| rotation |
Hi!
I will order the UCD 180 modules without op amp. I would like to know if it is possible to ad separated, maybe discrete op amp. Anyone experienced this?
Thanks Miha |
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| RX5 |
| hmmmmm I have not seen a discrete "op amp" YET..... not even close to a 741... :xeye: |
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| BWRX |
| No doubt it could be done, but you would need some kind of SO8 adapter to make that work. |
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| rotation |
| quote: | Originally posted by RX5
hmmmmm I have not seen a discrete "op amp" YET..... not even close to a 741... :xeye: |
I've made and used discrete op amp in preamps that sounds much better then integrated. Examples are 990, 2520, Melcor...
Where is placed op amp in UCD? Is it soldered directly to pcb or not? |
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| RX5 |
| i think it IS the small board in the main board of UCD.... |
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| BWRX |
The input buffer is an SO8 op amp. The upgraded modules use the AD8620.
That daugther board is the top secret modulator circuit, hence the potting. |
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| RX5 |
| quote: | Originally posted by BWRX
The input buffer is an SO8 op amp. The upgraded modules use the AD8620.
That daugther board is the top secret modulator circuit, hence the potting. |
so thats where it is :) |
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| RX5 |
Brian,
MPSA92(on daughterboard).... for? |
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| rotation |
Thanks for the replys. I think i will keep the NE5532 and use my own power supply. NE are ok, i used them for many preamps compressors..I listened to some tests with AD8620 vs NE5532 and i would say the AD is too bright, enhanced in some way. They wouldn't go with studio monitors i use.
Miha |
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| BWRX |
I don't know exactly what the MPSA92 is for. I only read that the daughter card contains the UCD modulator circuit components, so it's certainly part of the modulator circuit.
NE5532s sound ok in my op amp preamp, but I like the sound of the TL072s better. That would be another very cheap option you could try. |
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| RX5 |
| quote: | Originally posted by BWRX
I don't know exactly what the MPSA92 is for. I only read that the daughter card contains the UCD modulator circuit components, so it's certainly part of the modulator circuit.
NE5532s sound ok in my op amp preamp, but I like the sound of the TL072s better. That would be another very cheap option you could try. |
got a feeling MPSA92 IS part of current source.... :) it should be.. that tranny is rated 300V 500mA PnP.....
:smash:
TL072?? hhmmmmmm they are cheap too.. got one of them in my BOX.... i think they a pin2pin compatible with NE5532... still need to look at datasheet... |
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| rotation |
| Yes, it could be changed with TL072, but NE5532 is lower noise and has better driving capacity. |
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| BWRX |
| Try both and see which sounds better. They're so cheap that's it's nice to have a bunch of both around anyway if you want to experiment. |
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| rotation |
| Ok, thanks. Btw, did you ever made a/b test of Hypex amp with another good a class or something else. I know it was written a lot about it, but anyway.. |
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| RX5 |
| quote: | Originally posted by rotation
I've made and used discrete op amp in preamps that sounds much better then integrated. Examples are 990, 2520, Melcor...
Where is placed op amp in UCD? Is it soldered directly to pcb or not? |
ignorance
:D
my BAD :bawling: anyways, since I wanna try this discrete op-amps... maybe I will give it a go with API2520..... still looking for datasheets on what parts to swap with.... those listed in scheme might NOT be locally available... :) |
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| rotation |
| quote: | Originally posted by RX5
ignorance
:D
my BAD :bawling: anyways, since I wanna try this discrete op-amps... maybe I will give it a go with API2520..... still looking for datasheets on what parts to swap with.... those listed in scheme might NOT be locally available... :) |
I think it's really worth trying it. 2520 in API is a bit colorated. Maybe because of output transformer..Give a try to 990; it's very clean and much better sounding than any of ic op amps i tried. I suggest you to get schematics and pcb from Prodigy pro. They have pcb's for other op amps also. Ask them which would be good for UCD.
Miha |
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| lucpes |
| quote: | Originally posted by rotation
I think it's really worth trying it. 2520 in API is a bit colorated. Maybe because of output transformer..Give a try to 990; it's very clean and much better sounding than any of ic op amps i tried. I suggest you to get schematics and pcb from Prodigy pro. They have pcb's for other op amps also. Ask them which would be good for UCD.
