Jan-Peter: I have UcD400 and want to upgrade the onboard caps, do you have the circuit diagram of it? Thanks.
starn02 said:
I have compared it with a UcD400AD. Although these t amps sound very good, I prefer the UcD-AD.
Hello,
I am starting down the DIY speaker-enclosure construction path, and do not yet have the electronics I will be using on the speakers I plan to construct.
It occurred to me that I could DIY my amp, as well as the speakers it would run.
The speakers require an amp that is 4ohm stable, but beyond that will not be difficult to drive for a decent amp.
After looking into the options available for DIY amps, I am looking at constructing one from the following components:
UCD-180ST (pair)
Hypex ST Power Supply (single)
500VA AVEL TOROIDAL Tx w/ 30V secondaries (single)
This BOM, including misc connectors and what not, runs ~ $400. The only issue I see, is that a search does not turn up info on the ST Power Supply being used in a project. I wonder if this is because it is so "obviously" insufficient/inferior, that no one would mention it here. Seems to be a reasonablely high, average knowledge level around here! Or is it that it is a new addition to the Hypex lineup?
I was thinking the thermal protection offered by the Hypex Softstart module would be nice, but with it the project gets to almost $500 (with at least one thermistor). Worth it? Why, exactly?
I found the following amps on Audiogon for no more than what I would pay for the DIY amp using my BOM with Softstart:
B&K ST-2140 (from 2001) 140 watt/channel $400 plus S/H
Acurus A-150 $290 plus S/H
Consonance Opera A100 Plus 80w/channel $395 includes S/H
Linn LK100 $450 plus S/H
Adcom 555 $350 plus S/H
Classe Seventy balanced -in $450 plus S/H
Acurus A200 $385 plus S/H
Rotel RB980BX $280 plus S/H
Ps Audio 100 Delta $500 includes S/H
Reality Check Time
Could an amp built in either configuration definately exceed what I found on Audiogon, as far as sound quality?
The DIY aspect would be a good learning experience, but I will not want sub-standard (even just equivilent) equipment plus all the extra work. Could I change my DIY BOM and get better performance/$, should this combination not get me there? So, what does every one think?
Thanks in advance!
I am starting down the DIY speaker-enclosure construction path, and do not yet have the electronics I will be using on the speakers I plan to construct.
It occurred to me that I could DIY my amp, as well as the speakers it would run.
The speakers require an amp that is 4ohm stable, but beyond that will not be difficult to drive for a decent amp.
After looking into the options available for DIY amps, I am looking at constructing one from the following components:
UCD-180ST (pair)
Hypex ST Power Supply (single)
500VA AVEL TOROIDAL Tx w/ 30V secondaries (single)
This BOM, including misc connectors and what not, runs ~ $400. The only issue I see, is that a search does not turn up info on the ST Power Supply being used in a project. I wonder if this is because it is so "obviously" insufficient/inferior, that no one would mention it here. Seems to be a reasonablely high, average knowledge level around here! Or is it that it is a new addition to the Hypex lineup?
I was thinking the thermal protection offered by the Hypex Softstart module would be nice, but with it the project gets to almost $500 (with at least one thermistor). Worth it? Why, exactly?
I found the following amps on Audiogon for no more than what I would pay for the DIY amp using my BOM with Softstart:
B&K ST-2140 (from 2001) 140 watt/channel $400 plus S/H
Acurus A-150 $290 plus S/H
Consonance Opera A100 Plus 80w/channel $395 includes S/H
Linn LK100 $450 plus S/H
Adcom 555 $350 plus S/H
Classe Seventy balanced -in $450 plus S/H
Acurus A200 $385 plus S/H
Rotel RB980BX $280 plus S/H
Ps Audio 100 Delta $500 includes S/H
Reality Check Time
Could an amp built in either configuration definately exceed what I found on Audiogon, as far as sound quality?
The DIY aspect would be a good learning experience, but I will not want sub-standard (even just equivilent) equipment plus all the extra work. Could I change my DIY BOM and get better performance/$, should this combination not get me there? So, what does every one think?
Thanks in advance!
I hesitate answering because I have not yet completed my project (4 UcD180 and 2 UcD400) and I have only listened to Classe, Adcom and Rotel but not the same models.
But here is what I think and what I based my project on (your mileage may vary):
1. With your current plan I think (but have not experienced it) you will get a much better amp that most of the amps you are listing.
2. instead of going for additional protection from the sofstart, I would spend the money to get the UcD180ADs instead.
