Placette’s Q&A is a largely bollocks. If there are only two resistors active at a time that means there are multiple contacts added in the cct and all contacts are audible and the number should be minimized.
Every part has a sonic signature and a particular part may not be idea in a particular application.
Passive volume controls should be optimized for the system and one-size-fits-all may be fits-only-a-few.
""I know the sound of every resistor, every capacitor—everything. I know what tonal balance will be created when I mix this with that. So, when I started to develop the N11, I had a sound in my head. I made the schematic, optimized the layout to measure well, and then began listening and tuning with small parts. I adjusted the capacitor contacts, chose the correct parts for the desired sound, and determined what kind of silk screen on the printed circuit board would create the sound that would best fit Noble Line target customers." from Jurgen Reis in MBL Noble Line N11 line preamplifier
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@ieales - Typically, the only people touting a MIRACLE CURE are the people selling a MIRACLE CURE, - unless of course you are talking about a properly oriented colored fuse.
@larryi - The value of a buffer is for impedance matching as you noticed when comparing the passive Placette volume control to the unity gain Placette linestage, which is basically their volume control with a buffer. I would not suggest a buffer as a tone control, although the improvement in impedance matching (compared to a passive) is typically heard as improved dynamics and tonal quality. I believe with the Placette units, there are only two Vishay S-102 resistors active at one time so the only thing affected by their 125 volume steps is a that the user has a greater choice in controlling the volume, it would have no sonic affect whatsoever.
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I don't think the number of steps in an attenuator is a particular problem, when it is a matter of relays switching in different resistors. How does it hurt to have more steps? A Levinson No. 32 preamp I owned had much more steps than that (.1 db steps). I thought the Levinson steps were crazy small because one cannot easily hear a full db change with music, but, when I adjusted balance, I found that one can hear a .2db change in level of one channel, which explains why they offered such small increments of change.
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128 steps is overkill and can negative cable consequences. If one has to use more than the middle 10 of 20 the gain structure is messed up somewhere as in 700mV/500w amp on 101dB/2.83v speakers.
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A local dealership that sells only tube electronics (some made in-house) sells an in-line transformer buffer. I did not need it, but, I did get to hear what it does. It makes the sound seem more "open" and expansive (more enveloping soundstage), and whether or not this is artificial, it sounded good to me. But, I didn't think I needed it because my gear is stuffed with iron--the linestage has transformer inputs and transformer outputs, and my amplifier has transformer inputs and, of course, output transformers. All of these transformers are quite old Western Electric parts.
I have heard only the Silver Rock transformer volume control and the MyEmia autoformer volume control, but, neither was actually in my system. I have not played around with different forms of volume controls, but, I have heard various passive linestages with different types of volume control, including light-dependent resistors. In my own system, I heard Placette's passive linestage with a 128 step relay switched attenuator, and their unity gain active linestage with the same 128 step attenuator. I bought the active stage; it sounded more lively than the passive even if it had no gain.
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I never thought about the contribution of those transformers to the sound
E V E R T H I N G contributes to the system sound, including the room, furnishings and weather!
So when someone says a specific product is the MIRACLE CURE, hightail it in the opposite direction.
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Bumpy had "phono" in his original post. The use of "phone" in my post was either an auto correction or more likely the result of a brain to finger malfunction.
@larryi - Thank you for the link to information about transformers. I have tried transformer volume controls and was not a fan, although I could see the appeal as they have a smooth sound.
Transformers are also used by some preamp/amplifier manufacturers on the input/output sides of things as they can offer benefits related to impedance matching and galvanic isolation, can be used to convert balanced signals, and can add about +6dB gain. The SMc mods to my TLC-1 preamp (now buffer) included Lundahl transformers on the output side, the same as used in their VRE-1 preamp. In addition to their already well-regarded line of transformers, Lundahl offers two higher level (or at least more expensive) transformers - one wound using Cardas copper wire and one wound with silver wire. My TLC-1 has the Cardas wire version as the silver was quite expensive. I never thought about the contribution of those transformers to the sound of the preamp so your linked article was quite interesting to me.
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Yep autocorrect, it is indeed phono.
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Yeah, I actually had to read that twice in the original post before I caught on. When he said "phone inputs" he was talking about what many would call an rca connector or an rca chassis mount socket.
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Sorry Kingsleuy, but I never mentioned a turntable. I did talk about phone plugs (UK) which in America I think you call RCA plugs
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Looking at pictures of the inside of the First Watt B1. Just Bypass, jump the volume controls with one wire on each pot.
I am another that is confused. I am understanding that you would like to plug your turntable (phono) into this the First Watt B1. Outputs to your passive volume control. Which feeds your power amplifier? Question. Where is the RIAA de-emphasis accomplished? Output of a Moving Magnet cartridge is about 4 millivolts. That is not enough to drive a power amp.
