Grounding is a s important as signal routing, but most people can't picture whats going on since they think that ground is just a flat plane. The currents within the grounding scheme can be significant and the small resistances within ground wires can cause those currents to develop significant hum which is inductively coupled to the signal wires.
The case, which is ultimately the circuit ground, can even develop significant voltage differences across its surface - especially around inductive components.
It helps to have a conceptual picture of whats going on, like my water model so that you have a tool to think about what every single ground wire is actually doing with the potential differences and the induced currents.
Shoog
The case, which is ultimately the circuit ground, can even develop significant voltage differences across its surface - especially around inductive components.
It helps to have a conceptual picture of whats going on, like my water model so that you have a tool to think about what every single ground wire is actually doing with the potential differences and the induced currents.
Shoog
Found on internet, don't remember where now,
One of the best amplifier power supply grounding schemes is a “star” ground system, where all the local grounds for each stage are connected together, and a wire is run from that point to a single ground point on the chassis, back at the power supply ground. Even better is a two-point star, where the power supply grounds (PT center tap, first filter cap ground) and output stage grounds (output tube cathodes for fixed bias, or cathode resistors for cathode biased, and output transformer secondary ground) are connected together and to the chassis at a single point, right at the ground of the first filter capacitor. The ground of the second filter capacitor, after the choke or filter resistor, is the star ground point for the preamp stage grounds. Use a local common point for each preamp stage ground, and run a wire from this common point back to the second star point. If two stages are out of phase with each other, the can share a common local ground, but don’t use more than two stages per local common ground. This concept can even be taken further, with multiple star points for various amplifier stages.
One of the best amplifier power supply grounding schemes is a “star” ground system, where all the local grounds for each stage are connected together, and a wire is run from that point to a single ground point on the chassis, back at the power supply ground. Even better is a two-point star, where the power supply grounds (PT center tap, first filter cap ground) and output stage grounds (output tube cathodes for fixed bias, or cathode resistors for cathode biased, and output transformer secondary ground) are connected together and to the chassis at a single point, right at the ground of the first filter capacitor. The ground of the second filter capacitor, after the choke or filter resistor, is the star ground point for the preamp stage grounds. Use a local common point for each preamp stage ground, and run a wire from this common point back to the second star point. If two stages are out of phase with each other, the can share a common local ground, but don’t use more than two stages per local common ground. This concept can even be taken further, with multiple star points for various amplifier stages.
Update!
Everything going fine, been listening many many hours now and it sounds very good but a bit "cold" and heartless. No tubewarmth whatsoever.
I won some GE 5670W tubes and also got hold of two NOS Sylvania and Westinghouse 5V4G.
I heard they are more musical then the russian. They were cheap so i gotta try.
http://www.hifitubes.nl/weblog/wp-content/general-electric-gl-5670.pdf
Anyone think i can replace them straight over? Pinlayout is the same atleast.
Also 2pcs of RIKE S-CAP 1,0uF is on the way plus a MCAP 630V for psu. (to get rid of the bulky wimas...)
Everything going fine, been listening many many hours now and it sounds very good but a bit "cold" and heartless. No tubewarmth whatsoever.
I won some GE 5670W tubes and also got hold of two NOS Sylvania and Westinghouse 5V4G.
I heard they are more musical then the russian. They were cheap so i gotta try.
http://www.hifitubes.nl/weblog/wp-content/general-electric-gl-5670.pdf
Anyone think i can replace them straight over? Pinlayout is the same atleast.
Also 2pcs of RIKE S-CAP 1,0uF is on the way plus a MCAP 630V for psu. (to get rid of the bulky wimas...)
That is an indication of a good circuit and a good layout.
If you want "tube sound" you must abandon SRPP, just try another topology and biasing the valve to work in its less linear region, so you would have lots of distortion.
