Extra lead length
Yes, even a little bit extra will increase the amount of residual carrier on the output. I have been experimenting with this very thing and believe the amount extra you have would increase the residual by 10-20%. As it already is quite low this may not be a problem but do Chris's AM radio check and see if you can live with the result.
Roger
Yes, even a little bit extra will increase the amount of residual carrier on the output. I have been experimenting with this very thing and believe the amount extra you have would increase the residual by 10-20%. As it already is quite low this may not be a problem but do Chris's AM radio check and see if you can live with the result.
Roger
Roger,
Do you have the new auricap yet & have any listening impressions? Does the form factor make it a drop in replacement?
Regards,
Dean
Do you have the new auricap yet & have any listening impressions? Does the form factor make it a drop in replacement?
Regards,
Dean
Chris, no prob. at all. No difference in radio reception. My FM tuner is 10cm away from the amp. in fact right under it on a shelf.classd4sure said:
But the sound(with the other cap.) really is different, darker, more bass, heavier. Not bad really...have to get used to it. It sounds fuller. If you think about it....just 1 cap. change????? The wonders of audio he!
PS just measured(with scope) the HF carrier ripple on the output...exactly the same as with the other cap. So no difference here.
Doing the final test with 2 exactly the same amps. (stereo UCD400/AD8620)and direct A-B switching, with a relay box(0,010 ohm contact resistance) switching the amps. output, and the only difference being the output filter cap. it showed a.........minor difference in sound. How 1 can fool himself by believing it makes a huge difference. Its all in the mind. Have to test it further though. To compare hardware mods. using 2 equally build amps. is the way to go(for me). The mind has his own findings.
Will ask other people to see if they can hear differences.
Will ask other people to see if they can hear differences.
Just got my UcD400's Today
😀
My UcD400's arrived today!
Took off work a bit early, and after about 5 hours, had two amps up and running!
I had a hum at first, because I didn't ground the rca ground.
I used a 2k to ground to kill ground loops. I would have used a 100ohm, but that was back at work.
So far, so good.
I wasn't very impressed at first, but I swear there getting better.
Never much believed in break in.
Might just be optimism over my finishing!
Its late, and I can't really let them loose.
I'm sure its in here somewhere, but what caps are the coupling caps?
THanks
Mike
😀
My UcD400's arrived today!
Took off work a bit early, and after about 5 hours, had two amps up and running!
I had a hum at first, because I didn't ground the rca ground.
I used a 2k to ground to kill ground loops. I would have used a 100ohm, but that was back at work.
So far, so good.
I wasn't very impressed at first, but I swear there getting better.
Never much believed in break in.
Might just be optimism over my finishing!
Its late, and I can't really let them loose.
I'm sure its in here somewhere, but what caps are the coupling caps?
THanks
Mike
Hi Matjans,
What power supply caps/values are those ?
If they have been changed , did they make any difference to the sound ?
The filter cap. Was that also changed ? If so , did it improve the sound ?
Thanks,
Ashok.
What power supply caps/values are those ?
If they have been changed , did they make any difference to the sound ?
The filter cap. Was that also changed ? If so , did it improve the sound ?
Thanks,
Ashok.
Re: Just got my UcD400's Today
Hi,
Just realize that you can get alot more quality out of it than you're hearing now, just by how you wire it, and long before you consider any tweaks. It's really a big difference.
Break in is a very real thing, based on the physics of things and not voodoo. In a few day's they'll be settled for the most part.
I'd wait until then before doing any tweaks at all.
Regards,
Chris
Portlandmike said:
Hi,
Just realize that you can get alot more quality out of it than you're hearing now, just by how you wire it, and long before you consider any tweaks. It's really a big difference.
Break in is a very real thing, based on the physics of things and not voodoo. In a few day's they'll be settled for the most part.
I'd wait until then before doing any tweaks at all.
Regards,
Chris
Re: Re: Just got my UcD400's Today
I've noticed they are starting to do a few things.