Miha |
There are some (simple) discrete buffers on this page (scroll down): http://myweb.tiscali.co.uk/nuukspot...ainclone2.html, haven't tried anything but it might be a good place to start. |
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| RX5 |
hmmm...:xeye:
It would be -better- if I could make a discrete op-amp that could surpass an NE5532.. :D
rotation,
could you post direct link? :smash:
lucpres,
link dont work.... :dodgy:
anyone know other schemes?? :cannotbe: |
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| RX5 |
ok got it.... thanks for the link.. I was wondering If I could swap transistors with readily available ones... of course , they have to be the low noise types (BC549C) etc... anyways, I will add this up to my "to-do" list... :)
Regards,
Raff |
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| RX5 |
Hi Lucpres,
been reading almost all relevant issues.... so this 990 is sort of like an LM386 eh.. It CAN directly drive a speaker (or low ohms) .... depending on output transistors....
NE5532 has also low impedance output.... hmmmmmm thats good, i think... compatible??
but I have to make 2 of this 990 to come up with a dual op-amp :)
in a week or two.. maybe, ill make one up ....
Cheers,
Raff |
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| RX5 |
@rotation,
since you told me you already have done the 990, have you tried swapping it in place with a dual op-amp(TL072,NE5532)???
I plan to make 2 DOA and swap with an NE5532, my main goal :D
-Raff |
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| beppe61 |
| quote: | Originally posted by rotation
Hi! I will order the UCD 180 modules without op amp.
I would like to know if it is possible to ad separated, maybe discrete op amp.
Anyone experienced this?
Thanks Miha |
Where I can find the specs of the UcD modules without the op-amp?
Is this op-amp inside any feedback loop?
Is it removable?
I have already what I deem a nice single ended line stage that I would like to use in order to drive these modules without the input op-amp for better sound.
It has voltage gain=6 and can drive comfortably impedances as low as 5kohm.
Is this feasible?
Is a balanced line stage mandatory ?
Any info would be extremely appreciated here.
Thank you very much and kind regards,
beppe
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| rotation |
| quote: | Originally posted by RX5
@rotation,
since you told me you already have done the 990, have you tried swapping it in place with a dual op-amp(TL072,NE5532)???
I plan to make 2 DOA and swap with an NE5532, my main goal :D
-Raff |
Lucpes: That is good idea, but do you think it's worth investing time in LM based amp? To my ears none of them sound good, at least if compared to discrete designs.
RX5: I tried 990 in API 3124 preamplifier. I think i could use OPA, NE with socket instate. What i know is that 990 sounds better than other two. |
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| RX5 |
| you say OPA? than its a GO GO! :) but not now... maybe some time next weeek...... kinda busy with something else.. hehe BUT i WILL post that -something else- this week.... |
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| rotation |
Yes, OPA. But don't experiment, BUY kit (it's cheap) and make as it should be.
Please comment your results.
Good luck
Miha |
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| gl |
Hi Beppe61,
There is an application note on the Hypex site that you need to read here:
http://www.hypex.nl/docs/gainappnote.pdf
This shows that the UCD module is made up of two cascading sections. The first is a balanced-in / balanced out stage with a gain of about 4 or 5 made up of two op-amps. The second stage is the PWM comparator and output section. The impedance values you asked for are given. It also has a gain of 4.5. Each or the two sections has its own feedback structure. There is no overall feedback. You could drive the comparatot inputs directly but your gain would only be 12 to 14 dB. Not very much - but it might be enough for your system.
There is a Philips app note that contains a schematic which looks like it would be close to the UCD schematic - at least for your purposes. It is here:
http://www.nxp.com/acrobat_download...s/UM10155_1.pdf
A good source on discrete op-amp design from Nelson Pass is here:
http://www.passdiy.com/pdf/diyopamp.pdf
I am building a pair of UCD700AD monoblocks. I will run them with the 8620's to start with and I am then planning on replacing the front end with a discrete design. It will take several more months to complete the basic amps and I plan on posting the results on this site. It will take several more months beyond that to complete the discrete version and evaluate it.
I would like to encourage you in your efforts. There are other people (like me) that have the same goals you do. Please post the your results of your work as your project progresses.
Regards,
Graeme |
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| RX5 |
rotation,
I know its cheap, 10$ a piece..actually 2 for replacing NE5532... but My main goal is TO EXPERIMENT with locally available components.... just like my diy UCD...it might not have the actual parts used in the commercial units, but IT PERFORMS.. sont worry, i WILL post results... but that would have to be a few weeks from now.. need to look for parts that are available here... I really am impatient with mail orders.. coupled to that, I dont have much resource :D |
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| fokker |
I have always questioned why they went with the buffer design.
their topology, from what I read, is a differential design so you need to convert a SE input to differential output. That's understandable.
