t. said:Great stuff thank you
I'd like to try and find a pair of even smaller SMPS if I was to use SMPS, the transformer I have for the main amp is huge
Do the UCD's work and sound good at lower volumes too? A few friends have sensitive speakers which only need a small amount of watts so if they want to compare something like a 12watt tube amp against the UCD400 it would need to be good at similar volumes, I usually listen to low volumes at home, maybe the 400 would be a bit overkill for my needs but its nice to have that power available just incase
T,
It is a question of dynamic range and not low level linearity as it would be with most amps. What this means is that since you will be unable to use the higher end of the range you must take some rather extensive steps to insure the noise floor is as low as you can get it. Mostly this will be a grounding issue with wire twisting and routing being more important than usual. You will also want to have the modules physically separated a few inches at least so one doesn’t couple into the other. Aside from these provisions it should be no contest compared to an antique sounding single ended triode. This comparison will instantly show how hopelessly outdated the triode sound really is! Colorations, limited dynamics, dynamic compression, limited bandwidth and high distortion! The only real problem is a human one in that they will be used to the syrupy compressed sound and here you come along wanting to soundly kick their sacred cow right in the ***. You will meet with some resistance. A plan of attack, bring your own disks with some complex and difficult music as well as some well recorded vocals and piano. Make sure they are not familiar with them. Play these first with your amp then switch. As they had never heard the music before they have no preconceived notions as to how it should sound except the absolute reference, live acoustic music. When you switch in the tubes after establishing the UcD as the reference even they will realize how bad it really sounds!
Changing mind sets is far more difficult than changing equipment, be diplomatic and have fun!
Good luck,
Roger
Ps. Just thinking how much more fun it would be to do the comparison with an amp3 in a tiny little box with a separate SMPS. Even more so if it was done with a quality volume control and you could go direct to the CD player. This would really do a job on them.
t. said:
imo, yes they do. Perfectly. Although at somewhat higher levels i think they really start to excel. It's as if they really *want* to work, pump out those amperes...
They seem to have fun driving difficult loads at high volumes. Or maybe that's just my imagination and all the other amps that i've heard just couldn't cope.
No trouble at low volumes here either.
Better bass control than my class AB amp at low volume. Lower noise floor as well, don't expect problems there. I'm running N804's, those have 89db/w/m sensivity if I'm not wrong, with my ear against the tweeter I can barely hear noise. If I switch on my pre-amp though...
but it's true, i've been playing at higher volumes lately, and the dynamics are effortless compared to the old amp.
I couldn't stand listening to my old amp for a long time at high volumes (compression), with the UcD it's more open and dynamic, much better, no fatigue
Better bass control than my class AB amp at low volume. Lower noise floor as well, don't expect problems there. I'm running N804's, those have 89db/w/m sensivity if I'm not wrong, with my ear against the tweeter I can barely hear noise. If I switch on my pre-amp though...
but it's true, i've been playing at higher volumes lately, and the dynamics are effortless compared to the old amp.
I couldn't stand listening to my old amp for a long time at high volumes (compression), with the UcD it's more open and dynamic, much better, no fatigue
sx881663 said:
The sound advice from you is much appreciated Roger
If the tube guys read the above
I personally am not biased towards any amp type, the biggest part of class A/B amps have sounded poor IMHO as do a lot of classA so if the UCD kicks their *** then thats great, when the beast is finished I will take some of my own cd's to use to compare.Some of their tube amps do seem lacking with detail and dynamics but theres a couple of monsters that do really sound very very good, the little Amp3 would possibly be better than some but I doubt it would come close to at least two I have heard.
If the UCD400 can better those it would cause some real upset
I've yet to hear any amp that can make piano sound real so if the UCD400 can make piano totaly convincing I would be very happy
Have you ever thought that piano sounds slightly electronic with most other amps?classd4sure said:
No, I did mean one 2700vA with a pair of 40-0-40 secondarys (6 wires) , this came out of a 3kW amp, the amps psu was wired to give around 112v DC, the amp was beyond repair so I salvaged the transformer and soft start module, it saves using two transformers if its suitable to use with the UCD's.
lawbadman said:
They was both diy, I wouldn't like to mention any names if thats ok, I don't want to go upsetting anybody
I will say that they was far from cheap to build
The only expensive commercial amps I've listened to was at shops or Hi-Fi shows, a shop not too far away from me has a pair of these http://www.wavac-audio.jp/he833_e.html
It would be fun to walk into there to see if they are interested in comparing them against the UCD's.
I must have listened to dozens of expensive solid state amps and was never really impressed with any, its the main reason I'd prefer diy
t. said:
The sound advice from you is much appreciated Roger
If the tube guys read the above
Some of their tube amps do seem lacking with detail and dynamics but theres a couple of monsters that do really sound very very good, the little Amp3 would possibly be better than some but I doubt it would come close to at least two I have heard.
