Haven't tried the AD8620 without the CRD (My 400 already has it) but from what I hear it is a great improvement!
ok, so here is the million dollar question (or questions)...
1.) how do you tell if your module already has it (or doesnt)
2.) how do you install it
1.) how do you tell if your module already has it (or doesnt)
2.) how do you install it
Hi,
First off you need the AD8620. If you have a very recent module that included that op amp, odds are good you have it already.
Otherwise, look for around the op amp for two empty three pad footprints, very small in size sot-23, named T21 & T22.
If they're empty get yourself some sot-23 SST511's from mouser, as far as installing them, good luck, it's a pain. I tinned the pads first, then used hot air to tack them down loosely, then touched them up with the iron. That worked fine on the first three, the last one I had to tape down and just tack it the air wasn't doing it at all strangely enough. Be VERY careful if you try hot air, the slightest tap on the module while the solder is reflowed and all those little parts are going to go sliding. Make sure they're nice and level first too.
Actually little bit of glue under them would be a great idea before you solder.
Regards,
Chris
First off you need the AD8620. If you have a very recent module that included that op amp, odds are good you have it already.
Otherwise, look for around the op amp for two empty three pad footprints, very small in size sot-23, named T21 & T22.
If they're empty get yourself some sot-23 SST511's from mouser, as far as installing them, good luck, it's a pain. I tinned the pads first, then used hot air to tack them down loosely, then touched them up with the iron. That worked fine on the first three, the last one I had to tape down and just tack it the air wasn't doing it at all strangely enough. Be VERY careful if you try hot air, the slightest tap on the module while the solder is reflowed and all those little parts are going to go sliding. Make sure they're nice and level first too.
Actually little bit of glue under them would be a great idea before you solder.
Regards,
Chris
ah ok. my modules are about a month or two old, and they are the AD8620's too. so i probably already have it. ill check it out though. thanks.
FC bypass caps might be an issue
Chris,
I know you mentioined that Bruno picked the stock cap for its ESR.
I don' t know if you've ever looked at what happens when you parallel two caps, but its interesting.
The ESL of the big cap, say the PS big electrolytics (plus wire L) resonates with the board cap.
Thus, what you get is a peak in the rail impedance. It gets kind of ugly. Its easy to simulate.
This is huge in modern layout for high speed circuits. You usually want to use X7R ceramics rather than NPO's becuase the ESR actually damps the impedance. The NPO's will give you lower imedance at some frequency, but a peak at another.
In modern high speed layout you must use board capacitance or your dead.
So, for the UcD's, I imagine that the devil is in the details.
The FC's might be better or worse depending on how long the hook up wires from the main bypass is, and where the series resonance and anti-resonance occur.
I also think that if the noise on the rails is larger, but due to the current, its likely better than a ringing of higher frequency but lower amplitude, and this will smear the transitions.
When my boards show up, I'll take a good look at what the supply noise looks at and post results.
Anyone know how long delivery takes?
They shipped monday with the fastest shipping method.
Best Regards,
Mike
Chris,
I know you mentioined that Bruno picked the stock cap for its ESR.
I don' t know if you've ever looked at what happens when you parallel two caps, but its interesting.
The ESL of the big cap, say the PS big electrolytics (plus wire L) resonates with the board cap.
Thus, what you get is a peak in the rail impedance. It gets kind of ugly. Its easy to simulate.
This is huge in modern layout for high speed circuits. You usually want to use X7R ceramics rather than NPO's becuase the ESR actually damps the impedance. The NPO's will give you lower imedance at some frequency, but a peak at another.
In modern high speed layout you must use board capacitance or your dead.
So, for the UcD's, I imagine that the devil is in the details.
The FC's might be better or worse depending on how long the hook up wires from the main bypass is, and where the series resonance and anti-resonance occur.
I also think that if the noise on the rails is larger, but due to the current, its likely better than a ringing of higher frequency but lower amplitude, and this will smear the transitions.
When my boards show up, I'll take a good look at what the supply noise looks at and post results.
Anyone know how long delivery takes?
They shipped monday with the fastest shipping method.
Best Regards,
Mike
More on the bypass caps
Chris,
Here is a quote from the www.oliveaudio.com site:
"Today the fashion of sound quality is partly the musicality, and relaxed sound, but also with a perfect sound stage. A sound that will show the performers with a holographic precision. To get this property you have to use single point power sources for your amplifier. This means no parallel capacitors, of anywhere near equal sizes. You can parallel 10000 uF with 10 nF. Not 100 nF. You will start losing a little bit of the holographic effect. Also materials in the signal path start to become important to maintain the holographic effect. The mentioned silver / teflon mains wire will help. "
Interesting, and I think what's being talked about is this LC resonance when caps and paralleled.
