaper passive one and thought that the later sounded better, much less shared any tears. 

[sphinxsix]

1 minute ago, Summit said:

much less shared any tears. 

That was just a poetic figure.

[The Computer Audiophile]

Lighten up guys. This can be an enjoyable discussion.

[bbosler]

4 hours ago, The Computer Audiophile said:

Lighten up guys. This can be an enjoyable discussion.

 

Really? I think this may be one of the least contentious discussions I've ever been involved in. perhaps you are a bit too sensitive?

 

4 hours ago, Summit said:

don’t know anyone who have compared a top active preamp to a cheaper passive one and thought that the later sounded better

 

we've never met unless you consider this to be meeting. If you do then you just met one. minus the tears. In addition, there are thousands of people with the funds to do otherwise who prefer a passive over an active. I don't want to make assumptions about your knowledge and background, but the vast majority of those who hold your views have zero knowledge about how electronics actually work. I'm pretty sure the vast majority of them also speak anecdotally having never done the comparison themselves... I have.

 

An active  preamp is simply a passive volume control (potentiometer, stepped attenuator, transformer, etc) and a line level amplifier that may or not have gain. The active stage is usually, almost always, after the volume control to act as a buffer i.e. an impedance matcher that presents a high impedance to the volume control and therefore the source while having a low output impedance to drive the amp. Some put an active stage before and after the volume control and a few put it only before. .  If the source is capable of driving the power amp directly, which many of them are, and the power amp has a relatively high input impedance, which most of them do, then all you may achieve by adding an active preamp is to add coloration. Granted, you may prefer that coloration, but it will be there.

 

Many DACs and other sources are perfectly capable of driving a power amp. Many are designed to do just that with a built in volume control. Most, like the Rossini, control the volume in the digital domain so I prefer to do it after the DAC once the D to A is complete.  DCS even recommends avoiding the use of too much digital attenuation.

 

Kal, I can't imagine a setup where you can't get your sources closer to the front than 30 feet. No need to go into all of the reasons why, but if you are serious about this, and from all I can see you are indeed very serious, of all the compromises we have to make in this hobby running 30 foot cables to my main channels would be at the bottom of my list. If you are locked into that, then you might try the preamps for those channels in the front at the end of the 30 foot run from the source and short cables from the pre to the amps so the attenuation is at the end instead of the beginning. Run a 30 foot cable from your IR repeater to those preamps. The downside is the source has to drive the long cable which may be worse, but you won't know until you try it. You waste a preamp channel doing it that way unless you run a long cable back to the surround channel amp, but a small price to pay for maximum fidelity if it turns out to be better. Interestingly, if you are using the Parasound A31amp up front, the Benchmark preamp has a lower input impedance than the amps so in that regard you are better off with the preamp driving the long cables. .

 

regarding your options, I see that you have none when it comes to multiple input 7.1 AVRs and preamps. Even the ones that have a single set of 7.1 inputs digitize the analog to be processed so for me that would be a non-starter. I would also advise against the custom Placette I proposed since when you decide to move on, and you will move on, you will have a $10K+ boat anchor that isn't heavy enough to serve that purpose. If you decide to try Placette I would get multiple stereo units and use like  the Benchmarks. Your solution of running a bunch of stereo preamps, whether Benchmark or some others,  looks to be the only solution other than the possibility of a pro audio sound console used for mixing. Maybe what  the pros use to mix/create the multichannel recordings ??

[The Computer Audiophile]

7 minutes ago, bbosler said:

 

Really? I think this may be one of the least contentious discussions I've ever been involved in. perhaps you are a bit too sensitive?

 

 

we've never met unless you consider this to be meeting. If you do then you just met one. minus the tears. In addition, there are thousands of people with the funds to do otherwise who prefer a passive over an active. I don't want to make assumptions about your knowledge and background, but the vast majority of those who hold your views have zero knowledge about how electronics actually work. I'm pretty sure the vast majority of them also speak anecdotally having never done the comparison themselves... I have.

 

An active  preamp is simply a passive volume control (potentiometer, stepped attenuator, transformer, etc) and a line level amplifier that may or not have gain. The active stage is usually, almost always, after the volume control to act as a buffer i.e. an impedance matcher that presents a high impedance to the volume control and therefore the source while having a low output impedance to drive the amp. Some put an active stage before and after the volume control and a few put it only before. .  If the source is capable of driving the power amp directly, which many of them are, and the power amp has a relatively high input impedance, which most of them do, then all you may achieve by adding an active preamp is to add coloration. Granted, you may prefer that coloration, but it will be there.

 

Many DACs and other sources are perfectly capable of driving a power amp. Many are designed to do just that with a built in volume control. Most, like the Rossini, control the volume in the digital domain so I prefer to do it after the DAC once the D to A is complete.  DCS even recommends avoiding the use of too much digital attenuation.

