Hi, here is a description of my tube line stage, it is a SRPP dual mono design, using 6922's. I think its quite radical in some aspects but see for yourself (this is a 200k pdf file hosted on a fileserver)....
http://www.badongo.com/file/5263908
hope you like it! any feedback is welcome....
http://www.badongo.com/file/5263908
hope you like it! any feedback is welcome....
hesener said:
Sorry cannot read it; I get something called "BADONGO" all in French...
An externally hosted image should be here but it was not working when we last tested it.
7N7
Re: file download
Well, mine was in French, and despite my French name, and the fact I have lived here for two-and-a-half years, my French is rubbish - impossible language - but I'll have another go
It's a case of courage I think
7N7
hesener said:
Well, mine was in French, and despite my French name, and the fact I have lived here for two-and-a-half years, my French is rubbish - impossible language - but I'll have another go
It's a case of courage I think
An externally hosted image should be here but it was not working when we last tested it.
7N7
Now I get this:
* NOUVEAU * Recevez des points premium avec vos fichiers! * NOUVEAU *
Vue synoptique des fonctionnalités
Doesn't look like a line stage to me...
7N7
* NOUVEAU * Recevez des points premium avec vos fichiers! * NOUVEAU *
Vue synoptique des fonctionnalités
Doesn't look like a line stage to me...
An externally hosted image should be here but it was not working when we last tested it.
7N7
here is another link for downloading the pdf
http://www.filehosting.at/files/download.php?file=15f389314bf049a0ad6fb32441883b05
should work easier..... if this doesnt work email me and I will send the file
sorry for the confusion...
http://www.filehosting.at/files/download.php?file=15f389314bf049a0ad6fb32441883b05
should work easier..... if this doesnt work email me and I will send the file
sorry for the confusion...
Sure I have never seen individual SRPP's in parallel: when I saw the picture I thought: ECC88's triodes in parallel, and then in an SRPP. Does CJ also parallel individual stages?
Do you think it is necessary to have this large amount of paralleled stages? There have been quite some discussion on microdetails being lost due to parallel operation of tubes. Have you, by chance, tested (compared) the performance of a single stage versus the four paralleled stage's? I imagine that the output impedance of a single stage (including the step down trafo) will still be low enough to drive a power amp?!
BTW. the construction seems to amazingly well done (pictures are a bit small, but still)!
Have a nice time listening to it!!
Erik
Do you think it is necessary to have this large amount of paralleled stages? There have been quite some discussion on microdetails being lost due to parallel operation of tubes. Have you, by chance, tested (compared) the performance of a single stage versus the four paralleled stage's? I imagine that the output impedance of a single stage (including the step down trafo) will still be low enough to drive a power amp?!
BTW. the construction seems to amazingly well done (pictures are a bit small, but still)!
Have a nice time listening to it!!
Erik
Yes, beautifully made.
SRPP will certainlly drive anything, so for a line stage they would work well and easily drive the capacitance of cables.
I wonder though why so much gain is required (E88CC, µ = about 30).
I suppose I would have opted for a diff pair with cathode followers, but that's me! For example I posted a picture and a few details here
7N7
SRPP will certainlly drive anything, so for a line stage they would work well and easily drive the capacitance of cables.
I wonder though why so much gain is required (E88CC, µ = about 30).
I suppose I would have opted for a diff pair with cathode followers, but that's me! For example I posted a picture and a few details here
7N7
thanks everybody for the comments.
I did not try an individual stage, guess there are quite a few SRPP preamps (single stage) out there, and if they drive a tube power amp with high input impedance, located closely to the line stage, that should not limit bandwidth I think. In my case, two meters of shielded cables and an input impedance of 10k...
Chose the 6922 primarily for its linearity (and because CJ chose it, I admit) and with the 4:1 stepdown at the output I can get around 10V unclipped which is a good value, I think, enough headroom. I did try without, and the sound had an "edge", sounded slightly brighter and more forward. I did not measure but I think this comes down to the lower load impedance, causing more distortion with the load line being more inclined so you get closer to the non-linear portions of the output curves.
In the ACT preamp, CJ does parallel quite a few 6922's, and they use one common anode resistor and two diodes (!) in the cathode to create the grid bias. It is just a triode stage, even less feedback than in the SRPP case. same amount of capacitors though. The diodes mean you are folding an exponential characteristic into the square characteristic of the tubes, and if done correctly it eliminates the third harmonics, making it sound even nicer.....
I did not try an individual stage, guess there are quite a few SRPP preamps (single stage) out there, and if they drive a tube power amp with high input impedance, located closely to the line stage, that should not limit bandwidth I think. In my case, two meters of shielded cables and an input impedance of 10k...
Chose the 6922 primarily for its linearity (and because CJ chose it, I admit) and with the 4:1 stepdown at the output I can get around 10V unclipped which is a good value, I think, enough headroom. I did try without, and the sound had an "edge", sounded slightly brighter and more forward. I did not measure but I think this comes down to the lower load impedance, causing more distortion with the load line being more inclined so you get closer to the non-linear portions of the output curves.
In the ACT preamp, CJ does parallel quite a few 6922's, and they use one common anode resistor and two diodes (!) in the cathode to create the grid bias. It is just a triode stage, even less feedback than in the SRPP case. same amount of capacitors though. The diodes mean you are folding an exponential characteristic into the square characteristic of the tubes, and if done correctly it eliminates the third harmonics, making it sound even nicer.....
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.