Got a chance to turn them up a bit this morning. Certainly nothing bad sounding. In fact I think they sound better turned up :>)
Nice enough stage. They lack some detail, but the "sins are in omission!"
I recall Jan Peters saying the new boards didn't have coupling caps. Hate to short the wrong ones, but then I can just get them to a scope and figure it out too I guess. They wouldn't be 22uF would they?
Mine are clearly different then the one in the pics as I recall.
Install was a breeze. I used some old Harmon Kardon Hk775 monoblocks. 400VA shielded toroid with 15000uF 71V caps. Mongo heat sinks, things barely feel above room temp.
I'd recommend them if someone wants an easy monoblock. They don't go for much on ebay anymore.
I think a fred bridge might be worth while, but way down the road.
Wiring?
I think I did a careful job of wiring. What kinds of things do you mean?
I used 14 gauge silver plated multistrand for power ground and the speaker outputs.
I wired +Vin to the hot RCA, and -Vin to RCA common. I used a 2k resistor from RCA common to signal ground. ( I would have used a 100ohm, but didn't have any at home.)
Power wires come right from the mains cap terminals. Chassy ground is taken from there also, tied only at one point.
The "star ground" is the mains cap ground terminal.
Any recommendations/ things to try?
Also, I agree with any tweaking should wait, and I plan to do that. I would bypass any coupling caps though. Don't need 'em.
Regards,
Mike
I've noticed they are starting to do a few things.
Got a chance to turn them up a bit this morning. Certainly nothing bad sounding. In fact I think they sound better turned up :>)
Nice enough stage. They lack some detail, but the "sins are in omission!"
I recall Jan Peters saying the new boards didn't have coupling caps. Hate to short the wrong ones, but then I can just get them to a scope and figure it out too I guess. They wouldn't be 22uF would they?
Mine are clearly different then the one in the pics as I recall.
Install was a breeze. I used some old Harmon Kardon Hk775 monoblocks. 400VA shielded toroid with 15000uF 71V caps. Mongo heat sinks, things barely feel above room temp.
I'd recommend them if someone wants an easy monoblock. They don't go for much on ebay anymore.
I think a fred bridge might be worth while, but way down the road.
classd4sure said:
Wiring?
I think I did a careful job of wiring. What kinds of things do you mean?
I used 14 gauge silver plated multistrand for power ground and the speaker outputs.
I wired +Vin to the hot RCA, and -Vin to RCA common. I used a 2k resistor from RCA common to signal ground. ( I would have used a 100ohm, but didn't have any at home.)
Power wires come right from the mains cap terminals. Chassy ground is taken from there also, tied only at one point.
The "star ground" is the mains cap ground terminal.
Any recommendations/ things to try?
Also, I agree with any tweaking should wait, and I plan to do that. I would bypass any coupling caps though. Don't need 'em.
Regards,
Mike
ashok,
This is not my picture, i 'borrowed' it from I think it was Julien.
I've changed the standard 470uF caps to 680uF Panasonic FC's (which everybody else seems to dislike, here) and imho they have not only changed the sound, they have, in my case, improved on details and depth of the bass. Maybe it's due to the wiringf my psu's. Output filter cap I've changed to bc/vishay mkp379, same value as the original.
This is not my picture, i 'borrowed' it from I think it was Julien.
I've changed the standard 470uF caps to 680uF Panasonic FC's (which everybody else seems to dislike, here) and imho they have not only changed the sound, they have, in my case, improved on details and depth of the bass. Maybe it's due to the wiringf my psu's. Output filter cap I've changed to bc/vishay mkp379, same value as the original.
Hallo,
Matjans, don't get me wrong, I'm in love with the added bass that the FC's provide. Finally my speakers are being put to work... I can feel the thunder in my chest even at medium low volume levels! It's very nice.
However in direct comparison they seemingly lacked air.
I know they're supposed to be low impedance but it just doesnt' sound like it at mid to high frequencies.
