Question about transistors

Recording Techniques, People Skills, Gear, Recording Spaces, Computers, and DIY

Moderators: drumsound, tomb

Post Reply
honkyjonk
dead but not forgotten
Posts: 2182
Joined: Wed May 07, 2003 10:50 pm
Location: Portland

Question about transistors

Post by honkyjonk » Thu Mar 09, 2006 5:25 pm

What do you look for in a replacement transistor?
By that I mean,

If a transistor says AAMPS 8098 EBC, what is the important part in those numbers/letters to find in a replacement?
I'm guessing the "AAMPS" is just the brand name right? What do the 8098 EBC stand for?

Other ones:

AAMPS 2222A EBC

What about these: "TIS58", "TIS50"- What are the "TIS" and the following numbers referring to?

[/i]

User avatar
rolandk
buyin' gear
Posts: 535
Joined: Sun May 18, 2003 4:52 pm
Location: Portland, Oregon
Contact:

Post by rolandk » Thu Mar 09, 2006 7:08 pm

EBC is the pin layout: Emitter, Base, Collector. Awful nice of them to print it on there.
my band: Mission 5

honkyjonk
dead but not forgotten
Posts: 2182
Joined: Wed May 07, 2003 10:50 pm
Location: Portland

Post by honkyjonk » Thu Mar 09, 2006 8:21 pm

Hey Roland,

Are you saying awful nice in a sarcastic sort of way because the legs are always configured the same way? Or are they actually sometimes configured say, ECB, or something?

User avatar
rolandk
buyin' gear
Posts: 535
Joined: Sun May 18, 2003 4:52 pm
Location: Portland, Oregon
Contact:

Post by rolandk » Thu Mar 09, 2006 8:53 pm

I was being serious, they can be configured in different ways and sorting it out can be a PITA sometimes. You either have to look up the transistor data sheet or look on the schematic and go something like "Uh, lets see here, the emitter goes to R13", then measure from R13 to each leg of the transistor until you find the one with continuity and repeat for the other legs.
my band: Mission 5

xonlocust
tinnitus
Posts: 1228
Joined: Wed May 07, 2003 3:38 pm
Location: Chicago
Contact:

Re: Question about transistors

Post by xonlocust » Thu Mar 09, 2006 9:33 pm

honkyjonk wrote: What about these: "TIS58", "TIS50"- What are the "TIS" and the following numbers referring to?
texas instruments. usually the first thing i do in similar situations is go to the big guys, mouser, newark, digikey, and search for the part # as listed on the part. most times they have a match. if not, hit google. i hit mouser and newark and didnt find anything, but google turned up this:

http://www.1sourcecomponents.com/partinfo/tis58.htm

somewhat confusing cuz TL074 are super common in audio shite. that is also texas instuements. (TL, not TIS). OPA is burr brown, which is now TI. AD - analog devices. those seem to be the major ones.

i could be wrong, i've had a few...

nclayton
steve albini likes it
Posts: 323
Joined: Sat Feb 11, 2006 8:08 am

Re: Question about transistors

Post by nclayton » Fri Mar 10, 2006 9:11 am

honkyjonk wrote:What do you look for in a replacement transistor?
By that I mean,

If a transistor says AAMPS 8098 EBC, what is the important part in those numbers/letters to find in a replacement?
I'm guessing the "AAMPS" is just the brand name right? What do the 8098 EBC stand for?

Other ones:

AAMPS 2222A EBC

[/i]
In the case of these two transistors the AA must have something to do with the manufacturer. The actual part numbers are MPS 8098 and MPS 2222A. MPS is a pretty common prefix for transistors. The MPS 2222A is equivalent to a 2N2222 I believe, which, last time I checked (probably years ago, to be honest) you could get at Radio Shack. The MPS8098 is not much harder to find, it's current production by fairchild and others, and I know Mouser has it. According to Mouser it's basically equivalent to 2N3904, which is super common and I think radio shack probably has it in stock. Most MPS number transistors are selected from a more general transistor process, and I'm not sure what the 8098 is selected for. I don't know if it's low noise, or narrower HFE range or what, but chances are you could use a 2N3904 and not have noticeable degradation of performance, but I'm not sure.

Ned

honkyjonk
dead but not forgotten
Posts: 2182
Joined: Wed May 07, 2003 10:50 pm
Location: Portland

Post by honkyjonk » Fri Mar 10, 2006 10:55 am

awesome.

Good info. Thanks Ned.

User avatar
bantam
suffering 'studio suck'
Posts: 480
Joined: Sun Oct 12, 2003 3:55 pm
Location: boston MA
Contact:

Post by bantam » Fri Mar 10, 2006 4:32 pm

is there a sonic difference in say one brand of 2N2222 and another. I know theres a hell of alot of difference in tubes, do the same rules apply?

