Re: MIDDLE OF THE ROAD.
Hi,
Uhhh, so EVIL even order distortion. Uh so EVIL Distortion. So very EVIL, even more EVIL than Kuei Yang Wang
DISTORTION is DISTORTION is DISTORTION is DISTORTION.
Evil distortion. All DISTORTION IS EVIL. ALL EVIL IS DISTORTION
The ear produces in it's mechanical system around 32% 2nd Harmonics DISTORTION at 94db SPL.
Evil Ear. EVIL DISTORTION EAR. Ear should not listen Music.
Must cut of ear for faithfull reproduction....
Why feel I suddenly compelled sunflowers to paint and strawhats to wear?
The absence of measurable simple distortion does not guarante subjectively neutral "sound" just as the presence of measurable distortion does not automatically lead to "colorations".
The world is one of many dimensions, experiences and nuances.
There is no "Black" or "White" is the real world. And light is the left hand of darkness.
End of sermon/brainfart.
Sayonara
Hi,
Uhhh, so EVIL even order distortion. Uh so EVIL Distortion. So very EVIL, even more EVIL than Kuei Yang Wang
DISTORTION is DISTORTION is DISTORTION is DISTORTION.
Evil distortion. All DISTORTION IS EVIL. ALL EVIL IS DISTORTION
The ear produces in it's mechanical system around 32% 2nd Harmonics DISTORTION at 94db SPL.
Evil Ear. EVIL DISTORTION EAR. Ear should not listen Music.
Must cut of ear for faithfull reproduction....
Why feel I suddenly compelled sunflowers to paint and strawhats to wear?
The absence of measurable simple distortion does not guarante subjectively neutral "sound" just as the presence of measurable distortion does not automatically lead to "colorations".
The world is one of many dimensions, experiences and nuances.
There is no "Black" or "White" is the real world. And light is the left hand of darkness.
End of sermon/brainfart.
Sayonara
Distortion, distortion, distortion
To paraphrase Gertrude Stein: distortion is distortion is distortion.
It is perfectly true that if we want low distortion - rreally low distortion, then we ahve a transistor amplifier, perhaps with loads of feedback. Ugh! Sounds cold.
On the other hand to mangle a metaphor, I do not want to listen to my music through rose-coloured spectacles.
This is what I have heard listening to 300Bs single-ended driving Lowthers etc. All very cosy but not what I want.
Must be my ears I suppose
7N7
To paraphrase Gertrude Stein: distortion is distortion is distortion.
It is perfectly true that if we want low distortion - rreally low distortion, then we ahve a transistor amplifier, perhaps with loads of feedback. Ugh! Sounds cold.
On the other hand to mangle a metaphor, I do not want to listen to my music through rose-coloured spectacles.
This is what I have heard listening to 300Bs single-ended driving Lowthers etc. All very cosy but not what I want.
Must be my ears I suppose
7N7
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Bringing this back up top...any comments on substituting the 6C45pi for the 6dj8 in Steve Bench's 12ay7/6dj8 cascode phono pre(other than slight changes in network values)? Would it be more prone to oscillation, etc.,...?
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http://members.aol.com/sbench101/Preamps/RIAA5.gif
hi,
I use the 417a, 5842 to drive my 45 tube SE amp.
I use 91ohm in the cathode resister.
I try from 150ohm to 47ohm.
91 ohm I feel the best.
the 6c45 driver 300B use 1:1 interstage I still testing.
Its is not easy to find a very high quality 1:1 interstage.
Good bankwidth, not more than 30ma. If more than 50ma the sound was quite rough.
Too low is very easy to core saturate & lack of bass.
thanks
Thomas
I use the 417a, 5842 to drive my 45 tube SE amp.
I use 91ohm in the cathode resister.
I try from 150ohm to 47ohm.
91 ohm I feel the best.
the 6c45 driver 300B use 1:1 interstage I still testing.
Its is not easy to find a very high quality 1:1 interstage.
Good bankwidth, not more than 30ma. If more than 50ma the sound was quite rough.
Too low is very easy to core saturate & lack of bass.
thanks
Thomas
The 6C45P is very prone to escillation indeed. But if handled with proper care it won't be a problem. Be sure to use grid AND kathode stoppers as close to the tube as possible. Keep all the leads very short. This will solve all the oscillation problems. If this doesn't help enough then shield half of the tube with copper foil and connect it to earth. Do not shield the whole tube, it has to dissipate heat, shielding half the tube was good enough for me.
I have used some very thin copper foil (0.01mm) and wrapped it around the tube. This is held in place by a piece of silverwire wrapped around it ande twisted on the ends. This wire was connected to earth.
By Cathode stoppers I mean that the 6C45P has four legs on the tube wich are all connected to the cathode. Use all four of them and solder a small resistor of 10 to 22 Ohms directly on them, as close as possible. These four resistor come together at the other end.
