Hello!
Rumour has it that the circuit can use CCS for cathode follower.
How?
What about this one?
http://www.pmillett.com/current_source.htm
Thanks!
Rumour has it that the circuit can use CCS for cathode follower.
How?
What about this one?
http://www.pmillett.com/current_source.htm
Thanks!
Hi Tubenstein,
CCS circuit can be used for either plate load or cathode follower.
CCS circuit can be used for either plate load or cathode follower.
I found people talked about this phono circuit and which might not have enough gain for some cartridge. Therefore, would choke loaded or CCS loaded overcome this issue? I'm also wondering.
Can CCS or choke loaded a good idea for the plate load of this circuit? Well.....would it be too much gain??
Can CCS or choke loaded a good idea for the plate load of this circuit? Well.....would it be too much gain??
Sounds like plate choke cannot be used in the phono circuit, I know Tamura has made a step up transformer for MM cartridge.
Here what I found about current source for plate loading.
The seller of the CCS recommended :
"You could use a CCS on the plate of the first 12AX7 section, and also on the cathode of the 12AU7 cathode follower without disrupting anything. Not so clear on the second 12AX7 section - it may have some effect on the EQ. Probably not a huge change though?.......it would work there. The JFET version with low current is best for the 12AX7, since it only is running 1-2 mA typically."
http://www.pmillett.com/CCS.html
The seller of the CCS recommended :
"You could use a CCS on the plate of the first 12AX7 section, and also on the cathode of the 12AU7 cathode follower without disrupting anything. Not so clear on the second 12AX7 section - it may have some effect on the EQ. Probably not a huge change though?.......it would work there. The JFET version with low current is best for the 12AX7, since it only is running 1-2 mA typically."
http://www.pmillett.com/CCS.html
You can use a CCS in a cathode follower. It is done quite often and is often preferred because it has a much higher impedance than a resistor or a choke/inductor.
The catch is that you have to make sure you have extra voltage in order for the CCS to operate correctly. Lets say you want to swing +/- 10 volts on the output. This would mean that you are swinging from 0-20 volts. Your CCS might need as much as 5v to operate which means you need to swing from 25v-5v. That way your CCS always has 5v to operate correctly.
You can design a CCS that has a very low dropout voltage, or you can raise your voltage window, or both. Either way, it is something to keep in mind.
The catch is that you have to make sure you have extra voltage in order for the CCS to operate correctly. Lets say you want to swing +/- 10 volts on the output. This would mean that you are swinging from 0-20 volts. Your CCS might need as much as 5v to operate which means you need to swing from 25v-5v. That way your CCS always has 5v to operate correctly.
You can design a CCS that has a very low dropout voltage, or you can raise your voltage window, or both. Either way, it is something to keep in mind.
Sure. Treat it like a plate resistor that needs a few extra volts.
Your CCS will be in parallel with the impedance of the next stage. So if you are driving a stage with several hundred thousand ohms, then your load line will be very close to horizontal. If you are driving a stage with an input impedance of say 40K ohms, then that will dominate your load line.
Your CCS will be in parallel with the impedance of the next stage. So if you are driving a stage with several hundred thousand ohms, then your load line will be very close to horizontal. If you are driving a stage with an input impedance of say 40K ohms, then that will dominate your load line.
Tjj226,
If both plate load resistors (270K and 100K) can be replaced by CCS, what do you think about plate choke?
Plate choke sounds pretty good based on what I heard in the past.
I guess it might be a problem to use plate choke for both positions. What about CCS for the first stage ECC83 and plate choke for the second one?
Thanks 😊
If both plate load resistors (270K and 100K) can be replaced by CCS, what do you think about plate choke?
Plate choke sounds pretty good based on what I heard in the past.
I guess it might be a problem to use plate choke for both positions. What about CCS for the first stage ECC83 and plate choke for the second one?
Thanks 😊
Using plate choke in this device is funny.
Even second stage requires 800H choke!
BTW using plate choke in small signal stages is the nightmare, you can't usually eliminate the hum.
Use for both stage CCS...if you really want ... but designing CCS for few hundred uV isn't simple task, requires -for example- LND150 cascode CCS.
P. Millett use CCS for -at least- an order of magnitude bigger current.
Why do you want to replace (very large) anode resistors?
Even second stage requires 800H choke!
BTW using plate choke in small signal stages is the nightmare, you can't usually eliminate the hum.
Use for both stage CCS...if you really want ... but designing CCS for few hundred uV isn't simple task, requires -for example- LND150 cascode CCS.
P. Millett use CCS for -at least- an order of magnitude bigger current.
Why do you want to replace (very large) anode resistors?
This design has -about- 24dB gain.
As phono it's a few (at least 40dB recommended), as preamp to much ... and first stage terribly distorting at large/r/ input.