This is the last hang up on me ordering everything I need for my JFET line-amp....
I need 24v +/- regulators. If I do not find them I have to go battery. The ones I have found are what look to be crap from parts express, or impossible to find for sale LT1033CTs.
This is driving me nuts.
I need 24v +/- regulators. If I do not find them I have to go battery. The ones I have found are what look to be crap from parts express, or impossible to find for sale LT1033CTs.
This is driving me nuts.
Do you mind building one from scratch (discrete)? If so
I could find/advise you on one. What is current required?
newark.com has both +24v and -24v on semi regs in
stock for .22c and .55c,
but if you want more current I have circuits for trimmable
precision voltage reference /741/3055-2955 based
high power regs. (I use these in my homemade lab
supply , only 2-3 microvolts ripple😀 @ 5A)
I could find/advise you on one. What is current required?
newark.com has both +24v and -24v on semi regs in
stock for .22c and .55c,
but if you want more current I have circuits for trimmable
precision voltage reference /741/3055-2955 based
high power regs. (I use these in my homemade lab
supply , only 2-3 microvolts ripple😀 @ 5A)
I've got a scalable regulator board to spare that will do 400 mA pretty comfortably. See this thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=75994
To bump it up from 15V to 24V would require a resistor change and changing the output caps to 35V rating. Pretty simple, and sounds better than 3 pin regulators to my biased ears.
To bump it up from 15V to 24V would require a resistor change and changing the output caps to 35V rating. Pretty simple, and sounds better than 3 pin regulators to my biased ears.
Why don't you create a clean DC reference voltage then build a descrete amplifler to amplify that reference voltage to 24V? Then build an equal but opposite polarity circuit. You will be able to get a nice wide bandwidth if you design it right. If there is no IC solution to your problem, maybe descrete is the way to go.😉
I'm sure there are folks here that could help.
I'm sure there are folks here that could help.
I am willing to go discrete. I am looking for 1a per regulator should be the most I will ever need. I suspect the draw to be less but there are no numbers on it.
CBS240 that sounds fairly good but as far as designing that might be to far.... (I have to research etc because my abilities are not up high enough)
CBS240 that sounds fairly good but as far as designing that might be to far.... (I have to research etc because my abilities are not up high enough)
What are the output requirements other than 24V? What is the load this regulator (amplifier) is to drive?
here are circuits... /Power_supply/
Lab ps (2nd one down is good) or for real precision
low noise voltage reference buffered by 741/current
follower would give you the lowest ripple.
Lab ps (2nd one down is good) or for real precision
low noise voltage reference buffered by 741/current
follower would give you the lowest ripple.
The PSU that they are going in is just a simple four diode and some caps. Originally, I am up to new ideas.
The PSU will be driving 4 JFET K170BLs, with around 44k of resistance a piece or so... to complete the circuit. This is just a line amp. (super high quality one though even with just the couple of parts)
The PSU will be driving 4 JFET K170BLs, with around 44k of resistance a piece or so... to complete the circuit. This is just a line amp. (super high quality one though even with just the couple of parts)
If you want something quick with good performance, go for a LM317 for the positive reg and an LM337 for the negative reg.
Go onto the Natsemi website, you can pick up the data sheets there with full cct diagrams and calcs required to give your desired output voltage.
On these regs, you can bypass the reference pin with a cap and get very low noise.
Go onto the Natsemi website, you can pick up the data sheets there with full cct diagrams and calcs required to give your desired output voltage.
On these regs, you can bypass the reference pin with a cap and get very low noise.
very good suggestion, Bonsai, the 317/337 is much better than
the 78/79XX combo for ripple as well as the ability
to trim it to exact voltage.(10 turn trimmer)
With decoupling caps at ADJ and output less than 1mv
can be acheived at output.🙂
As far as sound, I use these in preamp and sub EQ
op-amp circuits with the relay circuits added and can
see no glitch/ripple or hear no noise.
For the low current use no heatsink or a small clip-on
will save space.
the 78/79XX combo for ripple as well as the ability
to trim it to exact voltage.(10 turn trimmer)
With decoupling caps at ADJ and output less than 1mv
can be acheived at output.🙂
As far as sound, I use these in preamp and sub EQ
op-amp circuits with the relay circuits added and can
see no glitch/ripple or hear no noise.
For the low current use no heatsink or a small clip-on
will save space.
I hate to be a total *** but I use a computer at the library and it has no calculator and my phone will do not calculations...
http://cache.national.com/ds/LM/LM137.pdf
Could some one help me out? I know I need 2 120ohm resistors, 2 10uf caps (think I will use 22uf so I can use FM's), and then I might just use 8 (4 per side) 33uf caps for low impedence on the ouput. I can not calculate R2 though without a calculator
.
http://cache.national.com/ds/LM/LM137.pdf
Could some one help me out? I know I need 2 120ohm resistors, 2 10uf caps (think I will use 22uf so I can use FM's), and then I might just use 8 (4 per side) 33uf caps for low impedence on the ouput. I can not calculate R2 though without a calculator
.2184 ohms. Use 2.2k, and trim by putting high values in parallel until it comes out right.
You mean the computer doesn't even have Excel on it????? I know it's overkill, but it works.
You mean the computer doesn't even have Excel on it????? I know it's overkill, but it works.
Showing my age, but a pencil and paper work for simple calculations, too. 😉
2K2 is close enough - The tolerance of the chip is further off than that. You can absorb a few millivolts difference in the rails.
