Modified Laney VH100R lacks mids

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Reeltarded
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Re: Modified Laney VH100R lacks mids

Post by Reeltarded »

There is a (100k) resistor on the board coming from the plate of that stage. The capacitor goes over it in parallel.
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Emetal
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Re: Modified Laney VH100R lacks mids

Post by Emetal »

Ok there is a problem with schematics Page 2 says that V1A A. goes to PAD 6 and then to R7 100K. V1B A. goes to PAD 5 and then to R5 100K.

Page 4 says reverse: V1A A. goes to R5 and V1B A. goes to R7.

Situation in my amp looks like page 2. So than I would be putting this cap parralel to R5?
Last edited by Emetal on Thu Apr 11, 2013 8:15 pm, edited 1 time in total.
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Re: Modified Laney VH100R lacks mids

Post by Reeltarded »

What stage os the 22pF on? What did Voodoo do and what is stock? I am confused.
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Emetal
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Re: Modified Laney VH100R lacks mids

Post by Emetal »

Reeltarded wrote:What stage os the 22pF on? What did Voodoo do and what is stock? I am confused.
Problem with schematics I just edited above post look up :-)
We should be looking at the page 2 becouse that is what my amp looks like, so Voodoo mod 22pF was on V1B stage.
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Re: Modified Laney VH100R lacks mids

Post by Emetal »

So if I am to put new cap in same stage where 22pF was- that is V1B stage then in reality I am going to put it over R5
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Re: Modified Laney VH100R lacks mids

Post by Reeltarded »

Yes. R5 is first stage plate.
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Emetal
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Re: Modified Laney VH100R lacks mids

Post by Emetal »

Nope...
Last edited by Emetal on Thu Apr 11, 2013 9:49 pm, edited 2 times in total.
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Re: Modified Laney VH100R lacks mids

Post by Reeltarded »

Grid stopper right on the grid pin? I wish I could see this amp. Leave the grid stops. Again, I am confused.
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Emetal
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Re: Modified Laney VH100R lacks mids

Post by Emetal »

Ok this is getting crazy, does everybody understand that Voodoo mod has 22uF in B stage of V1 and 10K grid stopper is in A stage of V1. They are not in the same stage. Further V1A A. is going to PAD 6 and then to R7!!! And V1B A. is going to PAD 5 and R5!!! This is how it is on the PAGE 2 of PDF and in my amp. PAGE 4 is WRONG. Now if I remove that 22uF from B stage of V1 (which I would like to remove it sounds nicer with extra highs), what should I do with the grid stopper from stage A should I put back the original 68K?
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Re: Modified Laney VH100R lacks mids

Post by Reeltarded »

This is tweaking. I have stages across several amps with 33k to 470k stoppers. If you remove the 22p you have to experiment with the value of your grid stop, which is properly a..

Hold on..

The input jack has a 1M. That is the ground ref.

68k is a typical grid feed resistor.

Whatever works with regards to your ear (smallest possible without squealy crap) right on the grid pin at the tube socket is a grid stopper.

Pads and mistakes in schematics vs modification... headache for me!
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Emetal
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Re: Modified Laney VH100R lacks mids

Post by Emetal »

Here is the V1 photo with A side to the left and B side to the right of the green line..
On this pic you can also see that plate from the A side (blue wire) is going to the PAD 6 and then to R7, and plate from B side (purple wire) is going to PAD 5 and then R5.
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Last edited by Emetal on Sun Apr 21, 2013 4:33 pm, edited 1 time in total.
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Reeltarded
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Re: Modified Laney VH100R lacks mids

Post by Reeltarded »

Aha. I would remove the 22p then see what happens. If it runs into squeal with the gain up start throwing caps over the 100k plate.

Even tiny caps there make it pinchy sounding. Hate that!
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Emetal
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Re: Modified Laney VH100R lacks mids

Post by Emetal »

It does have more microphonics when 22pF removed I tried it today remember, but it brings out more nice highs, and what do I do with 10K if 22pF pulled out - revert back on 68K ? and where do I try those caps to to stop microphonics? over plate resistor on A side which is R7 or plate resistor on B side which is R5?
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Re: Modified Laney VH100R lacks mids

Post by Reeltarded »

That cap is one of the ways to kill incoming RF on that stage.

He told me he couldn't drill plexiglass when I called for a mod a guy I was recording couldn't live without. My client is still alive and I learned to work on amps and drill plexiglass. A fact.
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Cameron
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Re: Modified Laney VH100R lacks mids

Post by Cameron »

Emetal wrote:It does have more microphonics when 22pF removed I tried it today remember, but it brings out more nice highs, and what do I do with 10K if 22pF pulled out - revert back on 68K ? and where do I try those caps to to stop microphonics? over plate resistor on A side which is R7 or plate resistor on B side which is R5?
Being that none of us are able to see this amp you are going to have to just try something. try the 68k learn what it does. try the a 500pf over the plate see what it does.take out the 22pf see what this does ...ect. You might also want to read some amp repair books...there is also good stuff on line.....read Merlin's stuff.
You need to get a better grasp of what is going on in the amp.
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