I did transformer for SYMEF today, the original spec on it was 1500VA and had two 100VAC secondaries.
I have rewound it to 2x31VAC which ends up at around 40-43VDC which is right in the middle of the voltage range the symef amp wants.
Currently i am load testing the transformer to see how warm it gets and how much the voltage drops.
Noload with the secondaries in series i get 62.8VAC, with a 4.1ohm load across it, the voltage drops to 59.2-59.6VAC and the transformer barely gets noticably warm, i will try 2 ohms once the bridge turns off and see how warm the transformer gets and how much the voltage drops.
A pic:
I have rewound it to 2x31VAC which ends up at around 40-43VDC which is right in the middle of the voltage range the symef amp wants.
Currently i am load testing the transformer to see how warm it gets and how much the voltage drops.
Noload with the secondaries in series i get 62.8VAC, with a 4.1ohm load across it, the voltage drops to 59.2-59.6VAC and the transformer barely gets noticably warm, i will try 2 ohms once the bridge turns off and see how warm the transformer gets and how much the voltage drops.
A pic:
Attachments
I have 2 pcb's in the mail (I hope 🙂 )
Starting to collect pieces.
Is this the right place to bring some questions? Technical and not so technical?
Best Regards.
Starting to collect pieces.
Is this the right place to bring some questions? Technical and not so technical?
Best Regards.
Now why did you go and spoil it with a fan???? It is not supposed to be a PA amplifier. Normal use in the home will hardly get those heat sinks warm let alone the need to be fan force cooled.
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These heatsinks are undersize and do get hot and that was in free air on my lab table, so in a chassi they'd overheat and burn up without the fan.
Also this amp is not the amp that is going into this chassi, im just making it a temporary home for the symef amp for now.
The rear panel of the chassi is done:
Also this amp is not the amp that is going into this chassi, im just making it a temporary home for the symef amp for now.
The rear panel of the chassi is done:
Attachments
Tekko I was wondering what was taking you soo long 😀. Been looking forward to your fully asembled unit, that is so that you can take it out for competitions 😉
If there is any device out there that is better, we need to know and do a comparative analysis and further improve the model 😉
Atm i an wearing away on a hole for the power switch in the front panel with a step drill and a not so cordless drill, i wish i had a square file.
I'm unlikely to take this amp with me anywhere, it weights a ton :/
I'm unlikely to take this amp with me anywhere, it weights a ton :/
Dear folks. Regarding max rail voltage. Some say 40vdc is max some say it can be higher....
Sound quality. Will it change alot when cranking up the rail voltage?
One said the "amp woke up" with 47vdc rail voltage? I am somewhat confused here.
The reason I ask because I have a really good 2*42v-800va transformer... But I guess this will be far out here? Or if the transistors are changed to others?
hmm - difficult for a novice this....
I also have 4 pcs Elne Cerafine 18000uf/63 caps that I intend to use in the psu. I think they are ok 🙂
Sound quality. Will it change alot when cranking up the rail voltage?
One said the "amp woke up" with 47vdc rail voltage? I am somewhat confused here.
The reason I ask because I have a really good 2*42v-800va transformer... But I guess this will be far out here? Or if the transistors are changed to others?
hmm - difficult for a novice this....
I also have 4 pcs Elne Cerafine 18000uf/63 caps that I intend to use in the psu. I think they are ok 🙂
WOW! 😱 You are giving me inadequacy issues with those numbers!
I've only planned on puny (in comparison) 300VA per monoblock.. 😀
Seriously, you could probably run 5-7 channels off that PSU. Are you planning to build a HT setup around SYMEF? 🙂
PS: even though the chassis is a little rough, I think the layout looks really good!
Its one of those cheapie antek chassis from ebay for like a hundred or so dollars, compared to the higher quality modusshop or whatever the name is, where u can fork out up to 1000 dollars for the bigger models.
Im mimicing the internal construction of the old QSC MX1500, and im not particularly proud of my work but with nothing but a few drill bits, a not so cordless drill and a step drill and a hacksaw blade, theres only so much you can do before things start looking homemade and bad, as in misaligned holes and such. And i still need to figure out how to mount the caps which are 22000µF 63V nippon chemicon PCB mount ones, i could use the four 10000µF 100V screw terminal clamp mount ones though, but 100V rating seems like a bit of a waste with mere 40VDC rails.