3. in all cases you should consider bypassing the input caps and using external 2uF 200 V auricaps ($9.95 partsconnexion, you need only one per amp for RCA unbalanced input) or at least replacing them by Black Gates (NX Hi-Q 47uF 6.3v $2.50 at partsconnexion).
4. the cost of 2 good caps (eg 10000uF Cerafines $35 at partsconnexion) plus two bypass caps (eg Solen 6.2uf polyproplene) plus one rectifier bridge with 4 snubber caps (eg Vishay/BC Components Radial Metallized Polyester Film Capacitor Lacquered .10UF 250V) is less than the ST power supply but will give you an awesome power supply of a sound quality probably equivalent or surpassing the HG. This is why few people go with the ST power supply.
5. 500VA Toroidal does not really require a softstart but if you want a simple softstart you could place one 5 amp inrush limiter (2 in parallel for 1KVA) in series with the primaries (code KC006L-ND at digikey).
6. look at the cost of buying two avel 230VA (about $38 each) or 250VA toroids (if partsexpress do not have these go on the avellindberg web site then email or call them to get a quotation) instead of a single 500VA. Add another power supply and you have an awesome dual mono. Very high-end amp for probably not much more than $500.
I don't know it the DC protection that comes with the Hypex PS is important to have. I would think this is only required for people who do not use any input cap (DC coupled) - without DC protection any DC coupled amp might one day have DC at the input and fry the speakers and/or the amps. But with input caps there should be no problem.
Guy
But here is what I think and what I based my project on (your mileage may vary):
1. With your current plan I think (but have not experienced it) you will get a much better amp that most of the amps you are listing.
2. instead of going for additional protection from the sofstart, I would spend the money to get the UcD180ADs instead.
3. in all cases you should consider bypassing the input caps and using external 2uF 200 V auricaps ($9.95 partsconnexion, you need only one per amp for RCA unbalanced input) or at least replacing them by Black Gates (NX Hi-Q 47uF 6.3v $2.50 at partsconnexion).
4. the cost of 2 good caps (eg 10000uF Cerafines $35 at partsconnexion) plus two bypass caps (eg Solen 6.2uf polyproplene) plus one rectifier bridge with 4 snubber caps (eg Vishay/BC Components Radial Metallized Polyester Film Capacitor Lacquered .10UF 250V) is less than the ST power supply but will give you an awesome power supply of a sound quality probably equivalent or surpassing the HG. This is why few people go with the ST power supply.
5. 500VA Toroidal does not really require a softstart but if you want a simple softstart you could place one 5 amp inrush limiter (2 in parallel for 1KVA) in series with the primaries (code KC006L-ND at digikey).
6. look at the cost of buying two avel 230VA (about $38 each) or 250VA toroids (if partsexpress do not have these go on the avellindberg web site then email or call them to get a quotation) instead of a single 500VA. Add another power supply and you have an awesome dual mono. Very high-end amp for probably not much more than $500.
I don't know it the DC protection that comes with the Hypex PS is important to have. I would think this is only required for people who do not use any input cap (DC coupled) - without DC protection any DC coupled amp might one day have DC at the input and fry the speakers and/or the amps. But with input caps there should be no problem.
Guy
Is thermal protection worth it for a 180 based amp? I dont' really think so, it's an added level of protection though, vent the case nicely and build it right.. it'll never even get warm.
Is soft start worth it? With a 500VA and a large cap bank, possibly, though it may not be an absolute requirement, you're being alot nicer to your parts at least, and if you do buy it, a PTC is a cheap extra to throw in.
The real question is if you want the learning experience or not, and how much do you want to learn? I haven't heard any of the amps you mentioned, but suffice it to say you'll need to pick up a few skills in order to approach their performance, more so if you do it via building your own supply as opposed to purchasing a ready made one. Most people likely feel it's worth opting for the HG supply if they can... I can't comment I haven't compared them.
You just don't do yourself any favors by slapping whatever bypassing you think got good reviews/comments etc. Better to do some research on proper snubbing and if you're not up to that, you may end up better off with a designed supply from Hypex.... maybe.
I've used a 500VA with stereo 180's, worked great! I think I'd prefer that to dual 250's and what a manufacturer might call "headroom" I'd call worse regulation. When I cranked my amps up they pounded without breaking a sweat and no drop off in power like in your usual commercial junk, but then you don't have monoblocks... which are more expensive anyway, and you have the option of using the extra money you save by going stereo to buy better components with.
