150k resistor

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Jhyatt2012
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Location: East Texas

150k resistor

Post by Jhyatt2012 »

If I omit the Fet circuit, what happens if I don't include the 150k resistor to ground?
vibratoking
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Re: 150k resistor

Post by vibratoking »

You won't have the same load on B+ and all your voltages will drift up. Some say the tone is different. I tried it without and with...I didn't notice a big tonal change, but I don't have dog ears. Just include it if you don't want to adjust your bias string and/or worry about the tonal implications.
Jhyatt2012
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Re: 150k resistor

Post by Jhyatt2012 »

That's kind of what I figured. I don't think I would mind the voltages being a little high going in, scaling down isn't a problem.
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martin manning
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Re: 150k resistor

Post by martin manning »

It's easier to put it in than to fiddle with the dropping string. It will be worth 20-25V on V1's plates.
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ToneMerc
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Re: 150k resistor

Post by ToneMerc »

martin manning wrote:It's easier to put it in than to fiddle with the dropping string. It will be worth 20-25V on V1's plates.
So true, just tack a 150K bleeder to ground at B5.

TM
talbany
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Re: 150k resistor

Post by talbany »

It will on some amps affect the low end response.. :) it can make it feel a bit softer on some amps..Some people hear it others not..I attach mine from the V1 plate junction to the center of the tag strip holding the grid resistors...Easy enough

Tony
" The psychics on my bench is the same as Dumble'"
vibratoking
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Re: 150k resistor

Post by vibratoking »

Oh, FWIW, I like the FET circuit with a Strat.
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rogb
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Re: 150k resistor

Post by rogb »

vibratoking wrote:Oh, FWIW, I like the FET circuit with a Strat.
You know I had never really tried my USACG Strat through the FET.
I just went and did it. Boy, is that a top tip!
Like night and day, it just brings it alive.
Of course, the OD trigger and all the pots need readjusting but I really liked what I heard. It's a very EJ sounding guitar and the FET brings the harmonic shimmer to the table.
I have not really used this Strat with the #102 but I definitely will now.
Thanks VK.

To the OP, I forgot to ground the FET sim resistor tail in my first build - the voltages were high and it sounded a lttle fizzy. When the TAG members pointed that out, it was a lot better.

But having the FET, is IMO, well worth it. Acoustics sound amazing , as was HAD's original intention.
Lap steel and slide is great through it too.
Bob Simpson
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Re: 150k resistor

Post by Bob Simpson »

Speaking of dogears...

Where'd he go?

Seems like he and Brandon disappeared at about the same time...

Bob Simpson
Please understand that IMO an answer to this question is of no practical relevance at all. - Max
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ToneMerc
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Re: 150k resistor

Post by ToneMerc »

Bob Simpson wrote:Speaking of dogears...

Where'd he go?

Seems like he and Brandon disappeared at about the same time...

Bob Simpson
2 years ago SL got sick, recovered and then dropped off from here, Brandon has been gone since 09.

TM
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glasman
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Re: 150k resistor

Post by glasman »

As stated the 150K adds a bleed to the B+ rails for all tubes in the amp.

Removing it to my ears things get bright and edgy. I usually trim the amps I built so that V1 has about 195V on the plates. Lower it looses definition, about 200V or so it gets edgy.

Depends a lot on the tubes you are using as well.

Remember Alexander was (for the most part) using Fender iron from old amps and as such they normally had a higher B+ available due to the changes in line voltage over the years (110 to 115 to 120).

The value I use for my amp amps range from 180K to 270K depending on the tubes used. But my transformers are speced for 120V not 110 like the old fenders.

You can acheive the same effect by changing (increasing) the first dropping resistor and it can also improve the "squish" feel of the amp due to the longer recovery time for the following stages.

Gary
Located in the St Croix River Valley- Afton, MN
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification

www.glaswerks.com
dcribbs1412
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Re: 150k resistor

Post by dcribbs1412 »

glasman wrote:As stated the 150K adds a bleed to the B+ rails for all tubes in the amp.

Removing it to my ears things get bright and edgy. I usually trim the amps I built so that V1 has about 195V on the plates. Lower it looses definition, about 200V or so it gets edgy.

Depends a lot on the tubes you are using as well.

Remember Alexander was (for the most part) using Fender iron from old amps and as such they normally had a higher B+ available due to the changes in line voltage over the years (110 to 115 to 120).

The value I use for my amp amps range from 180K to 270K depending on the tubes used. But my transformers are speced for 120V not 110 like the old fenders.

You can acheive the same effect by changing (increasing) the first dropping resistor and it can also improve the "squish" feel of the amp due to the longer recovery time for the following stages.

Gary
Great info
Great to see you posting again

Thanks
Darin
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