Solid State Regulator for tube amp

NBBN_amplifiers · 14th March 2008, 02:06 PM

Hi Folks,

Let me introduce. I'm from Brazil and i'm here in USA working as Electronic Engineer as i've graduated in Brazil.
I had a small company in Brazil which we use to manufacture old push pull amplifiers AB class for cars. In Brazil they call this amplifiers boosters. For so many reason in the economy i've decided to quit the company and move to USA.
I've never had built a tube amplifier, but i've decided to buy a DYNACO ST-35 to start. As a lover audiophile the sound was amazing. I really liked, but i have some problems and i would like to fix it.
First the power supply is keeping the voltage higher than it could be because i use another kind of transformer wich deliver 394 volts for the EL-84 where it should have maximum 300V right?
So i would like to build a High voltage solid state regulator for that using some mosfet. Is anybody have some idea. I know that it's hard to find some circuit to start because nobody seems to want a solid state to regulate high voltage.

Thanks guys,

Luiz Nickel

Cal Weldon · 14th March 2008, 04:42 PM

Hello Luiz and welcome to the forums. You might wish to post this in another of the forums. This is only the introduction area and not everyone will look here.

PH104 · 14th March 2008, 04:55 PM

check out dynaco-doctor.com. There's a schematic on:

http://www.dynaco-doctor.com/paregsch.gif

Phil

NBBN_amplifiers · 14th March 2008, 05:39 PM

Ok Phil,

Thanks for that... I'm going to take a look..
How can i post in another forum ?

Luiz

NBBN_amplifiers · 14th March 2008, 07:30 PM

Hi Phil,

I was trying to undestand the SCH, but who is the IC1 and other parts ? How much current this circuit can provide ?
Don't you have the part list for all ?

Thanks,

Luiz

leadbelly · 14th March 2008, 08:21 PM

Here's a tip: try out that Search button you may have missed. This is a topic discussed frequently in the Tubes forum.

If you need a complete schematic you can follow this:

http://www.national.com/an/LB/LB-47.pdf

NBBN_amplifiers · 15th March 2008, 02:22 AM

Hi guys,

Thanks,

Actually now that i'm home i had more time to research and i found the discussion topic and i've got some circuits to start.
I'm going to post some pictures of my baby for everybody...
And when i got more questions i'll be i touch.

Luiz

SY · 15th March 2008, 02:32 AM

I'll move this over to Tubes where it can get more play.

And I'd read the classic:

www.national.com/ms/LB/LB-47.pdf

SpreadSpectrum · 15th March 2008, 02:45 AM

Luiz,

Seja bem-vindo aos Estados Unidos. (Welcome to the US)

Wavebourn · 15th March 2008, 04:02 AM

One MOSFET, for example IRF740, couple of SG-4S gas discharge tubes in series, 10KOhm / 5W resistor, and one 12V Zener to protect gate. Nothing more is needed. Except may be one 22 Ohm / 5W resistor to protect MOSFET against sudden surge current.
I.e. parametric stabilizer + source follower.

More than adequate regulation for your particular case, also nice purple glow.

14th March 2008, 02:06 PM	#1
NBBN_amplifiers diyAudio Member Join Date: Mar 2008 Location: Metuchen, NJ Blog Entries: 2	Solid State Regulator for tube amp Hi Folks, Let me introduce. I'm from Brazil and i'm here in USA working as Electronic Engineer as i've graduated in Brazil. I had a small company in Brazil which we use to manufacture old push pull amplifiers AB class for cars. In Brazil they call this amplifiers boosters. For so many reason in the economy i've decided to quit the company and move to USA. I've never had built a tube amplifier, but i've decided to buy a DYNACO ST-35 to start. As a lover audiophile the sound was amazing. I really liked, but i have some problems and i would like to fix it. First the power supply is keeping the voltage higher than it could be because i use another kind of transformer wich deliver 394 volts for the EL-84 where it should have maximum 300V right? So i would like to build a High voltage solid state regulator for that using some mosfet. Is anybody have some idea. I know that it's hard to find some circuit to start because nobody seems to want a solid state to regulate high voltage. Thanks guys, Luiz Nickel __________________ Nickel

14th March 2008, 04:42 PM	#2
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Hello Luiz and welcome to the forums. You might wish to post this in another of the forums. This is only the introduction area and not everyone will look here. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

14th March 2008, 05:39 PM	#4
NBBN_amplifiers diyAudio Member Join Date: Mar 2008 Location: Metuchen, NJ Blog Entries: 2	Voltage Regulator Ok Phil, Thanks for that... I'm going to take a look.. How can i post in another forum ? Luiz __________________ Nickel

14th March 2008, 07:30 PM	#5
NBBN_amplifiers diyAudio Member Join Date: Mar 2008 Location: Metuchen, NJ Blog Entries: 2	Hi Phil, I was trying to undestand the SCH, but who is the IC1 and other parts ? How much current this circuit can provide ? Don't you have the part list for all ? Thanks, Luiz __________________ Nickel

14th March 2008, 08:21 PM	#6
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	Here's a tip: try out that Search button you may have missed. This is a topic discussed frequently in the Tubes forum. If you need a complete schematic you can follow this: http://www.national.com/an/LB/LB-47.pdf __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

14th March 2008, 04:55 PM	#3
PH104 diyAudio Member Join Date: Nov 2001 Location: New Mexico	check out dynaco-doctor.com. There's a schematic on: http://www.dynaco-doctor.com/paregsch.gif Phil

15th March 2008, 02:22 AM	#7
NBBN_amplifiers diyAudio Member Join Date: Mar 2008 Location: Metuchen, NJ Blog Entries: 2	Voltage regulator Hi guys, Thanks, Actually now that i'm home i had more time to research and i found the discussion topic and i've got some circuits to start. I'm going to post some pictures of my baby for everybody... And when i got more questions i'll be i touch. Luiz __________________ Nickel

15th March 2008, 02:32 AM	#8
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	I'll move this over to Tubes where it can get more play. And I'd read the classic: www.national.com/ms/LB/LB-47.pdf __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

15th March 2008, 02:45 AM	#9
SpreadSpectrum diyAudio Member Join Date: Nov 2007	Luiz, Seja bem-vindo aos Estados Unidos. (Welcome to the US)

15th March 2008, 04:02 AM	#10
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	One MOSFET, for example IRF740, couple of SG-4S gas discharge tubes in series, 10KOhm / 5W resistor, and one 12V Zener to protect gate. Nothing more is needed. Except may be one 22 Ohm / 5W resistor to protect MOSFET against sudden surge current. I.e. parametric stabilizer + source follower. More than adequate regulation for your particular case, also nice purple glow. __________________ The devil is not so terrible as his mathematical model! Wavebourn: We Create Creativity!

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