So you have all kinds of options to look at, and I'm afraid that's part of the fun of DIY, which is why I I hesitated to answer.
Also, double the cost of your first estimated BOM and when it's all said and done you won't be too disappointed with yourself.
I seriously would not use something like that inrush limiter, it will modulate your power since class d doesn't draw a steady current from the supply like a class A amp would, especially at that rating.
To say you can slap something together that can be equivalent or even better than the HG, while I haven't heard one, I think you'd seriously have to do your homework, and alot of trial and error type rework.
In the end though if you do a good job you'll likely be very pleased with it, and I doubt you'll find anything to compare it to.
Is soft start worth it? With a 500VA and a large cap bank, possibly, though it may not be an absolute requirement, you're being alot nicer to your parts at least, and if you do buy it, a PTC is a cheap extra to throw in.
The real question is if you want the learning experience or not, and how much do you want to learn? I haven't heard any of the amps you mentioned, but suffice it to say you'll need to pick up a few skills in order to approach their performance, more so if you do it via building your own supply as opposed to purchasing a ready made one. Most people likely feel it's worth opting for the HG supply if they can... I can't comment I haven't compared them.
You just don't do yourself any favors by slapping whatever bypassing you think got good reviews/comments etc. Better to do some research on proper snubbing and if you're not up to that, you may end up better off with a designed supply from Hypex.... maybe.
I've used a 500VA with stereo 180's, worked great! I think I'd prefer that to dual 250's and what a manufacturer might call "headroom" I'd call worse regulation. When I cranked my amps up they pounded without breaking a sweat and no drop off in power like in your usual commercial junk, but then you don't have monoblocks... which are more expensive anyway, and you have the option of using the extra money you save by going stereo to buy better components with.
So you have all kinds of options to look at, and I'm afraid that's part of the fun of DIY, which is why I I hesitated to answer.
Also, double the cost of your first estimated BOM and when it's all said and done you won't be too disappointed with yourself.
I seriously would not use something like that inrush limiter, it will modulate your power since class d doesn't draw a steady current from the supply like a class A amp would, especially at that rating.
To say you can slap something together that can be equivalent or even better than the HG, while I haven't heard one, I think you'd seriously have to do your homework, and alot of trial and error type rework.
In the end though if you do a good job you'll likely be very pleased with it, and I doubt you'll find anything to compare it to.
Thanks for the tip and explanation about the inrush limiters, I was wondering about this myself but they seemed fine in the two high-power stereo Tripath amps I built (1KVA tranny, 30000uF, modded eval boards, +/- 80 V DC rails!!). Maybe I will add a manual switch to bypass the limiters for critical listening - or better a time-delayed relay so that it is all automatic? Without inrush or sofstart people say that the slow-blow fuses get modified by half-melted cycles and that can also affect performance.
I think I shouldn't have said that it is easy to make a power supply that is equivalent or better than the HG especially when I have not heard the HG. That is probably true for the ST supply though since you would put the same money into better components.
And yes there is no avoiding choice and risk when going DIY. But that is also true for off-the-shelf amps! And the potential reward and value is much higher. But you need to enjoy the research and the challenge.
I think I shouldn't have said that it is easy to make a power supply that is equivalent or better than the HG especially when I have not heard the HG. That is probably true for the ST supply though since you would put the same money into better components.
And yes there is no avoiding choice and risk when going DIY. But that is also true for off-the-shelf amps! And the potential reward and value is much higher. But you need to enjoy the research and the challenge.
I think there is another scenario when the DC speaker protection circuit is needed (is that the Hypex' DC protection you are referring to?): when your own amp fails (v.g. one Mosfet) and you get the PS VDC at the speaker binding post
, right ClassD?That is worring me at the moment, though Mosfet failure seems to be an infrequent accident, as noone has reported it here to my knowledge, you won't have the time to say ooops! when your woofer will pass as a rocket near your sofa 😱
A few considerations have delayed my decision:
*Price: now I know how to build one (copy one 😉 )
*space: I will need space for TX-PS and PCB, unless I use a future "separate opamp PS and TX"...wich lets me to the next point...
*sound: will the relay degrade sound?
will a shared PS degrade sound? ( PS ground should be common to UCD module's ground and opamp's PS ground).
Any comments/advices are welcome.
Regards
M
Yeah, you'd be wise to have some form of protection in case the module's output stage goes, and that would certainly be DC protection.
The big worry will be that if it does happen and you don't have protection, you can pretty well count on a fire worst case, blown speaker best case.
