JLH2003 class A 22W input voltage range ?

[nickthevoice]

Hi !

I have already built JLH1969 class A 11W not bad amplifier with this input operating voltage range: DC 12V-35V.

Now I build her big sister the JLH2003 class A 22W same amp but with 4 transistors VS 2 for the JHL2003.

My problem is all the sellers say input voltage 18+/- VDC nobody talk about range input like the JLH1969.
But I have a +/- 20VDC input. That voltage work or it's too high !?... I don't want blow the amplifier board

Thanks in advance !

nicK

 

[amplidude]

I believe it can run on 33 volt dc.
Here's a link with a table that shows voltages and bias currents and power output.
The Class-A Amplifier Site - JLH Class-A Update

 

[grunf]

Hi !

I have already built JLH1969 class A 11W not bad amplifier with this input operating voltage range: DC 12V-35V.

Now I build her big sister the JLH2003 class A 22W same amp but with 4 transistors VS 2 for the JHL2003.

My problem is all the sellers say input voltage 18+/- VDC nobody talk about range input like the JLH1969.
But I have a +/- 20VDC input. That voltage work or it's too high !?... I don't want blow the amplifier board

Thanks in advance !

nicK

What transistors do you have on the board?
I had + / 22V, with one pair of outputs and a current of 2A before I installed the regulators. The power was almost 25W on 8ohm and now with the regulator it is about 18W because now I have 3V voltage drop on the regulator.

https://www.diyaudio.com/forums/solid-state/3075-jlh-10-watt-class-amplifier-563.html#post5974952

 

[nickthevoice]

JLH2003-class-A.jpg - Google Drive

Picture or the transistors

 

[Ian Finch]

Hmm....the pic shows a Chinese ?? kit with a blurred Motorola bat device on shiny, new 20 years + aged transistors? They are fakes - maybe good fakes and OK for a low power class A amplifier but not what they seem to be. If the marks can be rubbed off with solvent, you will know with greater certainty: Counterfeit Transistors

 

[nickthevoice]

I know
the China recycled all around the world old electronics parts desoldering all the parts and rebuilded a fake brand new product with that old crap!
I see lots of fake capacitors because it's easy to stick a new paper with the name of hi-fi brands.

But about my question: can I put 2V more than the recommended or it will blow !? I'm sure the capacitor can hold the voltage but my question is for the transistor in this circuit.

Thanks again guys !

nicK

 

[Mooly]

-/+20 volts (40 volts total) would be a low value Vce for a power transistor. The ancient TIP31 (with no suffix) is the only one I can think of at the moment that is so low.

Two answers...

Yes it will be OK because 2 volts isn't going to make any practical difference. If its going to be unreliable -/+20v then it will also be unreliable on -/+18.

Proper answer... you say you know they are fakes and therefore all bets are off. Your question has no reliable answer because we don't know for sure what you have.

They might be BC107's in a big can... and while probably not, we just don't know.

 

[nickthevoice]

I'll try it and whatever happens, happens !

By the way I just buy this cheap amplifier board to test and compare the sound of the class A versus my home made class A/B hi-fi parts lm3886, tda7293 and lm4780. This is why I don't want to spend again lots of money on that.

Thanks again !

nicK