That extra air with the stock decoupling caps really produced a euphonic 3d holographic effect which I really liked because the sound wrapped right around you and so was much more involving.
I think there's a good chance the FC caps I got are just too big and thus have higher inductance.
At any rate, I hate to say it but I'm not satisfied with it yet. I think I'll be puttting back the stock decoupling caps and re-evaluating them with the new CRD's and filter cap.
I may also try smaller FC's if I can get some.
Regards,
Chris
Matjans, don't get me wrong, I'm in love with the added bass that the FC's provide. Finally my speakers are being put to work... I can feel the thunder in my chest even at medium low volume levels! It's very nice.
However in direct comparison they seemingly lacked air.
I know they're supposed to be low impedance but it just doesnt' sound like it at mid to high frequencies.
That extra air with the stock decoupling caps really produced a euphonic 3d holographic effect which I really liked because the sound wrapped right around you and so was much more involving.
I think there's a good chance the FC caps I got are just too big and thus have higher inductance.
At any rate, I hate to say it but I'm not satisfied with it yet. I think I'll be puttting back the stock decoupling caps and re-evaluating them with the new CRD's and filter cap.
I may also try smaller FC's if I can get some.
Regards,
Chris
Re: Re: Re: Just got my UcD400's Today
Hi Mike,
Alot of those "omissions" come from the coupling electrolytics, 22uF 50Vdc I believe. They're side by side. You should spot them easily enough, also in accordance with the picture where you can see they've already been removed. It might be best to remove them instead of just bypassing.
They give it kind of a spongy feel because there's no DC bias across them, and I think the same is likely true with the output filter cap as well.
As far as wiring ..
That ground lift is a bit of a bandaid, and a source of error.
Try breaking the loop by unearthing the chassis, and float the supply from it as well, then reference your signal ground to the RCA common at point of entry. This way it will be referenced to the same common point as the source itself.
It might be a better idea to keep your chassis grounded and hack away the earth of your source, but do float the supply from the chassis so there's no loop from output ground to signal ground, while keeping the most accurate reference point to the source as possible. Hypex recommends you build the supply using double insulation techniques in such a case... proceed with extreme caution.
Alternatively you could get a new source and run it fully balanced. I actually did that and found very little difference.
Such a change in wiring should produce a much deeper and wider soundstage, having better definition. Removing the coupling caps will tighten up the sound a great deal, mostly for the bass and mid range I think, and changing the output filter cap to a more suitable type will do the same for the highs. Although, that pertains mostly to the old stacked polyester cap. I understand you have some sort of red panasonic cap on the new module, and maybe it doesn't need improving on? Do you know what kind of cap it is?
Anyway, at worst that's really all it needs to make it sing. You can take it a step further by employing an auxiliary regulated supply for the input stage, and maybe for the drivers too. The usual choice of components also makes a big difference, but of course that's where the cost really creeps up fast.
Regards,
Chris
Portlandmike said:
Hi Mike,
Alot of those "omissions" come from the coupling electrolytics, 22uF 50Vdc I believe. They're side by side. You should spot them easily enough, also in accordance with the picture where you can see they've already been removed. It might be best to remove them instead of just bypassing.
They give it kind of a spongy feel because there's no DC bias across them, and I think the same is likely true with the output filter cap as well.
As far as wiring ..
That ground lift is a bit of a bandaid, and a source of error.
Try breaking the loop by unearthing the chassis, and float the supply from it as well, then reference your signal ground to the RCA common at point of entry. This way it will be referenced to the same common point as the source itself.
It might be a better idea to keep your chassis grounded and hack away the earth of your source, but do float the supply from the chassis so there's no loop from output ground to signal ground, while keeping the most accurate reference point to the source as possible. Hypex recommends you build the supply using double insulation techniques in such a case... proceed with extreme caution.
Alternatively you could get a new source and run it fully balanced. I actually did that and found very little difference.
