Is this Thread dead ?
I can't believe there is nothing more to discuss about this beauty
So I post a picture of my HT amp 5 L15D's fed by a SMPS1000 from Christi .
I changed the input capacitors with Elna Simic II and the decouplers with Panasonics 820uF low ESR's from RS .
I was a bit dissappointed by the damping factor I measured , only 30 after the 30 amp relays in the DC protection . So I'm upgrading to a FET relay now , still figuring out what FET's to use for the lowest Rdson and reasonable gate capacity .I used 18 AWG wiring for the output , but the longest is only half a feet , so that could't be the reason
As far as the sound , This sounds very good ! on my 3839 Tannoys
There is some noise , but hey , does one stick their ears in a speaker before listening to Nora Jones .
All I can say , from a well experienced listener , this is a good amp !
Attachement doen't work right now , so I post it later ,
Cheers
Rens
I can't believe there is nothing more to discuss about this beauty
So I post a picture of my HT amp 5 L15D's fed by a SMPS1000 from Christi .
I changed the input capacitors with Elna Simic II and the decouplers with Panasonics 820uF low ESR's from RS .
I was a bit dissappointed by the damping factor I measured , only 30 after the 30 amp relays in the DC protection . So I'm upgrading to a FET relay now , still figuring out what FET's to use for the lowest Rdson and reasonable gate capacity .I used 18 AWG wiring for the output , but the longest is only half a feet , so that could't be the reason
As far as the sound , This sounds very good ! on my 3839 Tannoys
There is some noise , but hey , does one stick their ears in a speaker before listening to Nora Jones .
All I can say , from a well experienced listener , this is a good amp !
Attachement doen't work right now , so I post it later ,
Cheers
Rens
wow nice!
I've been using my pair of L20D, powered with a smaller Cristi PSU, switched on all the time (except when we went on holiday) for 5+ months, it continues to be quiet, reliable, and sounding great. I should finish the project, need to make a front panel and tidy up the wiring, but it has been fine "as is".
I haven't upgraded the resistors, haven't had any heat problems, but I'm mostly running at quite low volumes.
Hi,
just waiting to free the connex SMPS held back by the customs and I will have something to post.
By the way it's for a 4 channel system, 2 LD20's + 1 tk2050 T2. Hope to get it done before the summer.
BTW nice design!
Did you listen to the amps before the changes?
Why do you think the low damping factor is caused by relay contacts and not the amp module itself?
Nice job on the amp construction.
What kind of case it that?
We did listen to the amp , I have one spare amp and that’s original .
We did some blind AB testing between the original and the modified and we ( The wife and son included ) all found the modified sounding a tat better . A little tighter bass and more transparent .
It was a mono test , so I expect it to be even better in stereo or 5 channel .
I checked the damping factor of the remaining four channels this morning and they were between 80 and 87 . After measuring the relay contact resistance of the low damping channel it was almost 0.120 ohms . I changed it and that solved the problem .
The other relays measured between 28 and 35 milliohms
So in the worst case my Amp internal resistance including the relay and wiring is 8/80=0.1 ohm
If I change the relay with 2 mosfets with an Rdson of 3.5 mOhms in series , my new damping factor will be something like 8/(0.1-0.035+0.007) makes 111 and I’m happy with anything above 100
I made the case myself from two Heat sink profiles I had laying around for the sides , I used 3mm aluminium sheet from the local hardware store for the front , back , bottom and top sprayed it black with a can of spray-paint and used 6mm MDF for the front on top of the 3mm aluminium, again sprayed black and covered with two layers of “Royal coat” decoupage finish satin , that gives an almost perfect ” Brushed” aluminium finish to match my Emotiva UMC-1
I cut a toslink cable in 5 and connected them with some 3 mm PVC tubing to the status LED’s on the amps and the other ends of the 1 mm fibres stick in the MDF front . Looks real good !
I used a plastic kitchen cutting board to mount the SMPS on the bottom of the case to safely isolate the high voltages .
Cheers ,
Rens
We did some blind AB testing between the original and the modified and we ( The wife and son included ) all found the modified sounding a tat better . A little tighter bass and more transparent .
It was a mono test , so I expect it to be even better in stereo or 5 channel .