2K2 is close enough - The tolerance of the chip is further off than that. You can absorb a few millivolts difference in the rails.
Good choice, Dest. OS, simple ..but will do the job
here is my preamp supply:
Notice D1/2.. D1 protects against reverse bias of device
and D2 makes it short circuit proof. Just reverse the diodes to
make the negative (lm337) half of your PS.
R2 I use a 5k 10 turn trimmer. easy to get >.01V at
output, A really foolproof power supply.😀
here is my preamp supply:
An externally hosted image should be here but it was not working when we last tested it.
Notice D1/2.. D1 protects against reverse bias of device
and D2 makes it short circuit proof. Just reverse the diodes to
make the negative (lm337) half of your PS.
R2 I use a 5k 10 turn trimmer. easy to get >.01V at
output, A really foolproof power supply.😀
I can just reverse the diodes to have the second do -24v correct?
At this rate I think I might go four transformers. I will have dual mono line amps. (why not I thought I was going to be spending way more money) This will also insure 1a worth to each line-amp.
Also I am going to use two extra diodes per 24v supply.
Parts list.
16 MUR860 Diodes (already have Cool (full bridge rectifying)
$1.16 x 8 = $9.28
4 Transformers (power in)
$2.88 x 4 = $11.52
4 LM317T
$2.25 x 4 = $9.00
4 120ohm Caddock MK123 resistors (needed in circuit)
$2.00 x 4 = $8.00
4 2.2kohm Caddock MK123 resistors (define value of 24v)
$2.00 x 4 = $8.00
4 10uf FC Panasonic capacitors (in circuit capacitors)
$.28 x 4 = $1.20
16 56uf FM Panasonic capacitors (output capacitors, four per output, should be super low impedence)
$.14 x 16 = $2.30
4 Panasonic X2 .01uf caps (for on each transformers, although I already got pretty sweet AC filtering)
$.91 x 4 = $3.64
1 Velleman ECS2 2 Hole Island Euro Card 3.9" x 6.3" ("bread board" but easier to deal with)
$8.76
Total = $58 for a pretty nice PSU, of course not nearly as nice as what it is going to drive but...
Anything else?
That makes my total for line-amp, with 4 JFETs $16, four Vishay resistors $7 a pop, $28, two RCA jack pairs $6.50 so $13.00, 4 feet jupiter copper $1.10 a foot $4.40, and two Sonicap platinum .01 teflon caps $18 a pop, $36
$97.41
$155 dollars for a only matched by other DIY buffers with slightly nicer stuff, no matter how much money you spend, and paid for by my good old pre-amp I had for phono! Sweet!
Thank you for your help everyone. Especially for helping me get the right resistor value. I forgot about Excel, yeah they have it, the new one that confuses me even more!
At this rate I think I might go four transformers. I will have dual mono line amps. (why not I thought I was going to be spending way more money) This will also insure 1a worth to each line-amp.
Also I am going to use two extra diodes per 24v supply.
Parts list.
16 MUR860 Diodes (already have Cool (full bridge rectifying)
$1.16 x 8 = $9.28
4 Transformers (power in)
$2.88 x 4 = $11.52
4 LM317T
$2.25 x 4 = $9.00
4 120ohm Caddock MK123 resistors (needed in circuit)
$2.00 x 4 = $8.00
4 2.2kohm Caddock MK123 resistors (define value of 24v)
$2.00 x 4 = $8.00
4 10uf FC Panasonic capacitors (in circuit capacitors)
$.28 x 4 = $1.20
16 56uf FM Panasonic capacitors (output capacitors, four per output, should be super low impedence)
$.14 x 16 = $2.30
4 Panasonic X2 .01uf caps (for on each transformers, although I already got pretty sweet AC filtering)
$.91 x 4 = $3.64
1 Velleman ECS2 2 Hole Island Euro Card 3.9" x 6.3" ("bread board" but easier to deal with)
$8.76
Total = $58 for a pretty nice PSU, of course not nearly as nice as what it is going to drive but...
Anything else?
That makes my total for line-amp, with 4 JFETs $16, four Vishay resistors $7 a pop, $28, two RCA jack pairs $6.50 so $13.00, 4 feet jupiter copper $1.10 a foot $4.40, and two Sonicap platinum .01 teflon caps $18 a pop, $36
$97.41
$155 dollars for a only matched by other DIY buffers with slightly nicer stuff, no matter how much money you spend, and paid for by my good old pre-amp I had for phono! Sweet!
Thank you for your help everyone. Especially for helping me get the right resistor value. I forgot about Excel, yeah they have it, the new one that confuses me even more!
no no, D. OS... You must buy 2-LM317 (pos) AND 2-LM337 (neg)
build the same circuit as I posted with The 317 and
substitute 337 and flip diodes (D1-2). you are getting ripped
for price.. try newark.com or mcm electronics. I built circuit for 20$$.
I get 317T for 0.22c😀
build the same circuit as I posted with The 317 and
substitute 337 and flip diodes (D1-2). you are getting ripped
for price.. try newark.com or mcm electronics. I built circuit for 20$$.
I get 317T for 0.22c😀
No no I listed for four circuits.
I do not have to invert diodes and use other regulator I found out. I can just use two different transformers, and connect the negative and positive to the opposites for one of them.
I do not have to invert diodes and use other regulator I found out. I can just use two different transformers, and connect the negative and positive to the opposites for one of them.
- Status
- Not open for further replies.