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Author Topic: voltage regulator for guitar amp  (Read 315 times)

Online ivancarlovillaruel

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voltage regulator for guitar amp
« on: November 18, 2017, 04:49:32 PM »
patulong mga sir...

yung amp ko, unstable ang bias ng power tubes
pag mahina supply ng kuryente sa gig. pero pag dito lang sa bahay,
stable naman.

ano kaya magandang voltage regulator para stable yung kuryente?




Offline chito_eoi

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Re: voltage regulator for guitar amp
« Reply #1 on: November 18, 2017, 04:53:02 PM »
Try as well to post here:
https://m.facebook.com/groups/300774140429498




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Offline titser_marco

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Re: voltage regulator for guitar amp
« Reply #2 on: November 18, 2017, 10:47:41 PM »
patulong mga sir...

yung amp ko, unstable ang bias ng power tubes
pag mahina supply ng kuryente sa gig. pero pag dito lang sa bahay,
stable naman.

ano kaya magandang voltage regulator para stable yung kuryente?
Does it cause any problems? What do you mean unstable bias? If bias is unstable, it rarely is the power but the actual bias circuit in the amp. If the bias circuit is faulty no amount of regulation can fix that.

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Online ivancarlovillaruel

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Re: voltage regulator for guitar amp
« Reply #3 on: November 19, 2017, 12:03:00 AM »
it didnt cause any problems last night, but the man who built it
said "it might" when running through unstable voltage.

when the bias is cold, say 20-25mV for kt66, i can hear that
its a bit thin sounding, considering i am using jtm45 who has
this woofy bass sound because of the big cap 220uf V1 cathode.

then he told me to check the wall voltage, and saw that it was unstable.
fluctuating between 223v to 230v. causing the bias to go
25-27mV. i have set the bias to 35-40mV here in my
house, which the wall voltage is a solid
235v reading.

so i think i might need a voltage regulator, that i dont know
much about.

« Last Edit: November 19, 2017, 12:07:24 AM by ivancarlovillaruel »

Offline titser_marco

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Re: voltage regulator for guitar amp
« Reply #4 on: November 19, 2017, 09:50:34 PM »
it didnt cause any problems last night, but the man who built it
said "it might" when running through unstable voltage.

when the bias is cold, say 20-25mV for kt66, i can hear that
its a bit thin sounding, considering i am using jtm45 who has
this woofy bass sound because of the big cap 220uf V1 cathode.

then he told me to check the wall voltage, and saw that it was unstable.
fluctuating between 223v to 230v. causing the bias to go
25-27mV. i have set the bias to 35-40mV here in my
house, which the wall voltage is a solid
235v reading.

so i think i might need a voltage regulator, that i dont know
much about.



223v-230v is ok, it shouldn't be a problem.

Cathode caps aren't the only thing that can give you that girth. What are your filter cap values?
I'd rather be sharp than flat.


Online ivancarlovillaruel

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Re: voltage regulator for guitar amp
« Reply #5 on: November 20, 2017, 01:53:00 PM »
223v-230v is ok, it shouldn't be a problem.

Cathode caps aren't the only thing that can give you that girth. What are your filter cap values?

220-230v is ok, but the unstability of th wall voltage that night made the amp's bias crazy. and that voltage is a bit low where i bias my amp to 235-240v. that is why i think i need a voltage regulator to make it stable.

http://www.ceriatone.com/british-style-jtm45/

that's my humble amp, everything is in there including all the caps and everything. love this amp. im still doing a lot of research on how the voltage in every place will be stable. thanks for the inputs

Offline randymarsh

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Re: voltage regulator for guitar amp
« Reply #6 on: November 20, 2017, 03:03:57 PM »
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Online j.escueta

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Re: voltage regulator for guitar amp
« Reply #7 on: November 20, 2017, 06:51:08 PM »
wow ceriatone.

I consulted tony tecson from pinoydvd because parang ganyan rin prob ng peavey 6505MH ko.  Pag sa house ok sya, pero once i bring it to other places, yun na.  Topak na.  He told me to buy a servo AVR.  Haven't tried it yet though.

Offline titser_marco

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Re: voltage regulator for guitar amp
« Reply #8 on: November 21, 2017, 09:05:42 PM »
220-230v is ok, but the unstability of th wall voltage that night made the amp's bias crazy. and that voltage is a bit low where i bias my amp to 235-240v. that is why i think i need a voltage regulator to make it stable.

http://www.ceriatone.com/british-style-jtm45/

that's my humble amp, everything is in there including all the caps and everything. love this amp. im still doing a lot of research on how the voltage in every place will be stable. thanks for the inputs


IMO unless the the voltage swing (and resultant bias shift) causes redplating in any of the tubes, it shouldn't worry you. I

In principle if the wall voltage goes down, so would all other voltages in the amp, including bias voltage and the B+ since most amp designs use a multitap secondary in its power transformer. If the B+ at 230v say is at 450vDC and  bias  voltage is at -53vDC, any upward swing in the wall (say 240vAC) would mean approx 270vDC and a bias voltage of -55vDC. The higher B+ is going increase the flow of electrons BUT the accompanying negative bias should more or less be countering that effect.

Now of course if your amp uses a separate transformer altogether for B+ / or bias (very unlikely) this rule should be taken with caution.

But hey your amp your rules.

PS. The mV readings you have are not bias voltages. They are approximations of tube dissipation (which is controlled by adjusting the bias voltage). Think of the bias voltage as a flame control on your stove: the higher the bias voltage, the less LPG (electrons) go to the plate, resulting in a colder amp.
« Last Edit: November 21, 2017, 09:08:05 PM by titser_marco »
I'd rather be sharp than flat.

Online ivancarlovillaruel

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Re: voltage regulator for guitar amp
« Reply #9 on: November 23, 2017, 09:26:24 PM »
i'll just get an avr or ups tomorrow, and if it doesnt solve the issue (having the bias reading fluctuating in the hotel where i play), maybe its time to have a visit on a tube amp tech.