Cathode Bias, can cap be switched in/out?

[GlideOn]

I see now what he was eluding to, but doesn't a resistor in series with a cap limit the effectiveness of said cap? That's not necessarily something I'm looking for...

Duh Huh!

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[sluckey]

Duh Huh is slow southern speak for yeah yeah. The idea of the switch is to make the cap totally ineffective. That's exactly what you hope to do. The idea of the resistor across the switch is... well read and understand Ingram's first reply.

BTW, removing the cathode bypass cap from the power tubes will provide some regenerative (negative) feedback and that will give a cleaner sound. It will also audibly reduce the sound level, most noticeably in the lower frequencies. IOW, switching the cap in/out will produce a very noticeable change in sound level from the speaker. Could be useful as a boost. Try it and tell us what you think.

[GlideOn]

Right on

I suppose it's the best of the options thus far, I can live with a little bit of a gain reduction if that's the price to pay of making it all work silently.

The resistor is the component that is in circuit at all times - the cap still gets switched or paralleled in, which I thought is always the correct way to approach switching so that it is never left without a connection!

Though there was a concern raised by @Stevem about there being oscillation issue running all the way across the amp to the push-pull pot.

Is this valid or does the switching scheme help mitigate that/isn't an issue? It goes about 9in from the cathode pin, across the amp over the board to the pot. That's a fair amount of wire that's not shielded. Would have to rework the grounding/shielding scheme in the diagram if so.

[sluckey]

The resistor is the component that is in circuit at all times

Not so. The resistor is shorted out when the cap is switched in.

Though there was a concern raised by @Stevem about there being oscillation issue running all the way across the amp to the push-pull pot.

That's possible. Only you can know.

By now you should know everything about this simple cap switch. Time to snip the cap positive lead and see if you even like the sound with no cap. Should'a done this when you had your first cup of coffee. Could be you don't even like it and discover you've wasted the entire day just thinking about it. Now that would be a lot of wasted effort! I have plenty of time to waste. How 'bout you?

[GlideOn]

The resistor is the component that is in circuit at all times

Not so. The resistor is shorted out when the cap is switched in.

Though there was a concern raised by @Stevem about there being oscillation issue running all the way across the amp to the push-pull pot.

That's possible. Only you can know.

By now you should know everything about this simple cap switch. Time to snip the cap positive lead and see if you even like the sound with no cap. Should'a done this when you had your first cup of coffee. Could be you don't even like it and discover you've wasted the entire day just thinking about it. Now that would be a lot of wasted effort! I have plenty of time to waste. How 'bout you?

How is the cathode resistor not always connected??

Also, which direction is the push/pull done within the diagram you drew up?

[Bergheim]

The resistor is always connected, that is, the switch doesn't physically snip off the leads and connect them back into the circuit. Think about where the current wants to go when the switch is engaged (in parallel across the resistor). There is about ~0 ohms through the switch, and 10k in the resistor. "Bypassed" might be a better word in this context.

We all want to help you out, and help you learn something. But time and time again I get the feeling that you, rather than just go ahead and spend those 15 mins of work it takes to do the mod, want to sit on the fence and procrastine over the solutions we provide, always asking for more insight on how we think you might like the outcome, or if we are 100% sure everything is going to work out as expected. We are sure that we don't suggest something that is dangerous to carry out. All other parameters is really up to you to evaluate.
IMO we are doing some solid favours here, spending our time explaining the stuff for you. From my point of view, it would be a lot more motivating to continue spending that time if you'd do your "homework". Learning to use schematics is part of that homework. Some of the mods you are asking us to work out for you are pretty complex, and some are really simple, and we end up spending an unproportionally big amount of time and effort to lay it out for you, even on the simple things like the switcheable bypass cap, just because you probably doesn't feel it's worth your time and effort to learn schematics, but rather expect us to accept your layouts to work off, which is a much more difficult task for everyone but yourself.
I admit this chapter might have come across as a little grumpy, but at the same time I don't think it's inappropriate. Other members have hinted at this several times, across various threads.

