Help improve pp-18 tone

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TomOlsen1
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Post by TomOlsen1 »

Hi Gary

The swiil is present at max VVR with the usual +/-10v zener, and reducing VVR corresponding with my rotary zener selector. However, some of the swirl disappears at max VVR when keeping the rotary at lowest value (around 4v if memory serves me right)

My lowest usable VVR volume is a bit higher than TV volume, but not more than a loud stereo. Certainly not going to annoy the neighbours too much.

Regards,
Thomas
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Bronsboi
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Post by Bronsboi »

My lowest usable VVR volume is a bit higher than TV volume, but not more than a loud stereo. Certainly not going to annoy the neighbours too much.
I definitely agree with the above.

I tested this in normal and cascade mod (ZP intergalactic mod) You still get a bit of fizz with VVR at full tilt but nothing compared to when the ruby fix is switched off. With the VVR at about 8-9 oclock it sound great and not much louder than a stereo.

I have installed the 3v zeners and the 13V zeners on a switch...They both are an improvement on the "no ruby fix" tone.
The 3v zeners improve the punch and fullness of sound across the whole range of the VVR... Yes the fizzy swirl is gone, but to my taste, that's no loss!!

I think the 13V zeners are redundant now, cos the 3V zeners improve the sound even when not using the VVR (don't know how!!). I am gonna hard wire the 3v zeners in and get rid of the switch.

I have dialed up the treble a bit to compensate, but that is the only drawback, to my ears at least.

Just one question I could only get 0.5 watt zeners. Is this enough?

Really pleased with how this has worked out. Thanks to Katoplan, Tom Olsen and ZP for all the help and advice. I'm really grateful
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katopan
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Post by katopan »

0.5W should be fine.
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Isaac Stuckey
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Re: Help improve pp-18 tone

Post by Isaac Stuckey »

Since this thread is SO long I haven't read it all, but fizz can be helped in easier ways I'd think. One that instantly comes to mind, is the 820 ohm resistor in the PI vs the vox value 1k2, (that was mentioned already) and I don't know about this one, but one way I like to tame fizz is just to put a 47pf cap across the plates of the PI tube, it has worked for me many times on several amps. I hope if you hadn't fixed it already, that this will help.


Rock city, regarding your amp being loud, try installing a PPIMV (post phase inverter master volume). Search that on this 18watt forum and you should get lots of older threads regarding it. Hope that helps you, it has helped others, also you could look into getting a good attenuator.
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rock city
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Re: Help improve pp-18 tone

Post by rock city »

Thanks, I am just scanning posts Read
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312_Jura
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Re: Help improve pp-18 tone

Post by 312_Jura »

Isaac Stuckey wrote:one way I like to tame fizz is just to put a 47pf cap across the plates of the PI tube, it has worked for me many times on several amps.
Cheers!
This way?
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Isaac Stuckey
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Re: Help improve pp-18 tone

Post by Isaac Stuckey »

Yea I've done it on several different amps. Actually never on an 18w based... but I never needed it there. The 1974x's always work for me, they are special. :)
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312_Jura
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Re: Help improve pp-18 tone

Post by 312_Jura »

Isaac Stuckey wrote:Yea I've done it on several different amps. Actually never on an 18w based... but I never needed it there. The 1974x's always work for me, they are special. :)
Cheers, I'll give it a try. What kind of cap should it be please? (Aye, I'm green as a leaf.. just assembled the PP18 few days ago)
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Isaac Stuckey
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Re: Help improve pp-18 tone

Post by Isaac Stuckey »

A regular 47PF will work fine. I have used a 100PF too before I think, but I'm not sure. Either way, assuming I've only ever used 47PF, it has always gotten rid of some fizz/buzz and made it a little smoother. 100Pf will be more extreme, but not bad. Don't go too high otherwise you will get rid of all the highs, anyway, just experiment with it, and try it with more than one guitar, since you could use a tele and it has less treble and it sounds awesome, but it might not be as good with a les paul. Just experiment.
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echuta13
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Re: Help improve pp-18 tone

Post by echuta13 »

Just make sure the cap is of the appropriate voltage for the section. :wink:
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Isaac Stuckey
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Re: Help improve pp-18 tone

Post by Isaac Stuckey »

One other thing that should also lessen treble a tad, and possibly add some more interactivity on the tone control, is to change out the 4.7nf (.0047uf) on the tone control for a .01. I like the .01 more than the .0047 in some other amps with that tone control.
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