# J201 Subs??? Cobalt Drive aka Blues Driver



## EZS (Jan 1, 2023)

Theres a total of 4. Has anyone built or know of a successful substitute in this circuit? 
Thanks in advance.


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## Robert (Jan 1, 2023)

MMBFJ201's on through-hole adapter boards would be the most likely candidate.


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## RetiredUnit1 (Jan 1, 2023)

Antique tube supply has the Fairchild J201 in stock, oddly enough the MMBFJ201's are not.  I have a wholesale with their sister company CE Dist, and I've been buying from them since they opened 24 years ago.  Reputable company!!!



			https://www.tubesandmore.com/products/transistor-j201-jfet-n-channelto-92


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## Locrian99 (Jan 1, 2023)

I used the smd versions Robert mentioned in my bd clone worked great.   The pre soldered ones in the store make it easy.


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## Dan0h (Jan 1, 2023)

RetiredUnit1 said:


> Antique tube supply has the Fairchild J201 in stock, oddly enough the MMBFJ201's are not.  I have a wholesale with their sister company CE Dist, and I've been buying from them since they opened 24 years ago.  Reputable company!!!
> 
> 
> 
> ...


Why are these $4.95  but smallbear has some for $1.49 ? Are the ones at small bear questionable? Mouser used to have Fairchild’s but they are all gone now.


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## temol (Jan 1, 2023)

RetiredUnit1 said:


> Antique tube supply has the Fairchild J201 in stock, oddly enough the MMBFJ201's are not.  I have a wholesale with their sister company CE Dist, and I've been buying from them since they opened 24 years ago.  Reputable company!!!



$5 for a piece? You can buy ten MMBFJ201 for $5...


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## EZS (Jan 1, 2023)

temol said:


> $5 for a piece? You can buy ten MMBFJ201 for $5...


Im way to cheap. Dont try Ebay though. 3 time counterfeit attempts for me.


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## temol (Jan 1, 2023)

MMBFJ201 JFET (SMD) - PedalPCB.com
					

SMD JFET (5 pcs)




					www.pedalpcb.com
				



$6 for 10 pieces...


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## manfesto (Jan 1, 2023)

Since the pro-soldered ones are currently sold out. these









						MMBFJ201 JFET (SMD) - PedalPCB.com
					

SMD JFET (5 pcs)




					www.pedalpcb.com
				




soldered to these









						SOT23 Through Hole Adapter - PedalPCB.com
					

SOT23 Adapter




					www.pedalpcb.com
				




If you’d prefer pre-soldered and can’t wait for the restock, Aion’s got stock of theirs right now









						J201 JFET with TO-92 Adapter
					

The legendary J201 JFET in SMD format, pre-soldered to adapters for use in through-hole applications.




					aionfx.com


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## RetiredUnit1 (Jan 1, 2023)

temol said:


> $5 for a piece? You can buy ten MMBFJ201 for $5...


You are aware the mmbf are smd?  So most people can't use them unless they've been soldered to an adapter.  Adapters on PPCB sell for 50 cents, and then there's labor.  I was able to find some adapters at CE Dist 0.22 each for 100 and got 100 of the mmbf's for 0.37 each both figures include freight.  Now that's .59 each and they still need to be soldered together, so no labor $ for me since I'm retired and the government pays me whether I watch tv or solder, lol.

This was back in November, and NO body had them in stock.  Since then CE Dist does, and from reading smallbear they found about 1000 of them and put them on sale for a *great* price.  Kudos to them, but NOS discontinued products have wildly varying prices....


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## RetiredUnit1 (Jan 1, 2023)

Dan0h said:


> Why are these $4.95  but smallbear has some for $1.49 ? Are the ones at small bear questionable? Mouser used to have Fairchild’s but they are all gone now.


It says at smallbear that they found them in their old stock section, they didn't have any a couple months ago when I looked.  And they have 1000+, when they are gone, THEY ARE GONE.  CE Dist is buying them *someplace* and of course has to pass the cost on to the customer to stay profitable.


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## RetiredUnit1 (Jan 1, 2023)

EZS said:


> Im way to cheap. Dont try Ebay though. 3 time counterfeit attempts for me.


I bought some, tested them they weren't even JFET's.  Got my money back, reported them to a friend that is the chief detective in my town.  He said he'd forward the info to the FBI counterfeiting division.....






						Federal Bureau of Investigation (FBI) | STOPfakes.gov - Intellectual Property Rights Resources and Assistance
					






					www.stopfakes.gov


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## Locrian99 (Jan 1, 2023)

manfesto said:


> Since the pro-soldered ones are currently sold out. these
> 
> 
> 
> ...


If pedal pcb is out or the pre soldered ones.   Aion does offer them as well.


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## temol (Jan 1, 2023)

RetiredUnit1 said:


> You are aware the mmbf are smd?



Of course I'm aware of this. And I still vote for smd, regardless of the extra cost (adapter) and labor (soldering).


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## swyse (Jan 1, 2023)

If you can get the SMT ones you can get these adapter boards for super cheap on oshpark. Also the original didn't use J201, so you could find the original transistor as well which I believe is 2sk117/2sk184/2sk209 depending on package.


