Hi all,
I was interested in building a Small Stone clone.
I have seen in this post that jetbat is substituing the IC with some discrete diodes/transistors.
Is there really a quality difference between the 2 solutions? If so, what makes these components better? The size, the materials or the manufacturing?
Many thanks!
I was interested in building a Small Stone clone.
I have seen in this post that jetbat is substituing the IC with some discrete diodes/transistors.
Is there really a quality difference between the 2 solutions? If so, what makes these components better? The size, the materials or the manufacturing?
Many thanks!
Oups, forget the link
http://www.diyaudio.com/forums/parts/138186-building-discrete-ca3094.html
http://www.diyaudio.com/forums/parts/138186-building-discrete-ca3094.html
You mostly can't buy 3080. RCA is dead, the factories are shopping malls or brownfields. Harris had some 13080 subs once, but I haven't seen any in stock. I bought some 3080 from Jameco four years ago but don't know if they still have them.
They were used IMHO because in ~1988 they were about the fastest slew rate amp IC. Run rings around a NJM4558.
Depending on application, you might be able to use something really fast like LM4562 or something. there is a single version, with LM49xxx name, I don't know what. You'd have to rework the inputs to use an operational amplifier instead of a transconductance amplifier like the 3080.
The discrete daughter board is a clean solution. There are faster transistors than the ones he used.
I think organ supply of marengon IN used to build these for repairmen.
They were used IMHO because in ~1988 they were about the fastest slew rate amp IC. Run rings around a NJM4558.
Depending on application, you might be able to use something really fast like LM4562 or something. there is a single version, with LM49xxx name, I don't know what. You'd have to rework the inputs to use an operational amplifier instead of a transconductance amplifier like the 3080.
The discrete daughter board is a clean solution. There are faster transistors than the ones he used.
I think organ supply of marengon IN used to build these for repairmen.
Depends on the circuit. The Peavey DDS circuit that uses a 3080 to measure how much high frequency is in the incoming signal, I think you could fiddle it to use a LM4562. They needed the slew rate of an OTA in 1988. Peavey immediately transfers the current 13080 to a voltage to control the allowed signal though a jfet, so they were really doing voltage in voltage out.
Operational transconductance means voltage in current out, operational amplifier means voltage in more voltage out. So depends on the load and circuit details a lot, what you can get away with. Resistors are devices that turn current into voltage for less than $.01 each, so it is no big mystery how to get from one to the other.
I'm no expert on subtle circuit details, but post your circuit (if not copywrited) and see if some circuit expert will slum long enough in instruments/amps to tell us something.
Operational transconductance means voltage in current out, operational amplifier means voltage in more voltage out. So depends on the load and circuit details a lot, what you can get away with. Resistors are devices that turn current into voltage for less than $.01 each, so it is no big mystery how to get from one to the other.
I'm no expert on subtle circuit details, but post your circuit (if not copywrited) and see if some circuit expert will slum long enough in instruments/amps to tell us something.
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> You mostly can't buy 3080.
Small Bear Electronics has facilitated known-good new-production LM3080. Him and Rochester (who makes them) are AFAIK the only for-sure sources.
> they were about the fastest slew rate amp IC.
The special point of the '3080 is not the speed but the CONTROL. You can vary the gain. In a Stone, you vary the gain of a phase-shift network and comb-filter the audio, then sweep the comb.
StompBox forums have found multiple work-arounds. Aside from getting Bear's good '3080, many of the classic phasers can be worked with LM13700-like chips, which are still widely available (but beware unknown sources who sell fakes of every chip in demand).
Small Bear Electronics has facilitated known-good new-production LM3080. Him and Rochester (who makes them) are AFAIK the only for-sure sources.
> they were about the fastest slew rate amp IC.
The special point of the '3080 is not the speed but the CONTROL. You can vary the gain. In a Stone, you vary the gain of a phase-shift network and comb-filter the audio, then sweep the comb.
StompBox forums have found multiple work-arounds. Aside from getting Bear's good '3080, many of the classic phasers can be worked with LM13700-like chips, which are still widely available (but beware unknown sources who sell fakes of every chip in demand).
> TL061 ...is a substrator if I understand
"substrator"??
TL061 is an ordinary though low-power Op-Amp.
TL061 Low-Power JFET-Input General-Purpose Operational Amplifier | TI.com
Where many opamps eat 2+mA power current, the '061 is 0.2mA.
If you have a looong phase shifter run on battery, the low supply current may matter; an equivalent discrete design would eat more or be very difficult.
If you use a wall-power supply, TL072 is the logical replacement, lower hiss. Even fancier chips are available, though dart-board selection may be disappointing. You can not hand-design a "better" stage than these half-dollar chips.
"substrator"??
TL061 is an ordinary though low-power Op-Amp.
TL061 Low-Power JFET-Input General-Purpose Operational Amplifier | TI.com
Where many opamps eat 2+mA power current, the '061 is 0.2mA.
If you have a looong phase shifter run on battery, the low supply current may matter; an equivalent discrete design would eat more or be very difficult.
If you use a wall-power supply, TL072 is the logical replacement, lower hiss. Even fancier chips are available, though dart-board selection may be disappointing. You can not hand-design a "better" stage than these half-dollar chips.
Thanks PRR,
There is actually a lot of posts/vendors claiming that discrete components offer a better quality but after more investigations and feedback from electronics forums, it seems that this is pure marketing tricks/speculation.
I'll stick with the IC and make sure to select the more appropriate. I can however make sure that I am selecting the best surrounding components possible.
There is actually a lot of posts/vendors claiming that discrete components offer a better quality but after more investigations and feedback from electronics forums, it seems that this is pure marketing tricks/speculation.
I'll stick with the IC and make sure to select the more appropriate. I can however make sure that I am selecting the best surrounding components possible.
The TL06x series is indeed a group of very low power consumption devices; however it is at the cost of performance. The TL07x devices are better performers (about 7 db less noise, and much less distortion) but consume 7x the power. And, as stated, they are priced very low. The next step upwards in performance would be the OPA1652---about a dollar more per I.C., but 36 db less distortion and 12 db less noise than the TL072.
Just to be clear -- the OPA1652 is a CMOS front-end, the OPA1642 is the JFET part. Both are pretty miserly on power, especially compared to the venerable 5532
> use a NE5532 for audio
Most audio. Probably including the insides of a phase shifter.
For the specific case of interfacing to guitar pickup, the BiPolar input devices will induce high hiss in the high impedance of a guitar (much higher than almost any other audio interface except condenser mike capsule). The TL07x/TL08x are the classic real-good go-to devices for guitar input. There may be newer devices with better specs. As the TL07x is already 2X-100X "better" than a 12AX7, what guitars were developed for, I see no shame in a 19 cent chip.
Most audio. Probably including the insides of a phase shifter.
For the specific case of interfacing to guitar pickup, the BiPolar input devices will induce high hiss in the high impedance of a guitar (much higher than almost any other audio interface except condenser mike capsule). The TL07x/TL08x are the classic real-good go-to devices for guitar input. There may be newer devices with better specs. As the TL07x is already 2X-100X "better" than a 12AX7, what guitars were developed for, I see no shame in a 19 cent chip.
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