Need some TO-3 power transistors for a couple of vintage 60W and 100W amps I'm restoring, and someone pointed me to All Electronics. The transistors are Toshiba 2SD424's and 2SB554's The 2SB554 is only $3.75 U.S each and the 2SD424 is only $2.75 each. This seems real, real low to me...
Doesn't seem like these would be likely candidates to counterfitting, since they are kind of run-of-the-mill, but then again, the normal price I've seen for these devices is about $8-$10 or so.
So, I have some on order. What to look for guys? Steel case certainly, but what else? And how should I go about testing them (i.e., trying to break 'em?) I have a couple of dummy loads, should I just crank the amp up to 60W output and see if it can take it for an hour?
Any suggestion is welcome...
Doesn't seem like these would be likely candidates to counterfitting, since they are kind of run-of-the-mill, but then again, the normal price I've seen for these devices is about $8-$10 or so.
So, I have some on order. What to look for guys? Steel case certainly, but what else? And how should I go about testing them (i.e., trying to break 'em?) I have a couple of dummy loads, should I just crank the amp up to 60W output and see if it can take it for an hour?
Any suggestion is welcome...
You could also try to swap them with the nice big Motorola's MJ15015 and MJ15016. Halojoy's favorites. Should be On-Semiconductor these days..
/ Hugo - Lost in manufactures land..
/ Hugo - Lost in manufactures land..
Well...no one is selling the Motorola's that cheap, and if the Toshiba's are real and not counterfit, they should be about perfect for a 60-100 watt amp. If you know of a US supplier with decent prices on the Motorola devices, by all means let me know...
But still, any other suggestions on what to look for or how to test them?
But still, any other suggestions on what to look for or how to test them?
Replacement for 2SD424 and 2SB554
Hi EchoWars,
As these transistors were used in the GAS Ampzilla and now obsolete James Bongiorno, the designer of the beast, recommends ONsemi: MJ21193 and MJ21194. These are TO-3. I did the replacement in my own Ampzilla and noticed slightly better sound at very high volume. Well that is on efficient Klipschorns.
These transistors are available from www.farnell.com
Hope this helps
Halojoy MJ15015 too slow......
Hi EchoWars,
As these transistors were used in the GAS Ampzilla and now obsolete James Bongiorno, the designer of the beast, recommends ONsemi: MJ21193 and MJ21194. These are TO-3. I did the replacement in my own Ampzilla and noticed slightly better sound at very high volume. Well that is on efficient Klipschorns.
These transistors are available from www.farnell.com
Hope this helps
Halojoy MJ15015 too slow......
This is getting to be a bigger and bigger problem of late.
People will readily sustitute a particular type of device say a well respected TO3 packaged N Channel power MOSFET such as an IRF140 with a cheaper N channel powerfet that uses the same package. All you need to do is rub off the old silk screening and print on the new. If you buy up big job lots for cheap there are huge profits to be made. (Even more if you do it with chips, maybe an AD797 subbed with an NE5534)
Provided that the electrical behaviour is kind of close, many folks will never pick the difference.
Where it all starts to fall down is when people are building ccts that need close matching or run close to the power, voltage, current or dissapation limits.
Companies that buy in "distress" or "run out" stock often get swindled into buying dodgy components in this way and unknowingly passing onto their customers substandard items.
My personal thought is that if it looks too good to be true, it probably is.
My own experience is as follows:
Farnell in Australia will sell me single AD797's (which I want for an upcoming project) at about 32 dollars Australian each (16 dollars US). They have a pretty vicious markup and I could get them for about 75% of that if I purchased 1000 instead of 2.
By buying offshore in the US I can get them for about 8 dollars US each but then have to pay freight plus import duty if applicable and also wear the loss if they go missing (or pay for insurance).
I either pay extra and Farnell cops all the risk or I take my chances and save a bit. My choice.
BUT
If there was someone in Australia who said that they could sell me 797's for $10 OZ each I'd have expect that they were either stolen or were re-silkscreened NE5534's.
No free lunch I'm afraid.
Anything below 50% of the single item purhcase price for small orders simply has to be regarded with suspicion.
The only way i can think of to test one is to find out EXACTLY waht all the perameters are supposed to be and put one through hell. If it has the right Gain, handles the max continuous current continuously, tolerates the max rated voltages and voltage differences and so forth when properly heatsinked then I guess things are ok.
Does it look, swim and quack like a duck?
drew
People will readily sustitute a particular type of device say a well respected TO3 packaged N Channel power MOSFET such as an IRF140 with a cheaper N channel powerfet that uses the same package. All you need to do is rub off the old silk screening and print on the new. If you buy up big job lots for cheap there are huge profits to be made. (Even more if you do it with chips, maybe an AD797 subbed with an NE5534)
Provided that the electrical behaviour is kind of close, many folks will never pick the difference.