I checked the damping factor of the remaining four channels this morning and they were between 80 and 87 . After measuring the relay contact resistance of the low damping channel it was almost 0.120 ohms . I changed it and that solved the problem .
The other relays measured between 28 and 35 milliohms
So in the worst case my Amp internal resistance including the relay and wiring is 8/80=0.1 ohm
If I change the relay with 2 mosfets with an Rdson of 3.5 mOhms in series , my new damping factor will be something like 8/(0.1-0.035+0.007) makes 111 and I’m happy with anything above 100
I made the case myself from two Heat sink profiles I had laying around for the sides , I used 3mm aluminium sheet from the local hardware store for the front , back , bottom and top sprayed it black with a can of spray-paint and used 6mm MDF for the front on top of the 3mm aluminium, again sprayed black and covered with two layers of “Royal coat” decoupage finish satin , that gives an almost perfect ” Brushed” aluminium finish to match my Emotiva UMC-1
I cut a toslink cable in 5 and connected them with some 3 mm PVC tubing to the status LED’s on the amps and the other ends of the 1 mm fibres stick in the MDF front . Looks real good !
I used a plastic kitchen cutting board to mount the SMPS on the bottom of the case to safely isolate the high voltages .
Cheers ,
Rens
Attachments
I am really impressed with your work, I am an emotiva fan myself and you really pulled off the look just fine.
Good job! Nice build, great detail. The real question... Have you driven all channels to see if the 1000 is enough? I am planning a similar build and keep coming up short on power in my head with a single 1000. I keep thinking linear is the way to go, but SMPS is so much cheaper and smaller. I keep hearing about horible buss pumping on multi channel class d setups, have you checked into it to see how bad yours is?
Good job! Nice build, great detail. The real question... Have you driven all channels to see if the 1000 is enough? I am planning a similar build and keep coming up short on power in my head with a single 1000. I keep thinking linear is the way to go, but SMPS is so much cheaper and smaller. I keep hearing about horible buss pumping on multi channel class d setups, have you checked into it to see how bad yours is?
I used 3 WLX-7 speaker protection boards from zoe_tsang .
They work pretty good . ( The only mod I made was a 24V zener in series with the flyback diode to improve the off time ) The circuit uses Songle SLA relays . I think I messed up the relay , because I did some pretty abusive testing on this particular one . I simulated 50 Volt rail voltage in an 8 ohm dummy load a couple of times on the input of the circuit and my Lab supply is current limited at 5 Amps . I wanted to be sure it operates as it should , because the Tannoy recones are ridiculous expensive ( and I had quite a few over the years
once due to DC on output with my Dynaco Stereo 400 the rest due to much partying )I tested all other relais , but only once , so they probably survived .
I don't have an unused one , so don't know the original contact resistance .
Thanks ,
For me the SMPS1000 is quite enough . I had this one specially build by Christy because our high mains voltage between 250 and 255 Volts with the whole neighboorhood (including myself) with solar feed-in to the grid .
The transformer has stranded wire , so the continues power is 1100 watts .
I use 50 volt rail voltage for the Amps and because my whole system uses high sensitive Tannoys ( 93dB ) I can reach very high sound pressure without any issues . I never had any bus pumping ( see post #379 )
When I drive the system in unrealistic very high volumes , the current limiter of the smps1000 kicks in ,but that never happens during a movie or listening to very loud stereo music .
Cheers ,
Rens
Doctordata - The comments about your speaker protection peaked my interest too. During the test after the mods, you did find the turn off time to be proper? I am not sure how fast the time really is, 1S or shorter? I have been pondering the protection scheme for some time. The bus pumping phase shifter of your is quite nice too! I planned on using cristy's BIPS module to offer the nice finished look of the jacks, and offer some line driver capabilities too.
Overall it sounds like you put your system through the ringer regarding testing. Its nice to know the ebay speaker protection circuit actually do work.
My multichannel setup would be for home theatre, driving a total of 8 full range speakers. The sub would probably be qty2 L25 bridged. Just cause I'm anal about commonality of looks and parts, I would probably use all L25 modules. My main speakers are 93db too and cannot wait to really push them hard. I have an antique onkyo reciever only "claiming" 60Wx2 in stereo mode. In multichannel it is pretty poor for my setup. My whole system is made up of athena audition series, not great but a really good speaker for little money.
