Hello, You who know, I want to build a hifi amplifier, what do you think about it?
View attachment amp_op_1000w.pdf
View attachment amp_op_1000w.pdf
741 op amp is pretty hissy at low volume. Buy a cs800 generation A or B and listen to it, that uses one. 4580 is nice.
Those 1943/5200 will toast at 500 w. Use 8 pairs. or try MJ15024/25which in 5 pairs can get you to 400 w/ch. CS800 again. The best bang for the buck these days is MJL21193/94. Rating by soa, which makes output transistors last.
Those drivers are obsolete too, use MJE15031/32.
The spreader diodes D3 D4 need to be mounted on the heatsink with the OT's. Also parallel one with a pot to adjust the idle current to 20-30 ma after you've built it.
The .22 ohm emitter resistors don't do a lot to prevent thermal runaway. Peavey achieved their market share by using .5 ohms, two 1 ohm resistors in parallel. People that don't mind repairing their amps a lot use .33 ohms. At $50 a set of output transistors I try to avoid that process, myself. Tears up speakers too when the DC comes out the end. No DC detect and disconnect relay on output, use only $10 salvage speakers without one.
Or buy a junk cs800 and learn how the pros did it. ~$150. I did.
Those 1943/5200 will toast at 500 w. Use 8 pairs. or try MJ15024/25which in 5 pairs can get you to 400 w/ch. CS800 again. The best bang for the buck these days is MJL21193/94. Rating by soa, which makes output transistors last.
Those drivers are obsolete too, use MJE15031/32.
The spreader diodes D3 D4 need to be mounted on the heatsink with the OT's. Also parallel one with a pot to adjust the idle current to 20-30 ma after you've built it.
The .22 ohm emitter resistors don't do a lot to prevent thermal runaway. Peavey achieved their market share by using .5 ohms, two 1 ohm resistors in parallel. People that don't mind repairing their amps a lot use .33 ohms. At $50 a set of output transistors I try to avoid that process, myself. Tears up speakers too when the DC comes out the end. No DC detect and disconnect relay on output, use only $10 salvage speakers without one.
Or buy a junk cs800 and learn how the pros did it. ~$150. I did.
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I have in my possession 16 MJL4281AG / MJL4302AG and MJE15031 / MJE1532 I thought to use them, I also have 2 toroidal transformers of 70-0-70 of 800 V.
Regarding the OP on the PCB it uses tl071 in another post they recommend me they told me to change it for the ME5532 I am looking to build a hiFI amplifier, any recommendations
Regarding the OP on the PCB it uses tl071 in another post they recommend me they told me to change it for the ME5532 I am looking to build a hiFI amplifier, any recommendations
Mjl4302/4502 are very good, have 1.0 amp soa @ 100v.
Mjl21193/21194 have about the same, but are tested @ 2.25 A @ 80 v.
Both better than 2sa1943/2sc5200 maybe .5 A soa @ 100 v.
TL071 are only okay on hiss, better than 741. 5532 is better. 5532 is not pin compatible with tl071.
If you buy a blown up or sort of working CS800, you also get VI limiter, some sort of DC protect, excellent protection in case of cs800x or cs800s. also heat sinks, fans, connectors, transformer, volume pots etc etc. your 400 va 70 vac transformer is about okay on voltage but lightweight on voltamps. Used Crowns QSC's and Yamahas are also competent, but may cost more.
In my home with sensitive speakers 102 db 1W1m, I find 70 w/ch is fine. I use about 1/4 W base level power, 70 W gives me about 70 db of peak response which is all that great CD's will put out. I'm not deaf, I've always used earplugs near excessive noise emitters, my base level power may be less than yours. Also 80 db 1W1m is pretty common sensitivity among speakers.
Mjl21193/21194 have about the same, but are tested @ 2.25 A @ 80 v.
Both better than 2sa1943/2sc5200 maybe .5 A soa @ 100 v.
TL071 are only okay on hiss, better than 741. 5532 is better. 5532 is not pin compatible with tl071.
If you buy a blown up or sort of working CS800, you also get VI limiter, some sort of DC protect, excellent protection in case of cs800x or cs800s. also heat sinks, fans, connectors, transformer, volume pots etc etc. your 400 va 70 vac transformer is about okay on voltage but lightweight on voltamps. Used Crowns QSC's and Yamahas are also competent, but may cost more.
In my home with sensitive speakers 102 db 1W1m, I find 70 w/ch is fine. I use about 1/4 W base level power, 70 W gives me about 70 db of peak response which is all that great CD's will put out. I'm not deaf, I've always used earplugs near excessive noise emitters, my base level power may be less than yours. Also 80 db 1W1m is pretty common sensitivity among speakers.
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6 pairs mjl4281/4302 might safely put out 6 amps rms or 228 w into 8 ohms.
TIP42c as driver I have tried. The highs were inferior to RCA 40409 on the other channel. Not enough Ft IMHO to make 10-14 khz (which I can hear). MJE15032 as replacement sounded much better, equivalent to surviving 40409/40410 (which can't be bought).
This schematic also lacks speaker DC protection, VI limiter, May be limited on slew rate with the wimpy drive. You won't be able to find toshiba or sanyo original input transistors, just generic clones that leave out all the specs.
