Funny I prefer how the OP27s sound at lower voltages, generally around 8-10 V rails.
Totally off topic, I got an email the other day saying that Mac users found it difficult to open some of the files that can be downloaded from the RJM audio website. He didn't get back to me when I asked him which files were the problem.
If anyone can confirm this or give me any details, please email.
Thanks,
Richard
Totally off topic, I got an email the other day saying that Mac users found it difficult to open some of the files that can be downloaded from the RJM audio website. He didn't get back to me when I asked him which files were the problem.
If anyone can confirm this or give me any details, please email.
Thanks,
Richard
Hi, apologies for asking a question probably asked before, but the Search function seems to have its limits...
I've just scratch-built a 50dB gain VSPS with LM337/317 regulation and Hexfred rectifier diodes - running before I can walk TBH, but aiming to keep PS noise as low as possible and hoping to get this right first time...
I don't have access to an oscilloscope so usually test projects with a DMM and then "live" with a "sacrificial" NAD amp and Mission speakers bought for a few pounds.
Today' dry runs were fine, and so far as I can tell everything was OK until connected to the amp, where a high level of ?50Hz buzz was audible.
Nothing smoked or overheated, so I put the amp in standby, powered down the VSPS and disconnected everything with a view to working over the circuit to see what was amiss.
As I examined the disconnected phonostage, the amp sat in standby decide now was a good moment to smoke a ceramic cap!!! (The international voltage switch had fallen apart it turns out and was shorting) Suppose I'm glad it waited until the VSPS was disconnected, but now I'm left with no way I can test the VSPS "live" without risking my main rig...
So, what this lengthy overexplanation is leading up to - can someone tell me what ballpark VAC / VDC I should expect at the various outputs of the 5532 op-amp and at the VSPS' outputs?
And any other way I can be sure the phonostage is at least safe to try "live", as it'll take a while just dismantling the old NAD?
Sorry it's a long one, regards all, Sod
I've just scratch-built a 50dB gain VSPS with LM337/317 regulation and Hexfred rectifier diodes - running before I can walk TBH, but aiming to keep PS noise as low as possible and hoping to get this right first time...
I don't have access to an oscilloscope so usually test projects with a DMM and then "live" with a "sacrificial" NAD amp and Mission speakers bought for a few pounds.
Today' dry runs were fine, and so far as I can tell everything was OK until connected to the amp, where a high level of ?50Hz buzz was audible.
Nothing smoked or overheated, so I put the amp in standby, powered down the VSPS and disconnected everything with a view to working over the circuit to see what was amiss.
As I examined the disconnected phonostage, the amp sat in standby decide now was a good moment to smoke a ceramic cap!!! (The international voltage switch had fallen apart it turns out and was shorting) Suppose I'm glad it waited until the VSPS was disconnected, but now I'm left with no way I can test the VSPS "live" without risking my main rig...
So, what this lengthy overexplanation is leading up to - can someone tell me what ballpark VAC / VDC I should expect at the various outputs of the 5532 op-amp and at the VSPS' outputs?
And any other way I can be sure the phonostage is at least safe to try "live", as it'll take a while just dismantling the old NAD?
Sorry it's a long one, regards all, Sod
The VSPS has capacitively coupled output, so the DC offset at the output RCA should be zero. The AC (hum+noise) should measure no more than a few mV.
There should be no DC offset and AC measured at the input RCA input, though a voltmeter may flicker around the lowest point of the scale.
So, if, with the VSPS powered up, there are no significant AC or DC components to the input or output, then you can go ahead and connect it up to the audio system to test with no risk of damage.
/R
There should be no DC offset and AC measured at the input RCA input, though a voltmeter may flicker around the lowest point of the scale.
So, if, with the VSPS powered up, there are no significant AC or DC components to the input or output, then you can go ahead and connect it up to the audio system to test with no risk of damage.
/R
Thank-you for that 
Sorry to be thick, but this is my first ever signal level project - and I have everything still to learn about electronics - but does the same comment apply to the op-amp's outputs? Or should I expect a certain ballpark voltage there even with no input?
The faint whiff of dead capacitor in my room is making me paranoid!
cheers, sod
Sorry to be thick, but this is my first ever signal level project - and I have everything still to learn about electronics - but does the same comment apply to the op-amp's outputs? Or should I expect a certain ballpark voltage there even with no input?
The faint whiff of dead capacitor in my room is making me paranoid!
cheers, sod
Thanks again - I'll pop a chill pill and have a play tonight!
