Its also better to connect the ultrapath capacitor direct to the filament of the tube and not after your 50ohm resistors.
When you really want a better sound think about use of Rod Coleman Filament regulators for the 45. This is really a improvement over AC heating. I also use this regulators to heater- bias my C3o IDHT driver and get rid of the cathode capacitor.
When you really want a better sound think about use of Rod Coleman Filament regulators for the 45. This is really a improvement over AC heating. I also use this regulators to heater- bias my C3o IDHT driver and get rid of the cathode capacitor.
Cagomat,
Any C3 tube type in Triode Wired mode should be able to drive any quality 5k Ohm 1:1 interstage transformer.
But any C3 tube type in Pentode wired mode, will not drive a 5k Ohm 1:1 interstage, unless you want two things:
Midrange frequencies only
Very bad looking square-waves
Now, you are correct, a C3 in Pentode mode as a driver can work very well, but only if . . .
1. You increase the B+ to the C3 circuit so that you can either use a plate load resistor, or so you can use a solid state current source plate load.
2. Then take out the interstage transformer, and use RC coupling from the C3 plate to the output tube grid.
Just my opinions.
Any C3 tube type in Triode Wired mode should be able to drive any quality 5k Ohm 1:1 interstage transformer.
But any C3 tube type in Pentode wired mode, will not drive a 5k Ohm 1:1 interstage, unless you want two things:
Midrange frequencies only
Very bad looking square-waves
Now, you are correct, a C3 in Pentode mode as a driver can work very well, but only if . . .
1. You increase the B+ to the C3 circuit so that you can either use a plate load resistor, or so you can use a solid state current source plate load.
2. Then take out the interstage transformer, and use RC coupling from the C3 plate to the output tube grid.
Just my opinions.
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I have looked at the anode curves of the EML45 b. The operating point of the tube is totally off. At this anode voltage you need a cathode resistor of 1800 Ohm which results in an anode current of 45mA.
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Sure RC coupling 🙂, I have tested the whole C3 family as driver tubes and found that they are not better than a 6SN7 when operated as triode. But as a pentode they sound outstanding. This is only surpassed by a DHT as a driver.
banpuku,
1. Your amplifier, like all amplifiers, has some 2nd harmonic and some 3rd harmonic distortion.
Your speakers look to be very good, but like all speakers, they have some 2nd and 3rd harmonic distortion.
So . . . Try changing the polarity connection from amp+ to speaker+, and speaker- to amp common;
to amp Common to speaker+, and amp- to speker+.
Doing that will change the System of the amplifier and speakers Total 2nd Harmonic distortion to be either less, or more; since they will partially cancel or add.
2. You may find that your very open non-directional woofer/mid driver might benefit from the near field experience, and that would give less reflected/delayed sound.
3. If you have a CD player, try
Reference Recordings RR-79CD Pictures at an Exhibition Eiji Oue
Channel Classics CCS 4392 Birds, Beasts, and Battles Monica
Harmonic Mundi HMU907212 !Jacaras! Spanish Baroque Guitar (and castanets and percussive dancing shoes).
Happy listening!
1. Your amplifier, like all amplifiers, has some 2nd harmonic and some 3rd harmonic distortion.
Your speakers look to be very good, but like all speakers, they have some 2nd and 3rd harmonic distortion.
So . . . Try changing the polarity connection from amp+ to speaker+, and speaker- to amp common;
to amp Common to speaker+, and amp- to speker+.
Doing that will change the System of the amplifier and speakers Total 2nd Harmonic distortion to be either less, or more; since they will partially cancel or add.
2. You may find that your very open non-directional woofer/mid driver might benefit from the near field experience, and that would give less reflected/delayed sound.
3. If you have a CD player, try
Reference Recordings RR-79CD Pictures at an Exhibition Eiji Oue
Channel Classics CCS 4392 Birds, Beasts, and Battles Monica
Harmonic Mundi HMU907212 !Jacaras! Spanish Baroque Guitar (and castanets and percussive dancing shoes).
Happy listening!
OK, several experiment results to report back:
1. Changed the C3g cathode bypass cap from Jupiter to Russian KY PIO. Very much like the Russian PIO. Better tonality, detail and dynamics. Keeping the Russian in this spot until further notice.
2. Tried 100H choke between B+ and 45B cathode bypass ultra-path cap. Terrible sounding. congested, no bass, limited dynamics. Removed immediately.
3. Tried 100H choke between Interstage Tranny and C3g plate. Terrible terrible terrible sounding. Super congested, no bass, limited dynamics, opagque. Removed immediately.
4. Replaced 45B grid bias resistor to 1.5K from 1.K. Huge improvement. (thanks Cagomat). Very transparent, much improved dynamics. Great micro detail and tonality. 1.5K seems to create a great opearting point for the 45B. I may try 1.8K and report back.
5. 6A3sUMMER - great classical music selections, especially the Jacaras and Birds/Beasts. Here are a few of my recent favorites. Please note, I listen to late 20th and 21st century chamber and solo music. Eastern European to be more specific. Here are some nice examples:
Saunders: Fury for Double Bass Solo
In alto: Laura Menegozzo
Also, see attached snapshot of my "5 out of 5" stars list.
1. Changed the C3g cathode bypass cap from Jupiter to Russian KY PIO. Very much like the Russian PIO. Better tonality, detail and dynamics. Keeping the Russian in this spot until further notice.
2. Tried 100H choke between B+ and 45B cathode bypass ultra-path cap. Terrible sounding. congested, no bass, limited dynamics. Removed immediately.
