Hello everbody,
Do some of you members have any diy information on building a tube output buffer for a cd player?
Do some of you members have any diy information on building a tube output buffer for a cd player?
What are your requirements? If you want to increase the output level of your CD player, you might build a SRPP stage.
If you don't need more output level, a simple Cathode Follower stage would be a good choice.
The benefit of these two types of amplifier stages is their low output impedance, making the choice of audio cables less critical.
You might want to look at this website.
http://www.bonavolta.ch/hobby/en/audio/audioel.htm#Line preamps
If you don't need more output level, a simple Cathode Follower stage would be a good choice.
The benefit of these two types of amplifier stages is their low output impedance, making the choice of audio cables less critical.
You might want to look at this website.
http://www.bonavolta.ch/hobby/en/audio/audioel.htm#Line preamps
Frank Berry said:
Thanks Frank,
Thats a great link.
I want no gain so i think i'll go for the simple cathode follower.
ebijma said:
The specs say those tubes can run at 24V but higher is better. You might try 35V or even up to 70 or 80V.
Hi,
Exactly.
The cct shown by Ebijma was developped for a Gainclone amp where this bipolar supply was already available.
Upping B+/B- should noticeably improve dynamic range and linearity.
Another useful technique to improve on it is to stick a CCS on the tail end.
Various other buffer types exist so pick your poison...
Cheers,😉
Exactly.
The cct shown by Ebijma was developped for a Gainclone amp where this bipolar supply was already available.
Upping B+/B- should noticeably improve dynamic range and linearity.
Another useful technique to improve on it is to stick a CCS on the tail end.
Various other buffer types exist so pick your poison...
Cheers,😉
If you're looking for a low gain line section, I'd recommend Manfred Huber's "cheapskate's transformer coupled line preamp" over a cathode follower
Here is the schematic.
Here is the schematic.
fdegrove said:
There's another version of the buffer with a CCS, how's that?
An externally hosted image should be here but it was not working when we last tested it.
(from http://www.diyzone.net/diy/references/tube/6dj8buffer_2.htm)
Also, what modifications are required to run either of these circuits at say +/-35 or +/- 40V ?
/U.
Nisbeth, the circuit you posted is a simple self-biased cathode follower with an active load.
Not too sure what R1 is doing. If it is a grid stopper it should be as close to the grid as possible so the lead doesn't act as an antenna. I believe the 6DJ8 is known to self-oscillate, particularly used as a cathode follower... not certain on this though.
Since the output is capacitor coupled, a bipolar supply is not really needed... though it will work off one if you are going to install it into a SS amp and share the rails.
Not too sure what R1 is doing. If it is a grid stopper it should be as close to the grid as possible so the lead doesn't act as an antenna. I believe the 6DJ8 is known to self-oscillate, particularly used as a cathode follower... not certain on this though.
Since the output is capacitor coupled, a bipolar supply is not really needed... though it will work off one if you are going to install it into a SS amp and share the rails.
Active-Loaded Cathode Follower Buffer
I've drawn something with a 5687... (I happen to like this valve 🙂 ) and a single supply
It's probably over the top for its intended usage... and 200V is rather dangerous, and probably requires higher voltage rated components, especially in the power supply. But allowing more plate-cathode voltage lets the valve provide a greater swing, and avoids the murky area around 0V grid bias where you may or may not get grid current...
The LEDs in the schematic are for their voltage drop... I had something with Vf ~ 1.7V in mind when i drew it. The silicon diode is my attempt at temperature compensation... and the MJE340 may be happier with a small heatsink, as long as it is well insulated
For anyone reading this... don't go building this circuit unless you have knowledge and experience with high voltages and valve circuits. Apart from the 200V supply, I haven't triple-checked it and may contain mistakes
I've drawn something with a 5687... (I happen to like this valve 🙂 ) and a single supply
It's probably over the top for its intended usage... and 200V is rather dangerous, and probably requires higher voltage rated components, especially in the power supply. But allowing more plate-cathode voltage lets the valve provide a greater swing, and avoids the murky area around 0V grid bias where you may or may not get grid current...
The LEDs in the schematic are for their voltage drop... I had something with Vf ~ 1.7V in mind when i drew it. The silicon diode is my attempt at temperature compensation... and the MJE340 may be happier with a small heatsink, as long as it is well insulated
For anyone reading this... don't go building this circuit unless you have knowledge and experience with high voltages and valve circuits. Apart from the 200V supply, I haven't triple-checked it and may contain mistakesAttachments
What has changed in the schematic if voltage to increase from + /-24V to + /-32V??😕
Do we no change in the pattern of ECC88 replaced with 6n23p-EV?🙁
thank you
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