Another Super High End Phono Stage! No expense spared...
- Thread starter Fasterdamnit
- Start date
bsabel
Well-Known Member
You guys are too kind! I really hate the way the battery leads look but I need to keep them loose so I can pull the batteries out.
The hardest part of the whole process was getting the LED wired up. I soldered the resistor to the LED, lead wire to the resistor, and shrink-wrapped it. Then I soldered lead wire to the negative leg and shrink-wrapped the two LED leads (now with a resistor) together. Then I had to splice that with wires from the switch and the board. That, of course, got shrink wrap, too. So there was a lot of shrink-wrapping, PITA soldering, and some cussing. But it works great!
A fun little addition that I made was the ground lug strapped to the board's mounting screw. This is completely isolated from the circuits so the metal sides are now a shield!
But, seriously, that was fun, easy, inexpensive, and sounds great! It's pretty hard to beat that.
The hardest part of the whole process was getting the LED wired up. I soldered the resistor to the LED, lead wire to the resistor, and shrink-wrapped it. Then I soldered lead wire to the negative leg and shrink-wrapped the two LED leads (now with a resistor) together. Then I had to splice that with wires from the switch and the board. That, of course, got shrink wrap, too. So there was a lot of shrink-wrapping, PITA soldering, and some cussing. But it works great!
A fun little addition that I made was the ground lug strapped to the board's mounting screw. This is completely isolated from the circuits so the metal sides are now a shield!
But, seriously, that was fun, easy, inexpensive, and sounds great! It's pretty hard to beat that.
sachu888
Spare the tigers, kill me
bsabel
Well-Known Member
Ha! You're right!
How Screwed Am I?
How Screwed Am I? I got my order of Op-Amps today. The OPA134s are SMDs.
I see some guys who have adapters for SMD to 8 pin DIP. How awkward are they and how expensive. I got BOHICA'd on the price of these SMDs as it is. That is 3X what Mouser charges.
Thanks in advance!
How Screwed Am I? I got my order of Op-Amps today. The OPA134s are SMDs.
I see some guys who have adapters for SMD to 8 pin DIP. How awkward are they and how expensive. I got BOHICA'd on the price of these SMDs as it is. That is 3X what Mouser charges.
Thanks in advance!
Yeah, it isn't economically wise to go any further with the SMDs.
Yes at $3.00 each for the through hole chips it's not worth it.
There are a ton on ebay for way less. You've already got the money spent on the ICs. What sense does it make to spend more on more ICs?
Spend $4.40 on 10 adaptors and use what you have.
Take a look.
http://www.ebay.com/sch/i.html?_nkw=soic+to+dip+&_cqr=true&_nkwusc=soic+to+pdip&_rdc=1
Not to mention that all of the top of the line audio chips that have come out in the last few years are all SMD. The OPA827, OPA1642, OPA1612, LME49990 to name a few.
Better to get used to it. SMD is here to stay.
Spend $4.40 on 10 adaptors and use what you have.
Take a look.
http://www.ebay.com/sch/i.html?_nkw=soic+to+dip+&_cqr=true&_nkwusc=soic+to+pdip&_rdc=1
Not to mention that all of the top of the line audio chips that have come out in the last few years are all SMD. The OPA827, OPA1642, OPA1612, LME49990 to name a few.
Better to get used to it. SMD is here to stay.
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There in China, I ordered some a while back and they were cheap and did arrive, but it took six weeks.
The through hole ones are easier to change out, just put in a socket and away you go, no having to get adapters and solder them on. Also never buy op amps from ebay sellers in China, they are nearly always not what they are purported to be.
Are you saying that it requires different soldering than I do now?
Nope, you said you were screwed, or asked how screwed you were. I misunderstood that to mean you couldn't or wouldn't solder SMDs.
If you can then more power to you. I don't understand all the stink about the SMD op amps then.
Yep, they are on a slow boat from China.
I don't buy op amps from China either, why would you? Too many fakes. In fact I don't buy them off of ebay at all.
You can get manufacturer's samples for the cost of shipping or get them through the regular channels, eg, Mouser, Digi-Key, etc...
The adaptors work in the sockets too. In fact that's how I use them. Why would you solder the adaptors in place?
Your choices in through hole op amps is shrinking everyday.
ghazzer
Senior Member
Is there some structured way to troubleshoot an opamp?