However, for each side of the differential amp, why did they go with an inverting topology? what will happen if you go with a non-inverting design? would that have worked?
why did they go with a differential design? the philips application note suggests that a SE design would work. does hypex want to get to a certain power rating with the design? why wouldn't they just increase the rail voltage to do that? |
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| fokker |
to add to it: the pwm comprator outputs to complimentary signals. Wouldn't it be easier to just use the signal to run two half bridges, in a complimentary fashion to double the output? for example, use one pwm out to drive the high side of one half bridge and the low side of another half bridge, and the other pwm output to drive the low-side of the 1st half bridge and the high side of the 2nd bridge?
wiring the feedback would be a challenge, though. |
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| gl |
The op-amp buffers are set up with the comparator/outputs as a classic instrumentation amp topology. This is a well established approach. It's cheap and simple and gives good results.
You can achieve better results with discretes. Hypex even says so themselves (somewhere).
A discrete solution needs to provide the same things the dual op-amps do. There are a number of solutions. The most foolproof is two homebrew op-amps built with discrete parts.
Graeme |
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| RX5 |
fokker,
why not try and build one yourself.. :)
im going to do the JE990 dale version... |
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| lucpes |
1) I posted the link just for the input buffers schemtics availbable there - driving the UcD's modulator input instead of the LM3886.
2) To directly drive the modulator just use the coupling capacitor holes.
3) NE5532 sounds like **** IMHO, most people agree that if AD8620 sounds too bright the problem is elsewhere in your system. |
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| RX5 |
| quote: | Originally posted by lucpes
3) NE5532 sounds like **** IMHO, most people agree that if AD8620 sounds too bright the problem is elsewhere in your system. |
lol @ #3.. :)
regarding the changing of op-amps, I changed the JRC4558 with NE552 in my CD player... yup... I dont know If I could label it as TOO BRIGHT, but yeah.. a slight increase of treble though....as compared to the 4558....
I think it would be much brighter if I could change to AD8620? :smash: |
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| classd4sure |
| quote: | Originally posted by fokker
I have always questioned why they went with the buffer design.
their topology, from what I read, is a differential design so you need to convert a SE input to differential output. That's understandable.
However, for each side of the differential amp, why did they go with an inverting topology? what will happen if you go with a non-inverting design? would that have worked?
why did they go with a differential design? the philips application note suggests that a SE design would work. does hypex want to get to a certain power rating with the design? why wouldn't they just increase the rail voltage to do that? |
Guess Hypex needs the fully differential design to get the upper mosfet to switch :D
| quote: | Originally posted by fokker
to add to it: the pwm comprator outputs to complimentary signals. Wouldn't it be easier to just use the signal to run two half bridges, in a complimentary fashion to double the output? for example, use one pwm out to drive the high side of one half bridge and the low side of another half bridge, and the other pwm output to drive the low-side of the 1st half bridge and the high side of the 2nd bridge?
wiring the feedback would be a challenge, though. |
You really need to look at it more until these answers come to you, and you realize how very elegant it really is, and I don't mean the Philips app note either. Consider that they don't care to give you all the answers either. |
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| classd4sure |
| quote: | Originally posted by gl
...You can achieve better results with discretes. Hypex even says so themselves (somewhere).
A discrete solution needs to provide the same things the dual op-amps do. There are a number of solutions. The most foolproof is two homebrew op-amps built with discrete parts.
Graeme |
Bruno said "his" discrete front ends sound better. What's most foolproof is leaving the stock op amp in, unless maybe you think you can outdo the performance of an AD8620 ...
Personally I would not be too quick to think I can simply download whatever schematic from the web and slap it in there, and honestly expect some improvement. No way. It'd have to be taken a little more seriously. |
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| SSassen |
| quote: | | Bruno said "his" discrete front ends sound better. What's most foolproof is leaving the stock op amp in, unless maybe you think you can outdo the performance of an AD8620 ... |
I can wholeheartedly agree with that, if the performance of an AD8620 can be matched with a few discrete devices thrown together on a piece of breadboard, then why isn't Analog Devices selling that instead?