Where it all starts to fall down is when people are building ccts that need close matching or run close to the power, voltage, current or dissapation limits.
Companies that buy in "distress" or "run out" stock often get swindled into buying dodgy components in this way and unknowingly passing onto their customers substandard items.
My personal thought is that if it looks too good to be true, it probably is.
My own experience is as follows:
Farnell in Australia will sell me single AD797's (which I want for an upcoming project) at about 32 dollars Australian each (16 dollars US). They have a pretty vicious markup and I could get them for about 75% of that if I purchased 1000 instead of 2.
By buying offshore in the US I can get them for about 8 dollars US each but then have to pay freight plus import duty if applicable and also wear the loss if they go missing (or pay for insurance).
I either pay extra and Farnell cops all the risk or I take my chances and save a bit. My choice.
BUT
If there was someone in Australia who said that they could sell me 797's for $10 OZ each I'd have expect that they were either stolen or were re-silkscreened NE5534's.
No free lunch I'm afraid.
Anything below 50% of the single item purhcase price for small orders simply has to be regarded with suspicion.
The only way i can think of to test one is to find out EXACTLY waht all the perameters are supposed to be and put one through hell. If it has the right Gain, handles the max continuous current continuously, tolerates the max rated voltages and voltage differences and so forth when properly heatsinked then I guess things are ok.
Does it look, swim and quack like a duck?
drew
Counterfeit Toshiba's???
HaHaHa,
Nice line with the duck!
Even if the Toshiba's were original I did not want them for the following reason:
Toshiba made the clearance between the case and the emittor and base lead very small. Also the kind of alloy is very soft. Because of vibration the alloy smears over the gap making a hard short circuit blowing up the whole amplifier.
The Onsemis have much more clearance and a different kind of alloy.
One nice thing of Farnell is they don't sell you a replacement part but excatly the original. I received TL431 from Nedis without any brand name on it!😎
Hi drew,DrewP said:
HaHaHa,
Nice line with the duck!
Even if the Toshiba's were original I did not want them for the following reason:
Toshiba made the clearance between the case and the emittor and base lead very small. Also the kind of alloy is very soft. Because of vibration the alloy smears over the gap making a hard short circuit blowing up the whole amplifier.
The Onsemis have much more clearance and a different kind of alloy.
One nice thing of Farnell is they don't sell you a replacement part but excatly the original. I received TL431 from Nedis without any brand name on it!😎
counterfeit
Well, the Farnell prices really are no use for comparing. They will ship single items and pay the freight (in Holland and Belgium, at least). Of course they have a huge markup, you pay for your convenience. If you can accept that OK, I use them regularly. BUT I have seem cases that their price was 4 times the 10+ price at a distributor, who of course also had a healthy profit. So, if you get an offer for 1/3 of the Farnell price that doesn't mean it is counterfeit.
Jan Didden
PS Elso, you have Klipschorns?? We need to talk once mine are up and running in a month or so.
Well, the Farnell prices really are no use for comparing. They will ship single items and pay the freight (in Holland and Belgium, at least). Of course they have a huge markup, you pay for your convenience. If you can accept that OK, I use them regularly. BUT I have seem cases that their price was 4 times the 10+ price at a distributor, who of course also had a healthy profit. So, if you get an offer for 1/3 of the Farnell price that doesn't mean it is counterfeit.
Jan Didden
PS Elso, you have Klipschorns?? We need to talk once mine are up and running in a month or so.
Is someone operating an earthmover near your stereo gear? I can't imagine vibration severe enough to distort a metal transistor case.
Obsolete does not mean 'bad' or 'unusable'. The transistors that these Toshiba's will replace are rated for lower gain, lower voltage, and lower current. I've got a pile of vintage amps where damn near every transistor in it is 'obsolete'. They sound wonderful. Again, the Motorola's might be great, but in the quantities I need there is no way I can afford them (free lunch or no...I don't want a free lunch, but how about an affordable one?) Again, consider that these are kind of plain-Jane output devices, and common sense says that there would be little sense in counterfitting them.
However:
Perhaps when I get the parts in I'll post a few pics of 'em. But certainly I'm going to try and blow 'em up once installed. But if I see anything strange about them then I doubt I will even try them...don't feel like replacing a mess of transistors because some clown in China needed to pay for a new water buffalo.
Vibration, counterfeit transistors
No I don't have a earthmover next to my amp but the Ampzilla has a huge 1.5kW transformer that IS buzzing and also a fan near the transistors. It takes quite some time to get the shortcircuit but the clearance in my Toshiba's is VERY small.
