So, I've got it into my head to put together an "Umble" pedal for my guitar. I'd like to put the J201 transistors in sockets, but I can't seem to find any TO-92 sockets at Digikey or Mouser (or anywhere else really). Does anyone know where I can find some? Am I looking for the wrong thing; do people use something else as sockets for these things?
AllElectronics has them.
http://www.allelectronics.com/make-a-store/item/STR-92/TO-92-TRANSISTOR-SOCKET/-/1.html
http://www.allelectronics.com/make-a-store/item/STR-92/TO-92-TRANSISTOR-SOCKET/-/1.html
Transistors in a properly designed circuit should have a very long lifetime, probably longer than ours. Sockets reduce reliability- they can oxidize and the parts can vibrate free. They reduce high frequency performance. Commercial equipment almost never uses sockets, and not for cost reasons. OTOH, I've been known to use the nice Augat Teflon sockets for front end transistors where the frequencies are low and I want to play with careful matching. I've also been known to cut off a strip of 3 machined contact sockets from a break-away strip, and use them for TO-92 devices. I have a radio where static can blow the input device, and I keep that in a socket for easy replacement. I wouldn't say nobody ever uses sockets, but it's less and less common, especially since SMT is taking over everything anyway.
BTW, it's little known, but gold sockets are a waste of time unless you have gold leads. High pressure tin leaf types are best for tin IC leads.
BTW, it's little known, but gold sockets are a waste of time unless you have gold leads. High pressure tin leaf types are best for tin IC leads.
sneakers563 said:
Sorry for the slow reply, but basically what others have said.
The transistor socket is going to be a LOT less reliable than the transistor that's plugged in it - it's adding an unreliable part to a part which will most probably last longer than you need it to. Transistors are VERY, VERY reliable - small signal ones as used in an effect pedal will almost never fail.
When transistors do fail, it's usually because something nasty has been done to them - like plugging too many speakers on the output of an amplifier.
An effect pedal is a device that gets a LOT of abuse, thrown around, dropped, all this is going to make the transistor work loose from the socket and cause problems.
The reason why DIY Pedal builders use sockets in there pedals is so they can easilly change out different Transistors for getting a different sound and/or to mod the pedal.... Many Pedal builders do this.....And if they find a transistor they like then they have the option of Soldering them to the board....
What I use for transistor sockets are regular DIP opamp sockets and I just cut them down with a Pair of Nail clippers so there are 3 Pins in a row...
Cheers
PS: With that Curcuit , it would be a good Idea to use Sockets at first, at least till you get the Pedal working properly..why?? Because that curcuit uses JFets (J201) which are nortorious for haveing wide rangeing specs which can make curtain Fets practicly un-Biasable so you might have to try several fets before you can get the curcuit working optimally.... (I had to try about 20 J201 fets to get 4 that would Bias correctly in my DR.Boogie build)...
What I use for transistor sockets are regular DIP opamp sockets and I just cut them down with a Pair of Nail clippers so there are 3 Pins in a row...
Cheers
PS: With that Curcuit , it would be a good Idea to use Sockets at first, at least till you get the Pedal working properly..why?? Because that curcuit uses JFets (J201) which are nortorious for haveing wide rangeing specs which can make curtain Fets practicly un-Biasable so you might have to try several fets before you can get the curcuit working optimally.... (I had to try about 20 J201 fets to get 4 that would Bias correctly in my DR.Boogie build)...
Thanks again for all the advice. I'm actually thinking about using this thing as a preamp feeding an lm3886 power amp. I was going to use either the chipamp.com design or the one from generalguitargadgets.com. I know Minion has done something similar in the past.
This brings up another question:
Can I just hook the feed the output from the Umble circuit directly into the non-inverting input on the LM3886? The whole impedance thing is still a bit of a mystery to me, and I'm not sure how the input on an LM3886 might differ from the input on a garden variety amp. In other words, this Umble circuit was intended to be an effects pedal that would then be plugged into a conventional guitar amp that presumably has its own preamp section. Does that mean I have to do anything differently?
I've seen in earlier messages where Minion recommended an impedance buffer between a tube pre and an LM3886. Do I have to do something like that?
Obviously, I'm still new at this and have little idea what I'm talking about.
This brings up another question:
Can I just hook the feed the output from the Umble circuit directly into the non-inverting input on the LM3886? The whole impedance thing is still a bit of a mystery to me, and I'm not sure how the input on an LM3886 might differ from the input on a garden variety amp. In other words, this Umble circuit was intended to be an effects pedal that would then be plugged into a conventional guitar amp that presumably has its own preamp section. Does that mean I have to do anything differently?
