Ok when I was in high a guy my dad worked with gave me a audio related stuff he used to build amps and pre's in high school.
Well to make a long store short Ive got all these opamps and I was wondering , folishly mind you that He gave me some old school diamond in the ruff.
Ok here goes they are as follows
mc1302l
u5b 7741312
rm741t
These are the ones
Thanks Nick
Well to make a long store short Ive got all these opamps and I was wondering , folishly mind you that He gave me some old school diamond in the ruff.
Ok here goes they are as follows
mc1302l
u5b 7741312
rm741t
These are the ones
Thanks Nick
nhuwar said:
MC1302 I can't find. There is an Radio Receiver Circuit MC13020.
U5B7741312 Single General Purpose Op Amp Intersil Corporation
RM741 Single General Purpose Op Amp Raytheon Fairchild
I used this good link http://www.datasheetarchive.com/
to find datasheets and details for your chips
'741' is a very old and classic op-amp
but today we do not use it for Audio.
It can be used for other things alright, but for audio ... no!
U5B7741312
I don't know much about.
But I guess it is nothing specially good for a preamp.
---------------------------------------------
Advice:
Buy yourself a few good modern op-amps.
Most anything will give a better result than using those old ones.
They do not have to cost much.
If you want to play it very cheap, buy:
NE5534 (single amp), NE5532 (dual, stereo in one chip), TL071 (single), TL072 (dual).
If you need only a few pieces you can try some better AUDIO op-amps.
They won't ruin you of your money:
OPA2134 (dual), OPA227 (single), OPA2227 (dual)
well thanks for the input I think I'll stick with the old standard and go with a precision burr brown opamp.
Just have to pick one.
thanks
Just have to pick one.
thanks
What type of Impedances are you going to be working with???
For High Impedance Inputs the OPA134/2134 is a very good fet opamp (burr brown) for Lower input impedances something like the OPA604/2604 is a very good chip.....
I guess it depends on what you are going to use them for....
😉
For High Impedance Inputs the OPA134/2134 is a very good fet opamp (burr brown) for Lower input impedances something like the OPA604/2604 is a very good chip.....
I guess it depends on what you are going to use them for....
😉
the Apt-Holman preamp used TL072's, and it was a really good preamp.
the intersil and the 741 amps are probably good for dc control use like voltage regulators, DACs, LED drivers, etc...
the mc1302 is probably a MOT replacement for the LM302 voltage follower/buffer amp. the datasheet is available here:
http://www.datasheetcatalog.com/datasheets_pdf/L/M/3/0/LM302.shtml
the intersil and the 741 amps are probably good for dc control use like voltage regulators, DACs, LED drivers, etc...
the mc1302 is probably a MOT replacement for the LM302 voltage follower/buffer amp. the datasheet is available here:
http://www.datasheetcatalog.com/datasheets_pdf/L/M/3/0/LM302.shtml
normal low level high impedence input for a preamp correct me if i'm wrong but isn't the standard for most stereo equipment 15k
usually between 10 and 20k.... there was an article in Audio DesignLine recently about audio equipment I/O impedances, and unlike older equipment that had a 600 ohm impedance standard, modern equipment goes for voltage matching rather than impedance matching..... "line level" is usually anywhere bettween .5Vrms and 1.5Vrms depending on the manufacturer......
600 ohms is still used for balanced mic inputs, and phono cartridges vary between 1k and 10k
600 ohms is still used for balanced mic inputs, and phono cartridges vary between 1k and 10k
This is where my knowledge grows thin and I need help. For 1 I'm not sure if I want to go dig or analog I veer toward ana because I know it from my rf knowledge. I've got abit of dig adc's & dsp chips & I lnow I have more options in dig.
I't just going to be a learning exp. the chips i have are ti and b.b. you know free sample are great.
The question I have is do most of you etch your own boards or do you order them and if so you use something like eagle pcd or something else.
I't just going to be a learning exp. the chips i have are ti and b.b. you know free sample are great.
The question I have is do most of you etch your own boards or do you order them and if so you use something like eagle pcd or something else.
nhuwar said:
Well I don"t know about the rest of everybody but I personally have never used a Non-Home etched Board...
I design and etch all of my PCB"s (actually design about 90% but etch 100% of all of my boards) as I usually only make one or 2 Boards of each design so it would be very cost prohibitive to get pro quality boards made for a one or 2 off board.....
I get really good deals on Blank PCB material (about 5 square feet for $20) and use the toner transfer method so it costs next to nothing to make a Board.....
CHeers 😀
nhuwar said:
Minion said:
I am a Hardwire Man
this means I use as little as possible printed circuits, etched or bought
I solder transistor to transistor and to resistor - directly.
I can use some board, but just for a fundament, foundation of my components
I usually Glue them or Use double sided Tape on a board,
with pins, legs IN THE AIR upwards.
Same with OP-AMPS.
Glue upside Down, with pins in air.
Solder other components directly to pins of Op-Amp or using very thin solid wire.
lineup
This is a op-amp list which I can buy.
OPA134
OPA2604
OPA637
OPA627
OPA2228
My source siganl is sound card. Can you give some commend ? 🙂
thanks!
OPA134
OPA2604
OPA637
OPA627
OPA2228
My source siganl is sound card. Can you give some commend ? 🙂
thanks!
thanh said:
Always good with some data along with the questions.
Makes it easier to answer 🙂
Anyone of those op-amps are good audio chips!
At different prices .......
some missing data:
- Output voltage (average) from soundcard?