I've seen people try to use a tube based preamp to drive the modulator directly at some point and that was laughable at best. The only implementation I've actually seen to work is Bruno's own discrete solution. He himself acknowledges that even that might not be better perse than a AD8620 if implemented correctly (CRDs, seperate opamp supply, no coupling caps, 1K8/3K3 mini-melf in the feedback).
In order to improve upon the basic circuit of the UcD you'll need to outsmart Bruno, and trust me (coming from someone that knows Bruno personally) that's going to take a whole lot more than some experience with modding equipment or a high-school diploma.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com |
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| beppe61 |
| quote: | Originally posted by gl
Hi Beppe61,
There is an application note on the Hypex site that you need to read here:
http://www.hypex.nl/docs/gainappnote.pdf
This shows that the UCD module is made up of two cascading sections.
...
Regards,
Graeme |
Dear Mr Graeme, thank you very much for the kind and helpful advice.
The first is a balanced-in / balanced out stage with a gain of about 4 or 5 made up of two op-amps.
This is actually the stage I want to replace with my line stage (voltage gain=6; very low output impedance).
The overall voltage gain could be more than enough.
My room is limited and my speaker are 4ohm, 87dB/1W.
Nice to know that I have just to desolder two coupling caps and solder the new wires.
I think I can do this with a little help from my friend (he has a very nice desoldering machine at hand).
Thank you so much again.
Kind regards from Italy,
beppe |
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| beppe61 |
| quote: | Originally posted by SSassen
...I've seen people try to use a tube based preamp to drive the modulator directly at some point and that was laughable at best.
...
Best regards,
Sander Sassen
http://www.hardwareanalysis.com |
Excuse me Sir could you give some more details about which brand/model of preamp?
Maybe this result can be related to the low input impedance of the modulator ?
Which kind of problems emerged?
Thank you very much.
Regards,
beppe |
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| SSassen |
beppe,
Question: have you ever seen a tube preamp drive a ~2K load with low THD and yet plenty of voltage swing? No? Well, I have only seen a rare few examples and those weren't exactly in audio. Hence, due to the low impedance this will not work with tubes, perhaps when you use a transformer in between, but in that case we are back to square one, still think the AD8620 is a 'bad' solution?
Best regards,
Sander Sassen
http://www.hardwareanalysis.com |
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| beppe61 |
| quote: | Originally posted by SSassen
beppe,
Question: have you ever seen a tube preamp drive a ~2K load with low THD and yet plenty of voltage swing? No? Well, I have only seen a rare few examples and those weren't exactly in audio. Hence, due to the low impedance this will not work with tubes, perhaps when you use a transformer in between, but in that case we are back to square one, still think the AD8620 is a 'bad' solution?
Best regards,
Sander Sassen
http://www.hardwareanalysis.com |
I just did not know that the input impedance of the modulator is about 2K Sir.
Please excuse me. I thought some 10K.
Evidently I was completely wrong.
Not that 10K is easy for a tube preamp.
Anyway 2K is very very low indeed.
A nice buffer is mandatory then.
Thank for the very valuable information.
Kind regards,
beppe |
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| classd4sure |
Hi Beppe,
You should have read the application note that I linked you to the other day. All these things are answered there.
Hi Sander,
Not to worry, Bruno's work always speaks for itself.
I think your mentioned feedback values are just a little off though.
I personally think anyone trying to stick a toob in a class d amp is simply after a niche market where people have alot of money and absolutely no understanding.... shiny things impress.
Best Regards,
Chris |
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| SSassen |
Chris?
| quote: | | I think your mentioned feedback values are just a little off though. |
Uhm, no, those are for the input buffer, 560R/1K normally, but it sounds a whole lot better with 1K8/3K3.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com |
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| gl |
Hi Beppe,
Your plan sounds good. If I was you I would reduce the gain of your line stage to 4 or 5. The front end of the UCD modules are run off +-12V so you really don't want to exceed that swing into the modulator if possible. If you configure your amp to have single ended inputs you will also lose 6 dB of gain.
Please do not be discouraged by some of the remarks on this thread. There are many very good discrete op-amp circuits available that I would consider to have more potential than the AD8620. I encourage you to try different ones.
As for the other gentlemen here; Beppe is looking for encouragment and advice on discrete front ends. Bruno said it sounded good so why not give it a shot. I mean this is DIY right? He has requested politely and deserves to treated politely. As do people who try to help him. Members aspirations should not be ridiculed nor should they have their educational backgrounds called into question.
