2sc2240 as 2sc458 replacement

[toddbailey]

I'm planning on replacing 12 2sc458 with 2sc2240

MCM has toshiba parts in stock for .30 us each.
They also list a panasonic P-2sc2240gr, out of stock at 6.58 each

both are to-92 based parts so why the huge price difference?

[sgrossklass]

30 cents a pop is plenty for small-signal transistors like these. Pricing of out-of-stock items can be arbitrary, so I wouldn't read too much into that.

[toddbailey]

Yet some will spend over $10 for a boutique cap or resistor. Hmmm ?
I just wanted to find out if there is a good reason to pay more for a panasonic part over the toshiba brand. NTE lists their replacements at over $2.00 ea
Personally, I quite sure the "generic" will sound better than the noisy oem 2sc458 currently in the deck. The deck has 12 of them so co$t is a factor, MCM gave me a qty discount .28 ea. such a deal. $9 bucks to ship $4 in parts, something wrong here...

[homemodder]

Id say stick to the cheaper toshibas, panasonic never manufactured the 2sc2240, its probably a misprint or mistake by MCM.

But I suggest the first thing you do is some maths from BJT noise theory if the idea is for improving noise figures, not all is as its seems on the datasheets. 2sc458 looks like a very good transistor to me.

[toddbailey]

I'm just a messenger here, having a limited understanding of trans. specs. The issue I'm having with the 458 is similar to other posts regarding an Akai r2r GX235 with excessive noise w or w/o any signal present. white noise with low freq rumble, about the same level as a fm tuner with muting off and between stations. And it's intermittant.

Many have posted that the original 458 fails or degrade and introduce noise into the signal. Several posted the 2240 as a excellent replacement. Considering the cost of the sub, I went ahead and ordered a small quantity, and I'll just do a wholesale replacement. A newer 458 will probably fix the issue but I didn't find any stock, other than nte's replacement. But at apx $1.50 ea, I decided to go with Mcm's stock of the 2240 over Nte's replacement.

[homemodder]

Could be, I havent ever experienced transistors degrade myself but some coleages of mine have assured me in the past that it has happened.
It wouldnt be a much of a financial loss anyway if you can get the toshibas for 30 cents, nothing like trying.

[Ian Finch]

The 2sc2240 seems a wasted part anyway. As it is no longer in production, the prices of NOS can be as high as sellers like.
The 2sc458 and similar 2sc2310 are only 30V and 50V parts so you have a much larger range than high voltage types like the 2240 used in power amplifiers. It's quite likely even BC549C/550C will also deliver quite low noise. The best may be 2SC2547, also Renesas, very low noise and still produced. What's more. MCM only ask 74 cents, so prospects for lower prices again look good.

Just how low noise you actually get depends on the individual applications as much as the silicon..

[NMOS]

Originally Posted by Ian Finch

The 2sc2240 seems a wasted part anyway. As it is no longer in production, the prices of NOS can be as high as sellers like.
The 2sc458 and similar 2sc2310 are only 30V and 50V parts so you have a much larger range than high voltage types like the 2240 used in power amplifiers. It's quite likely even BC549C/550C will also deliver quite low noise. The best may be 2SC2547, also Renesas, very low noise and still produced. What's more. MCM only ask 74 cents, so prospects for lower prices again look good.

Just how low noise you actually get depends on the individual applications as much as the silicon..

2sc2547 its same like 2sc2240 not recommended for new design

[quadtech]

I used 2SC1815 (or KSC1815) to replace 2SC458 on the phono
board in a Marantz 2270.