Good place to buy obsolete semiconductors?

[Axtman]

I am working on few amps that may need a few obsolete semiconductors. (I sure hope not.) Where is a good reliable place to buy them? Thanks.

[Chuck H]

Where's Juan!!! Dammit! He's been absent too long now. I've had to ask this question twice in as many weeks when questions came up that were right up his alley('s he mas many) of expertise.

You might try PMing him. If he's set up for email notification and he reads it you might get a response.

[TomCarlos]

Perhaps the Parking Lot forum should have a new sub-forum called "Wanted." It would be there that we could post items we are seeking. Heck, I've got a small stash of Peavey parts just sitting around waiting to find their way to a new home.

I have successfully used the "Wanted" approach with Craigslist too. On numerous occasions, I post a "Wanted to buy ..." title looking for cheap or project amps. All too often, I get plenty of calls. I am amazed that guys monitor Craigslist daily but too lazy to create ads to sell their stuff.

Just a thought....

[Enzo]

If you have parts looking for a home, we do have the flea market, the opposite of wanted.

may need a few obsolete semiconductors. (I sure hope not.) Where is a good reliable place to buy them? Thanks.

How long is a piece of string? It surely depends upon WHAT obsolete semiconductors you might need. But usually, there is no need to use the exact parts of the original. Transistors are easily substituted. SOme ICs are not as easily replaced. What was that IC that Kustom (or was it Acoustic?) used in power amps SE9302 or SE540, or something? A little TO39 can IC.

[Chuck H]

What was that IC that Kustom (or was it Acoustic?) used in power amps SE9302 or SE540, or something? A little TO39 can IC.

Yep. Kustom used them I had to use a couple for a repair. Harder was an obsolete opamp chip that I sourced on *bay and arrived on a slow boat from the far east. Thankfully it wasn't the counterfeit dread that such parts are known for and everything worked out well. That doesn't mean it wasn't counterfeit. Just that if it was it wasn't a problem in this case. But I didn't suggest that route because it's been reported to go badly here too many times.

[tedmich]

You can get any semiconductor ever made as long as the markings alone need to match and $ is of no consequence
https://www.ebay.com/itm/MULLARD-PHI...cAAOSwmONdhfaw
caveat emptor!

[Mick Bailey]

Incredible. I have those brand new in original Mullard boxes. I'd be delighted If I saw that kind of money for them.

Obsolete electronics (especially semiconductors) are increasingly anything that has leads or pins. I buy a good deal of older parts through Ebay via reputable sellers. I'll leave those parts with zany prices to the mojo crowd who see something in them that I don't. Even the most obscure part can be substituted in some way and I've even made up pin-compatible modules to replace older linear ICs where there's room. Often the workarounds are well documented by people who have come across problems with compatibility. It does surprise me just how quickly parts disappear one they become end of life. At one time suppliers ran stock down but now it seems they decide to just clear parts out rather than maintain an inventory of a few items that may take years to sell.

Also you can find obsolete ICs still being made in SMD packages. I bought a load of 8-pin conversion boards for SMD to DIL that cost very little. I could do with the same thing for transistors to mount an SMD JFET or MOSFET onto a little board with three wire legs

EDIT: Well, I found these after writing this;

https://www.walmart.com/ip/Unique-Ba...x-15/140502678

[Axtman]

For example I "may" need a THAT Corporation DBX 2151 IC and/or a DBX 2252 IC.

[Chuck H]

THAT says they have an alternative part for the 2151 in a sip package and offers compatibility notes for retrofits. No problem there. But it doesn't look like they offer a sip replacement for the 2252. Even the east Asian copies on *bay are going for US$13 with shipping. The one time I had to use a couple of east Asian copies for obsolete chips I didn't have any problems. There are plenty of reports from people that have though. I'd gamble and buy the *bay part and see how it goes.

[Enzo]

I have ONE 2252 still in stock. NOS from when the amps were current models.



(SOLD, and shipped)

[The Dude]

Not that you can necessarily always believe them, but if I do search eBay for obsolete parts, I usually look for NOS parts. Less chance of fakes that way.

https://www.ebay.com/itm/dbx-2252-IC...gAAOSwA3dYTEcr

[glebert]

So where would one find examples of valuable old semiconductors? There is a surplus electronics store near me, as well as a friend who fixes organs and hoards parts. Curious if it would be worth my time to dig through their odds and ends bins and see if there is gold there. I know the surplus electronics store had a bunch of old Sunn knobs that they would sell for $0.50 until I made the mistake of telling them and now they put them on ebay for $8 each.