If you want a free luch try to get a sample. I find the Farnell prices quite reasonable, also considering I don't have to pay any shipping and handling USA based firms are famous for.😉
If you want simple replacement for cheap amplifiers just use 2N3055 and MJ2955 or perhaps the parts suggested by Halojoy or MJ15024 and 15025 as cheap alternatives.
Janneman, Yes I own Klipschorns now for 29 years...... Oops that makes me feel old..🙄
Hi EchoWars,EchoWars said:
No I don't have a earthmover next to my amp but the Ampzilla has a huge 1.5kW transformer that IS buzzing and also a fan near the transistors. It takes quite some time to get the shortcircuit but the clearance in my Toshiba's is VERY small.
If you want a free luch try to get a sample. I find the Farnell prices quite reasonable, also considering I don't have to pay any shipping and handling USA based firms are famous for.😉
If you want simple replacement for cheap amplifiers just use 2N3055 and MJ2955 or perhaps the parts suggested by Halojoy or MJ15024 and 15025 as cheap alternatives.
Janneman, Yes I own Klipschorns now for 29 years...... Oops that makes me feel old..🙄
if you consider the normal markup
the price at Allied Electonics is about 2X the price at All Electronic -- nothing out of the ordinary.
if you have a problem with a device that a big distributor like Newark, Allied, Avnet, (Avnet owns Allied), Pioneer etc. have, they most likely will take it back, so you pay a markup and you get reliability.
the price at Allied Electonics is about 2X the price at All Electronic -- nothing out of the ordinary.
if you have a problem with a device that a big distributor like Newark, Allied, Avnet, (Avnet owns Allied), Pioneer etc. have, they most likely will take it back, so you pay a markup and you get reliability.
FWIW, I've bought assorted items at All Electronics on numerous occasions, and even had to return a few. Never a problem, so if the transistors need to go back I anticipate zero issues.
Interestingly enough, I have since found a source for the Motorola components that is only a little more expensive than the Toshiba's that I have on the way. Wish I had found them before...oh well. If the Toshiba's are authentic they should do the job quite nicely (as long as I avoid the earthmovers🙂 )
Interestingly enough, I have since found a source for the Motorola components that is only a little more expensive than the Toshiba's that I have on the way. Wish I had found them before...oh well. If the Toshiba's are authentic they should do the job quite nicely (as long as I avoid the earthmovers🙂 )
BTW, received the transistors in today. There is nothing 'soft' about the steel case (I can barely scratch it with a machinists scribe), and the emitter/base lead clearance to the case looks pretty standard. The lettering looks fine and will not wipe off with acetone. I will install tonight and put the amp through a torture test, but these devices are almost certainly authentic.
OK..not that anyone is paying attention, but the Toshiba's passed the torture test. After blowing a few drivers using my patented 'fumble-fingers' technique, I ran the amp for 1 hour at 1/3 rated power (20W output) to burn the suckers in. Heatsink got hot enough to cook breakfast, but the amp didn't so much as hiccup. After that, 1 hour at full rated power. Again, not a problem.
Looking good...if anyone is looking for a fairly cheap source of output devices for an amp up to about +/-65V supply, these should work pretty well.
All Electronics
Looking good...if anyone is looking for a fairly cheap source of output devices for an amp up to about +/-65V supply, these should work pretty well.
All Electronics
Hi Echowars,
Just so as you know, at least I have been paying attention.
Glad to see your amp is working again. Also glad to hear that I
am not the only one with a 'fumble-fingers technique'.
Regards,
Tim
Just so as you know, at least I have been paying attention.
Glad to see your amp is working again. Also glad to hear that I
am not the only one with a 'fumble-fingers technique'.
Regards,
Tim
Hi Tim...
Sorry, I'm the fumblefingers pro. I put this thing together and was adjusting bias current, and slipped with my leads, taking out both drivers for that channel (the Toshiba output devices were unfazed! Nice...)
So I replace 'em. Go in to adjust bias again, telling myself to be careful this time! ............and I did it again!!! I was so PO'ed I had to go take a walk and a good swig of some nice Cognac (one thing the French do right😉 ) Second time only the PNP driver blew.
Anyway, amp works great as long as I put it back together and leave it the hell alone...
Me happy...mostly.
Sorry, I'm the fumblefingers pro. I put this thing together and was adjusting bias current, and slipped with my leads, taking out both drivers for that channel (the Toshiba output devices were unfazed! Nice...)
So I replace 'em. Go in to adjust bias again, telling myself to be careful this time! ............and I did it again!!! I was so PO'ed I had to go take a walk and a good swig of some nice Cognac (one thing the French do right😉 ) Second time only the PNP driver blew.
Anyway, amp works great as long as I put it back together and leave it the hell alone...
Me happy...mostly.
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