Nah currently there's a "footprint" in place for a dual op amp like they come with, but the opa627 is only available in single op amp IC's.
Once again we see just how nicely we're being catered to for the UCD700.... I'm already jealous of anyone who's got one 🙂
You can still buy an adapter PCB if you want to try an opa627, some hunting on google will bring it up quick enough.
It'll cost about twice what an AD8620 will + the adapter whatever that is, don't think it's much though.
Soldering required, I'm sure if you're that nervous about it you'll have no problem finding someone willing to do it for you, I would but I don't think you'd want to send it all the way here.
Cheers,
Chris
Once again we see just how nicely we're being catered to for the UCD700.... I'm already jealous of anyone who's got one 🙂
You can still buy an adapter PCB if you want to try an opa627, some hunting on google will bring it up quick enough.
It'll cost about twice what an AD8620 will + the adapter whatever that is, don't think it's much though.
Soldering required, I'm sure if you're that nervous about it you'll have no problem finding someone willing to do it for you, I would but I don't think you'd want to send it all the way here.
Cheers,
Chris
on another (dutch) forum, JP said planned time to market was about two months. That was allmost a week ago.
I just replaced the standard power caps on my ucd400 with 680uF 100v panasonic fc caps and the low voltage psu caps (22uF 50v) with (again) panasonic fc 22uF 25v ones. After a short burning in period (say ~3 hours?) i did a short listening test.
To my ears, the difference, although clearly present, wasn't absolutely shocking. It sounds clearer, more detailed and it seems to have a little more dynamics. Voices are more present (which, imho is a good thing). Better, but not as some people made me believe a shocking difference.
Worth the money though!
I just replaced the standard power caps on my ucd400 with 680uF 100v panasonic fc caps and the low voltage psu caps (22uF 50v) with (again) panasonic fc 22uF 25v ones. After a short burning in period (say ~3 hours?) i did a short listening test.
To my ears, the difference, although clearly present, wasn't absolutely shocking. It sounds clearer, more detailed and it seems to have a little more dynamics. Voices are more present (which, imho is a good thing). Better, but not as some people made me believe a shocking difference.
Worth the money though!
Quote:<<I just replaced the standard power caps on my ucd400 with 680uF 100v panasonic fc caps and the low voltage psu caps (22uF 50v) with (again) panasonic fc 22uF 25v ones. After a short burning in period (say ~3 hours?) i did a short listening test.>>
3 hours?? Even my soldering takes 5 days to burn-in! 😀
I predict further improvement from your mod
Let us know, please.
3 hours?? Even my soldering takes 5 days to burn-in! 😀
I predict further improvement from your mod
Let us know, please.
Forget the "bass roll-off".............using an electrolytic with very little DC bias, when compared to the AC voltage, isn't going to sound good.
As for the "squishy" test...........
Does not work with Teflon caps. So don't try it. Just ask Phred...........
Even though he won't admit it. Anyway, if you have to use Teflon caps, buy the ones in a metal case.
Jocko
As for the "squishy" test...........
Does not work with Teflon caps. So don't try it. Just ask Phred...........
Even though he won't admit it. Anyway, if you have to use Teflon caps, buy the ones in a metal case.
Jocko
Just an update on my latest UcD400 tweaks and modifications.
I replaced R3 with a 249 ohms resistor for 32dB gain.
Since I had the amp open, I replace my regular RCA's with Vampire OFC ones I recycled from my passive pre-amp after hardwiring its outputs. I also placed a small sheet of TI shield between the 2 modules. The shield is grounded to the chassis.
There was no apparent bad distortion with the gain increase. The sound actually improved with all these tweaks. I wasn't expecting so much difference. Since I did all 3 at the same time, It's hard to tell what did what. But I have the impression that the extra gain is responsible for the change in sound. It sounds like I added an active pre-amp to the circuit. The sound has more presence.
I might try the OPA627 in the future. But cost is a bit high...
I also have to improve my digital sources a bit more.
