How to matching PNP with NPN Transistor

senee · 2005-02-26 9:10 am

Hi,
Anyone to know, How to matching PNP with NPN Transistor?
I buy 2N5551= 20 ea. and 2N5401 = 20 ea. then hFE measure is more difference

hFE of 2N5551 = 110 to 130
hFE of 2N5401 = 210 to 230

I am making the power amplifier, when I put them in the circuit, It may be not good sound.

Have anyone suggestion?

sorry!!! My english is not good.

Senee

anatech · 2005-02-26 10:40 pm

Hi Senee,
The best you can do, short of buying more transistors, is put the closest ones together. If these are for n and p diff pairs, match your pairs then use the closest n and p pairs. This will be better than most production amps so don't worry too much about it.
-Chris

senee · 2005-02-27 5:52 am

Thanks, Chris

AndrewT · 2005-02-27 7:58 pm

Hi,
are you matching Hfe at 1 bias current?
Once you have sets that closely match try measuring the Vbe at a very low current(100uA to 1ma). Select for both Vbe and Hfe matching.

thanh · 2005-02-28 12:53 am

i think if you build a fully symmetry amp, you only need match npn ann npn, pnp and pnp .This topo has a very high capacity of cancel offset .I'm sorry! my english is not goog.Can you correct my sentence?

anatech · 2005-02-28 1:12 am

Hi thanh,
My experience shows that, in order of importance, the pairs must be matched (NPN to NPN, PNP to PNP). Then, each pair should be matched to the other. There is a difference if you include the last step.

If you match these at one current, say 1 mA (common test current), you are already ahead of the game. To complete a great job, thermally tie the pairs together. Now they track.

-Chris

DonoMan · 2005-02-28 1:18 am

You can choose different resistor values for each transistor to try to account for different gains. Though matching transistors is better.

K-amps · 2005-02-28 7:08 pm

DonoMan said:
You can choose different resistor values for each transistor to try to account for different gains. Though matching transistors is better.

Base resistors or emitters or both?

DonoMan · 2005-02-28 8:22 pm

Just a base resistor should do it, but don't change the DC offset.

I THINK (and someone please correct me if I'm wrong) that if Q1 HFE = 100 and Q2 HFE = 200, then R2 = (200 / 100) * R1

anatech · 2005-02-28 11:19 pm

I don't know about that. Why not just match them since you have measured them???

-Chris

K-amps · 2005-03-01 2:34 am

anatech said:
I don't know about that. Why not just match them since you have measured them???

-Chris

Cause you maybe dont have extras... ;-)

anatech · 2005-03-01 2:57 am

Arrrrrgh. I'm down to my last 2. How sad. :bawling:

senee · 2005-03-01 10:40 am

Hi Chris,

I would like to know your statistic for quantity of transistor to buy for matching 2 NPN TR. and 2 PNP TR. and what the brand is easyly to matching

I think, If we matching Hfe and Vbe is very difficult.

I am making a fully symmetry amp. I need matching the first diff. amp state. My idea, If we only matching NPN or PNP is not good sound becuase the half of positive wave and the half of negative wave is not symmetry. It is effect to bed sound.

Thanks,

Senee Somma
:smash:

K-amps · 2005-03-01 12:54 pm

I have found my batch of mj21195/96's very well matched. Then again I have a tray and pick adjecant parts...

anatech · 2005-03-01 10:38 pm

Hi Senee,
I normally buy signal transistors in lots of 20 or 40. Generally speaking I can get a decent match in pairs that way. I don't bother matching VBE, hFE is more important. I match them around 1mA collector current, but any suitable value will work. I get very good results this way.
In equipment I service and match diff pairs, they always sound better unless the amp is a piece of scrap to start with. Phase Linear and SAE respond well as do Haflers. So don't become so worried about it.
I match drivers and outputs also. Can make a difference.
-Chris

thanh · 2005-03-07 2:47 am

Base resistors or emitters or both?

i think resistor of emitter of Vas
in orcad,with identical model amp still has offset voltage .Changing the value of it ( resistor of emitter of vas) will decrease offset voltage but i dont know whether the sound get better

anatech · 2005-03-08 12:12 am

The differential pair only works properly when the gains are matched. To get rid og offset, inject a small current into one side of the diff. pair. This is what everyone did before servo amps. Marantz put temperature compensation in as well. Neat huh?

-Chris

31697B · 2019-03-14 12:37 am

Try this. Find your own values for the transistors you are matching.

-RNM

View attachment Compl matcher circuit.pdf

kct · 2019-03-14 12:49 am

senee said:
Hi,
Anyone to know, How to matching PNP with NPN Transistor?
I buy 2N5551= 20 ea. and 2N5401 = 20 ea. then hFE measure is more difference

hFE of 2N5551 = 110 to 130
hFE of 2N5401 = 210 to 230

I am making the power amplifier, when I put them in the circuit, It may be not good sound.

Have anyone suggestion?

sorry!!! My english is not good.

Senee

This little jig might help you.

anatech · 2019-03-14 1:29 am

Hi Richard,
Neat circuit, thank you. I guess R3 and R4 depend on the beta of the transistors?

Hi kct,
I see yours is fixed which measures level of match without the null pot. Another good idea, thank you.

-Chris

How to matching PNP with NPN Transistor

Member

Administrator

Member

R.I.P.

Member

Administrator

Member

Member

Member

Administrator

Member

Administrator

Member

Member

Administrator

Member

Administrator

Disabled Account

Member

Attachments

Administrator