Hi!
I am not an expert in DIY, but have just modified a DIY amp to use 6N7GT(RCA/GEC) as input/driver and 300B(WE/GDmp) as ouput.
The amp itself are pretty heavy with a big outbord power supply.
Since I do not have a lot of knowledge on this subject I wondered if anyone could help me a little choosing the right voltages (and cap/resistors to get this).
I do have 100db+ speakers so I do not nead high gain.
Here are the schematic.
I am not an expert in DIY, but have just modified a DIY amp to use 6N7GT(RCA/GEC) as input/driver and 300B(WE/GDmp) as ouput.
The amp itself are pretty heavy with a big outbord power supply.
Since I do not have a lot of knowledge on this subject I wondered if anyone could help me a little choosing the right voltages (and cap/resistors to get this).
I do have 100db+ speakers so I do not nead high gain.
Here are the schematic.
An externally hosted image should be here but it was not working when we last tested it.
Hi,
You really have some odd values for the PS caps there....
91K Rin? Why not 100K and a 1K gridstopper iso 91K and 100R.
If you MUST use a 6SN7 in // then at least use separate cathode Rs for better current sharing between both sections of the valve.
So, 2 * 1K3 individually bypassed.
Why two 5U4s in /// A single one should do if the powerxformer can supply the voltage you need.
Cheers,
You really have some odd values for the PS caps there....
91K Rin? Why not 100K and a 1K gridstopper iso 91K and 100R.
If you MUST use a 6SN7 in // then at least use separate cathode Rs for better current sharing between both sections of the valve.
So, 2 * 1K3 individually bypassed.
Why two 5U4s in /// A single one should do if the powerxformer can supply the voltage you need.
Cheers,
6N7 != 6SN7
Plate voltage on the driver needs to be *much* lower. Closer to 120-150V. Decrease Rk or increase Rp...whatever keeps it in the linear range.
6N7 isn't really good for anything IMO because it has such low pervenace. 6SN7 is much better for a driver and probably more common. Given how much gain you need for this I'd suggest something resembling a 6DJ8. Maybe a 6SL7, although some people complain about slew rate or some crap like that. 6DJ8 really is perfect because it has the current capacity, but I can't think of anything octal that resembles it.
Tim
Plate voltage on the driver needs to be *much* lower. Closer to 120-150V. Decrease Rk or increase Rp...whatever keeps it in the linear range.
6N7 isn't really good for anything IMO because it has such low pervenace. 6SN7 is much better for a driver and probably more common. Given how much gain you need for this I'd suggest something resembling a 6DJ8. Maybe a 6SL7, although some people complain about slew rate or some crap like that.
6DJ8 really is perfect because it has the current capacity, but I can't think of anything octal that resembles it.Tim
Thanks!
I do have to admit that I got a advice from someone else to DECREASE the Rp???
I also have a Heart Beat 300SE amp which use paralell-coupled 6SL7 insteed og 6N7 and that use 235V on the plate, but also have higher B+. Does the B+ voltage for the 300B be taken into account when deciding the operating points of the 6N7?
Hope you are wrong
As I told you I also have a Heart Beat that uses paralell-coupled 6SL7's as input/driver and think that amp sounds nice6SN7 is much better for a driver and probably more common. Given how much gain you need for this I'd suggest something resembling a 6DJ8. Maybe a 6SL7, although some people complain about slew rate or some crap like that.
Exept for a little less gain I do not understand that the 6N7 should be so much worse and a 6SN7 got ever less gain.
Please explain.
Thanks
Hi Torfinn,
Welcome at DIYAUDIO!
If you want you can delete your double post by clicking on the edit button and then go to the delete checkbox and click on the delete button on the right...
Regards,
Bas
Ps...I did not know Rp meant plate resistor...I thought Rp was the plate resistance of the tube itself...I thought that getting a tube with a Lower Rp would be better....I am confused now..
Hopefully someone can clear this up for me.
Welcome at DIYAUDIO!
If you want you can delete your double post by clicking on the edit button and then go to the delete checkbox and click on the delete button on the right...
Regards,
Bas
Ps...I did not know Rp meant plate resistor...I thought Rp was the plate resistance of the tube itself...I thought that getting a tube with a Lower Rp would be better....I am confused now..
Hopefully someone can clear this up for me.
Thanks Bas!
Nice to be here
I suppose that it is me that has misunderstood the Rp question.
Regarding the use of the 6N7 I really gonna try it
And since as far as I can see the 6N7 has lower plate resistance than a parell coupled 6SL7 as used in the Heart (and as I like) I really can't understand why this not gonna work.
And since I like the Heart so much maybe I should try to use the same operating points as the Heart does, or?
Can I just copy the values from the Heart or is the 6N7 way different from the 6SL7 so I have to use total different resistors?
Nice to be here
I suppose that it is me that has misunderstood the Rp question.
Regarding the use of the 6N7 I really gonna try it
And since as far as I can see the 6N7 has lower plate resistance than a parell coupled 6SL7 as used in the Heart (and as I like) I really can't understand why this not gonna work.
And since I like the Heart so much maybe I should try to use the same operating points as the Heart does, or?