I replaced R3 with a 249 ohms resistor for 32dB gain.
Since I had the amp open, I replace my regular RCA's with Vampire OFC ones I recycled from my passive pre-amp after hardwiring its outputs. I also placed a small sheet of TI shield between the 2 modules. The shield is grounded to the chassis.
There was no apparent bad distortion with the gain increase. The sound actually improved with all these tweaks. I wasn't expecting so much difference. Since I did all 3 at the same time, It's hard to tell what did what. But I have the impression that the extra gain is responsible for the change in sound. It sounds like I added an active pre-amp to the circuit. The sound has more presence.
I might try the OPA627 in the future. But cost is a bit high...
I also have to improve my digital sources a bit more.
Julien:
Do you feed your UCDs from unbalanced NOH's outputs? Did you get humm from balanced outs?
I use a heavily moded M-audio superDAC that has high Vout from its balanced outputs and works great with my TVC and UCDs.
I guess high V balanced signal is better than smaller V unbalanced signal for a more sensitive amp, from a noise point of view.
In other words, wouldn't it be better to increase source output than increase amp's input sens?
Respectfuly yours...
Mauricio
Do you feed your UCDs from unbalanced NOH's outputs? Did you get humm from balanced outs?
I use a heavily moded M-audio superDAC that has high Vout from its balanced outputs and works great with my TVC and UCDs.
I guess high V balanced signal is better than smaller V unbalanced signal for a more sensitive amp, from a noise point of view.
In other words, wouldn't it be better to increase source output than increase amp's input sens?
Respectfuly yours...
Mauricio
maxlorenz said:Quote:
I predict further improvement from your mod
Let us know, please.
In my case, difference almost no audible (Elna cerafine 470/63 instead Yageo), and of course measured specs the same.
😕
maxlorenz, you were right 🙂
The sound has opened up, there seems to be more top-end, more fluid highs. Voices have become a little clearer and the amp seems to have improved in the bass region. Not more bass, just more detailed and with some more definition.
After having received the mkp479's I've finally found the time to replace the output filter caps. I'll let you know how they sound.
Julien_M: if you promise to only use the 627's for the ucd400's and promise to post a few pics of how you implemented them, i'll send you some pdip opa627(bp)'s (for free). Just send me an email.
The sound has opened up, there seems to be more top-end, more fluid highs. Voices have become a little clearer and the amp seems to have improved in the bass region. Not more bass, just more detailed and with some more definition.
After having received the mkp479's I've finally found the time to replace the output filter caps. I'll let you know how they sound.
Julien_M: if you promise to only use the 627's for the ucd400's and promise to post a few pics of how you implemented them, i'll send you some pdip opa627(bp)'s (for free). Just send me an email.
Attachments
Dear matjans:
I'm happy for you 😀
Bruno has talked about this effect of better defined/controled bass when you achieve more HF transparency/extension. At first one thinks that bass is leaner but then (maybe complete burn-in) you hear this grip and you can't go back to that loose, fat, smoggy bass 😉
Just my humble opinion
BP's for free??? 😱 😱 😱 Are you the son of some Emir by chance?
Good luck
Mauricio
I'm happy for you 😀
Bruno has talked about this effect of better defined/controled bass when you achieve more HF transparency/extension. At first one thinks that bass is leaner but then (maybe complete burn-in) you hear this grip and you can't go back to that loose, fat, smoggy bass 😉
Just my humble opinion
BP's for free??? 😱 😱 😱 Are you the son of some Emir by chance?
Good luck
Mauricio
No, I just have some left overs from a preamp project. I don't like the sound of them. Maybe it's me but I just couldn't get them to sound decent. Too sharp with grainy highs and strange bass.
in the mean time, i'm not sure whether I like the mkp479's in the output filter. They give the music much more detail, so much even I get nervous listening to "Inside Job" by Ilse Delange (cd: Dear John). And when driving I can listen to Fear Factory at a more-than-decent-volume for a half hour without speeding. A bit of a nervous edge to the sound so far.