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## EZS (Jan 1, 2023)

temol said:


> MMBFJ201 JFET (SMD) - PedalPCB.com
> 
> 
> SMD JFET (5 pcs)
> ...


I saw this a moment too late  Next order Ill get some.


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## MichaelW (Jan 1, 2023)

@EZS, DM me your address, I'll send you some MMBFJ201's for your Cobalt.


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## EZS (Jan 1, 2023)

MichaelW said:


> @EZS, DM me your address, I'll send you some MMBFJ201's for your Cobalt.


I Love this community! Thank you.


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## RetiredUnit1 (Jan 1, 2023)

temol said:


> Of course I'm aware of this. And I still vote for smd, regardless of the extra cost (adapter) and labor (soldering).


So your question was rhetorical......


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## MichaelW (Jan 1, 2023)

Hey @Robert, has the Cobalt been updated with SMD pads or is he going to need the adapters? I have them both ways.


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## Robert (Jan 1, 2023)

He'll need the adapters.     I need to get it updated with SMD pads but haven't gotten to that one yet.


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## spi (Jan 1, 2023)

swyse said:


> View attachment 39384
> If you can get the SMT ones you can get these adapter boards for super cheap on oshpark. Also the original didn't use J201, so you could find the original transistor as well which I believe is 2sk117/2sk184/2sk209 depending on package.


do you have a link to this project--none of my searches could find it?


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## cdwillis (Jan 1, 2023)

I can see this in my old orders on OSH Park and it seems like I can reorder them, but they won't come up in a search for some reason.


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## RetiredUnit1 (Jan 2, 2023)

cdwillis said:


> I can see this in my old orders on OSH Park and it seems like I can reorder them, but they won't come up in a search for some reason.
> 
> View attachment 39417


You can get five for .95 here


			https://www.tubesandmore.com/products/pcb-smd-thru-hole-adapter-sot-23-92-123-pinout


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## EZS (Jan 2, 2023)

RetiredUnit1 said:


> You can get five for .95 here
> 
> 
> https://www.tubesandmore.com/products/pcb-smd-thru-hole-adapter-sot-23-92-123-pinout


Sweet Ive been using these guys for amp parts, caps, pots etc for over 15 years. Ive had a cart building over time, just tossed some of these on there. Thanks!


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## swyse (Jan 2, 2023)

spi said:


> do you have a link to this project--none of my searches could find it?


https://oshpark.com/profiles/Pakir I believe the board I used was from this user.


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## Chuck D. Bones (Jan 2, 2023)

You can check my article(s) on the BD-2 in Chucks Boneyard for info on JFET subs and biasing.


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## EZS (Jan 2, 2023)

Chuck D. Bones said:


> You can check my article(s) on the BD-2 in Chucks Boneyard for info on JFET subs and biasing.


What a great write up! 


Chuck D. Bones said:


> You can find more than you ever wanted to know about the BD-2 here, here, here & here.


Wow!


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## RetiredUnit1 (Jan 2, 2023)

EZS said:


> Sweet Ive been using these guys for amp parts, caps, pots etc for over 15 years. Ive had a cart building over time, just tossed some of these on there. Thanks!


If you have a business license, you can apply for a wholesale account at https://www.cedist.com/ .  It's the *identical* company, address and website, but with lower prices!   I just placed an order with them last night, I have some heyborer transformers for a Champ being delivered tomorrow.  Some prices are much lower, some just so so.  The MOD electrolytic caps are really great, low prices.  

I recently bought a new drill press to replace my 1940's old school and it has a milling type cross sliding vise.  By using milling bits I'll be able to make precision square holes in metal now.  So I'm going to use the 10x6x2 hammond box to make a chassis for the champ I'm building.   



Still have to connect some wires but I have the component positions worked out......


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## EZS (Jan 2, 2023)

RetiredUnit1 said:


> If you have a business license, you can apply for a wholesale account at https://www.cedist.com/ .


Im close to retiring from my trade. This is a great tip, or way to save on a fixed income, lol.


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## Locrian99 (Jan 2, 2023)

Of note Newark has the mmbf201 in stock I just ordered 100 of them, tho it came out to 26 cents each before shipping.


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## RetiredUnit1 (Jan 2, 2023)

Locrian99 said:


> Of note Newark has the mmbf201 in stock I just ordered 100 of them, tho it came out to 26 cents each before shipping.


And .37 after shipping!  9.99 flat rate....  I bought 100 of them back in November


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## RetiredUnit1 (Jan 2, 2023)

EZS said:


> Im close to retiring from my trade. This is a great tip, or way to save on a fixed income, lol.


In California you have to file a DBA (doing business as) in your local newspaper (a special low price add) and then you take that to the county business tax place and give them a nominal fee.  After you get that license you can setup accounts at Mojo and CE Dist.  Between the two they have just about everything you could need.....

edited:  You can probably do this online now, post covid most county functions are online.....


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## Locrian99 (Jan 2, 2023)

RetiredUnit1 said:


> And .37 after shipping!  9.99 flat rate....  I bought 100 of them back in November


Probably more than I’ll ever need, but figure I don’t want to be searching in a couple years if I need some.


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