The Kuartlotron - keantoken's simple error-correction superbuffer

Hello everyone!

@Jean Paul: :D

I started an implementation for a version with two channels of Kuartlotron (without power on the card Firstly) with standard components.

Before going further, do you think that this provision is interesting?
But as keantoken working to propose a layout, should I continue?

Regard's!
 

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Hello everyone!

@Jean Paul: :D

I started an implementation for a version with two channels of Kuartlotron (without power on the card Firstly) with standard components.

Before going further, do you think that this provision is interesting?
But as keantoken working to propose a layout, should I continue?

Regard's!
I can't see the reason for a one version pcb only;)
You must continue working:)
 
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Joined 2002
Hello everyone!

@Jean Paul: :D

I started an implementation for a version with two channels of Kuartlotron (without power on the card Firstly) with standard components.

Before going further, do you think that this provision is interesting?
But as keantoken working to propose a layout, should I continue?

Regard's!

Looks good but please reroute inputs to one side and outputs to the other side. Think how it will be wired in a case and where the RCA input- and output plugs will be located. In 99% of cases inputs are at one side and outputs at the other side. Tidy wiring adds to the final result. You don't want cross wiring of inputs and outputs. Please add pads for Alps RK27 (minimum standard for quality volume control), input- and output caps and a muting relay just like Mezmerize has as you will need it. Adding pads for a a simple PSU (rectifier diodes + RC filters + LM317/337) will give you the opportunity to use it before you will be drawing a spectacular symmetrical low noise PSU :) If you leave the connector block you will be able to wire the new PSU later on. I would also add a simple RC filter at the inputs to filter out HF/RF. The point with high bandwidth is.... you know what I mean.

Just go on, if it is not for others it will be for yourself and it will make your skills better. I was busy with it as well but decided to change to a new GB project that needs much time.
 
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With the DCB1 someone came up with running the MOSFETs at very high currents (so called "hotrodding"). This was supposed to sound better. I haven't tried but knowing that the circuit only draws a few mA I never even bothered. In my Mezmerize samples I used small heatsinks in standard config but let's say the MOSFETs only get lukewarm at standard current even without the heatsinks. Maybe Salas can give advice on suitable TO220 devices. I would add TO220 heatsink pads for heatsinks that can be soldered on the PCB in case you will use TO220 MOSFETs.

BTW "horrendously oversized devices" is a standard in audio land. I bet they won't break down in this application :) You either design "can I get away with it?" when working for a manufacturer or "over dimensioned" when it's DIY. There seems to be no middle solution in audio. Those that "over dimension" get all the girls. Fact !
 
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Looks good but please reroute inputs to one side and outputs to the other side. Think how it will be wired in a case and where the RCA input- and output plugs will be located. In 99% of cases inputs are at one side and outputs at the other side. Tidy wiring adds to the final result.
I thought a provision like this.
 

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TNT

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Do as you like but that is cross wiring. They taught me to keep inputs grouped together, same with outputs.

I think that a 3D connection topology can solve this. x / y for signals and z for power feeding. This means all power feed taken off the board and just injected where needed from z direction. This is also good as fields from power feed is orthogonal to signal carrying lines.

What say you?

//
 
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Joined 2002
It needs a TO-220 part that's as slow as the IRF240 to make it stable. Or I could just add another resistor and use the IRF710. Thoughts?

Never change a winning team. Just use the proven parts and be done with it. They are not expensive and no heatsinks necessary. You can use the somewhat larger board space for other useful stuff... Please compare to using V8 engines in cars ;) Horrendously oversized, polluting and uneconomic but they are still used in some countries.

I think that a 3D connection topology can solve this. x / y for signals and z for power feeding. This means all power feed taken off the board and just injected where needed from z direction. This is also good as fields from power feed is orthogonal to signal carrying lines.

What say you?

//

Eh ? I never saw the Matrix. On second thoughts: I think I understand what you mean. It can also be done by turning the active parts of the design 180 degrees, leave the potentiometer where it is now and make the board somewhat larger. Then regroup inputs brotherly together and flip them to the other side of the board. This board just needs SMD parts :) ... and a PSU... :devilr:
 
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With the DCB1 someone came up with running the MOSFETs at very high currents (so called "hotrodding"). This was supposed to sound better. I haven't tried but knowing that the circuit only draws a few mA I never even bothered. In my Mezmerize samples I used small heatsinks in standard config but let's say the MOSFETs only get lukewarm at standard current even without the heatsinks. Maybe Salas can give advice on suitable TO220 devices. I would add TO220 heatsink pads for heatsinks that can be soldered on the PCB in case you will use TO220 MOSFETs.

Jean-Paul, I can confirm that running the DCB1 "hotrodded" with higher current in the supply does sound better. I assume it is because of a lower PSU output impedance. This is not the thread to go into it in any detail.
 
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Think in terms of class A amp CCS loaded. HR ups gfs & lowers Zo. Ohmic division between SER & PAR sections increases. Rail AC modulation by load current swing decreases. That residual uV AC on rails also shows less THD. TO-247s mount easier and sturdier on case floor as sink. Silpad is enough to isolate. No weird grommets. Take HR heat gracefully. Need analogous TO-220s? Use IRF9630 & 630. On board sinks won't allow fanatical HR level though.

Disclaimer: DCB1 was "voiced" as a whole. I.e. the audio part and the psu part were meticulously evaluated and tweaked for values and devices to sound synergistic to my ears and taste. That's highly subjective, was done after the technical groundwork. Thus no suggestion was ever made that the psu part is the best mate for just any other preamp. Don't blame me if you will not like it in this preamp in other words.
 
Think in terms of class A amp CCS loaded. HR ups gfs & lowers Zo. Ohmic division between SER & PAR sections increases. Rail AC modulation by load current swing decreases. That residual uV AC on rails also shows less THD. TO-247s mount easier and sturdier on case floor as sink. Silpad is enough to isolate. No weird grommets. Take HR heat gracefully. Need analogous TO-220s? Use IRF9630 & 630. On board sinks won't allow fanatical HR level though.

Disclaimer: DCB1 was "voiced" as a whole. I.e. the audio part and the psu part were meticulously evaluated and tweaked for values and devices to sound synergistic to my ears and taste. That's highly subjective, was done after the technical groundwork. Thus no suggestion was ever made that the psu part is the best mate for just any other preamp. Don't blame me if you will not like it in this preamp in other words.

I need a legend for all the acronyms here. If I'm not mistaken you said what I was thinking.

How much current is the hot rod running? I'm wondering about transformer size.

This design makes me more curious about resistor choices and bypasses (not that Gerhard has replied), for voicing.
 
The MOSFET gets faster at higher current. Also you take it out of subthreshold conduction which makes it less like a BJT and more like an FET.

According to simulation with accurate models, the regulator resonates around 5MHz. Higher current makes this much, much worse. So here is more info suggesting that people actually prefer resonant rails or even oscillating regulators in some situations. It also means the decoupling needs to have a certain amount of inductance to keep it stable, which means the ground plane could cause problems.
 
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It does not resonate in real life. That one was designed in 2008 on the bench and tested with oscilloscope on the rails. Put together a prototype and measure it before proceeding if in any doubt. At least if concerned for possible trouble in another layout.