If the UCD400 can better those it would cause some real upset
I've yet to hear any amp that can make piano sound real so if the UCD400 can make piano totaly convincing I would be very happy
T,
It's all your fault, you ask interesting questions!
As to the piano, a rather long story but I think worth repeating. In my younger days I had a girl friend that was studying to be a classical pianist. She was actually quite accomplished and it was from sitting on the bench beside her that I learned a life long appreciation/love for the classics. This being my real and true reference even though the piano was mostly junk had left me with a problem. I could never stand to listen to recorded piano as it sounded so bad. It was only recently that I finally developed a system that I could listen to and enjoy the classic piano again. This has been an inadvertent life long goal. To me if you can’t clearly hear the difference between a Bösendorfer and a Steinway, it ain’t good enough. With this newly developed system that included my own design of A/B amp I was still troubled by something as the music still wasn’t conveying the emotion I was looking for. Unfortunately/fortunately I am blessed/cursed with a really good aural memory so knew something was wrong but was unable to put my finger on what it was. Along comes the little Sonic Impact and from the first note I realized what had been missing, no other amps I had heard got the attack and decay of the piano right, with most of them you can’t even hear the pedal effects.
This lead to a series of improvements/projects involving upgrades to the SI, then on to the amp 3 and finally the UcD400’s. All these amps extend my musical enjoyment much further but I still can’t close my eyes and be back there on the bench. Now we need an equally great speaker system, some far better recordings and as good as the UcD’s are there is still room for improvement.
Roger
A transformer question
T,
I was thinking about your killer transformer. I assume it is from a pro sound amp. The series connection you talked about is common for higher efficiency with class G or what ever they are currently calling it. Usually the center taps are done with 2 wires brought out together. I have successfully separated these center tap wires creating 4 independent outputs. If you can do this it will allow you to use 2 bridge rectifiers instead of just one. This means no ripple current in the grounds and a lower noise floor, a worthy goal for sure.
Roger
T,
I was thinking about your killer transformer. I assume it is from a pro sound amp. The series connection you talked about is common for higher efficiency with class G or what ever they are currently calling it. Usually the center taps are done with 2 wires brought out together. I have successfully separated these center tap wires creating 4 independent outputs. If you can do this it will allow you to use 2 bridge rectifiers instead of just one. This means no ripple current in the grounds and a lower noise floor, a worthy goal for sure.
Roger
sx881663 said:
The main disapointing thing about every tube amp I have heard is the sound of piano, its the main thing they never seem to get right so the colouration of tubes probably don't help.
I totaly agree with you that most amps get the attack and decay wrong, its either too soft or electronic sounding
There probably isn't any system that can get this as good as the real thing so we have to get the best we can with whats available.
It seems you have a good ear and have also tried a lot of other amp designs, you seem very happy with what you now use so I'll look forward to the UCD400
Re: A transformer question
Correct, it is from a Pro sound amp rated as class H
It wouldn't be a problem to separate the centre taps, Excellent idea btw!
I wouldn't be able to use the pair of AvondaleCap-6 modules with Schottkies which would be a shame but I do have plenty of those high rated square silver rectifiers and 4 x 22'000uf 100v PEH200 Rifa caps spare.
I've heard the difference that Schottkies make in other amps but if the above transformer arrangement would give better results I'll stick with separating the centre taps and going that route instead
sx881663 said:
Correct, it is from a Pro sound amp rated as class H
It wouldn't be a problem to separate the centre taps, Excellent idea btw!
I wouldn't be able to use the pair of AvondaleCap-6 modules with Schottkies which would be a shame but I do have plenty of those high rated square silver rectifiers and 4 x 22'000uf 100v PEH200 Rifa caps spare.
I've heard the difference that Schottkies make in other amps but if the above transformer arrangement would give better results I'll stick with separating the centre taps and going that route instead
A question of noise
T,
Tough call on that. I think the double bridge would be best because of the ripple current issue. Snubberizing the bridges will help a great deal and bring the noise level to nearly the same as with the expensive setup. If these are conventional bridges just adding caps across the legs would be all you would need, .01-.1uf would do an effective job. They should be at least 200V rated and polypropylene metalized film type.
Roger
T,
Tough call on that. I think the double bridge would be best because of the ripple current issue. Snubberizing the bridges will help a great deal and bring the noise level to nearly the same as with the expensive setup. If these are conventional bridges just adding caps across the legs would be all you would need, .01-.1uf would do an effective job. They should be at least 200V rated and polypropylene metalized film type.