Such a change in wiring should produce a much deeper and wider soundstage, having better definition. Removing the coupling caps will tighten up the sound a great deal, mostly for the bass and mid range I think, and changing the output filter cap to a more suitable type will do the same for the highs. Although, that pertains mostly to the old stacked polyester cap. I understand you have some sort of red panasonic cap on the new module, and maybe it doesn't need improving on? Do you know what kind of cap it is?
Anyway, at worst that's really all it needs to make it sing. You can take it a step further by employing an auxiliary regulated supply for the input stage, and maybe for the drivers too. The usual choice of components also makes a big difference, but of course that's where the cost really creeps up fast.
Regards,
Chris
matjans said:
Matjans,
I've been running my UcD400AD's for a good 24 hours. I shorted the input caps.
They do much right in image, but lack detail and the highs sound back a bit. The rest of the image is quite forward.
Tell me about the Wiring?
Also, what diode bride do you use. I've used "old bones from the 80's" so its NOT FRED's. If only I could get some more detail I'd be more happy 😉
Thanks
Mike
Re: Just got my UcD400's Today
HI Chris,
Thanks for the wiring tip. Its easy enough to short the resistor. (By the way, my amps don't have a "earth ground". I guess that means they are already double insulated. It would be a good addition perhaps, but it was a get done quick night!
I did follow the manual in grounding the chassey, but that's not the ideal recommendation I guess.
It also easy enough to hack the one wire that ties ground of the supply to the chassey.
They all ready stage pretty deep and wide, but the high's are a bit back compared to the mids. Sounds like the output filter cap might be worth doing.
by the way, I shorted the caps, for now.
I'll look at the output filter cap and see if I can tell what it is.
Is the BC/Vishay/mkp379 the one to get?
Now who sells them?
Anyone bothered trying to use metal films for the three op amp resistors or the feedback ones? It reminds me of the way my McIntosh MC240 sounded before I metal filmed it. kind of lacking detail and dynamics.
I have two through hole resistors on the board. Do you know what they are? Feedback resistors maybe?
Thanks Again, Looking forward to more improvement.
Its very listenable, and engaging, but leaves something to be desired yet.
Mike
classd4sure said:
HI Chris,
Thanks for the wiring tip. Its easy enough to short the resistor. (By the way, my amps don't have a "earth ground". I guess that means they are already double insulated. It would be a good addition perhaps, but it was a get done quick night!
I did follow the manual in grounding the chassey, but that's not the ideal recommendation I guess.
It also easy enough to hack the one wire that ties ground of the supply to the chassey.
They all ready stage pretty deep and wide, but the high's are a bit back compared to the mids. Sounds like the output filter cap might be worth doing.
by the way, I shorted the caps, for now.
I'll look at the output filter cap and see if I can tell what it is.
Is the BC/Vishay/mkp379 the one to get?
Now who sells them?
Anyone bothered trying to use metal films for the three op amp resistors or the feedback ones? It reminds me of the way my McIntosh MC240 sounded before I metal filmed it. kind of lacking detail and dynamics.
I have two through hole resistors on the board. Do you know what they are? Feedback resistors maybe?
Thanks Again, Looking forward to more improvement.
Its very listenable, and engaging, but leaves something to be desired yet.
Mike
Re: Re: Just got my UcD400's Today
the through hole resistors are used in the circuit that generates the supply voltage for the input opamps. So changing them has probably no impact on the sound.
Portlandmike said:
the through hole resistors are used in the circuit that generates the supply voltage for the input opamps. So changing them has probably no impact on the sound.
Chris,
I followed your wiring recommendation and removed the resistor.
It got better, just as you discribed. Thanks.
the resistors that I suspect will improve things are the three gain setting resistors around the dual op amp.
Shouldn't be to tough, but I'm enjoying them to much to bother right now!
Thanks again,
Mike
I followed your wiring recommendation and removed the resistor.
It got better, just as you discribed. Thanks.
the resistors that I suspect will improve things are the three gain setting resistors around the dual op amp.
