Hi,
Not really...
In my case I need 20 of those per channel (10 6080s), so I buy 50 with 1% tolerance and I found them all to be exactly 1 Ohm.
If I were to use 10 Ohm the Zo of the amp would go up a little as its an OTL this is important to me.
BTW, if a 6AS7/6080 goes south the 10/1 Ohm resistor will serve as a fuse. So you better have some spares.
Cheers,😉
Not really...
In my case I need 20 of those per channel (10 6080s), so I buy 50 with 1% tolerance and I found them all to be exactly 1 Ohm.
If I were to use 10 Ohm the Zo of the amp would go up a little as its an OTL this is important to me.
BTW, if a 6AS7/6080 goes south the 10/1 Ohm resistor will serve as a fuse. So you better have some spares.
Cheers,😉
"Patently" obvious...
It was a just a quip on some other recent threads 🙂 Sorry if it sounded rude out of context😱
In fact there are several resistive ways to do this:
G must decide whether all the cathode resistance is to be bypassed. Not bypassing even a small amount of resistance will cause a considerable increase in Ra. This will lead to higher distortion, which will only be partly offset by the small amount of feedback produced by the cathode degenerative process.
To achieve this, it is probably best to split the cathode bypass cap into 2 parts.
Of course if the design calls for some unbypassed resistance, then the designer has probably taken this into account.
Cheers,
Hi Bas,Bas Horneman said:
It was a just a quip on some other recent threads 🙂 Sorry if it sounded rude out of context😱
In fact there are several resistive ways to do this:
G must decide whether all the cathode resistance is to be bypassed. Not bypassing even a small amount of resistance will cause a considerable increase in Ra. This will lead to higher distortion, which will only be partly offset by the small amount of feedback produced by the cathode degenerative process.
To achieve this, it is probably best to split the cathode bypass cap into 2 parts.
Of course if the design calls for some unbypassed resistance, then the designer has probably taken this into account.
Cheers,
pros and cons
Nice thought G. As the tubes age, and they seem to age differently, one could balance the tubes. This would only be a static balance, but maybe better than nothing. With only one resistor, the value is half of that used if two resistors were used (and no balancing pot). This will keep Ra down.
On the other hand, the concept of two tubes would mean twice the output capacitance (and input capacitance). Be interesting to see how the extra capacitance would affect HF response, and any resonance problems with the OPT and with the driver tube response.
10 ohm or even 1 ohm resistors are good for measuring individual tubes. One could argue they will affect sonics, so I would be careful what brand you use.
Nice thought G. As the tubes age, and they seem to age differently, one could balance the tubes. This would only be a static balance, but maybe better than nothing. With only one resistor, the value is half of that used if two resistors were used (and no balancing pot). This will keep Ra down.
On the other hand, the concept of two tubes would mean twice the output capacitance (and input capacitance). Be interesting to see how the extra capacitance would affect HF response, and any resonance problems with the OPT and with the driver tube response.
10 ohm or even 1 ohm resistors are good for measuring individual tubes. One could argue they will affect sonics, so I would be careful what brand you use.
Hi Steve,
The driver for these two tubes would be running at about 20mA so I don't think the extra input capacitance would be too much of a problem but my footing is not too firm with those calculations yet so that is not a definative answer. This is probably going to be one of those "let's build it and see what happens" projects that probably won't take place for some time. I'm just in the planning stages. Thanks for the input.
G
The driver for these two tubes would be running at about 20mA so I don't think the extra input capacitance would be too much of a problem but my footing is not too firm with those calculations yet so that is not a definative answer. This is probably going to be one of those "let's build it and see what happens" projects that probably won't take place for some time. I'm just in the planning stages. Thanks for the input.
G
Hi John,
Nope not rude...but I did not see the point of it...that is why I wanted to resolve it.
To be precise I have no motives for being here or posting other than to help others or help myself to knowledge.
Cheers,
Bas
Was not aware of those quips..
Guess I was outta line...must look like an assh*le now.
Cheers,
Bas
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