Roger
Re: A question of noise
I could convert the transformer anyway and first try out the double bridge, Rifa caps and then try out the Cap-6 modules by connecting both the centre taps to the Cap-6 modules, it has two spades for the grounding input so I can still compare both ways
sx881663 said:
I could convert the transformer anyway and first try out the double bridge, Rifa caps and then try out the Cap-6 modules by connecting both the centre taps to the Cap-6 modules, it has two spades for the grounding input so I can still compare both ways
Comparison
Sounds like a plan to me. I assume the Rifa's are MKP types? Let us know your observations and if you have a sensitive meter please measure static noise levels with the inputs shorted. This might be the only way you will detect a change without 100db+ efficiency speakers. As a side note do the measurements with a resistor load or even no load. Speakers can act like sensitive microphones and put acoustically generated noise back into the amps output. Not so much a problem with the UcD’s low output impedance but this can really mess with your head when it happens, been there done that!
Roger
Sounds like a plan to me. I assume the Rifa's are MKP types? Let us know your observations and if you have a sensitive meter please measure static noise levels with the inputs shorted. This might be the only way you will detect a change without 100db+ efficiency speakers. As a side note do the measurements with a resistor load or even no load. Speakers can act like sensitive microphones and put acoustically generated noise back into the amps output. Not so much a problem with the UcD’s low output impedance but this can really mess with your head when it happens, been there done that!
Roger
Re: Comparison
Ok Roger I'll post the results when its up and running
I have a pair of huge high powered 8ohm loading resistors which should be fine for testing, my speakers are rated 8ohms 89db efficiency
Sorry I mean't the 22,000uf Rifa's, I do have some Evox 0.1uf mkp's I could use for the snubbers.
Each cap-6 module have 6 x 6800uf caps (3 each for +/-) with a choke inbetween each cap so I don't know if the big Rifa's are as good as this arrangement
I'll be ordering the UCD400's in a couple of weeks maybe sooner
I'm just having a browse through the threads to see what sort of bi-wired cable is recommended for these amps
sx881663 said:
Ok Roger I'll post the results when its up and running
I have a pair of huge high powered 8ohm loading resistors which should be fine for testing, my speakers are rated 8ohms 89db efficiency
Sorry I mean't the 22,000uf Rifa's, I do have some Evox 0.1uf mkp's I could use for the snubbers.
Each cap-6 module have 6 x 6800uf caps (3 each for +/-) with a choke inbetween each cap so I don't know if the big Rifa's are as good as this arrangement
I'll be ordering the UCD400's in a couple of weeks maybe sooner
I'm just having a browse through the threads to see what sort of bi-wired cable is recommended for these amps
Re: Re: Comparison
Best wire you can find or want to spend on of course.
Bruno sums it up as "microphone" cable.
I think I like the looks of the Cardas stuff though.
t. said:
Ok Roger I'll post the results when its up and running
I have a pair of huge high powered 8ohm loading resistors which should be fine for testing, my speakers are rated 8ohms 89db efficiency
Sorry I mean't the 22,000uf Rifa's, I do have some Evox 0.1uf mkp's I could use for the snubbers.
Each cap-6 module have 6 x 6800uf caps (3 each for +/-) with a choke inbetween each cap so I don't know if the big Rifa's are as good as this arrangement
I'll be ordering the UCD400's in a couple of weeks maybe sooner
I'm just having a browse through the threads to see what sort of bi-wired cable is recommended for these amps
Best wire you can find or want to spend on of course.
Bruno sums it up as "microphone" cable.
I think I like the looks of the Cardas stuff though.
passive attenuator & coupling caps
A couple of pages back we talked about a passive attenuator scheme for the UCD and a comment was made about how placing caps in the + and - leads will destroy the CMRR of the balanced setup because it is impossible to get closely matched caps.
Wouldn't the impedence of the coupling cap over audio frequencies (and above) be so low that a mismatch would not significantly matter (or you have problem with low frequency rolloff)?
If it does matter then would it be better to swap the coupling caps on UCD module itself between the opamp and modulator? Apparently there are two of them so are they running in balanced mode here also (and suffer from the same effect)?
Regards,
Dean
A couple of pages back we talked about a passive attenuator scheme for the UCD and a comment was made about how placing caps in the + and - leads will destroy the CMRR of the balanced setup because it is impossible to get closely matched caps.
Wouldn't the impedence of the coupling cap over audio frequencies (and above) be so low that a mismatch would not significantly matter (or you have problem with low frequency rolloff)?
If it does matter then would it be better to swap the coupling caps on UCD module itself between the opamp and modulator? Apparently there are two of them so are they running in balanced mode here also (and suffer from the same effect)?
Regards,
Dean