Shouldn't be to tough, but I'm enjoying them to much to bother right now!
Thanks again,
Mike
0.68uf Auricaps finally arrived (not the new ones)
Should hopefully get them in tonight and give them a good run in
Hi Mike,
I wasn't too impressed with my UCD180 at first, the vocals sounded too weak with sort of hollow mids.
After a good run in, some tweaks like the CRD mod, experimenting with the wiring etc things have really improved🙂
BTW I found the rectifier diodes to have more than a noticeable effect, MBR10100 are my current favourite, some may find these bass light, I've got some MBR1560 to try next
Should hopefully get them in tonight and give them a good run in
Hi Mike,
I wasn't too impressed with my UCD180 at first, the vocals sounded too weak with sort of hollow mids.
After a good run in, some tweaks like the CRD mod, experimenting with the wiring etc things have really improved🙂
BTW I found the rectifier diodes to have more than a noticeable effect, MBR10100 are my current favourite, some may find these bass light, I've got some MBR1560 to try next
Portlandmike said:
My pleasure, glad to have helped
Do you know what variety of resistors are currently in use?
Regards,
Chris
My UCD tweaks
Hi fellows,
I have much older UCD400 boards. Recently I replaced the 470uF
KMG PSU caps with 680uF Panasonic FC with nice results. Sound is now darker
(I have very sensitive ribbon tweeters) with the same detail but somehow
I felt that bass precision is now lacking. It's not as punchy and pinpoint as before. As for the other caps, the
overall consensus seems to be to actually leave them on the board
so I didn't bother spending a fortune on Black Gates because I love
to get stuff locally (avoid shipping costs). Next, I may try to DC couple
my setup.
About the 680nF C filter cap - has anyone found a suitable quality type
on RS-Components or Farnell? These would be my favorite
suppliers (low shipping cost for me...)
Ah...and I will move my terrible 800VA "hummers" from the
amplifier enclosure to an external MDF box. These no-name
torodials are driving me crazy.
Regards,
Mike
Hi fellows,
I have much older UCD400 boards. Recently I replaced the 470uF
KMG PSU caps with 680uF Panasonic FC with nice results. Sound is now darker
(I have very sensitive ribbon tweeters) with the same detail but somehow
I felt that bass precision is now lacking. It's not as punchy and pinpoint as before. As for the other caps, the
overall consensus seems to be to actually leave them on the board
so I didn't bother spending a fortune on Black Gates because I love
to get stuff locally (avoid shipping costs). Next, I may try to DC couple
my setup.
About the 680nF C filter cap - has anyone found a suitable quality type
on RS-Components or Farnell? These would be my favorite
suppliers (low shipping cost for me...)
Ah...and I will move my terrible 800VA "hummers" from the
amplifier enclosure to an external MDF box. These no-name
torodials are driving me crazy.
Regards,
Mike
Re: My UCD tweaks
Hi Mike,
I've had the FC's in my UCD180 for about a week now, to be honest I still do not like the results even now after a week, the sound is not involving at all for my taste, I have just fitted the 680nf Auricaps for the output filter and the amp is currently running into a pair of loading resistors to burn them in, If the sound does not improve over the weekend with the new output filter caps I'm going to solder the brown KMG's back in
BTW I also use Ribbon tweeters🙂
I'm also trying to find some other polypropylene 680nf caps locally I can compare against the Auricaps, theres not much choice in the UK
mlihl said:
Hi Mike,
I've had the FC's in my UCD180 for about a week now, to be honest I still do not like the results even now after a week, the sound is not involving at all for my taste, I have just fitted the 680nf Auricaps for the output filter and the amp is currently running into a pair of loading resistors to burn them in, If the sound does not improve over the weekend with the new output filter caps I'm going to solder the brown KMG's back in
BTW I also use Ribbon tweeters🙂
I'm also trying to find some other polypropylene 680nf caps locally I can compare against the Auricaps, theres not much choice in the UK
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