Ohhhh wait. You don't have one of those turntables that has a built in preamplifier (taking care of the gain increase and RIAA) and maybe even USB outputs, do you? The buffering you are looking for should be in that preamplifier.
Ummmmm.....
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What DAC and what is the output impedance?
What volume control and what is its resistance and attenuation type?
What amp and what is its input impedance?
Balanced or unbalanced?
What interconnects?
There is nothing that is ’transparent’. You are adding connectors and cables, along with circuitry, all of which color the sound.
I ran [self-designed] passives for years, both in the studio and at home. I only went with active control when I tri-amped.
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+1 on the Schiit Saga with tube buffer, especially for inexpensive systems. It sounds better than it has any right to at the price!
My Cary SLP-05 is more organic sounding, but for the price difference, it should!
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@cat_doorman
Hattor has a nice looking tube buffer meant to be used with their passive preamps. It might have some fixed gain though. I’m not sure if that can be defeated, bypassed or altered as an option.
I own one of those and they sound very nice. The default is 9dB gain, which really isn’t that much but Arek can build them to your specification. We compromised and mine has 6dB gain.
I spent some time trying to find a preamp with little to no gain, even started a thread on it here, but eventually broadened my search. While I didn’t need any gain, getting a little hasn’t seemed to hurt anything.
If you want a great sounding preamp with no gain, the SMc Audio VRE-1 C comes with 6dB gain through the transformers. However, I believe Steve can build it with unity gain as he did with my modified TLC-1, which I use as a unity gain buffer along with the Hattor passive, which provides volume control and other convenient functionality.
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Contact Bob latino, I'm pretty sure he can build you one. If it's really just an itch, amazon has cheapish tube buffers in their chifi electronics section.
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It may not be up to the standard of the rest of your system, but that’s pretty much what a Schiit Saga does. Unity gain if you turn the stepped attenuator all the way up. There’s a solid state and tube model.
Hattor has a nice looking tube buffer meant to be used with their passive preamps. It might have some fixed gain though. I’m not sure if that can be defeated, bypassed or altered as an option.
i spent some time trying to find a preamp with little to no gain, even started a thread on it here, but eventually broadened my search. While I didn’t need any gain, getting a little hasn’t seemed to hurt anything.
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noromance
Unless I'm sadly mistaken, they don't seem to be available.
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Erik,
The problem with most transformer volume controls was the limited number of volume steps—the right volume seemed to always be between adjacent steps. The are some nice ones offered my MyEmia (autoformer) that has many steps and remotely controlled volume and balance. They used to offer the autoformer and relay switching as a kit, so one could build the control into one’s own gear, but I think the kit days are long past.
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I think Luxman, maybe among others, experimented with transformer based volume controls. I have to say I've always been intrigued by using transformers either as volume controls or output buffers offering galvanic isolation and balanced outputs.
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The unity gain "buffer" that I like involves the use of transformers. I've heard a few and liked how they remove hard and artificial sounding "edginess" without sounding murky or dynamically dull. The attached is a discussion of the subject:
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@erik_squires You literally just described the reason preamps exist.
Yes, Erik has it right, the pre-amp can amplify the signal, it also attenuates the signal and sends a signal to the amp at the right impedance. I've never seen a top audio system without a preamp (some pretty good ones without but not state of the art systems).
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You are looking for a unity gain (i.e., voltage in = voltage out) buffer.
There are some tube buffers available such as one made by Tortuga and the two linked already in this thread but, as you pointed out, you do not need or want the volume control. I suspect it would be easy to construct the Pass B1 buffer without a volume control. It appears they still sell the board through the store. I suspect you would replace the VC with the correct value resistor, assuming you will operate it from the output of your current VC. I am not the one to help with that but I suspect it would be easy to do. This article may also be of some help.
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Thanks noromance. My system is built around simplicity and all the cathode followers I have found have volume controls or, like the ifi, lots of redundant circuitry.
Picture the First Watt B1 with volume controls removed and that is what I would like to buy
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Sorry if I did not explain fully. I have no need for any gain in my system so the preamp needs to add no amplification.
Additionally after a lot of trial and error the passive volume control is great.
What I want to do is to better match the output impedance of the DAC with the input impedance of the power amp. PVCs work against you in this.
It could be argued if it sounds great now, then why change it. Its just an itch to be scratched.
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Cathode Follower tube circuit
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I am super super confused.
You are pretty much building a preamp as separates. Just get a great preamp. You literally just described the reason preamps exist.
Otherwise I suggest the Schiit Loki, with the tone controls set to neutral would work.
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