It's your choice but you ought to be clear what you're gambling with, and if you decide not to use it, I wouldnt' leave the amp powered unattended, just in case.
Would a relay affect sound..... what doesn't? Probably not to any great extent though.
I'm not sure what you're asking regarding shared PS's and grounds, dual mono and shared with an aux psu for input stage or stereo shared? Grounds should be common but only ever at 1 point, best to make that at the input /shield, and so you float the outputs.
The big worry will be that if it does happen and you don't have protection, you can pretty well count on a fire worst case, blown speaker best case.
It's your choice but you ought to be clear what you're gambling with, and if you decide not to use it, I wouldnt' leave the amp powered unattended, just in case.
Would a relay affect sound..... what doesn't? Probably not to any great extent though.
I'm not sure what you're asking regarding shared PS's and grounds, dual mono and shared with an aux psu for input stage or stereo shared? Grounds should be common but only ever at 1 point, best to make that at the input /shield, and so you float the outputs.
ClassD:
I meant, with my UCD400's monoblocks I would have 1 main PS plus 1 PS for the input opamp and 1 other PS for the speaker DC protection/inrush current (maybe), all with common ground. This could eventually (or certainly) feed noise into the sensitive module stages, right?
Thanx
M.
I meant, with my UCD400's monoblocks I would have 1 main PS plus 1 PS for the input opamp and 1 other PS for the speaker DC protection/inrush current (maybe), all with common ground. This could eventually (or certainly) feed noise into the sensitive module stages, right?
Thanx
M.
redone amp. I must say the amp. sounds great. Housing is 23x23x8 cm. Very short wiring.
An externally hosted image should be here but it was not working when we last tested it.
Bgt said:
Hi Bert,
I'm wondering what type of wire you're using for the supplies and speaker outputs?
Sure is some tight clearance from your caps to the case, wow. I think I'd put something there to ensure they can't contact the case, that's scary close from the looks of things.
Only little change I can recommend though is it looks like you can get away with about 1/3 that length of wire on the speaker outputs, with the idea of getting them away from the mains wires especially.
While they are "high voltage" as opposed to the inputs, which are shielded, these aren't shielded, will pick up some level of noise, and it's the "micro" small signal stuff that really makes your imaging and soundstage, so for that reason I'd do all I can to conserve them, even if you don't hear any type of hum, and there's also all the HF noise on the lines ..
If it makes it easier maybe you can consider reversing the fast on tabs on the right module so they stick out the other side of the board, or just solder the wires to the stubs on the back of it.
the caps are a bit big for these kind of small cases but the only alternative would be the T-Nets. I just don't want to compromise on the psu's caps.
The wiring possibilities are a bit limited by the speaker protection unit in there. Will have a look if there is a possibility to do it in a different way.
The wiring possibilities are a bit limited by the speaker protection unit in there. Will have a look if there is a possibility to do it in a different way.
Acceptable DC
Hi,
if I eliminate the coupling caps, would it be acceptable to have 20mV on the input of the final stage of UCD180?
Thanks
Stephan
Hi,
if I eliminate the coupling caps, would it be acceptable to have 20mV on the input of the final stage of UCD180?
Thanks
Stephan
Re: Acceptable DC
You mean 20mv out from the preamp?
if so multiply it with the gain to see if the output is too high.
I would not allow my UCD's output to be more than 50mv offset DC if possible(AD8620=fit for the job).
Since I have a gain of 60 that allows for a very small dc input value. 1 of the advantages of a passive preamp(when not using caps. in the audiopath at all).
reins said:
You mean 20mv out from the preamp?
if so multiply it with the gain to see if the output is too high.
I would not allow my UCD's output to be more than 50mv offset DC if possible(AD8620=fit for the job).
Since I have a gain of 60 that allows for a very small dc input value. 1 of the advantages of a passive preamp(when not using caps. in the audiopath at all).
Re: Acceptable DC
20mV times the gain of 26dB (20x) is 400mV which I think is a bit much.
Gertjan
reins said:
20mV times the gain of 26dB (20x) is 400mV which I think is a bit much.
Gertjan
Re: Re: Acceptable DC
Yeah, when I first answered that I think I totally neglected to see he had said at the "input" of the UCDD....
sorry.
ghemink said:
Yeah, when I first answered that I think I totally neglected to see he had said at the "input" of the UCDD....
sorry.Could you please clarify your question I find this confusing?
At the input you can't have more than 1.2mV, but 20mV at the output of the UCD is fine.