Last week i have make me the headphone PCB. And today i assembled the board with the parts i already got. I still waiting for some parts. But here a preview of the board.
An externally hosted image should be here but it was not working when we last tested it.
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For the headphone amp i have created a new thread.
http://www.diyaudio.com/forums/tubes-valves/207587-6n16-headphone-amplifier.html
http://www.diyaudio.com/forums/tubes-valves/207587-6n16-headphone-amplifier.html
Ian, the SRPP has the lowest distorsion when driving a high impedance.( read Elektor Audio special part 5) Then you can not drive a highcurrent source. Therefore you need behind the SRPP a bufferstage of any kind. It is all about choices and what you like for sound. For me i learned over the years that i like no feedback designs, SE amps, and circuits with as less sand as possible.
Every tube circuit has it lowest distortion driving a high impedance. If you want low distortion then the SRPP topology is not your first choice; a regular CC stage would probably do better and your best bet would be a mu follower.
Cheers
Ian
You might try to find Merlin Blencowe's excellent article on SRPP (AudioXpress, May 2010). He showed (and I did some measurements of my own and confirmed) that there's an optimum load for the SRPP where distortion reaches a minimum. That load is surprisingly low.
A common cathode stage has lowest distortion into a high load, but this is NOT the case for SRPP.
SY, i just read the article. And it says all i know and confirm why i like the sound of the circuit.
Article: SRPP_Blencowe.pdf
Quote:
Whether or not the SRPP really is an SRPP depends on the load. If there is no load on the valve (e.g., it is DC coupled to another stage) then there is nowhere for current to go but straight through both valves, and so the stage is entirely single-ended, as in fig. 4a. This is not an SRPP but a common-cathode gain stage with an active load, and the maximum peak current flow is then equal to the quiescent current, as it always is with single ended operation. Such a circuit is obviously intended only for voltage gain, and is not widely used*.
So the first stage is a commoncathode stage with an active load. With operate single ended.
Article: SRPP_Blencowe.pdf
Quote:
Whether or not the SRPP really is an SRPP depends on the load. If there is no load on the valve (e.g., it is DC coupled to another stage) then there is nowhere for current to go but straight through both valves, and so the stage is entirely single-ended, as in fig. 4a. This is not an SRPP but a common-cathode gain stage with an active load, and the maximum peak current flow is then equal to the quiescent current, as it always is with single ended operation. Such a circuit is obviously intended only for voltage gain, and is not widely used*.
So the first stage is a commoncathode stage with an active load. With operate single ended.
Unfortunately that article contains a number of errors, but nevertheless it is true that an SRPP stage distortion varies with load. With no load you may choose to call it a CC with an active load but the active load is a poor one and the plate load is only about the top tube's cathode resistor multiplied by its mu and that is why the SRPP has a typically high distortion even with no load. As I said before a better active load is the mu follower which will produce significantly less distortion. And as I said before a straightforward CC stage operating into a CF will produce less distortion than an SRPP. So I ask again, what is the point of the SRPP stage?
Cheers
Ian
Ian,
when i compare the Cc - Cf with a SRPP of the same tube with the same components. I prefer the sound of the SRPP. But i can understand that another likes another kind of stage. Listening experience is for everybody different.
If higher distorsion would tell that the sound is bad, nobody would use tubes again. It is all about the tubes and components you use. And that is what i like about DIYaudio.
when i compare the Cc - Cf with a SRPP of the same tube with the same components. I prefer the sound of the SRPP. But i can understand that another likes another kind of stage. Listening experience is for everybody different.
If higher distorsion would tell that the sound is bad, nobody would use tubes again. It is all about the tubes and components you use. And that is what i like about DIYaudio.
Hi Koifarm!Now you have possible a point regarding the DC voltage.
But my experience with this kind of output decoppling in the last 40 years is that never a condensor is gone defect, but there is always a first time.
Maybe i do not have any problems because i use always a parallel capacitor on the two serie capacitors.
Output buffers of all cd players of a welknown brand.
This schematic buffers with tube 6n3 with which the anode voltage is supplied + B =?
I need a good schematics for tube buffer or cathode follower with tube 6n8s (6n7GT) for my CD-player, if you happen please to have send.
thank you!
Also sorry for the very late respons.
About the B+ for the shanling buffer, this is 200V.
Just a simple supply with rectifier bridge, 2 capacitors and 1 inductor.
Rubycon has a nice explanation of why one does not stack Aluminum Electrolytic capacitors as show. See Q2 at bottom of the page.
Product Information: Aluminum Electrolytic Capacitors FAQ/Capacitor, Power Supply Units RUBYCON CORPORATION
I expect that power cycles will over time degrade the lower cap (+ to ground). Even if it does not fail catastrophically, it will lose capacitance.
Product Information: Aluminum Electrolytic Capacitors FAQ/Capacitor, Power Supply Units RUBYCON CORPORATION
I expect that power cycles will over time degrade the lower cap (+ to ground). Even if it does not fail catastrophically, it will lose capacitance.
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