- What gain would your preamp have?
- What would you attach to output of preamp? (=worst case load)
If you aim for a normal line level preamp, with lower gains: 4-10,
then I would buy OP134 (single version of 2134 )
because you would not need any expensive Audio Op-Amp.
Also there are more people that likes OPA2134 better than OPA2604.
From your list, I think, only 'lowprice' that are unity gain stable
are OPA134 and OPA2604.
This means you have not to bother with external compensation components. (caps etc.)
Let's hear some opinions of others, too.
I am sure there is a bit more to say😉
lineup
I like the sound of AD847/827 http://www.analog.com/UploadedFiles/Data_Sheets/AD847.pdf
I use it with a buffer to drive my HD650 headphones.
Another one is LT1468/69 http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1154,C1009,C1022,P1676,D3207
A softer sound than AD847,wich has a clear sound.I have tested all of the ones you listed and these 2 are my favorites..😎 🙂
I use it with a buffer to drive my HD650 headphones.
Another one is LT1468/69 http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1154,C1009,C1022,P1676,D3207
A softer sound than AD847,wich has a clear sound.I have tested all of the ones you listed and these 2 are my favorites..😎 🙂
An awesome preamp.
I bui;t a preamp based off of the ESP sound p88 project. I really only used the esp site as the conceptual schematic. His pre uses 2134 throught as buffer and gain stage but i felt it was missing musicality. for the buffer before the volume pot i used an opa627 for one channel biased into class a with a 4.7k resistor to the negative rail. the gain/linedrive stage is based on the walt jung ad744/ad811 composite op amp with the ad811 used as a current drive unity gain bufffer and output is take from pin 5 of the ad744 which bypasses the slower output transistors. a schematic can be found on walt jungs website.. i have also added this buffer/composite op amp to the output of my rotel cd player with stellar results...
Colin
I bui;t a preamp based off of the ESP sound p88 project. I really only used the esp site as the conceptual schematic. His pre uses 2134 throught as buffer and gain stage but i felt it was missing musicality. for the buffer before the volume pot i used an opa627 for one channel biased into class a with a 4.7k resistor to the negative rail. the gain/linedrive stage is based on the walt jung ad744/ad811 composite op amp with the ad811 used as a current drive unity gain bufffer and output is take from pin 5 of the ad744 which bypasses the slower output transistors. a schematic can be found on walt jungs website.. i have also added this buffer/composite op amp to the output of my rotel cd player with stellar results...
Colin
Re: An awesome preamp.
Walt Jung is one of the world's most know persons,
when it comes to Op-Amps and Op-Amp circuits.
He has been involved in design of operational amplifier chips, I think.
He has got so many good papers in His Library.
with examples of circuits and other good audio stuff.
visit and download 😎 http://waltjung.org/Library.html 😎
lineup
vynuhl.addict said:
Walt Jung is one of the world's most know persons,
when it comes to Op-Amps and Op-Amp circuits.
He has been involved in design of operational amplifier chips, I think.
He has got so many good papers in His Library.
with examples of circuits and other good audio stuff.
visit and download 😎 http://waltjung.org/Library.html 😎
lineup
Re: An awesome preamp.
Did you try a CCS instead of the resistor to force the output into ClassA?
Three opamps to replace one in the Rotel:
and it still sounds better!!
What did you do for power pin bypassing?
Thanks for that.vynuhl.addict said:
Did you try a CCS instead of the resistor to force the output into ClassA?
Three opamps to replace one in the Rotel:
and it still sounds better!!
What did you do for power pin bypassing?
Hi Andrew,
I never tried a CCS on the opa627 as soundwise i didnt find it neccessary. I suppose i could get elaborate with transistors but I dont hear anything to justify the added complexity especially in the role its used in, as a buffer before the volume control. As for adding the buffer to the output of my rotel cd player its a funny situation, the existing op amp(dual2604 since replaced by ad823 per channel) performs the role of I/V converter and gain stage. as i really liked the sound of the ad823 in this role its weakness is its current drive capability, (like most id rather design with more drive than i need for effortless dynamics and sound). The composite op amps are decoupled at each pin with a 100uf 35v Nichicon vx cap and Arcotronics 100nf 100v metallised polyester films.To be honest, I will use whatever poly/films i can get my hands on for a decent price when its not in the AC signal path..I can see why the opa2134 is used alot in audio, it works good enough, its easy to implement and saves on alot of parts count and final $$$ markup..In my opinion it cannot come close to walt jungs combo/or a painstakingly well designed discrete as a line driver at all..
Colin
I never tried a CCS on the opa627 as soundwise i didnt find it neccessary. I suppose i could get elaborate with transistors but I dont hear anything to justify the added complexity especially in the role its used in, as a buffer before the volume control. As for adding the buffer to the output of my rotel cd player its a funny situation, the existing op amp(dual2604 since replaced by ad823 per channel) performs the role of I/V converter and gain stage. as i really liked the sound of the ad823 in this role its weakness is its current drive capability, (like most id rather design with more drive than i need for effortless dynamics and sound). The composite op amps are decoupled at each pin with a 100uf 35v Nichicon vx cap and Arcotronics 100nf 100v metallised polyester films.To be honest, I will use whatever poly/films i can get my hands on for a decent price when its not in the AC signal path..I can see why the opa2134 is used alot in audio, it works good enough, its easy to implement and saves on alot of parts count and final $$$ markup..In my opinion it cannot come close to walt jungs combo/or a painstakingly well designed discrete as a line driver at all..
Colin
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