TIP42c as driver I have tried. The highs were inferior to RCA 40409 on the other channel. Not enough Ft IMHO to make 10-14 khz (which I can hear). MJE15032 as replacement sounded much better, equivalent to surviving 40409/40410 (which can't be bought).
This schematic also lacks speaker DC protection, VI limiter, May be limited on slew rate with the wimpy drive. You won't be able to find toshiba or sanyo original input transistors, just generic clones that leave out all the specs.
It can not possibly work and if you were to build it as shown then you would just be left with a burned pile of parts...
The TIP41 is rated at only 40 volts, even a TIP41C is only 100v.
There is just so much wrong with these 'brute force' designs that an inexperienced constructor is just going to face huge disappointment even trying to get them to work.
The speaker will blow up already when switching on. The opamp output stage will saturate and hang on a rail for several ms. Voice coil will bump on the pole plate.
This design seems from 50 yrs ago probably with 3055/2955. But in those times superfast fuses in the rails were used, without success though.
This design seems from 50 yrs ago probably with 3055/2955. But in those times superfast fuses in the rails were used, without success though.
If you want something simple and brute force that works, try one of the Apex PA amps - he has a 500 and 900 watt design that have been tested and proven. Topologically very similar, but with enough refinement that you will probably have success. There are commercial offerings that are very similar all over the globe. For that matter you could copy a CS800 - I did (and refined the hell out of it). There is a similar amp (with discrete diff pair input) called the “Dirty Harry” floating around here somewhere. With any of these amps I would add a DC protect board to mute the turn-on thumps. When used with an 18” woofer with a 4” coil, turn-on transients aren’t an issue. With little hi-fi speakers you can launch the cone.
Why do we need such power? 100-150 W at 4 ohms is enough for the most insensitive acoustics.
Amplifiers, both circuits do not work, in the second low-power transistors are designed for 50 volts maximum. Colleagues have already written about powerful transistors.
Amplifiers, both circuits do not work, in the second low-power transistors are designed for 50 volts maximum. Colleagues have already written about powerful transistors.
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Times have changed, modern Subwoofer speakers need a lot of power, which has become cheap and efficient switch-mode wise.
https://www.parts-express.com/pedoc...ess-stw-350f188pr01-04-technical-overview.pdf
This speaker has 82.7dB/1W halfspace, to reach 105dB THX-spec in 4pi we will need 676W, when only 1 sub is used 2704W are needed.
https://www.parts-express.com/pedoc...ess-stw-350f188pr01-04-technical-overview.pdf
This speaker has 82.7dB/1W halfspace, to reach 105dB THX-spec in 4pi we will need 676W, when only 1 sub is used 2704W are needed.
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I read "741" and instantly thought "videorockola" or some obscure Indian design.
Forgetb it,so much wrong with it it isn´t even funny.
Go fornthe well designed and robust APEX projects, available in this very forum.
Besides that:
70-0-70V transformer is nonsense, it will give you 100 - 0 - 100 V DC rails.
Forgetb it,so much wrong with it it isn´t even funny.
Go fornthe well designed and robust APEX projects, available in this very forum.
Besides that:
70-0-70V transformer is nonsense, it will give you 100 - 0 - 100 V DC rails.
'True with professionally designed and built components but not necessarily so here. The guy who spec'd the power transformer probably had substandard, even home-built transformers in mind. Of course, this means regulation like a rubber band. i.e, the more current drawn, the lower the rail voltage - by a large margin, in my limited experience of this type of transformer.
That doesn't mean the transformer and amplifier will deliver anywhere near the claimed power but I suppose it satisfies many gullible, starry-eyed beginners with nothing but pictures and their imagination to teach them the facts of electronic design and build.
That doesn't mean the transformer and amplifier will deliver anywhere near the claimed power but I suppose it satisfies many gullible, starry-eyed beginners with nothing but pictures and their imagination to teach them the facts of electronic design and build.
Even with professionally designed equipment, the rail voltage drops down to about 70% of the low-load value at the maximum expected load (full sine into 4 or 2 ohms). That is usually far beyond the VA rating as they are sized for 1/8 noise power (prosumer brands) or 1/3 noise power (tour grade). With the junk-ola brands it’s far worse. By the time you’re playing it that loud, the distortion is intolerable, and there would usually be smoke and fire coming from the speakers if left that way for any length of time.
Nobody EVER sizes a power transformer for continuous operation at full sine into 2 or 4 ohms. Except maybe some esoteric high end stuff which costs a fortune, and of course if you build it that way. Improved regulation can improve the sound even if peak power is less. It just costs money. Even with them sized in the typical way intermittent operation at full sine, even for minutes at a time, is absolutely no problem. Heat sinking of the amp itself may be a different story, but a transformer takes a while to heat up.
Nobody EVER sizes a power transformer for continuous operation at full sine into 2 or 4 ohms. Except maybe some esoteric high end stuff which costs a fortune, and of course if you build it that way. Improved regulation can improve the sound even if peak power is less. It just costs money. Even with them sized in the typical way intermittent operation at full sine, even for minutes at a time, is absolutely no problem. Heat sinking of the amp itself may be a different story, but a transformer takes a while to heat up.