Don't worry about the effect of negative feedback that you create with this unbypassed cathode resistor. They are all in parallel, so four times 22 ohms is only 5.5 Ohms. That won't do much with feedback.
All of this sounds if the 6C45 is a horrible tube. It isn't, it just takes a few precautions and then it's as quiet as a good tube can be. I've had more problems to get an ECC88 in SRRP silent.
By Cathode stoppers I mean that the 6C45P has four legs on the tube wich are all connected to the cathode. Use all four of them and solder a small resistor of 10 to 22 Ohms directly on them, as close as possible. These four resistor come together at the other end.
Don't worry about the effect of negative feedback that you create with this unbypassed cathode resistor. They are all in parallel, so four times 22 ohms is only 5.5 Ohms. That won't do much with feedback.
All of this sounds if the 6C45 is a horrible tube. It isn't, it just takes a few precautions and then it's as quiet as a good tube can be. I've had more problems to get an ECC88 in SRRP silent.
RE:CATHODE STOPPERS.
Hi,
All these pins are already internally connected from what I see on the basing diagram.
Again, sorry, but I fail to see how these resistors are going to change anything.
Pin #4 and #5 are the most remote from the cathode proper, wouldn't it then make more sense to divide the calculated value for the cathode R in two and use these two resistors there?
I must say I'm not familiar with that particular tube so forgive me if I have the wrong of the stick here.
Cheers,
Hi,
All these pins are already internally connected from what I see on the basing diagram.
Again, sorry, but I fail to see how these resistors are going to change anything.
Pin #4 and #5 are the most remote from the cathode proper, wouldn't it then make more sense to divide the calculated value for the cathode R in two and use these two resistors there?
I must say I'm not familiar with that particular tube so forgive me if I have the wrong of the stick here.
Cheers,
I've experimented with 6C45, and found that it will oscillate.
If you use it as a cathode follower, it needs good local decoupling of the HT, plus grid-stoppers. A 200R cathode-stopper was also needed when I applied 2n capacitive load. (Same principle as adding a series resistor at the output of op-amp cable drivers.) I've never seen the point of connected to all grid, or cathode, pins. They are there to allow good RF layout in any design.
As the upper valve of a mu-follower, it gave far less trouble.
If you use it as a cathode follower, it needs good local decoupling of the HT, plus grid-stoppers. A 200R cathode-stopper was also needed when I applied 2n capacitive load. (Same principle as adding a series resistor at the output of op-amp cable drivers.) I've never seen the point of connected to all grid, or cathode, pins. They are there to allow good RF layout in any design.
As the upper valve of a mu-follower, it gave far less trouble.
Hi Frank,
I have found the same as Sjef with this little beastie. You must connect small cathode stoppers to all the cathode lugs or cut then off right against the base. They act as small LC stubs and set off the parasitic oscillations of the tube... This thing is a little rocket but can be tamed by standard good rf practice so I use grid stoppers and anode stoppers. I haven't needed ferrite beads yet or to shield the tube itself...but I stand ready too! Once that is done it is a great little tube and (to my taste) goes really well driving a 2A3 etc.
ciao
James
I have found the same as Sjef with this little beastie. You must connect small cathode stoppers to all the cathode lugs or cut then off right against the base. They act as small LC stubs and set off the parasitic oscillations of the tube... This thing is a little rocket but can be tamed by standard good rf practice so I use grid stoppers and anode stoppers. I haven't needed ferrite beads yet or to shield the tube itself...but I stand ready too! Once that is done it is a great little tube and (to my taste) goes really well driving a 2A3 etc.
ciao
James
By using all the grid and cathode connections you wil decrease the inductance lead to the grid/cathode. This inductance while very small makes an oscillation circuit with the parasitic capacitance of the tube, so keep it resistive instead of inductive. Remember that the tube tends to oscillate at MHz frequencies, not at audio frequencies. I don't if the inductance plays a big role here, but when you don't use all the gride/cathode pins they will make brilliant antennas with these frequencies.
You can see the cathode of the tube as it's second input. If you use a cathode resistor bypassed with a capacitor you create an almost zero Ohm lead to the Cathode via this capacitor. That's why adding an unbypassed small value resistor helps here. It doesn't degrade the sound, it doesn't cost anything (well some resistors), it's very easy to apply and it did help for me, so I don't see the problem here.
You can see the cathode of the tube as it's second input. If you use a cathode resistor bypassed with a capacitor you create an almost zero Ohm lead to the Cathode via this capacitor. That's why adding an unbypassed small value resistor helps here. It doesn't degrade the sound, it doesn't cost anything (well some resistors), it's very easy to apply and it did help for me, so I don't see the problem here.
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