Can I just copy the values from the Heart or is the 6N7 way different from the 6SL7 so I have to use total different resistors?
An externally hosted image should be here but it was not working when we last tested it.
Maybe I have made myself unclear again.
The 6N7 has just one cathode.
The 6SL7 shown in the Heart schematics do have two seperate cathodes and also have seperate cathode resistors. It was just something I did not change in the schematic (I just modified the 6N7 schematic).
Was it this you meant?
The 6N7 has just one cathode.
The 6SL7 shown in the Heart schematics do have two seperate cathodes and also have seperate cathode resistors. It was just something I did not change in the schematic (I just modified the 6N7 schematic).
Was it this you meant?
What is CCS ?
Interesting design and I have also been thinking about using the 6C45PI as well as 417A (as I have laying around), but because I have been told that both the 417A and the 6C45PI could sound a little clinical and too much "hifi" I starts with the 6N7 which someone tells are a sweeter sounding tube.
What about yours?
Does it sound light, dark, mudled, bright, soft, hard, open, closed in or what do you think of it?
Maybe your use of carbon resistor makes it less hifi sounding?
Very easy to try another thow when we have just a tw0 tube design and in my amp there is also socket's for both 6N7 types and 417A types input/driver tubes.
And I also have Mundort Supreme, Mundort silver in oil and Jupiter caps to try as coupling caps.
Interesting design and I have also been thinking about using the 6C45PI as well as 417A (as I have laying around), but because I have been told that both the 417A and the 6C45PI could sound a little clinical and too much "hifi" I starts with the 6N7 which someone tells are a sweeter sounding tube.
What about yours?
Does it sound light, dark, mudled, bright, soft, hard, open, closed in or what do you think of it?
Maybe your use of carbon resistor makes it less hifi sounding?
Very easy to try another thow when we have just a tw0 tube design and in my amp there is also socket's for both 6N7 types and 417A types input/driver tubes.
And I also have Mundort Supreme, Mundort silver in oil and Jupiter caps to try as coupling caps.
6N7
The 6N7gt was developed as a driver/o/p bottle just for audio use, from what I can gather, while many other valves that have a great following were developed as general purpose or even as voltage regulators, so the 6N7gt should sound great, so long as its used within spec.--This is my choice for my No-2, all Octal OTL!
The 6N7gt was developed as a driver/o/p bottle just for audio use, from what I can gather, while many other valves that have a great following were developed as general purpose or even as voltage regulators, so the 6N7gt should sound great, so long as its used within spec.--This is my choice for my No-2, all Octal OTL!
CCS
A CCS is a constant current source.
There is one in my schematic connected to the plate of the 6C45PI.
Other places to read more about CCS.
http://home.zonnet.nl/horneman/mosfet.htm
http://www.pacifier.com/~gpimm/
I am quite pleased with the CCS that is on the schematic above.
The 6C45PI is very quiet, I would call it very open and detailed, like someone took a pillow off the front of the speakers. The only problem is 6C45PI tend to oscillate, if you use them for a gain stage be sure to tie all grid leads back through resistors and the same for the cathode leads(see schematic). I have had better luck with Reflektor 6C45PI tubes than with Sovtek 6C45PI tubes.
The best thing is for you to go for the sound you are looking for, don't be afraid to experiment. If it sounds good to you and the parts are run within thier operating parameters, then there is no need to change it. The carbon comp resistors have no magnetic conductors or end caps, which to me seems to effect sound more than what the resistor is actually made of.
A CCS is a constant current source.
There is one in my schematic connected to the plate of the 6C45PI.
Other places to read more about CCS.
http://home.zonnet.nl/horneman/mosfet.htm
http://www.pacifier.com/~gpimm/
I am quite pleased with the CCS that is on the schematic above.
The 6C45PI is very quiet, I would call it very open and detailed, like someone took a pillow off the front of the speakers. The only problem is 6C45PI tend to oscillate, if you use them for a gain stage be sure to tie all grid leads back through resistors and the same for the cathode leads(see schematic). I have had better luck with Reflektor 6C45PI tubes than with Sovtek 6C45PI tubes.
The best thing is for you to go for the sound you are looking for, don't be afraid to experiment. If it sounds good to you and the parts are run within thier operating parameters, then there is no need to change it. The carbon comp resistors have no magnetic conductors or end caps, which to me seems to effect sound more than what the resistor is actually made of.
Still working on my 6N7-300B amp.
It begins to sound nice, but I do get a to bright sound with more treble than I prefer.
Any suggestions on why?
It begins to sound nice, but I do get a to bright sound with more treble than I prefer.
Any suggestions on why?
An externally hosted image should be here but it was not working when we last tested it.
Sound a bit too bright
The sound may be a bit bright because of the passive components.
I use Mundorf Silver and oil caps, and carbon comp resistors and the balance seems just right.
My driver tube is a 6N45PI with a CCS and no bypass cap on the cathode, but otherwise our circuits are very similar.
The sound may be a bit bright because of the passive components.
I use Mundorf Silver and oil caps, and carbon comp resistors and the balance seems just right.
My driver tube is a 6N45PI with a CCS and no bypass cap on the cathode, but otherwise our circuits are very similar.
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