I also made a design oops where the bridge rectifiers ended up right behind the vent holes in the front panel.
This transformer was not originally intended for the symef amp but is rather something i test wound to see how well regular stranded mains wiring works as a secondary.
I stuck the 4 secondaries in series parallel for 2x60VAC and strung that to a 2 ohm resistive load and the transformer only got a bit warm, so it'll do until i have the $$$ to buy the proper transformers or until i come across a good sized transformer or two with the right voltages and a good VA rating.
I guess you could call this project a poweramp on a budget.
Im mimicing the internal construction of the old QSC MX1500, and im not particularly proud of my work but with nothing but a few drill bits, a not so cordless drill and a step drill and a hacksaw blade, theres only so much you can do before things start looking homemade and bad, as in misaligned holes and such. And i still need to figure out how to mount the caps which are 22000µF 63V nippon chemicon PCB mount ones, i could use the four 10000µF 100V screw terminal clamp mount ones though, but 100V rating seems like a bit of a waste with mere 40VDC rails.
I also made a design oops where the bridge rectifiers ended up right behind the vent holes in the front panel.
This transformer was not originally intended for the symef amp but is rather something i test wound to see how well regular stranded mains wiring works as a secondary.
I stuck the 4 secondaries in series parallel for 2x60VAC and strung that to a 2 ohm resistive load and the transformer only got a bit warm, so it'll do until i have the $$$ to buy the proper transformers or until i come across a good sized transformer or two with the right voltages and a good VA rating.
I guess you could call this project a poweramp on a budget.
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I have alot in stock at home. However ordered most of the parts (and then some) from farnell.. yes they are a bit expensive... 
9696660 5 CAPACITOR, 100UF, 50V; Capacitance:100µF ECEA1HN101U
1848469 8 CAPACITOR, RADIAL, 63V, 33UF; Capacitanc EEUFC1J330
1281840 8 CAPACITOR, 33UF, 63V; Capacitance:33µF; 63ZL33MEFC6.3X11
2094122 4 CAPACITOR ALUM ELEC, 100UF, 16V, RADIAL; UKA1C101MDD1TD
1831283 4 CAPACITOR, RADIAL, 16V, 470UF; Capacitan 16ZLK470M8X16
9692053 5 CAPACITOR, 470UF, 16V; Capacitance:470µF EEUFC1C471
2094131 4 CAPACITOR ALUM ELEC, 470UF, 16V, RADIAL; UKA1C471MPD1TD
1311573 4 CAPACITOR SILVER MICA 39PF, 500V, RADIAL CD15ED390JO3F
9519955 2 CAPACITOR, 10PF +/-1PF, 160V; Capacitanc FSC 160V 10PF+/-1PF
1311598 2 CAPACITOR SILVER MICA 470PF, 500V, RAD; CD19FD471JO3F
1198291 5 CAPACITOR, CLASS X2, 0.022UF, 275V; Capa ECQU2A223ML
1636679 2 AUDIO CAPACITOR, 0.002UF, 630V; Capacita PF-XTI-AL-0.002/20/630
9843680 40 DIODE, DO-35,100V,200MA; Diode Type:Smal 1N4148
1470568 4 ZENER DIODE, 500mW, 3.3V, DO-35; Zener V 1N5226B-TR
