Analog Attenuator?

[The Computer Audiophile]

Hi Guys - I've been researching preamps, including those from one of my favorite companies the Bespoke Audio Company. I even configured a preamp from Bespoke with a single input and output. Then I thought, why the heck would I get a preamp with a single in and out, even though that's all I need, when I could just get some type of analog attenuator. 

 

I only need a single XLR input and single XLR output. 

 

I see Sonore has its analog attenuator, but it's unbalanced only. 

 

Question: What are the best analog attenuators people have seen or used (don't worry about price for now)?

 

 

[The Computer Audiophile]

12 minutes ago, ericuco said:

Have you looked at the Goldpoint Level Controls? I have one of their 47 step units with balanced input & output.

 

If your need is temporary, you are welcome to borrow mine as I am now using the HQP digital volume control.

Thanks Eric, I hadn't seen those. Looking more now. 

 

Is Roon controlling your volume using HQP or are you using HQP's interface?

[The Computer Audiophile]

4 minutes ago, sandyk said:

http://www.dact.com/html/attenuators.html?gclid=CjwKCAjw7LX0BRBiEiwA__gNw9b95o6kobwfiyUCQ454HU90qJd-WCDXeC8l1od0h__B9GMzoHPGyxoCFY8QAvD_BwE  Includes Balanced types

 

https://goldpt.com/

 

https://www.hificollective.co.uk/attenuators/khozmo-stereo-stepped-attenuator-mk2.html

Thanks Alex, I have no idea what to do with the attenuators on their own in a DIY sense. I'm looking for products that I can pop into my system.

[The Computer Audiophile]

4 hours ago, ericuco said:

I adjust volume in Roon which in turn adjusts HQP volume so in the end it is the HQP volume control. Works well.

Do you know the difference between Roon’s and HQP’s volume control?

 

Perhaps @Miska can help. 

[The Computer Audiophile]

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

 

[The Computer Audiophile]

4 minutes ago, bbosler said:

look no further

 

http://www.placetteaudio.com/remote_control.htm

 

to make a balanced version I assume  will be about twice as much since the bulk of the cost is the resistors used. It is what I'm using. Rossini w/clock - Placette balanced Passive - Pass XA30.8 - Avantgarde Duo Omega with bass horns. Remote control completely transparent volume control.... 

 

 

Very cool!

[The Computer Audiophile]

7 minutes ago, Kal Rubinson said:

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

You and all your channels :~)

[The Computer Audiophile]

4 minutes ago, Kal Rubinson said:

I did look at them and, judging from their technology, that would seem possible.  Unfortunately, their stuff is all SE and I need balanced.  Is yours?

 

"We offer truly balanced versions of all of our products at twice the cost of single ended units. To build a truly balanced volume control or preamp requires building four channels of everything instead of the usual stereo pair. Because of the very high cost of the Vishay® resistors and adding extra internal controls and interlocks, it's very expensive and it only offers an advantage in a very few situations. But, because of the extremely good tracking of our balanced four channel volume controls, noise cancellation is the very highest possible because the plus and minus signals are always exactly equal but opposite in phase at every volume setting."

 

http://www.placetteaudio.com/QandA.htm

 

[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. 

[The Computer Audiophile]

Lighten up guys. This can be an enjoyable discussion.

[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.

[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

 

 

 

[The Computer Audiophile]

I should note that I’m using 40 feet long interconnects from my preamp to my mono amps. The cable is from Gotham. 

 

specs:

Gotham GAC-4/1 11301 ultraPro XLR, starquad balanced single channel 5 times shielded audio cable! Ultraflexible professional audio cable for microphones. 'Double Reussen shield', velvet matte non-light reflecting PVC-jacket material. A unique construction new invented by Gotham design

Connector: Neutrik 3Pin Gold-plated XLR(M/F) Plugs

 

https://www.ghentaudio.com/part/x01.html
 

https://gothamcables.com/en/gothamcables/starquad/11301gac41ultrapro

 

GAC2017page09.pdf

[The Computer Audiophile]

4 hours ago, Summit said:

 

40 feet long interconnects will degrade the sound quality no matter which type of preamp or attenuator you use. For such long distance I believe balanced interconnects is the most important if the rest of your audio gear has balanced in- and outputs.

Can you back that up with any other information?
 

40 feet isn’t really that long. Every recording studio I’ve ever been to has cables well over 40 feet. In fact, I’d be surprised if any recording I own was done with shorter cables. 
 

All my interconnects are balanced. 

[The Computer Audiophile]

44 minutes ago, PeterSt said:

 

As long as you realize that any means of analogue attenuation degrades the sound first. 
Indeed 40 feet isn't long, but it is to be tested against a shorter length without aanalogue attenuation or gain (but use a good drive-means first).

 

40 feet of SE cable can easily be totally harmless, BUT use a cable with 5MHz bandwidth capability over more than 300 feet. Next do the math (at say 0.5dB roll off at 1MHz over that distance).

Balanced would be better if the bandwidth is comparable (I don't recall Gotham giving those specs) BUT which also includes the shielding of especially the SE cable (in the end the shielding of the Balanced cable just the same).

And thus remember, start out with an attenuator of any means that I know of, and you can buy cheap cables just the same.

 

I see a lot of apples and oranges here.

 

Something else:

Does anyone want to see the frequency response of a Placette ? You don't want to see that.

The internals of it then ? you definitely don't want to see that.

 

I never could make a satisfying analogue attenuation means. They *all* influence linearity on the frequency response, no matter what type. Voltage control of the D/A chip is the only solution.
Let me add to this that anyone who thinks that a balanced attenuator does not harm THD (wildly) ,,, please explain the "why not" of that. It just can't exist, not even with a differentially setup voltage controlled D/A chip. You can make "a best" all right, but it will always be worse (easily measurable on the THD alone) than a well done digital attenuator (and I mean purely in the digital domain - hence in-software).

 

My 2c.

Peter

 

Hi Peter, thanks for the post. Part of the fun of this audio journey is reading the different opinions and trying things out for oneself. 
 

I’m very interested in both analog and digital attenuation. I will start a thread for digital attenuation. 

[The Computer Audiophile]

As promised -