[Enzo]

Luck of the draw. You have to know what obsolete parts are in demand, then you rifle any old part stashes and see if you spot any. There is no formula, there is no look here and here. You come to my shop there are certain old things you will find, and thousands of others you won't. Go to the next shop down the road, and he will have a totally different inventory than I. I might have some Curtis chips, while he might have some SSM chips. Or we might both have them or neither.

[Chuck H]

So where would one find examples of valuable old semiconductors? There is a surplus electronics store near me, as well as a friend who fixes organs and hoards parts. Curious if it would be worth my time to dig through their odds and ends bins and see if there is gold there. I know the surplus electronics store had a bunch of old Sunn knobs that they would sell for $0.50 until I made the mistake of telling them and now they put them on ebay for $8 each.

Indeed! Go on *bay and plug in "NOS chip", "NOS semiconductor", "NOS opamp", etc. And then set the "sort by" to 'highest price first'. That should tell you what to look for in those old bins. Then YOU can go put them on *bay for $8 a piece.

Until about fifteen years ago I use to get all my vintage make preamp tubes at Halted Electronics in Santa Clara, Ca. They had a huge corrugated building and one wall was all shelves with cardboard boxes of pulled tubes and then a couple of old tube testers plugged in near by. I would go in there armed with all the alternative monikers and model numbers for "12ax7", "12at7", "12ay7", etc. and pull a dozen tubes that still had bright getter flash. I'd run them on the testers and any that showed good went home with me for a buck or two each. Then at home I'd plug them into an amp to cull the noisy and microphonic ones. Maybe one in four were useless and half of what was left couldn't be used in V1 because of slight microphony. Not unlike what you'd get from any on line vendor really. Used good pulls of coveted vintage tubes like Bugle Boy, Telefunken, RCA, Sylvania, etc. for two or three bucks each after culling. It was pretty great. After they saw me for the sixth or seventh time they started to get wise, looked into what I was buying and raised the prices to four to six bucks a tube for all the guitar amp applicable models. But nothing lasts forever. I must have pulled fifty great tubes from their stash. Some of which I still have.

[nosaj]

Indeed! Go on *bay and plug in "NOS chip", "NOS semiconductor", "NOS opamp", etc. And then set the "sort by" to 'highest price first'. That should tell you what to look for in those old bins. Then YOU can go put them on *bay for $8 a piece.

Until about fifteen years ago I use to get all my vintage make preamp tubes at Halted Electronics in Santa Clara, Ca. They had a huge corrugated building and one wall was all shelves with cardboard boxes of pulled tubes and then a couple of old tube testers plugged in near by. I would go in there armed with all the alternative monikers and model numbers for "12ax7", "12at7", "12ay7", etc. and pull a dozen tubes that still had bright getter flash. I'd run them on the testers and any that showed good went home with me for a buck or two each. Then at home I'd plug them into an amp to cull the noisy and microphonic ones. Maybe one in four were useless and half of what was left couldn't be used in V1 because of slight microphony. Not unlike what you'd get from any on line vendor really. Used good pulls of coveted vintage tubes like Bugle Boy, Telefunken, RCA, Sylvania, etc. for two or three bucks each after culling. It was pretty great. After they saw me for the sixth or seventh time they started to get wise, looked into what I was buying and raised the prices to four to six bucks a tube for all the guitar amp applicable models. But nothing lasts forever. I must have pulled fifty great tubes from their stash. Some of which I still have.

Another place is your local Ham groups. Most of them are hoarders and no telling what you'll find. I met one a couple years ago now helped him out and an now he is shifting his hoard to me as he realizes most of it will go to the dump when he passes. This way it finds a home. An now that I am a ham the group here shares like crazy. I put out a call I was looking for a climbing harness for my father in law who had suffered a stroke(he connects it to an aframe with an electric winch to pull him up and the winch is on a trolley so he can go back and forth practicing walking) and a ham offered me as many harnesses as I wanted with the precondition of it not to be sold but gifted if I no longer wanted them.

So don't discount your local people and hamfests, even if you don't find what your looking for you are networking and that helps down the road.

nosaj