2101821 4 DIODE, RECTIFIER, 200V, 1A, DO-41; Diode MUR120G
1219483 2 CAPACITOR, RADIAL, 470UF, 50V; Capacitan EEUFM1H471
1848400 8 CAPACITOR, RADIAL, 50V, 56UF; Capacitanc EEUFM1H560
9353755 2 TRIMMER, 25 TURN 2K; Track Resistance:2k 3299W-1-202LF
9557822 4 TRANSISTOR, NPN, TO-126; Transistor Pola MJE340G
2101379 2 TRANSISTOR, NPN, 350V, 4A, TO220; Transi MJE15034G
1542186 3 TRANSISTOR, NPN TO-264; Transistor Polar 2STC5200
1703970 8 BIPOLAR, TRANSISTOR; Transistor Polarity 2N5401G
1467881 4 TRANSISTOR, PNP, TO-92; Transistor Polar BC556B
1542183 4 TRANSISTOR, PNP TO-264; Transistor Polar 2STA1943
1273230 6 BIPOLAR TRANSISTOR, NPN, 160V TO-92; Tra 2N5551RLRAG
1861241 2 BIPOLAR TRANSISTOR, PNP, -350V, TO-220; MJE15035G
9557830 2 TRANSISTOR, PNP, TO-126; Transistor Pola MJE350G
1162740 4 FUSE HOLDER, PCB, 20X5MM; Voltage Rating 0031.8201
1769905 4 RESISTOR, METAL FILM, 22KOHM, 500mW, 2%; CCF0722K0GKE36
1571323 2 RESISTOR, METAL FILM, 750OHM, 250mW, 2%; RLR07C7500GSB14
1769910 6 RESISTOR, METAL FILM, 270OHM, 500mW, 2%; CCF07270RGKE36
1878829 4 RESISTOR, METAL FILM, 1.1 KOHM, 500 MW, CMF551K1000FHEB
1874195 8 RESISTOR, METAL FILM, 301 OHM, 500 MW, CMF55301R00FHEB
1768444 4 RESISTOR, METAL FILM, 4.7 KOHM, 500 MW, CMF554K7000FHEK
9474048 10 RESISTOR, FUSIBLE, 1R; Resistance:1ohm; NFR25H0001008JA500
1878489 4 RESISTOR WIREWOUND, 4.7KOHM, 5W, ±5%; Re CW0054K700JB12
1634072 5 RESISTOR, 6K8, 0.5W, 0.1%, 15PPM; Resist PR5Y-6K8BI
987815 10 RESISTOR, 7W 5% 0R22; Resistance:0.22ohm SQMW7R22J
1536676 4 RESISTOR, METAL FILM, 220OHM, 500mW, 1%; CMF55220R00FHEK
1765147 2 RESISTOR, METAL FILM, 2KOHM, 500mW, 1%; CMF552K0000FHEB
1634059 5 RESISTOR, 2K4, 0.5W, 0.1%, 15PPM; Resist PR5Y-2K4BI
1496879 2 RESISTOR, METAL FILM, 12 OHM, 1 W, ± 5%; PR01000101209JR500
4984201 4 RESISTOR, METAL FILM, 10 OHM, 3 W, ± 5%; PR03000201009JAC00
1767766 2 RESISTOR, METAL FILM, 100OHM, 500mW, 1%; SFR16S0001000FR500
5802180 2 RESISTOR, WIREWOUND, 680OHM, 1W, 5%; Res AC01000006800JA100
1772509 2 RESISTOR, METAL FILM; Resistance:680ohm; NFR25H0006800JR500
1536336 2 RESISTOR, METAL FILM, 100KOHM, 500mW, 1% CMF55100K00FHEK
1872089 2 RESISTOR, METAL FILM, 3.01 KOHM, 500 MW CMF553K0100FHEB
Still lacking.. Trannie, 1uH coil.
1848469 8 CAPACITOR, RADIAL, 63V, 33UF; Capacitanc EEUFC1J330
1281840 8 CAPACITOR, 33UF, 63V; Capacitance:33µF; 63ZL33MEFC6.3X11
2094122 4 CAPACITOR ALUM ELEC, 100UF, 16V, RADIAL; UKA1C101MDD1TD
1831283 4 CAPACITOR, RADIAL, 16V, 470UF; Capacitan 16ZLK470M8X16
9692053 5 CAPACITOR, 470UF, 16V; Capacitance:470µF EEUFC1C471
2094131 4 CAPACITOR ALUM ELEC, 470UF, 16V, RADIAL; UKA1C471MPD1TD
1311573 4 CAPACITOR SILVER MICA 39PF, 500V, RADIAL CD15ED390JO3F
9519955 2 CAPACITOR, 10PF +/-1PF, 160V; Capacitanc FSC 160V 10PF+/-1PF
1311598 2 CAPACITOR SILVER MICA 470PF, 500V, RAD; CD19FD471JO3F
1198291 5 CAPACITOR, CLASS X2, 0.022UF, 275V; Capa ECQU2A223ML
1636679 2 AUDIO CAPACITOR, 0.002UF, 630V; Capacita PF-XTI-AL-0.002/20/630