Mike
Chris,
Here is a quote from the www.oliveaudio.com site:
"Today the fashion of sound quality is partly the musicality, and relaxed sound, but also with a perfect sound stage. A sound that will show the performers with a holographic precision. To get this property you have to use single point power sources for your amplifier. This means no parallel capacitors, of anywhere near equal sizes. You can parallel 10000 uF with 10 nF. Not 100 nF. You will start losing a little bit of the holographic effect. Also materials in the signal path start to become important to maintain the holographic effect. The mentioned silver / teflon mains wire will help. "
Interesting, and I think what's being talked about is this LC resonance when caps and paralleled.
Mike
I removed the BC136 470uf with 0.5R resistor and fitted the higher value FC's underneath the modules the other day, its had a good few hours run in.
The sound is different from the BC136 but to be honest I think they sound worse, the tone is thicker, the thing is it sounds less involving to my ears
I think the brown KMG's are going back in tomorrow, they may not be the best caps you can buy but I prefer them against the others in this position, its still good to try these things out🙂
Next thing I'm going to try is the output cap, I'm actually looking forward to this, it seems the caps here has the biggest effect on the sound according to the posts.
I'm going to try the Auricaps and some different small sized polypropylenes that I can source locally to compare
I'd certainly recommend the CRD mod to anyone who has these missing on the AD8620 UCD board, its hard to explain the difference, all I can say is that the sound is more right😉
The sound is different from the BC136 but to be honest I think they sound worse, the tone is thicker, the thing is it sounds less involving to my ears
I think the brown KMG's are going back in tomorrow, they may not be the best caps you can buy but I prefer them against the others in this position, its still good to try these things out🙂
Next thing I'm going to try is the output cap, I'm actually looking forward to this, it seems the caps here has the biggest effect on the sound according to the posts.
I'm going to try the Auricaps and some different small sized polypropylenes that I can source locally to compare
I'd certainly recommend the CRD mod to anyone who has these missing on the AD8620 UCD board, its hard to explain the difference, all I can say is that the sound is more right😉
CRD's
Chris,
The references you quoted must be for the UcD180's right?
On the new 400's they are designated as T25, T26 and are marked as L1UUA. I didn't even know this change had been made. Thanks for the info.
Roger
classd4sure said:
Chris,
The references you quoted must be for the UcD180's right?
On the new 400's they are designated as T25, T26 and are marked as L1UUA. I didn't even know this change had been made. Thanks for the info.
Roger
Re: More on the bypass caps
Hi Mike,
The high ESR caps I mentioned are different ones entirely. The FC caps in question don't replace those, as they should be left in place for their dampening as I explained, or replaced with other caps with a rather high ESR.
What the FC caps do replace are already snubbed, which also has more to do than just dampen ringing, but extending bandwidth as well I believe, my counteracting ESL. I sure hope they're not snubbed with X7R due to their rather poor temperature stability. I'd much prefer COG or NPO, in conjuction with a fairly precise resistor. Wouldn't you agree?
I chose to address the PSU cap resonances by other means, namely // Jensen 4 poles.... of the same value, which led to a very fast, ultra revealing amp with rather extreme holography, for which I find the FC's responsible for diminishing upon replacement of the stock decoupling caps, likely due to higher ESL, which I'll be further investigating, but that doesn't answer the question of a good all around cap that performs well on both ends of the spectrum. As I was saying previously it could also be due to the size, my intuition is that it's more due to attack capability than the ratio between them and the supply cap's value. Smaller caps are just faster I think, but so are better caps, so the hunt for the best of both continues.
You'll see all this jives well with my observation of the stock caps being "peaky", or high Q favoring the higher frequencies, which really made the directional microdetail stand out, leading to a very holographic experience which the FC's fail to provide.
I find a great deal of irony in that.... I'll have to refrain from further comment there. To each their own huh?
I don't much buy into audio "fashion", I just know what I like, which is musical, rich in detail both macro and micro, revealing, neutral and yes holographic with the kind of soundstage that envelopes you.
I do alot of research and the experimentation which I'm able to do given my resources, my answers don't come from marketing.
Regards,
Chris
Portlandmike said:
Hi Mike,
The high ESR caps I mentioned are different ones entirely. The FC caps in question don't replace those, as they should be left in place for their dampening as I explained, or replaced with other caps with a rather high ESR.
What the FC caps do replace are already snubbed, which also has more to do than just dampen ringing, but extending bandwidth as well I believe, my counteracting ESL. I sure hope they're not snubbed with X7R due to their rather poor temperature stability. I'd much prefer COG or NPO, in conjuction with a fairly precise resistor. Wouldn't you agree?
