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Post by charleyphogg on Apr 4, 2008 0:39:51 GMT
Noooo, not that DC  . If I remeber correctly ;D, it is when the input or output has a cap across it. When one souce or amp is, and the other isn't it creates a problem. I just pulled the plug and bought on Ori OMZ 4.1 today, and was wondering if I need to worry about this with it, and my Solo? Thanks in advance. |
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Post by dc on Apr 4, 2008 2:19:57 GMT
I knew you had a thing for me  |
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Post by charleyphogg on Apr 4, 2008 2:36:30 GMT
I knew you had a thing for me  Couldn't pass it up man. Maybe it was you taking a shower with your clothes and head phones on.  |
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Post by Deleted on Apr 4, 2008 2:43:19 GMT
Vodka helps DC couple ! |
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Post by dc on Apr 4, 2008 3:24:27 GMT
But to your question, I don't think the OMZ has DC output caps
It has a little bit of DC offset but not much. Mine has about 5mV on each channel.
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Post by Deleted on Apr 4, 2008 3:34:47 GMT
Guys
Even if the OMZ 4.1 had around 5mV DC out, AND the input of the Solo was DC coupled, there would probably be less than 50mV DC out of the Solo at maximum volume. If you were listening at 12o'clock on the volume control in this scenario, because the volume control is logarithmic, the DC out would be FAR less than 25mV. The Solo most likely isn't DC coupled ?
Alex
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XTRProf
Fully Modded
Pssst ! Got any spare capacitors ?
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Post by XTRProf on Apr 4, 2008 7:46:36 GMT
No worry, just measure it when it arrives, man! Put on DC and not AC, ok? Unless you wanted to listen to AC/DC by clicking here:  ;D ;D ;D |
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Post by charleyphogg on Apr 5, 2008 4:33:51 GMT
Thats where the problem comes in. I don't have my multi-meter any more and I don't know anyone that does. Kinda hate to go out and buy one just for that. Although I'd love to get into DIY, but the odds of ever being able to do that are pretty slim. Even was rough on me building my own PC and all you do with that is slap the parts in, hook up some wires and route them so air can circulate. Will it be a noise issue, or if I hook then up could bad things happen? Guess I could ask Ori and Graham  Thank you for your replies. |
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Post by Deleted on Apr 5, 2008 6:33:05 GMT
charleyphogg
You can stop worrying. I understand that the amplifier has a 470nF (.47uF) input capacitor after the volume control.
SandyK
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Post by PinkFloyd on Apr 5, 2008 17:08:49 GMT
The Solo most likely isn't DC coupled ? Alex AC coupled. From my original interview with Graham ( Full article can be read here) Q: You say the amp is AC coupled Graham, what does this mean and why do you adopt AC coupling in your design? "Well, this all stems from my distrust of the overuse of electronics to achieve what in my opinion is a simple task. If I were to have done this as a DC coupled design I would have had to servo the output. A servo is necessary to zero the output offset. Either that or you ac couple the bottom of the NFB potential divider with a cap. If you use a cap it's going to have to be an electrolytic because of its size, and electrolytics don't behave all that well without some DC across them. So rather than messing about with diodes to establish a DC voltage (diodes are noisy [and have a big temp co-efficient] in my opinion and should not be at such a sensitive part of an amp), just ac couple the whole thing and you've got half the DC rail across your electrolytics - problem solved! It does mean however, that you've now got an input cap and an output cap to worry about. But at least the output cap has half the supply voltage across it to make it behave as a linear device." |
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Post by PinkFloyd on Apr 5, 2008 17:19:01 GMT
hehe..... I can't even remember writing that article and it's years since I read it..... I'd totally forgotten about this part......
A twist to the tweak tale:
Further to Graham's mods I decided to try out an AD823 Op amp in place of the AD826 op amp as I had good experience of the AD823 in other amps. It was clear, from the moment I switched the amp on, that the AD823 sounded even better than the AD826 (and then some!) I called Graham and asked him to try an AD823 at gsp headquarters and see what he made of it.
A few days later I got a call from a very enthusiastic Graham who was absolutely bowled over by the AD823. He had optimised the Solo circuit to get the best out of the AD823 and he told me what additional components I should change in order to get the absolute maximum performance out of the AD823.
It was out with the soldering iron again and under the bonnet to solder in the additional components. Oh My God! no wonder Graham was so enthusiastic! The difference between the optimised AD823 and the AD826 was truly night and day... Just when I thought it couldn't get much better.... it did! Graham explained that the "AD826 had the equivalent of a Mars bar when it was looking for current whereas the AD823 was swimming in a sea of chocolate" Everything was so much clearer, so much more attacking and so much BETTER in all departments.
The Solo has now come of age and Graham was so happy with the sound he decided to rework the enclosure so it looks as good as it sounds. This was a great exercise and it was a pleasure to be involved in the transformation of the Solo into this box of sonic magic.
Pinkie
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Post by charleyphogg on Apr 5, 2008 18:58:39 GMT
Thak you much, SandyK and Pinkie.
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Couldn't pass it up man. 