9843680 40 DIODE, DO-35,100V,200MA; Diode Type:Smal 1N4148
1470568 4 ZENER DIODE, 500mW, 3.3V, DO-35; Zener V 1N5226B-TR
2101821 4 DIODE, RECTIFIER, 200V, 1A, DO-41; Diode MUR120G
1219483 2 CAPACITOR, RADIAL, 470UF, 50V; Capacitan EEUFM1H471
1848400 8 CAPACITOR, RADIAL, 50V, 56UF; Capacitanc EEUFM1H560
9353755 2 TRIMMER, 25 TURN 2K; Track Resistance:2k 3299W-1-202LF
9557822 4 TRANSISTOR, NPN, TO-126; Transistor Pola MJE340G
2101379 2 TRANSISTOR, NPN, 350V, 4A, TO220; Transi MJE15034G
1542186 3 TRANSISTOR, NPN TO-264; Transistor Polar 2STC5200
1703970 8 BIPOLAR, TRANSISTOR; Transistor Polarity 2N5401G
1467881 4 TRANSISTOR, PNP, TO-92; Transistor Polar BC556B
1542183 4 TRANSISTOR, PNP TO-264; Transistor Polar 2STA1943
1273230 6 BIPOLAR TRANSISTOR, NPN, 160V TO-92; Tra 2N5551RLRAG
1861241 2 BIPOLAR TRANSISTOR, PNP, -350V, TO-220; MJE15035G
9557830 2 TRANSISTOR, PNP, TO-126; Transistor Pola MJE350G
1162740 4 FUSE HOLDER, PCB, 20X5MM; Voltage Rating 0031.8201
1769905 4 RESISTOR, METAL FILM, 22KOHM, 500mW, 2%; CCF0722K0GKE36
1571323 2 RESISTOR, METAL FILM, 750OHM, 250mW, 2%; RLR07C7500GSB14
1769910 6 RESISTOR, METAL FILM, 270OHM, 500mW, 2%; CCF07270RGKE36
1878829 4 RESISTOR, METAL FILM, 1.1 KOHM, 500 MW, CMF551K1000FHEB
1874195 8 RESISTOR, METAL FILM, 301 OHM, 500 MW, CMF55301R00FHEB
1768444 4 RESISTOR, METAL FILM, 4.7 KOHM, 500 MW, CMF554K7000FHEK
9474048 10 RESISTOR, FUSIBLE, 1R; Resistance:1ohm; NFR25H0001008JA500
1878489 4 RESISTOR WIREWOUND, 4.7KOHM, 5W, ±5%; Re CW0054K700JB12
1634072 5 RESISTOR, 6K8, 0.5W, 0.1%, 15PPM; Resist PR5Y-6K8BI
987815 10 RESISTOR, 7W 5% 0R22; Resistance:0.22ohm SQMW7R22J
1536676 4 RESISTOR, METAL FILM, 220OHM, 500mW, 1%; CMF55220R00FHEK
1765147 2 RESISTOR, METAL FILM, 2KOHM, 500mW, 1%; CMF552K0000FHEB
1634059 5 RESISTOR, 2K4, 0.5W, 0.1%, 15PPM; Resist PR5Y-2K4BI
1496879 2 RESISTOR, METAL FILM, 12 OHM, 1 W, ± 5%; PR01000101209JR500
4984201 4 RESISTOR, METAL FILM, 10 OHM, 3 W, ± 5%; PR03000201009JAC00
1767766 2 RESISTOR, METAL FILM, 100OHM, 500mW, 1%; SFR16S0001000FR500
5802180 2 RESISTOR, WIREWOUND, 680OHM, 1W, 5%; Res AC01000006800JA100
1772509 2 RESISTOR, METAL FILM; Resistance:680ohm; NFR25H0006800JR500
1536336 2 RESISTOR, METAL FILM, 100KOHM, 500mW, 1% CMF55100K00FHEK
1872089 2 RESISTOR, METAL FILM, 3.01 KOHM, 500 MW CMF553K0100FHEB
Still lacking.. Trannie, 1uH coil.
I omitted the coil, a good solid amplifier should not need neither the coil, nor the zobel.
Also i used MJW21195 and MJW21196 for the output transistors as they were what i had, also their SOA is almost double that of the 2SC5200/2SA1943.
Also i used MJW21195 and MJW21196 for the output transistors as they were what i had, also their SOA is almost double that of the 2SC5200/2SA1943.
Nice progress. If the transformer becomes a problem......we could change input transistors plus a few other things, let me know ...
I did work with metal at one time, but then everything was there, lathes, drills, furnace... etc