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DIYstompboxes.com  |  DIY Stompboxes  |  Building your own stompbox  |  substitutes , tranny , opamp , and timer ic 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: substitutes , tranny , opamp , and timer ic  (Read 895 times)
petey twofinger
Posts: 922



substitutes , tranny , opamp , and timer ic
« on: March 19, 2012, 09:41:57 AM »

need a BS250 , couldnt find one , ordered a BS170 , will this have much effect on the circuit , and what , exactly ?

it is goingin a Mayhem , lmc567 trem/ring mod based circuit .

jrc386D , well i have a jrc386BD same question .

the jrc , is that the same as a lm ? (  lm386 = jrc386 ? )

i read about lm386 1 , 2 , 3 , 4 being like 1 is the weakest output , the 4 being the strongest .

should i have assumed that the b would represent a 2 in that sequence ?

the uglyface layout i am using calls for a ICM7555 , i have a 555cn cmoss 555 timer , same questions .

the 386 is going in an uglyface

thanks !
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im learning , we'll thats what i keep telling myself
~arph
Posts: 1370


Arnoud P. - The Netherlands


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Re: substitutes , tranny , opamp , and timer ic
« Reply #1 on: March 19, 2012, 02:05:34 PM »

need a BS250 , couldnt find one , ordered a BS170 , will this have much effect on the circuit , and what , exactly ?

Won't work.. BS250 is a P-Channel MOSFET.. the BS170 is a N-Channel JFET... kinda like NPN vs. PNP transistors. (..totally different , but it shows the difference)

Quote
it is goingin a Mayhem , lmc567 trem/ring mod based circuit .

jrc386D , well i have a jrc386BD same question .

the jrc , is that the same as a lm ? (  lm386 = jrc386 ? )

i read about lm386 1 , 2 , 3 , 4 being like 1 is the weakest output , the 4 being the strongest .

should i have assumed that the b would represent a 2 in that sequence ?

the uglyface layout i am using calls for a ICM7555 , i have a 555cn cmoss 555 timer , same questions .

the 386 is going in an uglyface

thanks !

I think the last two will work fine. There is some difference between the 555 regular/cmos concerning power, but I do knot know the fine details.
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blueduck577
Posts: 91


Re: substitutes , tranny , opamp , and timer ic
« Reply #2 on: March 19, 2012, 02:07:29 PM »

The BS250 is a p-channel mosfet, where the BS170 is an n-channel.  So I'd say it will not work in the circuit.

You're correct about the LM386 being equivalent to the JRC386.  A lot of the time, this sort of equivalence is true, but you should always check the datasheets to make sure they are indeed the same.  This brings us to the 555 timer.  The ICM7555 is a cmos device.  You say you have a cmos 555 timer, but the 555cn is a bipolar device.  I don't know if this is a typo?  Usually these can be substituted for each other, with the bipolar device creating more noise and consuming more power.  However, the uglyface specifies that it needs a cmos 555, so it probably will not work as intended.

reference:
 
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R.G.
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Posts: 15917


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Re: substitutes , tranny , opamp , and timer ic
« Reply #3 on: March 19, 2012, 02:16:29 PM »

The general answer to this question, and the several zillion others that all have the form
"I need a part number [insert number here], will a [insert 'nother number here] work OK as a substitute?"
is "look up the datasheets for the two parts and compare the specifications".

If you don't (yet) have the technical background to do the comparison, then the question becomes "I've looked up the datasheets for [insert number here] and a [insert 'nother number here]. They look very similar - will they work work OK as substitutes?" The people who might help you will be very pleased if you give a link to the datasheets so they don't have to go do their own searches to find them.

In many cases, even a cursory reading of the datasheets will tell you if the answer is "no". In the case of the BS170 and BS250, the 170 is an N-channel and the 250 is a P-channel. These are fundamentally different, and so a circuit that works with one will NOT work with the other in all but the most degenerative cases, like using the body diode as a clipping diode. Anything that uses their transistor properties won't work.

Quote
jrc386D , well i have a jrc386BD same question .
http://semicon.njr.co.jp/njr/hp/productSearchResult.do
New Japan Radio Corporation has the confusing practice of listing their stuff as "NJMxxxx" and labeling it "JRCxxxx".  These are listed as the NJM386xx on the web site.

The "B" version is rated for higher power supply voltage and bigger output power.

Quote
the jrc , is that the same as a lm ? (  lm386 = jrc386 ? )
That's a good guess, and sometimes, but not always, the letter prefix and suffix indicate that. But you can never trust it fully till you actually look at the datasheet for each maker. In many cases, a second-source manufacturer will say in their datasheet that "this device is pin-for-pin compatible with the YYYYY". Sadly, JRC does not do that. When that happens, you have to compared the actual content of the datasheet for pin designations and device ratings.

But doing that, I see that yes, the JRC386... is pin-for-pin compatible with the LM386. Good guess, but always verify.

Quote
i read about lm386 1 , 2 , 3 , 4 being like 1 is the weakest output , the 4 being the strongest .
should i have assumed that the b would represent a 2 in that sequence ?
No. You should have thought "hmmm... it's possible that the B version is a higher power version" but not trusted it until you looked it up. In this case, it was a good guess that it was a higher power version, but I believe that the B version is like the "-4". Note that I have looked up the JRC386BD, but not the LM386-4. There's still some looking left to do.

Quote
the uglyface layout i am using calls for a ICM7555 , i have a 555cn cmoss 555 timer , same questions .
Same general answers.

« Last Edit: March 19, 2012, 02:18:08 PM by R.G. » Logged

R.G.

Every single NASA manned mission starting with the Gemini series has carried a roll of duck tape.
Yes, really. Look it up.
petey twofinger
Posts: 922



Re: substitutes , tranny , opamp , and timer ic
« Reply #4 on: March 19, 2012, 04:21:16 PM »

thank you very much for the replies .

i will have to make practice of comparing the data sheets , so i can figure this out myself .

i did order a few of each from mouser , it came to 10 for everything . it will be intersting to see , now that i will have a few different types of 386 and the timers if there is a preference or what just plain dont work .

really appreciate it !
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im learning , we'll thats what i keep telling myself
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