[sdiy] ARP VCO PNP-NPN exponential pair matching

[Csaba Zvekan]

If you ever need to pair/match  NPN-transistors you might want to look  
into building this also:

http://www.csaba.ch/index.php?option=com_content&task=view&id=14&Itemid=30

:)

Csaba


On Jun 8, 2008, at 7:32 AM, Dave Manley wrote:

> Dave Leith wrote:
>> I would like some advice on matching the ARP VCO exponential pair.
>> I've searched the archives and the only advice I found was - that  
>> they
>> don't need matching - either they are going to be OK and work or they
>> will be so far off that you should try another pair. Any other tips  
>> or
>> procedure that you would recommend?
>>
>> The circuit is in the standard PNP-NPN exponential pair Arp Odessey
>> (ver 2 and up) ARP Axxe VCO or ARP 4027-1 VCO module (can be found on
>> http://www.till.com/arptech/modmain.htm)
>>
>>
> The typical matching process is to pump a known current through each  
> transistor at the
> same temperature and measure the Vbe.
>
> There's a Moog transistor matching circuit about halfway down this  
> page:
>
> http://www.diyaudio.com/forums/showthread.php?threadid=43304
>
> -Dave
>
>
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