You can also add a bit mains hum, that will give you two IM peaks at 50Hz and 100Hz, many people like this, and describe it as more "warmth sound"
The goal is to hear the music, not the amp... just listen to Frank advice and enjoy the music !
Yes you're probably 100% right about that.
But at the same time it could be fun to try something else, topology i mean.
Does anyone know any other curcuit with 6n3p /5670?
Also wonder if someone uses pin 5 for screening on this tubes?
And will 5670 have same freqresponse with 1uf as with 6n3p?? Impedance differ or?
But at the same time it could be fun to try something else, topology i mean.
Does anyone know any other curcuit with 6n3p /5670?
Also wonder if someone uses pin 5 for screening on this tubes?
And will 5670 have same freqresponse with 1uf as with 6n3p?? Impedance differ or?
Hi,
6N3P is the ruskie equivalent of the 5670 AFAIK so that shouldn't change much. It will likely sound different, probably a little more to your liking as I find quite a lot of these Russian small signal tubes rather "thin" sounding too unless you pump some more current trough them.
Adding solid state regulation to the PS also has a tendency towards dryness in some cases.
If you want a little distortion (Popilin is going to kill me for teaching you all this trickery), you could undo the LED bias, replace it with the original cathode R and decouple the bottom one with a nice fat elco.
That will increase distortion a little, up gain a little and "slow" down the slew rate.
Voila, le plat "chaud" du chef,
6N3P is the ruskie equivalent of the 5670 AFAIK so that shouldn't change much. It will likely sound different, probably a little more to your liking as I find quite a lot of these Russian small signal tubes rather "thin" sounding too unless you pump some more current trough them.
Adding solid state regulation to the PS also has a tendency towards dryness in some cases.
If you want a little distortion (Popilin is going to kill me for teaching you all this trickery), you could undo the LED bias, replace it with the original cathode R and decouple the bottom one with a nice fat elco.
That will increase distortion a little, up gain a little and "slow" down the slew rate.
Voila, le plat "chaud" du chef,
Au contraire mon amie, le plat chaud du chef c'est à bon idée!
On the contrary my friend, hot dish of the chef is good idea!
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Yes, I remember I liked the R+C even though Popiliin suggested a higher value on the cap not to loose bass.
I will switch back n see. First try new tubes next week.
Frank; how much influence does rectifier have on sound? Having russian here too ... wonder how the americans are doing here.
Found a schematic from some German guy. What do you guys think. Cathode fallower was mentioned.
I will switch back n see. First try new tubes next week.
Frank; how much influence does rectifier have on sound? Having russian here too ... wonder how the americans are doing here.
Found a schematic from some German guy. What do you guys think. Cathode fallower was mentioned.
Attachments
Positive feedback to the cathode of the first tube? Increases gain and THD. I've seen that before but I can't figure out what it's good for.
Hi,
IMHO we just have to accept that everything has some sonic fingerprint.
At the end of the day you chose what suits you best.
Personally I try to strive for as much neutrality/fidelity as possible otherwise you just end up tuning to your own taste and system running around in circles.
IOW, do as you please but don't drive yourself nuts doing it.
That said, I have no idea whether the same type of rectifier, one of US origin the other of USSR origin would sound different. I guess probably they would as they'd likely use different materials and different construction methods.
That doesn't mean one would be better than the other but in the context of a means of fine tuning, yes you could hear it but as said above that kind of tuning could also drive you raving mad.
Again, in my experience there always is a good reason why something sounds different from something else that seems the same but isn't quite so in reality.
Having listening experience allows you to pick valves or caps or whatever with the least distortion (I know I can most of the time).
Having measuring experience (and understanding of what and of how to measure) is not only much faster it is also much more reliable.
As for the circuit posted, don't see what you could do with it in the context of your preamp in all honesty.
It's never a good idea to lift a piece of circuitry from a complete design such as an amplifier and try to use it out of its native context unless you really understand what it was doing there in the first place.
