SOT: How much are these AC128s and 2N270s worth?

[brett]

Hi
I've recently come across a few supplies of Ge transistors. 

What do you think 108 unsorted 2N270s (as used in the Maestro FZ1) are worth?  I was thinking US$150 to $200?
Also, I'm getting a quote on 450 ( ) unsorted AC128s.   What are they worth?

I wouldn't want to compete with Smallbear, who obviously offers a high-level service, but I thought I could offer packs of 10 unsorted devices to anyone who wants them.

cheers

[cd]

Enh - I'm cynical, but given the state of Ge these days, I would assume all large batches have been picked over at least once, and some more than that.  There's a few posts in the archives from a few years back about a handful of people cornering the market on certain Ge transistors.  FWIW I received a couple dozen AC128s recently from a trusted source who was assured a large, sealed batch of 300 or so was clean (not picked over) and none of them were any good.  In fact I was later told none in the entire batch were any good.  By "good" I mean less than 500uA of leakage and true gains from 80-110.  Most were way leaky, showing gains of 300 or more.

Try not to sink too much $ unless you can get some sort of guarantee.

[The Tone God]

My experience has been at best one in three are good in terms of leakage and gain range. The next step is how many pairs, assuming we are talking about FFs here, you can make from the gains. You can do the math to see if it is worth it.

Andrew

[mac]

I gave up on AC128s a long time ago. I've never bought a good one. They are all leaky and have random gain.
Even the 2N388 TI I bought recently (see my pict) are lower-than-spec-gain transistors.
Instead I began buying japanese transistors that are very consistent devices, readily available in my country and cheap. They never let me down and they sound as good as the ACs or even better.


mac

[Rick]

Yup I've got to agree with you Mac, I bought maybe a dozen as128s and I think "maybe" 2 were borderline useable. On the otherhand I do have quite a pile of japanese 2sbXXX that are quite reliable for the most part. I bought enough of these "good ones" to share if anyone wants for a decent price.   ...Rick

[petemoore]

  AC128's I recently bought...didn't last past a buncha swaps Vs. other part # Ge's...
  I bought six and just swapped em around in FF's and TB...maybe there's a good one in there/it just didn't get into the right socket or something...but I doubt it.
  Anything else sounded better IMO and mostly had alot less noise.
 

[alderbody]

2N270s (as used in the Maestro FZ1)

a bit off topic, but didn't Gibson use 2N2613/14's in the Maestro FZ-1 and FZ-1a ?

[MartyMart]

I've got hundreds of AC128's and AC127's .... most are just good for diodes !!

The best "stash" was when the guy was selling those mil spec CV7112's ( OC140's ) on Ebay at
very reasonable prices, I got hold of about 140 of them and have only found a handfull
that were out of spec/leaky !
I think that Steve/Aron and a few others have them all now

If you bought that many, you may get lucky and find a few good pairs, I bet that they have all been
picked through before .... at least once !

.... unless you found a stash from some "good ole boy's" loft , been there since '64 or something !!

MM.

[brett]

Thanks for the comments.

So far, I've had good luck with stashes of Ge transistors, especially 2SB, AC188 and AC128 devices.
Most lots have had 1/3 to 2/3 useful.  Especially the 2SBs, which usually leak less than 100uA (tho they are low hFE too - typically 60-80).

It'll be a day or two before the prices come in, so wish me luck with quality and price.

cheers

[Doug_H]

My advice is go NPN and get those Ge's that Aron sells. Those are really good transistors- seriously!!

Doug

[mac]

Thanks for the comments.
So far, I've had good luck with stashes of Ge transistors, especially 2SB, AC188 and AC128 devices.
Most lots have had 1/3 to 2/3 useful.  Especially the 2SBs, which usually leak less than 100uA (tho they are low hFE too - typically 60-80).

Yup I've got to agree with you Mac, I bought maybe a dozen as128s and I think "maybe" 2 were borderline useable. On the otherhand I do have quite a pile of japanese 2sbXXX that are quite reliable for the most part. I bought enough of these "good ones" to share if anyone wants for a decent price.   ...Rick

The 2SB172/75/76 family from Matsushita have an avarage leakage of 150uA and hfe 100. The 2SB176 have more gain, around 150 - 200. And they have a letter that indicates the hfe range. I've posted about my transistors here. I've breadborded a BMP with four 2SB176 of about hfe 200 and it sounded terrific.
2SA101/102 are my favourite for a FF, TB and RM.
¿ Mark Hammer posted recently that the best Rangemaster he has heard had an 2SB172 ?
The Toshibas I've got are very low leaky devices, all below 50uA. The 2SA49, 2SB54/56 have gains above 80.
Of about 200 transistors from Toshiba and Matsushita I had to trash 2 or 3.
2SB77 from Hitachi are acceptable. Sanyos and others, mmhh...
Some datasheets are available at datasheetarchive.com or alldatasheet.com. : 2sb172, 2sa102, 2sa49, 2sa52, 2sb54, 2sb77, 2sd72, 2ds352

mac

[Stephen]

http://www.geocities.com/stompbox2001/ac128.htm


CHECK THIS OUT!!!

[brett]

His praise for the AC188 fits my experience.  In fact, from about 40 good quality devices, including OC, AC, 2SB and NKT devices, I've chosen 2 AC188s for my fuzzface (hFE of 80 and 150)

[Stephen]

He is talking of AC 128 is that a typo?

http://www.cpcares.com/cgi-bin/sc/productsearch.cgi?storeid=*0c0431bba67f0c53


Here is a link to the 2sb176 ...I just bought some ..she said they where very good parts and I am having trouble with germaniums.....WHY....  I used to get them good all the time now people are selling me junk!!!!
They are praised in the earlier thread and I am gullable!!!

I like the Stellan versions of Fuzzes ...He doesnt post them anymore ...They sound so good!!!

[Stephen]

Sorry it is a dead link

www.cpcares.com/transistors/2SB176.html

Try this

[Stephen]

MAC how do they mark the 2SB176 for gain, the file on them says that they are 56 -140 gain hfe ...Do you know how they mark them..I am excited now to get them and try them in my test protos because everthing lately is junk.

The AC128 brand new should be a good one according to Jacques .......I have some of them coming from England I hope they arent nick picked too.........They are an electronics store and say they are brand new must be the cup shaped ones

[petemoore]

  http://www.muzique.com/pcb.htm#trans
  This link shows pictures of Various types of AC128 transistors, I read they have various characteristics, perhaps we're not naming closely enough 'which' AC 128's we're typing about.

[mac]

MAC how do they mark the 2SB176 for gain, the file on them says that they are 56 -140 gain hfe ...Do you know how they mark them..I am excited now to get them and try them in my test protos because everthing lately is junk.

The AC128 brand new should be a good one according to Jacques .......I have some of them coming from England I hope they arent nick picked too.........They are an electronics store and say they are brand new must be the cup shaped ones

2sb176 are clasiffied in this order:
R(57,74), P(66,86), O(76,99), M(89,115), N(105,140) @ Vce = 1V, Ib = 2mA
Mine are Matsushitas type R, but under RG test conditions hfe is higher (100 - 200).
Take a look at my post:
http://www.diystompboxes.com/smfforum/index.php?topic=46060


mac

[Stephen]

Thanks I will look for the details and I will check for sound qualiy too!!   what do you do with your germanium trannys ..Just saving them???

[mac]

Thanks I will look for the details and I will check for sound qualiy too!!   what do you do with your germanium trannys ..Just saving them???

Saving for the afterlife... 



mac