Linky here
My Man Cave - Home Theater Forum and Systems - HomeTheaterShack.com
Overall it sounds like you put your system through the ringer regarding testing. Its nice to know the ebay speaker protection circuit actually do work.
My multichannel setup would be for home theatre, driving a total of 8 full range speakers. The sub would probably be qty2 L25 bridged. Just cause I'm anal about commonality of looks and parts, I would probably use all L25 modules. My main speakers are 93db too and cannot wait to really push them hard. I have an antique onkyo reciever only "claiming" 60Wx2 in stereo mode. In multichannel it is pretty poor for my setup. My whole system is made up of athena audition series, not great but a really good speaker for little money.
Linky here
My Man Cave - Home Theater Forum and Systems - HomeTheaterShack.com
I didn't document the timing when I tested the protectionboards , but remember the scopesettings were somewhere around 100msec per division and the relay did open within one divison , so for sure less then 100 mseconds at 50Volts DC
WOW that is some hometheater !!!!
I received some PVI1050 couplers today and did some interesting measurements on the speaker relay on this link A DC Fault Protection Circuit for Audio Amplifiers . I put 30 volts over the Fets (IRVP44Z just for testing) in to 8 ohm dummy load . The switch times are very good 50usec offtime (Leds in series 30 ma,Fotocells in series ).The coupler is a bit slower , 200useconds .This Fets have only 3000 pF input capacitance and the ones I ordered (IRFB3077PBF) almost 10nF, so I put 20 nF parallel to the PVI1050 output . The switch time went up , about 100useconds but the big surprise for me was that the fet keeps switching off in 50 usec ! So very safe within SOA .
When I have my bigger Fet's I'll make some drop in PCB's for the WLX-7 boards and keep you posted . Before I switch the mechanical relays to the Mosfets I will document some measurements on the old one and compare them to the new ones .
Cheers ,
Rens
Yellow is Leds Blue is dummyload
Attachments
Typical americans, we do everything big. If some is good, alot is even better, then massive would be a awesome.... I spent very little money on it, I did all the work my self. Some people on the theatre forums spend more on their speakers and amplifiers than I did on my whole house. I saw a guy on there with 15 amps at something like $40K USD each. Just stupid. This is why i love the diy and LJM modules. I can spend $500 or so and have an awesome amplifier that could sound just as good as commercial amps.
I would have never believed that the mechancial relays were that fast opening the circuit. With the addtional fet protection, the speaker protection circuit would almost totally invisible, meaning the protection wuold kick in prior to hearing any such problems prior. It is a shame the LJM modules remove all of the AMP7 protection features. External is more robust than using the power mosfets anyway. Good testing information
I would have never believed that the mechancial relays were that fast opening the circuit. With the addtional fet protection, the speaker protection circuit would almost totally invisible, meaning the protection wuold kick in prior to hearing any such problems prior. It is a shame the LJM modules remove all of the AMP7 protection features. External is more robust than using the power mosfets anyway. Good testing information
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I think he did the right thing .
External is the only way to go to be sure !
I'm using a small 12 Vac extra transformer to feed my protection circuits .
Not that I'm not trusting Christi's SMPS aux or the IRF reference design , but a little transformer is far less complicated than a SMPS or the Iraudamp reference design and has a lot less components to fail .
Cheers ,
Rens
AC Line filter
Just read this thread about AC line filtering .http://www.diyaudio.com/forums/tubes-valves/211729-ac-line-filter.html#post3004682
Does it make any sense to filter the line when using SMPS's and class D amps .
I see or hear no influence of the smps or the carrier of my class D amps in the rest of my gear ( I did see some video distortion , but that was gone after I used the proper interconnects )
Cheers ,
Rens
Just read this thread about AC line filtering .http://www.diyaudio.com/forums/tubes-valves/211729-ac-line-filter.html#post3004682
Does it make any sense to filter the line when using SMPS's and class D amps .
I see or hear no influence of the smps or the carrier of my class D amps in the rest of my gear ( I did see some video distortion , but that was gone after I used the proper interconnects )
Cheers ,
Rens
Connexelectronic SMPS have mains filters embedded. Actually any serious smps should have. AFAIK, add a mains filter is redundant with SMPS. If you do add one, you better consider the interactions between the two filters.