I wanted to start this over in a new thread
alexcd said:
tryonziess said:that mean you are going to design a useable driver with this chip. make the boards as good as alex88 and i want some. have you noticed the neat bridges jrdg uses to transfer the output power in there amps. nice thick elevated copper covered in epoxy. nice!! if you can machine out about 75 pounds of solid aluminum for the case we could have some amps like that. otherwise 8000 dollars u.s. i am going to build my own thanks to alex boards. have fun
alexw88 said:
alexcd said:
alexcd said:
alexw88 said:
alexcd said:
alexw88 said:
The point is that OPA1632 may or may not be the right choice here. I would also like to find out if anyone else has a need for a line driver or other use for this circuit and wants to give input. I would like to make PCB's but obviously the more people the merrier.
is the opa chip better in this application than the ths from ti. you will need to provide a balanced line in from 2 op to the ths/opa1692 i guess. now is this far superior to a standard drv134 setup. the only really good point is the cmrr of the new ths is as good as a transformer. when you get the board built let me know i will need a few. still have not ruled out the lundahl transformer. there is also a good schematic at ti about this chip and the transformer in combination. with .000? thd on this amp i really do not want to garbage it up. so any help is appreciated. if you have access to a milling machine melt down a couple thousand beer cans and mill out a jrdg billet case. would be nice.
Good questions. I was hoping for someone to ask them. Personally, I think that a OPA2227/OPA1632 would be a mean combination with no worse than 1% resistors. I am more worried about the effects of the resistors than the chips.
That case idea sounds good but only if Sam Adams starts putting beer in cans. I wouldnt want cheap beer getting in my project.
That case idea sounds good but only if Sam Adams starts putting beer in cans. I wouldnt want cheap beer getting in my project.
THS4131 and OPA1632 are pin compatible if you keep pin 7 open. You can use the same pcb and try both chips.
For resistors, I agree 1% or even 0.1% should be used. You could hand match the 1% to get better accuracy.
What voltage regulator will you use? Ever thought of the new low noise LT1763?
For resistors, I agree 1% or even 0.1% should be used. You could hand match the 1% to get better accuracy.
What voltage regulator will you use? Ever thought of the new low noise LT1763?
more and more projects are requiring 0.1 or better resistors. has anyone found a place to buy bulk precision resistors in varying values at a reasonable price. i never thought the cost of resistors would enter the equation, but now its has. you can buy a fairchild op amp for less than a 0.1 vishay/dale resistor. any of you ever heard a leach amp playing music. i have been thinking about building a discrete amp after the chipamp projects. it looks like leach spent quite a lot of time debugging the original design and it should be quite reliable with present day components.
you could always melt the sam adams bottles and machine with diamond tooling. that would be one nice case. back light with leds. there are no limits imposed on diy projects just time. good choice in your brew.
you could always melt the sam adams bottles and machine with diamond tooling. that would be one nice case. back light with leds. there are no limits imposed on diy projects just time. good choice in your brew.
that driver
i just read the datasheet on the that line driver. it looks to be a dropin driver with all the advatages of the ths/opa and all in on little dip8 chip. price is about 3.00 dollars. you could mount it right on the main board. they also have some other neat stuff and mouser sells their products. i might give this little unit a go.
i just read the datasheet on the that line driver. it looks to be a dropin driver with all the advatages of the ths/opa and all in on little dip8 chip. price is about 3.00 dollars. you could mount it right on the main board. they also have some other neat stuff and mouser sells their products. i might give this little unit a go.
DRV134 I assume you mean? I can't find them anywhere! There seems to be a major lead time issue.
I'm using the OPA1632 in my new preamp.
I choosed the DGN package with thermal pad underneath, and have followed the powerpad layout suggestion.
This chip consumes quite large quiescent current of 14mA. The extra heat should be taken care of, if running with +/-12~15V supply.
I choosed the DGN package with thermal pad underneath, and have followed the powerpad layout suggestion.
This chip consumes quite large quiescent current of 14mA. The extra heat should be taken care of, if running with +/-12~15V supply.
Attachments
since the ths 4131 requires a low impedance input just what would the schematic look like if you include the buffer. what is a good buffer choice. i looked again and the that chip has poor specs not quite as good as the drv134. thanks
highly recommend you read Banana's preamp thread here : http://av-forums.net/plus/viewthread.php?tid=27503&extra=page=1&page=1
subscribe to the forum to see the pics. he has designed an excellent preamp with excellent measurement results. (THD+N at 0.0003%, noise floor at -130db
)
Banana, please share more here about opamps 🙂
subscribe to the forum to see the pics. he has designed an excellent preamp with excellent measurement results. (THD+N at 0.0003%, noise floor at -130db
)Banana, please share more here about opamps 🙂
I have some OPA2227's laying around that I was going to use. The TI dual opamp package is compatible with most other dual opamps so deciding now may not be required for layout at least. A little help with selection would be nice though. What are people's thoughts on a 8-DIP socket? Your choice of course but I'm going to use one if I want to swap out later. This knocks out SMD options for the buffer if I go this route.
the ths4131 and linear techs ltc1992 only come in 8soic package which is hard to work with. is there a pin socket for this configuration. and thanks alex i am going to read doc
Hi,
keep in mind that source impedance matching is just as (or more) important as around the differential impedance matching.
I have found that 1% and even 5% reistors can easily be matched to <=0.2% and with a bit more effort <=0.05%. That is total spread, not +-%
Electronic differential amps demand good matching at all usable frequencies to return the good numbers that they have initially been chosen for. Don't throw the baby out with the .....
keep in mind that source impedance matching is just as (or more) important as around the differential impedance matching.
I have found that 1% and even 5% reistors can easily be matched to <=0.2% and with a bit more effort <=0.05%. That is total spread, not +-%
Electronic differential amps demand good matching at all usable frequencies to return the good numbers that they have initially been chosen for. Don't throw the baby out with the .....
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