Hi belgiangenius,
What is wrong with the sm adapter PCBs? Just because a part is only available in surface mount doesn't count as a disaster, it's just another thing that increases the price and becomes another step. You figure surface mount devices have to be mounted on PCB material anyway.
-Chris
What is wrong with the sm adapter PCBs? Just because a part is only available in surface mount doesn't count as a disaster, it's just another thing that increases the price and becomes another step. You figure surface mount devices have to be mounted on PCB material anyway.
-Chris
It is just an extra step, is all. ...and since I have not seen them, I wonder how small the contacts are. Some SMD components are hard to solder manually!
You could try this guy:
http://www.diyaudio.com/forums/swap-meet/292716-fs-ad844-opa627-ad797-lt1028.html The circuit you have shown is NOT a good one for BP opamps---FETs will fare MUCH better. Best FET for the buck is the OPA1642.....but it's SOIC. Not THAT hard to solder!!!
http://www.diyaudio.com/forums/swap-meet/292716-fs-ad844-opa627-ad797-lt1028.html The circuit you have shown is NOT a good one for BP opamps---FETs will fare MUCH better. Best FET for the buck is the OPA1642.....but it's SOIC. Not THAT hard to solder!!!
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Hi belgiangenius,
The answer to your small lead soldering issues ... liquid solder flux designed for electronics. MG Chemicals (Sayal Electronics) 835-100ml. That's a bottle with 125 ml of flux. Use it with a nail polish bottle that has a brush in it, or use an old GC bottle that has this stuff in it.
The flux will keep the solder on the terminals and pads. I use a 3mm "screwdriver" soldering tip (it's a flat tip about 3 mm wide) for soldering sm components. The wide tip is fantastic for ICs and can make a factory looking soldering job. Use Lacquer Thinner to clean up (Canadian Tire paint department). Use a Q-Tip (not plastic shaft!) and / or a small, soft tooth brush - like for toddlers. I use both depending on how much flux I have to remove. Cleaning the flux allows you to check the solder joints for bridges or wire bits. Once you get the hang of soldering, you won't have any problems with soldering surface mount components. The exceptions are BGA and the ones where the leads are part of the package, just metalized areas. Those can be done, but they are a pain.
-Chris
The answer to your small lead soldering issues ... liquid solder flux designed for electronics. MG Chemicals (Sayal Electronics) 835-100ml. That's a bottle with 125 ml of flux. Use it with a nail polish bottle that has a brush in it, or use an old GC bottle that has this stuff in it.
The flux will keep the solder on the terminals and pads. I use a 3mm "screwdriver" soldering tip (it's a flat tip about 3 mm wide) for soldering sm components. The wide tip is fantastic for ICs and can make a factory looking soldering job. Use Lacquer Thinner to clean up (Canadian Tire paint department). Use a Q-Tip (not plastic shaft!) and / or a small, soft tooth brush - like for toddlers. I use both depending on how much flux I have to remove. Cleaning the flux allows you to check the solder joints for bridges or wire bits. Once you get the hang of soldering, you won't have any problems with soldering surface mount components. The exceptions are BGA and the ones where the leads are part of the package, just metalized areas. Those can be done, but they are a pain.
-Chris
Just to be 100% safe, it looks like his layout uses singles, so the opa1641.
That, along with others would be my recommendations:
1.) OPA134 if you don't want to mess with pdip-soic adapters
2.) OPA1641 if you're willing. The ones Mark links to seem quite nice.
Here's another option for SOIC (and other package) to DIP adaptors. I have used them in the past and quality is very good.
BrownDog Electronic Component Adapters | Cimarron Technology, Inc.
They are also a good, if expensive source for single and dual op-amps favored in the audio world.
BrownDog Electronic Component Adapters | Cimarron Technology, Inc.
They are also a good, if expensive source for single and dual op-amps favored in the audio world.
This really ought to be in solid state as I think about it, so I will move it there.
Might also want to consider Butler topology op-amps, like the OP176 and OP275. I have both a DAC and parametric EQ that use these devices and I found replacing them with more "modern" op-amps resulted in a reduction of sound quality rather than the elusive "improvement" I was seeking. I decided if I had to have op-amps in the path the OP275 was pretty acceptable. They may or may not be suitable for all circuit locations, but aren't terribly expensive compared to a 627 or 797.
The original poster's AdCom schematic shows a 1702 DAC driving an AD711 I/V stage. The AD711 is a FET device described on its own data page thusly: "the AD711 is ideal as a buffer for 12-bit D/A and A/D Converters and as a high-speed integrator" Hmmmm....perhaps not so 'ideal' for a 16-bit source such as a CD. The 1702 datasheet curiously specifies firstly an OPA627 as an I/V converter (in the block diagram), then later an OPA2604 (in the actual schematic)---??????? In any case, a FET-type device is certainly called for, and a better IC than an AD711 would certainly be a preference. Adcom also use a 5.9K/120pf feedback, as opposed to the 1702 datasheet's 2.5K/220pf. To add further confusion, the 1794's datasheet recommends an NE5532 as an I/V converter. Hmmmm......
In terms of application notes it depends entirely on who developed the application circuit and wrote the note. Application notes are only intended as a guide on how to use the part, certain critical aspects of the device's performance and best practices will be discussed, but a good design engineer may choose to implement things quite differently and this is fine provided that the end user performance targets are met.
I think both the 627 and 827 are fine sounding, IIRC the 827 is built using a newer process and was intended to perform similarly to the 627 at lower cost.
I think both the 627 and 827 are fine sounding, IIRC the 827 is built using a newer process and was intended to perform similarly to the 627 at lower cost.
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