Graeme |
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| classd4sure |
Hi Sander,
If you invert that, I'd agree they'd be OK values. Otherwise your input stage only has a gain of 2. Possibly the same ratio but lower values may be better too. |
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| SSassen |
Graeme,
| quote: | | There are many very good discrete op-amp circuits available that I would consider to have more potential than the AD8620. I encourage you to try different ones. |
With all due respect, but for someone without any experience as an analog designer to come up with a discrete solution that performs better than a AD8620 is like winning the lottery every time you buy a ticket.
That's not ridiculing, or making fun of someone, but that's a reality check, it might well save you valuable time trying to improve on something that you cannot improve on, not even in a hundred years. For that you'd need expert knowledge, a sound grasp of the underlying math and physics and a selection of expensive and dedicated tools and equipment. Honestly that's a bit out of reach for 99.9% of the audio enthusiasts that frequent these forums, which for the most part includes myself.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com |
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| classd4sure |
| quote: | Originally posted by gl
Hi Beppe,
Your plan sounds good. If I was you I would reduce the gain of your line stage to 4 or 5. The front end of the UCD modules are run off +-12V so you really don't want to exceed that swing into the modulator if possible. If you configure your amp to have single ended inputs you will also lose 6 dB of gain.
Please do not be discouraged by some of the remarks on this thread. There are many very good discrete op-amp circuits available that I would consider to have more potential than the AD8620. I encourage you to try different ones.
As for the other gentlemen here; Beppe is looking for encouragment and advice on discrete front ends. Bruno said it sounded good so why not give it a shot. I mean this is DIY right? He has requested politely and deserves to treated politely. As do people who try to help him. Members aspirations should not be ridiculed nor should they have their educational backgrounds called into question.
Graeme |
Sometimes the voice of reason doesn't tell you what you want to hear. Spare us the soap box, it is boring, and no one treated him anything close to impolite, so we don't need the sympathy routine either. Beppe should probably give them a listen to before tearing them apart to glue some download to it.
I trust he's buying a module because he wants something good, and I don't think download and wire will get him there. Have you even tried your own advice? |
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| fokker |
| quote: | Originally posted by beppe61
Anyway 2K is very very low indeed.
Kind regards,
beppe |
that, coupled with the desire to get differential output, is probably why they used a buffer. |
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| classd4sure |
| Hmmm it's one of the reasons, see if he gets more... but then why didn't philips use it :clown: |
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| fokker |
I am not sure if I buy off the gain argument: they can certainly increase the gain on the amp itself (8.2k/1.8k in the AN) to avoid the complexity of having a buffer, if gain were the sole consideration or even the main consideration.
anyway, going with an inverting AND differential design is a little weird for such a small power amp. |
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| SSassen |
Fokker,
| quote: | | I am not sure if I buy off the gain argument: they can certainly increase the gain on the amp itself (8.2k/1.8k in the AN) to avoid the complexity of having a buffer, if gain were the sole consideration or even the main consideration. |
Exactly what part of how an UcD amplifier works don't you understand? Please let us know, so we can educate you on this matter, or at least fill in some of the blanks. In short the gain is part of the equation that governs the self-oscillating nature of the UcD, it is closely tied with the loop-gain, bandwidth and oscillating frequency of the module. But hey, it is all explained in the documentation as provided on the Hypex website, I'd suggest you check it out yourself, there's some real gems to be found there, especially for the novice builder.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com |
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| classd4sure |
| quote: | Originally posted by fokker
I am not sure if I buy off the gain argument: they can certainly increase the gain on the amp itself (8.2k/1.8k in the AN) to avoid the complexity of having a buffer, if gain were the sole consideration or even the main consideration.
anyway, going with an inverting AND differential design is a little weird for such a small power amp. |
If you're not convinced, clearly you haven't read the link you've been giving what, three times just today? r e a d i t! Research what you read... it will come to you. It's very clearly spelled out in there in one very simple sentence from Bruno to you, so you may as well profit from it! You could also look into instrumentation amplifier theory if you still need more. |
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| beppe61 |
Excuse me Sirs but I would like to apologize and put a question.
If the modules are exceptionally good as stock why so many posts about modding them ?
Now I know that:
1) the excution of the PS is fundamental. Anyway I understand that practically no one use the standard power supply solutions by hypex.
2) it is better to power the input op-amps with a separated power supply (of course well filtered and so on). Not so easy to do.