3. Tried 100H choke between Interstage Tranny and C3g plate. Terrible terrible terrible sounding. Super congested, no bass, limited dynamics, opagque. Removed immediately.
4. Replaced 45B grid bias resistor to 1.5K from 1.K. Huge improvement. (thanks Cagomat). Very transparent, much improved dynamics. Great micro detail and tonality. 1.5K seems to create a great opearting point for the 45B. I may try 1.8K and report back.
5. 6A3sUMMER - great classical music selections, especially the Jacaras and Birds/Beasts. Here are a few of my recent favorites. Please note, I listen to late 20th and 21st century chamber and solo music. Eastern European to be more specific. Here are some nice examples:
Saunders: Fury for Double Bass Solo
In alto: Laura Menegozzo
Also, see attached snapshot of my "5 out of 5" stars list.
Attachments
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Hello Banpuku
Nice to hear that it's working better,😀 I noticed that the cathode capacitor of the C3g is much too small (30uF). According to my calculation, you should use at least 220uF. Otherwise you lose too much gain and bass. I can recommend Audio Note Kaisei (Partsconnexion) or Black Gate N or Nx. It's definitely better than Wima. 220uF 25Vdc KAISEI Polarized, Radial, Audio Note Electrolytic Capacitor
Nice to hear that it's working better,😀 I noticed that the cathode capacitor of the C3g is much too small (30uF). According to my calculation, you should use at least 220uF. Otherwise you lose too much gain and bass. I can recommend Audio Note Kaisei (Partsconnexion) or Black Gate N or Nx. It's definitely better than Wima. 220uF 25Vdc KAISEI Polarized, Radial, Audio Note Electrolytic Capacitor
Another point is that you still have 85mV ripple in the DC voltage for the 45b tube. This is too much, as you are coupling this into the cathode using Ultrapath. If you increase the Wima capacitor in the first LC circuit from 5 to 100uF, you only get 4mV ripple, which is much better.
Sorry I made a mistake, you have 165mV of ripple, and when you change both LC capacitors to 100uF you get 4mV. In my amplifier I have 50uV in B+ I use also ultrapath on the power tube (EML 20b)
Cagomat - thanks for the info. I have Rod's filament supplies and Raw CD supplies, so I think I will go this route over the next couple of days. In your experience, what kind of sonic changes / improvements have you heard using Rod's filament supplies vs. AC on the EML tubes?
Meanwhile, my LCLC power supply uses 10uF and 50uF caps. I can go with 50uF and 50uF without having to purchase any new caps. What do your ripple calculations show for 50uF and 50uF?
Finally, please comment on your experience with different kinds of EML tubes. I only have the 45B and was considering the 20B or 30A tube. Also, any special DHTs that you like for drivers? I was looking at the Aa, Ba and Ca tubes from Valvo and Telefunken. Lower mu compared to the C3g, but DHT driving DHT is something I would like to move toward.
Meanwhile, my LCLC power supply uses 10uF and 50uF caps. I can go with 50uF and 50uF without having to purchase any new caps. What do your ripple calculations show for 50uF and 50uF?
Finally, please comment on your experience with different kinds of EML tubes. I only have the 45B and was considering the 20B or 30A tube. Also, any special DHTs that you like for drivers? I was looking at the Aa, Ba and Ca tubes from Valvo and Telefunken. Lower mu compared to the C3g, but DHT driving DHT is something I would like to move toward.
I thought the C3g cathode bypass cap was a Wima DC Link?
You wouldn't use a plate choke AND an interstage - one or the other. Either the 100H plate choke plus FT-2 or FT-3 coupling cap, or just the primary of the Slagle interstage, leaving the secondary unconnected. But what are these gapped for? Whatever plate choke you use needs to be gapped for the current going through the driver tube.
The C3g cathode cap is a 30uF Wima DC Link. Then, I bypass it with a 0.47uF Russian KY PIO which is magical.
I have completely removed the 100H. The Slagle IT is made specifically for this circuit. The 100H were spare parts that I was trying to see if it would help within my amp. The 100H chokes were not made specifically for this amp.
Andy, what kind of bias topology do you use on your output tubes?
I have completely removed the 100H. The Slagle IT is made specifically for this circuit. The 100H were spare parts that I was trying to see if it would help within my amp. The 100H chokes were not made specifically for this amp.
Andy, what kind of bias topology do you use on your output tubes?
OK. I may try bypassing my DC Links. My 300b are simply in self bias with a 40uF DC Link cap. Larger DC Link caps get expensive, so I don't plan on making the caps bigger.
With 50u + 50u you get 35mA of ripple witch is too much for ultrapath. Your output tube is perfect, its better than 20b. I will go in the next time for the 12b. 20b or better 20AM meshplate are really great drivers but when your Linestage have enough gain, I would use a VT25. I love the sound of this tube.
Rod Coleman vs AC is much finer, with improved microdynamic and a dark black background. Important is to change R1 and C3 of the regulator. It improves the sound further
Cagomat - please share more thoughts regarding the RS241 as a driver. My b+ is 400V so it might work nicely without having to use a RC network to reduce the voltage. Would the RS241 work well with my existing 5K interstage transformer? Would it be able to fully drive the 45B? Any input would be appreciated.
The RS241 have Mu of 17 so you need 3V input from your Linestage for full power and yes it will work with your interstage transformer. But the availibility of the tube is a problem. Its really rare in good condition. The 20b from EML is infact a reconstruction of the RS241 and its avalible.