2SC1849 Transistor Data Sheet??? Gain???

[ragtime8922]

I aquired the semi-rare 2SC1849 as I am a true Ross Comp lover. Since my Ross experiment days I've used the 2SC1849 for other projects but never tested the gain or have been able to find a data sheet any where on the internet. Can anyone help?

      I just used the 2SC1849 on one of my Tube Screamer versions as the input transistor and it sounds great. Better than the MPSA18 IMO.

[Fret Wire]

Here's the NTE cross match. They are not always accurate, sometimes an approximation.

http://www.nteinc.com/specs/100to199/pdf/nte123ap.pdf

[ragtime8922]

Thanks Fret! An approximation is great as I have nothing at this point.

Robert Keeley told me to call him on Saturday and he'd look for the data sheet but the one he has is in Japanese.

Thanks again!

[Fret Wire]

No problem. For some reason, I can't locate my good cross reference sites. I did find one that said to use the 2SC2901 as a replacement. Cross checking with NTE shows the same NTE123AP. So I think you want to find the data sheets for both the 1849 and the 2901.

BTW, if you go to NTE's home page, you can download their Quick Cross V.11. It will allow you to cross check offline if you want. Of course, you have to be online to access the data sheets.
http://www.nteinc.com/

The 1849 has me intrigued now.

[phillip]

The 2SC1849 has a gain range of 200-300 or so.  The 2N4401 would be pretty darn close...they're in that same gain range.

Phillip

[Fret Wire]

Phillip do you have a datasheet for the 1849?

[phillip]

I did a Yahoo search for 2SC1849 and found this site with information about some of the 2SC transistors:

http://home.freeuk.net/nic.percival/2sc/2sc180.html

Phillip

[Fret Wire]

Now I really want to see a 2SC1849 data sheet. The 2n4401 also cross- matches to the NTE123AP. And so does the 2N3904.

2SC1849 crosses to NTE123AP
2SC2901 listed as a replacement for the 1849 crosses to NTE123AP
2N4401 crosses to NTE123AP
2N3904 crosses to NTE123AP

It'd be pretty interesting if the good old 3904 turns out to be a direct replacement.

[phillip]

Most of the 3904s that I've measured have been somewhere between 130-150 or so, which is a little low to match the 1849.  I used 2N4401 in my Ross Compressor clone, and they worked great.  I've heard that using 2N5088 are even better.

Phillip

[Fret Wire]

My 3904s were all in the 200-300 range. No 4401's to check. I have some 2N4400's that the whole batch fell in the magical fuzz face range, and sound good too.

[phillip]

Wow those are some hot 3904s!  The ones that I got from Small Bear (the ones with the "face" of the transistor painted white) were almost in the Fuzz Face range...around 125-130.

Phillip

[Fret Wire]

They are Fairchild 3904's.

[ragtime8922]

Yeah, Phillip, I was planning on using the 4401 after checking out your site. Shortly after that I aquired the 2SC1849's.

Fret, You seem real interested in the 2SC1849. Send me a SASE or e-mail me and I'll send you a set for the Ross. I'd love to get some other views of this transistor for the Ross/Dyna and other apps.

[ragtime8922]

Phillip, I just checked out that link and I am real surprised to see that the 2SC1815's Hfe is 70 and the 2SC1849's is 250. I thought I remembered Keeley stating something on his site about the 2SC1815 being the "back-up" transistor for the ross but he didn't like it. How can this be the back up? It's Hfe is WAY low.

[Fret Wire]

Thanks for the offer, I think I'll take you up on that. As far as the hfe question, that link gives only one value so it's misleading. The 2SC1849 can go from about 70-300 hfe. You could get one batch that tests around 250, another that runs 150. I don't know how consistant they were, never having had any. Luckily, they are Si, so if your DMM has a hfe test, it will be accurate.

The 2N4401 goes basically from 100-300
http://www.fairchildsemi.com/ds/2N/2N4401.pdf

Same for the 3904 (100-300)
http://www.fairchildsemi.com/ds/2N/2N3904.pdf

That's why I'd like to see a data sheet for the 1849, and measure a few. If there is no discernable on/off/signal/switching characteristics between the 1849 and 3904/4401, then that means there is also no magic in using them, and we've found a perfect match/substitute that's cheap and plentiful. Drop in components that work right beat handmatching/tweaking any day.

JFET's are different. Because they can't be manufactured with consistantcy, they are harder to sub. That's why the Japanese SK30A can be hard to sub correctly.

[ragtime8922]

Fret, I have one more question on this subject. You have mentioned the NTE cross references a lot. Do you use those regularly? The NTE (and others) replacement transistors scare me. For instance, Jameco catalog states "DO NOT USE THESE FOR NEW BUILDS, REPLACEMENT ONLY". Also, I've heard from a few others that these are mostly defects from various manufactures than happen to fit in to a very broad gain range. This is whay you got the same replacement match for like 4 or 5 transistors. Don't take my word for it. Take two or three transistors that you know to be different but semi close in gain range and do a search for the NTE match. I'll bet it's the same.

[phillip]

Yeah I'm kinda wary of NTE replacements...they do fit a very broad range of part numbers and tend to be a little pricey.  I would find a "2N" part number that's close to the 1849 and use that.  I think the 2N4401 is going to be the ticket...worked great in mine.

I've heard that the 2N5088 works even better in the Ross Compressor because it's a little higher gain and designed for lower noise operation.

I still want to mod the Ross Compressor so that it doesn't remove so many highs...turning it on was like throwing a wet blanket over the speakers.  I've heard that the Dynacomp is quite a bit brighter, but I've also heard that the Ross is a little better design-wise because the added parts make the circuit better sonically and electrically.  There should be a way to bring the highs back to the Ross circuit...maybe lowering the value of that 220pF on the input or lowering the value of the input capacitor?

Phillip

[ragtime8922]

Phillip, please post your mods if/when you do it. I'm a huge fan of the Ross and would be interested in any/all mods. I did try the mod on your site but that was before I fixed that "dark/bassy" problem but I liked what it did.
      BTW, the problem you are describing sounds just like the "dark" problem. You're sure that C11 is .001? Mine was .01 and I changed everything but that when I was trying to fix the problem. Thanks to this forum I fixed that yesteray. New life for my Ross!