I've seen in earlier messages where Minion recommended an impedance buffer between a tube pre and an LM3886. Do I have to do something like that?
Obviously, I'm still new at this and have little idea what I'm talking about.
No you won"t need a buffer between the effect curcuit and the LM3886, The Output impedance of the Effects curcuit is very low (unlike tubes) so you won"t have those issues with a solid state curcuit....
There should be no problem going into the effect curcuit and then directly into the LM3886 (With of cource the DC Blocking cap and Pulldown resistor as per the datasheet)....
If done right it should work very well, I don"t know if you are going to put both curcuits in the same enclosure but if you do you are going to need either 2 seperate power supplies (one for pre and one for power amp) or find a way to get 9v from your LM3886 PSU.....
Good luck
PS: I have a couple Guitar amps I have designed PCB"s for that use the TDA2030/40/50 line of chips(14w,20w,32w), they have the Power supply Preamp and Power amp on the same PCB and are only about 3.5in Square....They have a basic Volume ,Gain,Tone controll but with switchable Clipping diodes for a different Overdriven sound...They sound quite good through a good speaker...If you are interested I can post the design for you in case you wanted to build it at some point...It would probably be easier and cheaper than the project you are considering but you would have to etch your own PCB and source your own parts....
There should be no problem going into the effect curcuit and then directly into the LM3886 (With of cource the DC Blocking cap and Pulldown resistor as per the datasheet)....
If done right it should work very well, I don"t know if you are going to put both curcuits in the same enclosure but if you do you are going to need either 2 seperate power supplies (one for pre and one for power amp) or find a way to get 9v from your LM3886 PSU.....
Good luck
PS: I have a couple Guitar amps I have designed PCB"s for that use the TDA2030/40/50 line of chips(14w,20w,32w), they have the Power supply Preamp and Power amp on the same PCB and are only about 3.5in Square....They have a basic Volume ,Gain,Tone controll but with switchable Clipping diodes for a different Overdriven sound...They sound quite good through a good speaker...If you are interested I can post the design for you in case you wanted to build it at some point...It would probably be easier and cheaper than the project you are considering but you would have to etch your own PCB and source your own parts....
Minion said:
Great!
I've been thinking about that. My plan is to just use a separate 9 volt wall wart. But I was wondering if I could just tap into the +35 line coming off the power supply and use a voltage divider to bring it down to +9.
I'd love to see that. I actually have an amp6 from 41hz.com that I've been using as a hifi amp. The main reason I'm using the gainclone for this project is I happen to have a kit and transformer already lying around.
As an aside, my wife and I spent part of our honeymoon on Vancouver Island this spring. It was lovely. We're planning on hiking the West Coast Trail next year with some friends - I can't wait.
Hi ,Here is the latest guitar amp design I came up with ....
It is a very Basic design ,Simple Volume ,gain and a One knob Tone controll but with options for 3 sets of Clipping Diodes so you can get 4 different Overdrive/Distortion Tones ..(I used Germanium diodes, Silicone diodes and LED"s) ,and you can use a variety of Chips (TDA2030/2040/2050/LM1875) Just make sure your Transformer is the correct voltage for the Chip you are useing....
The PCB is 3.825in x 2.625in in case you wanted to etch at home...
The one I built I used a TDA2050 (32w) and I am playing it through a 12in 50w Yahama guitar amp speaker...It goes very loud and has great overdrive tones and goes loud enough to jam with a drummer....
yea...the island is nice, I"m glad you enjoyed your Visit here....
Cheers
It is a very Basic design ,Simple Volume ,gain and a One knob Tone controll but with options for 3 sets of Clipping Diodes so you can get 4 different Overdrive/Distortion Tones ..(I used Germanium diodes, Silicone diodes and LED"s) ,and you can use a variety of Chips (TDA2030/2040/2050/LM1875) Just make sure your Transformer is the correct voltage for the Chip you are useing....
The PCB is 3.825in x 2.625in in case you wanted to etch at home...
The one I built I used a TDA2050 (32w) and I am playing it through a 12in 50w Yahama guitar amp speaker...It goes very loud and has great overdrive tones and goes loud enough to jam with a drummer....
yea...the island is nice, I"m glad you enjoyed your Visit here....
Cheers
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