I chose to address the PSU cap resonances by other means, namely // Jensen 4 poles.... of the same value, which led to a very fast, ultra revealing amp with rather extreme holography, for which I find the FC's responsible for diminishing upon replacement of the stock decoupling caps, likely due to higher ESL, which I'll be further investigating, but that doesn't answer the question of a good all around cap that performs well on both ends of the spectrum. As I was saying previously it could also be due to the size, my intuition is that it's more due to attack capability than the ratio between them and the supply cap's value. Smaller caps are just faster I think, but so are better caps, so the hunt for the best of both continues.
You'll see all this jives well with my observation of the stock caps being "peaky", or high Q favoring the higher frequencies, which really made the directional microdetail stand out, leading to a very holographic experience which the FC's fail to provide.
Portlandmike said:
I find a great deal of irony in that.... I'll have to refrain from further comment there. To each their own huh?
I don't much buy into audio "fashion", I just know what I like, which is musical, rich in detail both macro and micro, revealing, neutral and yes holographic with the kind of soundstage that envelopes you.
I do alot of research and the experimentation which I'm able to do given my resources, my answers don't come from marketing.
Regards,
Chris
Re: CRD's
Hi,
Yeah if you still have the stock filter cap the FC's are pretty bad. I'd say leave them in though until you do try a different filter cap.
With the filter cap replaced the FC's are very decent and maybe you'll like the extra punch in the bass too. What value did you try anyway?
They however still lack high frequency extension, hence a less holographic experience.
Honestly I'm having a hard time wanting to give up the extended bass Vs the extended highs, and just won't be satisfied with that kind of a trade off.
So at this point, I think I'm going to try raising their Q by decoupling them further.
Yeah they're for the 180. You're very welcome.
Regards,
Chris
t. said:I removed the BC136 470uf with 0.5R resistor and fitted the higher value FC's underneath the modules the other day, its had a good few hours run in.
The sound is different from the BC136 but to be honest I think they sound worse, the tone is thicker, the thing is it sounds less involving to my ears
I think the brown KMG's are going back in tomorrow, they may not be the best caps you can buy but I prefer them against the others in this position, its still good to try these things out🙂
Next thing I'm going to try is the output cap, I'm actually looking forward to this, it seems the caps here has the biggest effect on the sound according to the posts.
I'm going to try the Auricaps and some different small sized polypropylenes that I can source locally to compare
I'd certainly recommend the CRD mod to anyone who has these missing on the AD8620 UCD board, its hard to explain the difference, all I can say is that the sound is more right😉
Hi,
Yeah if you still have the stock filter cap the FC's are pretty bad. I'd say leave them in though until you do try a different filter cap.
With the filter cap replaced the FC's are very decent and maybe you'll like the extra punch in the bass too. What value did you try anyway?
They however still lack high frequency extension, hence a less holographic experience.
Honestly I'm having a hard time wanting to give up the extended bass Vs the extended highs, and just won't be satisfied with that kind of a trade off.
So at this point, I think I'm going to try raising their Q by decoupling them further.
sx881663 said:
Yeah they're for the 180. You're very welcome.
Regards,
Chris
What's the first tweak
Chris,
Sounds like there is alot right about stock.
Are there any tweaks that clearly don't have downsides?
My amps still haven't yet arrived so I suspect they are pretty up to date, and won't have coupling caps and such if I read the threads right.
Thanks
Mike
Chris,
Sounds like there is alot right about stock.
Are there any tweaks that clearly don't have downsides?
My amps still haven't yet arrived so I suspect they are pretty up to date, and won't have coupling caps and such if I read the threads right.
Thanks
Mike
Hi Mike,
Did you order the AD or ST?
Only the AD includes the CRD's and AD8620 op amp. It should also have a different filter cap than the one I commented on.
Sadly it's going to have the AC electrolytic coupling caps and if you want to remove them you have to make sure your DC offset at the source is ~1.2mV or below.
Otherwise you can upgrade them as reported in this thread by moving them before the op amps and using film caps of your choice.
Regards,
Chris
Did you order the AD or ST?
Only the AD includes the CRD's and AD8620 op amp. It should also have a different filter cap than the one I commented on.
Sadly it's going to have the AC electrolytic coupling caps and if you want to remove them you have to make sure your DC offset at the source is ~1.2mV or below.
Otherwise you can upgrade them as reported in this thread by moving them before the op amps and using film caps of your choice.
Regards,
Chris
My UCD 400 to do list
Hi Chris,
The AD version.
So removing the bypass altogether or at least moving them to the input (and making them film) are big improvements, right?
Thus I should just listen for awhile, then maybe the output filter cap, right?