[GlideOn]

The resistor is always connected, that is, the switch doesn't physically snip off the leads and connect them back into the circuit. Think about where the current wants to go when the switch is engaged (in parallel across the resistor). There is about ~0 ohms through the switch, and 10k in the resistor. "Bypassed" might be a better word in this context.

We all want to help you out, and help you learn something. But time and time again I get the feeling that you, rather than just go ahead and spend those 15 mins of work it takes to do the mod, want to sit on the fence and procrastine over the solutions we provide, always asking for more insight on how we think you might like the outcome, or if we are 100% sure everything is going to work out as expected. We are sure that we don't suggest something that is dangerous to carry out. All other parameters is really up to you to evaluate.
IMO we are doing some solid favours here, spending our time explaining the stuff for you. From my point of view, it would be a lot more motivating to continue spending that time if you'd do your "homework". Learning to use schematics is part of that homework. Some of the mods you are asking us to work out for you are pretty complex, and some are really simple, and we end up spending an unproportionally big amount of time and effort to lay it out for you, even on the simple things like the switcheable bypass cap, just because you probably doesn't feel it's worth your time and effort to learn schematics, but rather expect us to accept your layouts to work off, which is a much more difficult task for everyone but yourself.
I admit this chapter might have come across as a little grumpy, but at the same time I don't think it's inappropriate. Other members have hinted at this several times, across various threads.

Friend, I thank you for the first part of your reply as it helps clarify what I feel I have been reasonably requesting. "Parallel," "bypass" are much more familiar terminology than "not grounded side," which sounds to me like positive (+) side, but I cannot be certain so I simply asked.

The second part of this however...

I take great care in the manner of which I ask or reply to things, often making a point to thank those who graciously spend their time doing so in kind. I don't feel at all that these were unreasonable questions I was asking for and so far after 21 replies into this, seems like a pretty tidy thread compared to most. Everyone seems to have been cordial so far and it's been otherwise delightful to talk about this and make some lighthearted humor over it in the process. I wouldn't presume to tell you what to feel, how to spend your time or speak on behalf of others who are also fee public members, so please let's graciously move past this and remember we're all human, no?

The reason why I may ask for clarification:

PXL_20250223_155847873.jpg

I am at a stopping point (lunchtime!). I have been working at this since Friday and hope to complete in time for practice this coming Saturday. Where I go from here depends on the answers I receive, which are entirely voluntary of course. Believe it or not, I am eager to wrap this up as it has been tedious and exhausting for me too!

If I need to use shielded wiring for this cathode switching, I may combine the NFB, the Presence and the Cathode too. It means a fair deal more than 15 minutes to wire it all up, shrink wrap the shielded wire so it's not shorting into anything, ground the shield at the ground bus about 1/3 the way into the length of the amp and find somewhere to zip tie them so they're secure for long-term use.

At this point I am convinced that despite the unknown, the known quantities outweigh any potential downsides.

And I am leaning towards doing just so - to wire it up all shielded.

Does this sound reasonable?

[sluckey]

Also, which direction is the push/pull done within the diagram you drew up?

see attached. If you want to reverse push/pull positions, swap connections for the two outside terminals.

[Bergheim]

It may be a simple thing to try, but it's not quite as simple wiring it all in permanently.

So I need to know it is worth the effort before I commit.

Try it before you commit to anything. Unsolder the negative cap lead and play guitar for a while. Now use a gator clip test lead to reconnect the cap and play some more. Simply disconnect/reconnect the gator clip to get a good comparison between the sounds. Not much effort IMO. Until YOU do a simple comparison like this using YOUR own ears, you will never know if it's worth the effort for YOU to make it permanent.

GlideOn my friend, did you see this one earlier in the thread? Sluckey even explains to you the commitment (or lack thereof) it takes to test this mod, before installing it permanently.
No need to make things more complicated than they need to be.

[GlideOn]

I think I've gotten out of this thread as much as I can hope to get. Any more dialogue I fear will just become pointless bickering so if it's all the same, I've requested this thread be locked.

Appreciate all of your help, @Sluckey @B Ingram

[Colossal]

Alright, alright....nothing to see here