An externally hosted image should be here but it was not working when we last tested it.
Hey.
Some problems here.
I got some heavy noise, hum and RF interference of all kind.
with the Input shorted, and I measured 50mV and 230mV at the output (no dcblock cap)
I tried to put a 220pf at the inputs. A success to kill all kind of noise, hum, RF interference. Actually I had to recheck that the VSPS was power on, twice, it was deadsilent.
But everything has its price. Now the dc at the out put is 1822mV at both channels.
I havent hooked it up with any turntables yet.
I guess te PCB routing is a mess to cause all that interfernce I got before ?"?"
Some problems here.
I got some heavy noise, hum and RF interference of all kind.
with the Input shorted, and I measured 50mV and 230mV at the output (no dcblock cap)
I tried to put a 220pf at the inputs. A success to kill all kind of noise, hum, RF interference. Actually I had to recheck that the VSPS was power on, twice, it was deadsilent.
But everything has its price. Now the dc at the out put is 1822mV at both channels.
I havent hooked it up with any turntables yet.
I guess te PCB routing is a mess to cause all that interfernce I got before ?"?"
Hello all,
I have just finished building VSPS. Since I wait to receive the power transformer, I decided to use a couple of 12V batteries for a first test connecting them on the terminals of the filter capacitors after the regulators. VSPS is working but humming is much louder than output signal...
Turntable is grounded onto the VSPS board(which I got from skycoral.com). Any ideas guys?
I have just finished building VSPS. Since I wait to receive the power transformer, I decided to use a couple of 12V batteries for a first test connecting them on the terminals of the filter capacitors after the regulators. VSPS is working but humming is much louder than output signal...
Turntable is grounded onto the VSPS board(which I got from skycoral.com). Any ideas guys?
web page help
Ok guys, I need some advice:
Back in the prehistoric days of the internet I made a web page for my audio stuff. The year was 1997. RJM Audio Cable has sat on Geocities ever since because a) I was too lazy to move it b) Geocities was free and c) I didn't want to break peoples links to my projects.
Well, Yahoo is going to shut down Geocities later this year and I would like some advice about what I should do about this.
The whole website is less than 7MB (really!) and and usually manages to stay within the 4.2MB/hr Geocities bandwidth cap.
I'd like to move it to somewhere where I could have my own web address, but doesn't cost very much.
I could upgrade to the paid Yahoo service, but being turfed out of Geocities after 12 years doesn't put me in the mood to turn around and pay them money if there was a reasonable alternative.
I'm completely out of touch with web-hsting services, it's something I've never had to deal with before.
And help would be greatly appreciated.
/Richard
Ok guys, I need some advice:
Back in the prehistoric days of the internet I made a web page for my audio stuff. The year was 1997. RJM Audio Cable has sat on Geocities ever since because a) I was too lazy to move it b) Geocities was free and c) I didn't want to break peoples links to my projects.
Well, Yahoo is going to shut down Geocities later this year and I would like some advice about what I should do about this.
The whole website is less than 7MB (really!) and and usually manages to stay within the 4.2MB/hr Geocities bandwidth cap.
I'd like to move it to somewhere where I could have my own web address, but doesn't cost very much.
I could upgrade to the paid Yahoo service, but being turfed out of Geocities after 12 years doesn't put me in the mood to turn around and pay them money if there was a reasonable alternative.
I'm completely out of touch with web-hsting services, it's something I've never had to deal with before.
And help would be greatly appreciated.
/Richard
Michiel gives good advice.
Hard to go wrong with Google right now.
I can't promise you 12 years but Google is the "current" best alternative.
And also, thank you for your gifts and contributions.
EDIT- Link to create a free account with Google:
https://www.google.com/accounts/New...8c8dfe64a835498027cd8593cc9f2f7a19aada&type=2
EDIT 2:
Once you have the account created you can create a new website here: <Google tries to make it VERY easy, their goal is for EVERYONE to be able to do it>
http://sites.google.com/
Hard to go wrong with Google right now.
I can't promise you 12 years but Google is the "current" best alternative.
And also, thank you for your gifts and contributions.
EDIT- Link to create a free account with Google:
https://www.google.com/accounts/New...8c8dfe64a835498027cd8593cc9f2f7a19aada&type=2
EDIT 2:
Once you have the account created you can create a new website here: <Google tries to make it VERY easy, their goal is for EVERYONE to be able to do it>
http://sites.google.com/
<they know they can count on me too>