 

Kal, I can't imagine a setup where you can't get your sources closer to the front than 30 feet. No need to go into all of the reasons why, but if you are serious about this, and from all I can see you are indeed very serious, of all the compromises we have to make in this hobby running 30 foot cables to my main channels would be at the bottom of my list. If you are locked into that, then you might try the preamps for those channels in the front at the end of the 30 foot run from the source and short cables from the pre to the amps so the attenuation is at the end instead of the beginning. Run a 30 foot cable from your IR repeater to those preamps. The downside is the source has to drive the long cable which may be worse, but you won't know until you try it. You waste a preamp channel doing it that way unless you run a long cable back to the surround channel amp, but a small price to pay for maximum fidelity if it turns out to be better. Interestingly, if you are using the Parasound A31amp up front, the Benchmark preamp has a lower input impedance than the amps so in that regard you are better off with the preamp driving the long cables. .

 

regarding your options, I see that you have none when it comes to multiple input 7.1 AVRs and preamps. Even the ones that have a single set of 7.1 inputs digitize the analog to be processed so for me that would be a non-starter. I would also advise against the custom Placette I proposed since when you decide to move on, and you will move on, you will have a $10K+ boat anchor that isn't heavy enough to serve that purpose. If you decide to try Placette I would get multiple stereo units and use like  the Benchmarks. Your solution of running a bunch of stereo preamps, whether Benchmark or some others,  looks to be the only solution other than the possibility of a pro audio sound console used for mixing. Maybe what  the pros use to mix/create the multichannel recordings ??

You're making my point very well.

[bbosler]

I'm sorry, I don't get your point at all. There was some discussion back and forth about the merits of passive versus active, no name calling, nothing disparaging that I could see, just a bit of disagreement on the relative merits of each, and you jump in and tell everyone to lighten up. If we can't offer a straightforward honest opinion about our preferences and experiences without getting scolded then i'm outta here.

 

if anything, you are the one who needs  to lighten up... put on your big boy pants

 

feel free to respond with "good riddance" if it makes you feel better

 

please delete my account while you are at it

 

 

[JohnSwenson]

Hi Chris,

I spent MANY years trying to find a volume control I really liked, pots, discrete resistors, active, passive but none of them seemed to get it just right, until I tried autoformer attenuators by Dave Slagle  from Intact Audio. The ARE just the transformers, you have to add a box and connectors, but for me that is easy.

 

Using the autoformer passives is VERY different than resistor based passive controls, you don't need the super short cables etc.

 

In my main system my passive "preamp" cost about $500, the SlagleFormers, an aluminum box, some really good connectors and a switch for the two inputs. To me in my system this sounds better than anything else I have ever heard, no matter what the cost.

 

Bent Audio used to sell a passive preamp using these autoformers that have balanced ins and outs, but now it is just on the used market.

 

that Townsend one mentioned earlier looks like a promising one, but I have not heard it. It looks like it is well done. If I was in the market for buying a commercial one I might go for that one.

 

I would highly recommend looking into autoformer based volume controls, to me they beat out anything else.

 

John S.

[The Computer Audiophile]

4 minutes ago, JohnSwenson said:

Hi Chris,

I spent MANY years trying to find a volume control I really liked, pots, discrete resistors, active, passive but none of them seemed to get it just right, until I tried autoformer attenuators by Dave Slagle  from Intact Audio. The ARE just the transformers, you have to add a box and connectors, but for me that is easy.

 

Using the autoformer passives is VERY different than resistor based passive controls, you don't need the super short cables etc.

 

In my main system my passive "preamp" cost about $500, the SlagleFormers, an aluminum box, some really good connectors and a switch for the two inputs. To me in my system this sounds better than anything else I have ever heard, no matter what the cost.

 

Bent Audio used to sell a passive preamp using these autoformers that have balanced ins and outs, but now it is just on the used market.

 

that Townsend one mentioned earlier looks like a promising one, but I have not heard it. It looks like it is well done. If I was in the market for buying a commercial one I might go for that one.

 

I would highly recommend looking into autoformer based volume controls, to me they beat out anything else.

 

John S.

Thanks John. Is the autoformer similar at all to what The Bespoke Audio Company is doing with its transformer design?

 

https://www.thebespokeaudiocompany.com/our-product

 

 

 

[RickyV]

Here are some exotic types
 

http://www.audio-consulting.ch/?Products:Preamplifier:Silver_Rock_Meteor_AVC

[Superdad]

1 hour ago, The Computer Audiophile said:

Thanks John. Is the autoformer similar at all to what The Bespoke Audio Company is doing with its transformer design?

 

Hi Chris:

I think the Bespoke units are nice, bu way too much wire.  

Here is the link to the Slagle Elmaformer: http://www.intactaudio.com/atten.html

47 silky-smooth positions, 1.25dB steps.

 

I built mine into a small case with a really big knob. In the case you see is the copper version. It blew me away (compared to my $10K Hovland HP200P-i with rhodium-contact relay attenuator) so much so that I had Dave Slagle make me his silver version.

 

As with John, I have been searching for decades for the finest attenuation means, and of course was involved in building fine resistor-based stepped attenuators--LONG before anyone in the high-end (I'm talking late 1970s; Hovland was the very first audio customer for Caddock resistors).  

This Slageformer is far and away the most transparent level control I've ever used--and it has no trouble driving 25 feet of single-ended cable into my amp.

 

Balanced versions are possible as is remote control. You have to hear one to believe it.

 

[Superdad]

Also see:

https://www.whatsbestforum.com/threads/emia-elmaformer-volume-control-review.29910/

and EM/IA, the collaboration between Jeffrey Jackson and Dave Slage: http://myemia.com