Family Hoof
buyin' a studio
Posts: 877
Joined: Mon Apr 19, 2004 5:30 pm
Location: NYC
Contact:

Post by Family Hoof » Fri Mar 10, 2006 10:51 pm

buschfsu wrote:is there a sonic difference in say one brand of 2N2222 and another. I know theres a hell of alot of difference in tubes, do the same rules apply?
IMHO, the answer is sometimes. TONS of different devices have been labeled with the 2222 spec, so in this case the answer is undoubtedly yes. A transistor device number has a certain set of specifications associated with it. The specs may be many or few, rigid or loose, leading various manufactures to interperet them differently. I personally have noticed sonic differences between different brands of a device in the following situations: when one is old and one is new (different fabrication processes over time), when one has seen much use and the other is brand new (P-N junctions may wear), when the device has loose specs e.g. 2N3055. And I really don't think such things are audible in most cases, only in simple circuits with very few transistors. Regardless, I believe it is usually the tolerance of operating characteristics within one brand that makes the biggest difference, not the difference between brands.


Also, for anyone who is still confused, transistors are labeled in the following format:

1. a prefix, such as "BC", "2N", "PN", "TIS", "MPSA", "MPS", "MJE", etc.
2. followed by the device number, almost always 4 or 3 digits long.
3. and sometimes a suffix of 1 to 3 letters. For example, the letters A, B, and C can be used to classify current gain (hfe) ranges. Other letters such as K or L may indicate a different order of pins, and there are now new combinations of suffix letters to indicate lead-free status. Then again, the suffix letter may be part of to the device # in some cases.
4. There are exceptions to the aforementioned format, often for specialty devices and certain companies like Sanyo.


AND, one of the most important websites you will ever use to find transistors --- http://www.findchips.com/

honkyjonk
dead but not forgotten
Posts: 2182
Joined: Wed May 07, 2003 10:50 pm
Location: Portland

Post by honkyjonk » Sat Mar 11, 2006 12:27 pm

Okay, I found these at mouser:
For the MPS8098 and MPS2222A:

MPS2222A- http://www.mouser.com/index.cfm?handler ... tid=340249

MPS8098- http://www.mouser.com/index.cfm?handler ... tid=249983

One is Vishay, the other is fairchild. I'm guessing these will suffice. The reason i'm asking is because I bought a broken echoplex EP4 for cheap from a guy, and I'm digging into it right now. In addition to replacing the electrolytic caps, I'm going to try and replace the transistors too because he had mentioned that he thought there might be a bad transistor. Anyway, it's just heresay, but these replacements will do, yes?

Any other info is surely appreciated. Thanks for the link Hoof!

honkyjonk
dead but not forgotten
Posts: 2182
Joined: Wed May 07, 2003 10:50 pm
Location: Portland

Post by honkyjonk » Sat Mar 11, 2006 5:03 pm

Hey guys,

one more question,

Would it be reasonable to assume if I found a Texas Instruments transistor with the part number TL58 or TL058 that it would be a suitable replacement for the TIS58 transistor?

nclayton
steve albini likes it
Posts: 323
Joined: Sat Feb 11, 2006 8:08 am

Post by nclayton » Sun Mar 12, 2006 9:42 am

honkyjonk wrote:Hey guys,

one more question,

Would it be reasonable to assume if I found a Texas Instruments transistor with the part number TL58 or TL058 that it would be a suitable replacement for the TIS58 transistor?
No. I believe TL prefixes are always for integrated circuits, TIS for discrete transistors, so they don't stand a chance.

The TIS58 is an N channel J-FET. This must have been obsoleted a long time ago because my 1969 "vintage" TI transistor data book says of the TIS58 "2N5949 thru 2N5953 are recomended for new designs". It also claims the 2N5953 is the closest equivalent, however, the pinout is different. If you're not sure this transistor is bad, I wouldn't replace it (actually I think that advice should apply to all the transistors you're thinking about replacing, but I know you're having fun).

Regarding transistor manufacturers, don't worry about it. There's not a premium "sound" transistor manufacturer. That's not to say that finding the exact right transistor for a circuit won't make a difference sometimes, but just that transistors from the exact same manufacturer and exact same batch vary so incredibly wildly from sample to sample that any hypothetical differences between manufacturers would be totally swamped (I mean this only with regard to the "sound quality" question...I think there are important manufacturer variations with regard to some transistor qualities, but most of these belong in the reliability category and aren't too important with small signal transistors like you're trying to replace.)

Speaking of all this, if any of the transistors you're considering replacing have painted-on stripes or dots that means they were selected, and you probably don't just want to stick any old transistor in there, even if it's the exact same model number. I'd also put these into the group you should resist the temptation to replace unless you know for sure they're bad.

Ned

honkyjonk
dead but not forgotten
Posts: 2182
Joined: Wed May 07, 2003 10:50 pm
Location: Portland

Post by honkyjonk » Sun Mar 12, 2006 10:24 am

Cool,

Okay, thanks Ned.

I'm placing a mouser order for some other stuff too so I'll order them, but I'll hold off on replacing them just yet.

Thanks so much,

Jon

Post Reply

Who is online

Users browsing this forum: No registered users and 42 guests