Paradise Builders

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#2,361
Bksabath said:
Strange that you get so poor match which brand did you buy?
Of the 3000 I have the Diotech show tight Hfe groupings

I still have problem matching PNP to NPN after 4 different orders to get different batches
but I have loads of matches whitinn the Type.

How did you mesure them and expecialy how constant is the ambient temperature

I am prety sure that like Simon is just question of luck to get the right batch
Click to expand...

That was exactly my problem. Tight matching in the same type but poor matching between NPN and PNP. These were Diotec from SOS Electronic, 4000 purchased (I thought they will be enough) with a difference of approx 70 between the averages. Ended up with 2000 more (CDIL, Fairchild, NOS ITT, and NOS Siemens) sourced from various suppliers... Measured several times each, until I built the fixture with the fan blower, and final matches were done at the same temperature.

I must admit, this was the Hell out of Paradise build , but you must have both or nothing 🙂
 
#2,362
metallicus69 said:
Measured several times each, until I built the fixture with the fan blower, and final matches were done at the same temperature.

I must admit, this was the Hell out of Paradise build , but you must have both or nothing 🙂
Click to expand...

Yes Hell but is worth the efort (I can promise you this)
I was doing most of the measuring in a cold loft with a lamp to keep the litle critters warm and a termometer to mesure the temperature near by

So how warm is the air you blowing then? and in the morning?
There is going to be same difference no mather what. just mesure the 3000 and sort then sort with finer match and then again and again

Funny....I still have the gigles as at the begining some one was making acusation that the GB transistors where pre sorted so it was not possible to get PNP and NPN match 😀
 
#2,364
Just to clairfy.

I will send small numbers of transistors out where people tell me exactly what value and how many they need. I won't send out 36 to one person, but i will help you finish your matching.

Some measurements from my last boards. All shunt outputs set to 18.5 volts.

Left channel
Op-amp pin 6 1.2v, (wanders 5mv)
Riaa 400mv wanders 50mv+/-
Vcascl 15.10v
Vcasch 15.11v
Input offset 0.0

Right channel
Op-amp pin 6 1.25v, (wanders 5mv)
Riaa 400mv wanders 50mv+/-
Vcascl 15.12v
Vcasch 15.09v
Input offset 0.0v

The matching on these voltages is at least 10x better than my first build- and my first build sounded great.
 
#2,366
sq225917 said:
Just to clairfy.

I will send small numbers of transistors out where people tell me exactly what value and how many they need. I won't send out 36 to one person, but i will help you finish your matching.

Some measurements from my last boards. All shunt outputs set to 18.5 volts.

Left channel
Op-amp pin 6 1.2v, (wanders 5mv)
Riaa 400mv wanders 50mv+/-
Vcascl 15.10v
Vcasch 15.11v
Input offset 0.0

Right channel
Op-amp pin 6 1.25v, (wanders 5mv)
Riaa 400mv wanders 50mv+/-
Vcascl 15.12v
Vcasch 15.09v
Input offset 0.0v

The matching on these voltages is at least 10x better than my first build- and my first build sounded great.
Click to expand...

These measurement look good, very good, exceptionally good, amazing! 🙂
You have a (almost) 1% match between the channels, nice!
 
#2,372
Hfe classification for 2SA970 and 2SC2240
GR:200-400
BL:350-700

I haven`t tried on this circuit for compatibility.
Beside having difference pins out, they do have difference electrical parameters.
I am afraid a direct substitute without altering the values of other components would work.
 
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