The Valve Wizards preamp layout

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telentubes
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Re: The Valve Wizards preamp layout

Post by telentubes »

This site is about R and D as much as anything. There are reams of ready to go schematics and layouts if that's what you want, but you'll find that they all went through an extensive process to get there. Most are still works in progress, constantly being tweaked. This thread is another work in progress.
ChopSauce
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Re: The Valve Wizards preamp layout

Post by ChopSauce »

sluckey wrote: Wed Feb 14, 2018 6:33 pm
modman wrote: Wed Feb 14, 2018 12:24 pm Then you end up spending 700USD on a Bassman kit that sounds like a 5W solid state practice amp.
Cheap shot!
Sure! Phil's dedication to the community deserves much more respect, & as almost everyone here, I guess he would be pleased to learn from you, as well.

About the schematic, now. Possibly you haven't read the book and do not know anything about it? I can scan it and send it you, if you want. I guess it's Fig 14.4 p. 256.

Of course one could argue about Dumble's circuits made available and not other's but that's slightly out of topic :?

That being written, I can't imagine a Valve Wizard layout departing from

Image

that is with the two caps separated by each triode components & vice-versa.
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roberto
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Re: The Valve Wizards preamp layout

Post by roberto »

pompeiisneaks wrote: Mon Feb 12, 2018 8:19 pm 'put the grid stopper as close to the grid to avoid miller capacitance' if I recall :P
It's the opposite, you have to get advantage of the miller capacitance to avoid autooscillations and disturbs from radiofrequencies, plus to limit the current flow on the grid in case of strong overdrive (positive grid).
pdf64
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Re: The Valve Wizards preamp layout

Post by pdf64 »

roberto wrote: Fri Feb 16, 2018 9:27 am
pompeiisneaks wrote: Mon Feb 12, 2018 8:19 pm 'put the grid stopper as close to the grid to avoid miller capacitance' if I recall :P
It's the opposite, you have to get advantage of the miller capacitance to avoid autooscillations and disturbs from radiofrequencies, plus to limit the current flow on the grid in case of strong overdrive (positive grid).
My understanding is that the grid stopper should be mounted at the socket terminal in order to minimise the antennae effect of any wiring between the resistor and the tube socket terminal.
eg Case 1, if the resistor is mounted remotely from the socket terminal, then any wiring between the resistor body and the terminal might act as a pick-up antennae. So any interference signal gathered at this pick up antennae is between the resistor and the tube socket. RF antennae by nature will tend to be low impedance, and so the low impedance of the antennae source will prevent the Miller capacitance having much attenuation of the interference signal.

Case 2, if the resistor is mounted at the socket terminal, then any wiring (and the interference signal its antennae effect may pick up) is on the 'other' side of the grid stopper resistor, and the interference signal has to pass via the grid stopper. As the grid stopper forms a low pass filter with the Miller capacitance, it will act to remove the high frequency content of the interference.
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pompeiisneaks
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Re: The Valve Wizards preamp layout

Post by pompeiisneaks »

modman wrote: Wed Feb 14, 2018 8:46 pm
sluckey wrote: Wed Feb 14, 2018 6:33 pm
modman wrote: Wed Feb 14, 2018 12:24 pm Then you end up spending 700USD on a Bassman kit that sounds like a 5W solid state practice amp.
Cheap shot!
That's ten letter of which one is a space...

Sorry, but I'm here to get some information about building these circuits from actual people who built it. Dude posts layouts he hasn't even built himself without sharing the schematics. Don't trust anything he says since that Bassman video demo.

Check the clip of the Bassman at 6:40 to the end, then come back and tell me what you hear.
Any chord or anytime more than one string is played, farting distortion all the way.
I don't even like the clean sounds, is overbiased in my humble amateur opinion.
Sounds like someone with an axe to grind. I do it because I enjoy it. I have passed that amp off to someone else that thought it sounded great, and they're quite a discerning amp collector. I'm suspicious you're rating the amps sound due to mediocre recording equipment and/or my mixing skill, but hey, if you like insulting people online, go for it. It must make you feel better as a person. Me, I'm not too worried, I didn't build it for you.

Also, I didn't feel comfortable sharing a schematic that's printed in a book by someone I respect, the valve wizard, and if I can point people to buy his book, I'll feel better still. Then you have the schematic and a layout.

To each their own.

Personally, I'd rather you not reply on any of my threads in the future if all you can do is bring insult and how amazingly awesome you are into the thread. That's my 2c.

If you have videos showing your work please share, I'd love to learn from it.

~Phil
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pompeiisneaks
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Re: The Valve Wizards preamp layout

Post by pompeiisneaks »

I just re-listened to the recording, hadn't in over a year since I built it, that was my third build. I know it's the recording that sucks. I've been getting better at my recording and mixing but it's never been my forte. The later amp demos show a bit better quality recording. In fact when my dog bumped the mic, it all of a sudden sounded a lot cleaner for a short time as the mic moved to a slightly better spot, but then I put it back into the 'suck zone'.

I welcome all feedback, as it's how I learn, just prefer people to treat me with respect as I try to as well.

~Phil
tUber Nerd!
ChopSauce
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Re: The Valve Wizards preamp layout

Post by ChopSauce »

(Just out of curiosity:) any possibility that we hear how sounds the outcome?
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pompeiisneaks
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Re: The Valve Wizards preamp layout

Post by pompeiisneaks »

I may build it at some point, just have too many projects on the 'to do' list right now :P Although this one may be less expensive than some of the others since it's just a preamp, so I may think of doing that sooner, than later.

~Phil
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