I’ve still got problems with my CNC. Right now both signals are coming out the right channel of the CNC, and the left signal is much lower. Right & left signals are OK at the RCA center conductor before being plugged into the jacks of the CNC (inputs this time!) and looked the same after being plugged in. I used the 1 KHz test tone from the balance tracks of a Shure test record as a source. Both signals measured as ~10mv with my uncalibrated scope. This table shows what I measured at the points around the first stage opamp.
Input........10mv @ 1KHz...............Input.........10mv @ 1KHz
...L1.........10mv @ 1KHz................R1............10mv @ 1KHz
...L2.........11mv @ 1KHz................R2............11mv @ 1KHz
...L3.......550mv @ 2.77MHz...........R3..............9mv @ 1KHz
...L4.......920mv @ 11.3 MHz..........R4...........340mv @ 1KHz
I have checked the resistor values, examined the solder joints with a loupe, and checked continuity with an ohm meter.
It did work for a few days, at least until I started measuring signal levels so I could calculate the gain. I only measured signals by placing the probe on resistor leads, not on the pins of the preamp.
Unless someone can give me a way to check out this LME49720 opamp, I guess that I’ll just order some LM833s and see if my CNC pp will work with different opamps.
This schematic has not been checked by anyone else yet, so please be cautious if you attempt to use it.
I’ve still got problems with my CNC. Right now both signals are coming out the right channel of the CNC, and the left signal is much lower. Right & left signals are OK at the RCA center conductor before being plugged into the jacks of the CNC (inputs this time!) and looked the same after being plugged in. I used the 1 KHz test tone from the balance tracks of a Shure test record as a source. Both signals measured as ~10mv with my uncalibrated scope. This table shows what I measured at the points around the first stage opamp.
Input........10mv @ 1KHz...............Input.........10mv @ 1KHz
...L1.........10mv @ 1KHz................R1............10mv @ 1KHz
...L2.........11mv @ 1KHz................R2............11mv @ 1KHz
...L3.......550mv @ 2.77MHz...........R3..............9mv @ 1KHz
...L4.......920mv @ 11.3 MHz..........R4...........340mv @ 1KHz
I have checked the resistor values, examined the solder joints with a loupe, and checked continuity with an ohm meter.
It did work for a few days, at least until I started measuring signal levels so I could calculate the gain. I only measured signals by placing the probe on resistor leads, not on the pins of the preamp.
Unless someone can give me a way to check out this LME49720 opamp, I guess that I’ll just order some LM833s and see if my CNC pp will work with different opamps.
This schematic has not been checked by anyone else yet, so please be cautious if you attempt to use it.
Is there some structured way to troubleshoot an opamp?
I’ve still got problems with my CNC. Right now both signals are coming out the right channel of the CNC, and the left signal is much lower. Right & left signals are OK at the RCA center conductor before being plugged into the jacks of the CNC (inputs this time!) and looked the same after being plugged in. I used the 1 KHz test tone from the balance tracks of a Shure test record as a source. Both signals measured as ~10mv with my uncalibrated scope. This table shows what I measured at the points around the first stage opamp.
Input........10mv @ 1KHz...............Input.........10mv @ 1KHz
...L1.........10mv @ 1KHz................R1............10mv @ 1KHz
...L2.........11mv @ 1KHz................R2............11mv @ 1KHz
...L3.......550mv @ 2.77MHz...........R3..............9mv @ 1KHz
...L4.......920mv @ 11.3 MHz..........R4...........340mv @ 1KHz
I have checked the resistor values, examined the solder joints with a loupe, and checked continuity with an ohm meter.
It did work for a few days, at least until I started measuring signal levels so I could calculate the gain. I only measured signals by placing the probe on resistor leads, not on the pins of the preamp.
Unless someone can give me a way to check out this LME49720 opamp, I guess that I’ll just order some LM833s and see if my CNC pp will work with different opamps.
This schematic has not been checked by anyone else yet, so please be cautious if you attempt to use it.
The schematic looks good, I meant to look over it but it's been really hectic at work lately.
It was extremely kind of you to offer. I have done as much and the Karma comes around. Thanks ! ! !
Ghazzer, how about a chip swap? Rather than from right to left, from first to second. Then see if the drop is OK. Maybe a fresh chip? It looks like the right channel OA in the first chip might have been "molested."