There must be at least a billion ways to design a line preamp. I think opting for an SRPP in this application is just fine as it check most of the boxes.
Sure, you can always try to squeeze the last ounce of performance out of it.
Just don't ask me to do it or you'll end up with a preamp containing a zillion valves occupying at least three times the current real estate of the Yaqin.
With a bit of luck it may be 10 to 15% "better" and then some....
Should you get bored (and we all know you will) we could always try and see what could be done to keep you busy.....
It's good to see you want to learn and try things but IMHO you should not be too hasty in changing things all the time. Allow the circuit to burn in, allow yourself to get to know it properly, then you can make sound decisions.
Just my opinion though.
Ciao,
IMHO we just have to accept that everything has some sonic fingerprint.
At the end of the day you chose what suits you best.
Personally I try to strive for as much neutrality/fidelity as possible otherwise you just end up tuning to your own taste and system running around in circles.
IOW, do as you please but don't drive yourself nuts doing it.
That said, I have no idea whether the same type of rectifier, one of US origin the other of USSR origin would sound different. I guess probably they would as they'd likely use different materials and different construction methods.
That doesn't mean one would be better than the other but in the context of a means of fine tuning, yes you could hear it but as said above that kind of tuning could also drive you raving mad.
Again, in my experience there always is a good reason why something sounds different from something else that seems the same but isn't quite so in reality.
Having listening experience allows you to pick valves or caps or whatever with the least distortion (I know I can most of the time).
Having measuring experience (and understanding of what and of how to measure) is not only much faster it is also much more reliable.
As for the circuit posted, don't see what you could do with it in the context of your preamp in all honesty.
It's never a good idea to lift a piece of circuitry from a complete design such as an amplifier and try to use it out of its native context unless you really understand what it was doing there in the first place.
There must be at least a billion ways to design a line preamp. I think opting for an SRPP in this application is just fine as it check most of the boxes.
Sure, you can always try to squeeze the last ounce of performance out of it.
Just don't ask me to do it or you'll end up with a preamp containing a zillion valves occupying at least three times the current real estate of the Yaqin.
With a bit of luck it may be 10 to 15% "better" and then some....
Should you get bored (and we all know you will) we could always try and see what could be done to keep you busy.....
It's good to see you want to learn and try things but IMHO you should not be too hasty in changing things all the time. Allow the circuit to burn in, allow yourself to get to know it properly, then you can make sound decisions.
Just my opinion though.
Ciao,
I won't be unkind with you, but after two month and more than 500 post, you must think to open a new thread, "My second preamp with tubes" perhaps?
As has been said - if you have designed and built your preamp correctly you will not be able to tell that its a valve design because you will have vanishingly small distortion. You would have to break the design to change this. I have three preamps - two of similar designs based on the Super Linear cathode follower and one based on a transformer coupled LTP. They all sound almost identical. I can tell the difference if I switch between the SLCF designs - for a minute or two and then the difference fades into the background. I will not be making any more line preamps - because there is no where to go, and chasing the last 10% improvement is futile and very very expensive.
Congratulate yourself of a job well done and having got it right first time. Your've probably saved yourself the effort of 5 years of trying to get that last 10% and suddenly realising that when you compared your latest offering to your first - they sound almost the same.
The only really big improvement I think you will get is if you upgrade your volume pot to a better quality stepped attenuator. I use wire wound pots in all my preamps and the step up was significant over Alps Blue Velvet. Not to everyones taste since they are linear tapper.
Shoog
Congratulate yourself of a job well done and having got it right first time. Your've probably saved yourself the effort of 5 years of trying to get that last 10% and suddenly realising that when you compared your latest offering to your first - they sound almost the same.
The only really big improvement I think you will get is if you upgrade your volume pot to a better quality stepped attenuator. I use wire wound pots in all my preamps and the step up was significant over Alps Blue Velvet. Not to everyones taste since they are linear tapper.
Shoog
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