Matching a pair of 2N3391A transistors for Rhodes Vibrato

[Skiroy]

I need a pair of matched 2N3391A transistors in the link

Mouser Electronics - Electronic Component Distributor 2N3391A

Is there anyway to get a matched pair because I was told if not the vibrato with fluctuate at slightly different rates causing issues in the sound. I know VV supposedly matches the transistors for you but I have to spend another $30.00 to make the order for $1.00 worth of parts. They are way over priced and I have alot of money into them already where I had no choice. But I hope that I can manage to get a pair of $.45 transistors.

Any info is appreciate. If I were to order 10 of them I should be able to match 2 right? Is there that much variation in them? How do you match them? Is it based of the Beta reading you get on the multimeter in diode mode to test for shorted junctions?

Thankx

[jrfrond]

Matching junction voltage will get you roughly in the ballpark, but they SHOULD be matched on a good transistor tester.

Matching is hit and miss. You may have to go through one or several dozen to find a perfect match, and time is money, hence the higher cost. We charge $5.00 ea for those if matching is required.

[doctor]

Matching junction voltage will get you roughly in the ballpark, but they SHOULD be matched on a good transistor tester.

Matching is hit and miss. You may have to go through one or several dozen to find a perfect match, and time is money, hence the higher cost. We charge $5.00 ea for those if matching is required.

Hi Skiroy,

Can you upload schematic, for which you want to use matched pair of transistors?
I doubt very much that you really need matched pair. Parameters of the same part number transistors that manufactured by modern industry differ very slightly (less then 1% in the same batch). Matching made sense in the seventies when transistors could vary by tens of percent. For this reason requirement of the matching was designated on the schematic. Today this designation may be used by unscrupulous companies in order to get money from shorn lambs and snobs.

[Skiroy]

Hi Skiroy,

Can you upload schematic, for which you want to use matched pair of transistors?
I doubt very much that you really need matched pair. Parameters of the same part number transistors that manufactured by modern industry differ very slightly (less then 1% in the same batch). Matching made sense in the seventies when transistors could vary by tens of percent. For this reason requirement of the matching was designated on the schematic. Today this designation may be used by unscrupulous companies in order to get money from shorn lambs and snobs.

Well mine is a 80watt peterson suitcase preamp.

Skip to 5:00 on this video and he expalins it.
Fender Rhodes Suitcase Piano Pre Amp Repair Pt.1 - YouTube


By the way he explains earlier in the vid that when testing the junctions the beta should be betweew 4-7. One of mine is at 856 so I assume its faulty right?

[doctor]

Well mine is a 80watt peterson suitcase preamp.

Skip to 5:00 on this video and he expalins it.
Fender Rhodes Suitcase Piano Pre Amp Repair Pt.1 - YouTube


By the way he explains earlier in the vid that when testing the junctions the beta should be betweew 4-7. One of mine is at 856 so I assume its faulty right?

Try to use the BC548B as a replacement (see attached datasheets).
Pay your attention that BC548B pin arrangement differs from 2N3391/92 one.

[gbono]

I doubt very much that you really need matched pair. Parameters of the same part number transistors that manufactured by modern industry differ very slightly (less then 1% in the same batch). Matching made sense in the seventies when transistors could vary by tens of percent. For this reason requirement of the matching was designated on the schematic. Today this designation may be used by unscrupulous companies in order to get money from shorn lambs and snobs

+1 Start with transistors with matching date codes.

[Enzo]

And if I had no 3391s, I might reach for a couple other general purpose xstrs like 2N4401 or whatever.

[J M Fahey]

Skiroy, you understood it upside down.
He´s not measuring *beta* but Vbe and Vcb.
And when he says "between 4 and 7" he means "between .4 and .7 Volts"
Quite imprecise talking chap.
Please avoid taking You Tube videos as the Gospel.