Mike
Hi Chris,
The AD version.
So removing the bypass altogether or at least moving them to the input (and making them film) are big improvements, right?
Thus I should just listen for awhile, then maybe the output filter cap, right?
Mike
Hi Mike,
Yeah, especially because the electrolytics need some DC bias to trick them into sounding OK but in this case they have none. It definatly is a step up.
Also how you implement them makes a big difference, long before you even start worrying about other upgrades. I chose some really good parts which I think allowed me to get away with a really bare bones setup, like no bypass caps across the rectifiers or anything yet, and there may never be at that.
I found the biggest thing was to ensure the output is properly referenced to the input, most easily done by floating the output grounds from the chassis, and grounding it only at the input.
You may also want to try and upgrade the stock 470uF decoupling caps too, just to see how how you like it. They have almost as drastic an effect on sound as the filter cap. In fact I hate to say it but I think I'll forgo that "extra" holography and keep the extended bass of the FC's. I find it much more appealing/relaxing with the extended bass Vs the extended highs, because without the bass it seems the highs are over emphasized I guess. I might try a smaller FC later on and see if they're any faster.
Using an auxiliary supply for the input stage is another good upgrade, which I haven't tackled myself yet, it's more for the long term. There's always a downside depending what you're looking at, cost/effort/ etc. I don't think any of those present you with the sort of trade off situation the caps seem to though.
Modifying these things is well worth it, but they really dont' need much, especially if you're starting off with the AD's already.
BTW I'd think you'd get your modules next week sometime. You're in for a treat!
Regards,
Chris
Yeah, especially because the electrolytics need some DC bias to trick them into sounding OK but in this case they have none. It definatly is a step up.
Also how you implement them makes a big difference, long before you even start worrying about other upgrades. I chose some really good parts which I think allowed me to get away with a really bare bones setup, like no bypass caps across the rectifiers or anything yet, and there may never be at that.
I found the biggest thing was to ensure the output is properly referenced to the input, most easily done by floating the output grounds from the chassis, and grounding it only at the input.
You may also want to try and upgrade the stock 470uF decoupling caps too, just to see how how you like it. They have almost as drastic an effect on sound as the filter cap. In fact I hate to say it but I think I'll forgo that "extra" holography and keep the extended bass of the FC's. I find it much more appealing/relaxing with the extended bass Vs the extended highs, because without the bass it seems the highs are over emphasized I guess. I might try a smaller FC later on and see if they're any faster.
Using an auxiliary supply for the input stage is another good upgrade, which I haven't tackled myself yet, it's more for the long term. There's always a downside depending what you're looking at, cost/effort/ etc. I don't think any of those present you with the sort of trade off situation the caps seem to though.
Modifying these things is well worth it, but they really dont' need much, especially if you're starting off with the AD's already.
BTW I'd think you'd get your modules next week sometime. You're in for a treat!
Regards,
Chris
Re: Re: CRD's
Hi Chris,
I'm using 680uf 63v, it was the highest FC I could get from Farnell in this value.
I agree regarding the highs😉 suppose I could leave them in until I get the output caps, these will have to make a fairly big difference though to be honest, at the minute it just lacks involvement
classd4sure said:
Hi Chris,
I'm using 680uf 63v, it was the highest FC I could get from Farnell in this value.
I agree regarding the highs😉 suppose I could leave them in until I get the output caps, these will have to make a fairly big difference though to be honest, at the minute it just lacks involvement
FYI
I recently received this email info from John @ Audience:
The .68uF Auricaps for Hypex amps are now available from Kevin Haskins at DIY Cables, (360) 452-9373.
Very Best,
John McDonald
President
Audience
I recently received this email info from John @ Audience:
The .68uF Auricaps for Hypex amps are now available from Kevin Haskins at DIY Cables, (360) 452-9373.
Very Best,
John McDonald
President
Audience
I trust he'll have the specifications on them then.
Would we be buying a good cap or just a name? So far all I've heard is a name, got any specs to go with it? Will partsconnexion be carrying them?
Would we be buying a good cap or just a name? So far all I've heard is a name, got any specs to go with it? Will partsconnexion be carrying them?
Thing is will these newer Auricaps actually sound better than the old ones, I've just ordered the normal ones
I don't really fancy wasting money to buy some more
I don't really fancy wasting money to buy some moreHere is my filter mod. Sounds very different. The thin sound is gone. The voice sounds deeper. It is a MKP479 680nf. Well....will see how it sounds after a week or so. Thanx Matjans for the caps.
An externally hosted image should be here but it was not working when we last tested it.
You weren't concerned with mounting it as close as possible? That's quite a bit of extra area there.
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