3) the output filter should be revised
4) the coupling caps should be removed
This leaves me a bit undecided.
I have to say that all in all they seem very difficult to use rightly.
It is not a matter of just connect them with wires and go.
Taking also in account that I am everything but an experienced DIYer my hesitation comes of consequence.
That said, honestly I have to admit I have said and asked too much.
Better to stop with posting for a moment, at least until I will have some new direct experience with these modules.
Surely I will keep looking to this forum with the greatest interest.
Thank you and kind regards,
beppe |
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| fokker |
| quote: | Originally posted by SSassen
Exactly what part of how an UcD amplifier works don't you understand? Please let us know, so we can educate you on this matter, or at least fill in some of the blanks. Sander Sassen
http://www.hardwareanalysis.com |
I am sorry that my questions so upset you, Mr. Highhorse.
first of all, please make sure you understand my simple questions before you get onto your high horse.
2ndly, please let me know which set of equations governs the work of this amp, lay them out here for us so that we poor souls can admire your mastery of such equations.
No need to hide behind "read this", "read that". if you have the ball, I will follow you to the fullest extent of your capabilities, and beyond a little.
Consider that as a challenge to you. |
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| classd4sure |
| quote: | Originally posted by fokker
I am sorry that my questions so upset you, Mr. Highhorse.
first of all, please make sure you understand my simple questions before you get onto your high horse.
2ndly, please let me know which set of equations governs the work of this amp, lay them out here for us so that we poor souls can admire your mastery of such equations.
No need to hide behind "read this", "read that". if you have the ball, I will follow you to the fullest extent of your capabilities, and beyond a little.
Consider that as a challenge to you. |
Sadly, it's up to you to read the available material, which has rather pathetically been handed to you on a platter a multitude of times.... equations and all. You obviously drop the ball time and again by ignoring it. You're either defensive or mostly offensive, when you should be receptive. It's all there, everything you've been speculating over in this thread since it began, really, what more can be said, read it! |
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| SY |
| :cop: Guys, please lose the personal stuff and stick to the topic. |
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| Daveis |
I have a Benchmark DAC1 connected to my UCD180ad's. Does the instrumentation opamp inputs of the UCD serve a purpose for me?
It seems to me that my DAC1 is providing a DC-blocked balanced source already. I also notice that I have the gain on the DAC1 turned very low even at loud listening levels. |
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| RX5 |
| so i guess I JUST LEAVE the NE5532 in... :) |
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| beppe61 |
I swear. This is the my last one post on the topic (more or less).
I got this final answer from Hypex to my questions.
Hi Giuseppe,
>> Can the UcD module actually work without the input dual op-amp ?
That is possible.
>> It has a voltage gain of 6 times and it can drive comfortably
>> impedances as low as 5kohm without particular problems.
The input impedance of the UcD modulator goes down to about 1k8.
>> Is a balanced input driver stage mandatory ?
UcD modules are balanced from input to output.
A non balanced input would not be beneficial for the total.
This mirrors completely the kind and extremely valuable advices I got in this 3D from friends.
Have a nice day !
beppe |
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| rotation |
| quote: | Originally posted by classd4sure
Bruno said "his" discrete front ends sound better. What's most foolproof is leaving the stock op amp in, unless maybe you think you can outdo the performance of an AD8620 ...
Personally I would not be too quick to think I can simply download whatever schematic from the web and slap it in there, and honestly expect some improvement. No way. It'd have to be taken a little more seriously. |
Hmmm, i think i metioned somewhere that 990 discrete op amp (from kit) sounds MUCH better if done with kit. I tried doing it on a veroboard and result was much worse than anything i heard before :)
So if you are not really experienced don't even think of outperforming TL, AD, NE with your design.
I never heard ucd from Hypex, but i think reason for mods is curiosity, not bad design by Hypex. So don't worry too much about mods. I think it's not so easy to outperform Hypex's design..But it's worth trying it, that's DIY, isn't it?
About 990 op amp: This design is proven by many recording studios around the world. Its the hearth of some most famous designs. It sounds excellent as it is, and outperforms commercial AD like op amps. I don't say AD and other op amps used mostly by audiophiles are not good, but by my experiences professional stuff is always much better. It's always possible to add nice tube preamp or even input transformer if some color is needed.
Regards from Miha |
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Hi Daveis,
In your case the DAC1 should be able to drive the UCD modulator directly. It I were in your place I would try it. Let us know how it turns out.
Graeme |
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