They still have to break in though...
in the mean time, i'm not sure whether I like the mkp479's in the output filter. They give the music much more detail, so much even I get nervous listening to "Inside Job" by Ilse Delange (cd: Dear John). And when driving I can listen to Fear Factory at a more-than-decent-volume for a half hour without speeding. A bit of a nervous edge to the sound so far.
They still have to break in though...
JP or Bruno
UCD 400AD
Any downside to removing the plastic bracket and 4 metal pins on the input. Also same for the 2 metal bars for speaker out put.
Want to solder input wires and speaker output wires directly to the board.
Thanks in advance.
UCD 400AD
Any downside to removing the plastic bracket and 4 metal pins on the input. Also same for the 2 metal bars for speaker out put.
Want to solder input wires and speaker output wires directly to the board.
Thanks in advance.
Hi,
Bruno already said solder connections can't beat a mechanical one, some googling on that will tell you why.
I'd probably opt for both, I really don't like loose wires.
Had you considered wire wrapping for the 4 pin plug? They used nice square leads... perfect for wire wrap and it's one of the best connections you can get, just have to use a solide core wire.
BTW I just repaired a Marantz tuner that actually used some wire wrapping inside on the small signal stuff, most were soldered as well, but the mechanical connection is certainly there.
Cheers,
Chris
Bruno already said solder connections can't beat a mechanical one, some googling on that will tell you why.
I'd probably opt for both, I really don't like loose wires.
Had you considered wire wrapping for the 4 pin plug? They used nice square leads... perfect for wire wrap and it's one of the best connections you can get, just have to use a solide core wire.
BTW I just repaired a Marantz tuner that actually used some wire wrapping inside on the small signal stuff, most were soldered as well, but the mechanical connection is certainly there.
Cheers,
Chris
Matjans:
Grainy highs and strange bass??
This doesn't sound to me as "BB sound". My limited experience with OPA627AP is replacing output opamps for a M-audio superDAC wich gave a really controled sound, detailed up to down, with a warm/dark taste and strong/articulated bass. Certainly HF is not grainy but on the liquid/sweet side but not too extended, IMHO.
Couldn't it be that OPA627 is not good for preamp use? 🙁
Or maybe your patience is smaller than your modding enthusiasm 😀
I would certainly give them a second chance. 😉
Good luck
Grainy highs and strange bass??
This doesn't sound to me as "BB sound". My limited experience with OPA627AP is replacing output opamps for a M-audio superDAC wich gave a really controled sound, detailed up to down, with a warm/dark taste and strong/articulated bass. Certainly HF is not grainy but on the liquid/sweet side but not too extended, IMHO.Couldn't it be that OPA627 is not good for preamp use? 🙁
Or maybe your patience is smaller than your modding enthusiasm 😀
I would certainly give them a second chance. 😉
Good luck
Impatient, yes, i can be impatient... Some people over at the chipamp forums say the opa627s are the best opamps around. I dropped the preamp project due to a lack of pc etching facilities around here. I got fed up with all that veroboard.
The good news is that a friend of mine (pitch254) has recently developed a pcb etching/router or something.
(frank, als je dit leest, ja ik moet nog eens een paar pcbtjes bakken!)
As said i've replaced the output filter cap with a mkp479. I guess they too have to "break in" so... When not applying any input to the amp nor hooking up a pair of speakers, will the filter cap still be busy filtering the carrier frequency or is there hardly any signal at the output in that case?
ie, if I let the amp powered on without speakers nor input, will this break in the output filter cap?
The good news is that a friend of mine (pitch254) has recently developed a pcb etching/router or something.
(frank, als je dit leest, ja ik moet nog eens een paar pcbtjes bakken!)
As said i've replaced the output filter cap with a mkp479. I guess they too have to "break in" so... When not applying any input to the amp nor hooking up a pair of speakers, will the filter cap still be busy filtering the carrier frequency or is there hardly any signal at the output in that case?
ie, if I let the amp powered on without speakers nor input, will this break in the output filter cap?
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