Hi guys!
Please could you help me giving me an information?
Well, I need to know the distortion value of the old TCA940 transistor at 8 watt (into 4 ohm) with a power supply of 22 volt.
Unfortunately I can't read this technical value in these sheets:
(Datasheet) TCA940N PDF - SGS : lOW AUDIO POWER AMPLIFIER (4-page)
I apologize for my ignorance (I'm a newbie)...however, please guys, help me!
Thank you and best regards!
Please could you help me giving me an information?
Well, I need to know the distortion value of the old TCA940 transistor at 8 watt (into 4 ohm) with a power supply of 22 volt.
Unfortunately I can't read this technical value in these sheets:
(Datasheet) TCA940N PDF - SGS : lOW AUDIO POWER AMPLIFIER (4-page)
I apologize for my ignorance (I'm a newbie)...however, please guys, help me!
Thank you and best regards!
Thank you very much Abraxalito!...it's a very beautiful reply for me!!!
Frankly I suspected a worse value than 0.5%: it's incredible that from 0.5% of 8 watt, the distortion value increases up to 10% with just 2 watt more.
Thank you very much for your precious support!
Regards
Thank you again dear Abraxalito!
Just another question and then I don't bother you more...it'a a personal curiosity of mine...I already said that I'm a newbie so please be patient:
In general is the 10% of distortion in the sound a very perceptible value to the human hearing?...I've to admit that I've always heard music with Hi-Fi amplifiers (now for example I've a Sansui AU-317)...so I can't image how my hearing can react with a 10% of distortion.
Please let me know your interesting opinion about that!
Thank you my friend!
regards!
Just another question and then I don't bother you more...it'a a personal curiosity of mine...I already said that I'm a newbie so please be patient:
In general is the 10% of distortion in the sound a very perceptible value to the human hearing?...I've to admit that I've always heard music with Hi-Fi amplifiers (now for example I've a Sansui AU-317)...so I can't image how my hearing can react with a 10% of distortion.
Please let me know your interesting opinion about that!
Thank you my friend!
regards!
The only thing I know about the sound distortion is that the maximum distortion value tolerated by the german DIN45500 hi-fi standards is 0.5%.
Surpassing the 0.5% of total harmonic distortion, you can't qualify any amplifier as "hi-fi" or at least as a well sounding advice: for this reason, in my case, I'm satisfied with 7 or at maximum with 8 watt.
Moreover I'll use two good 12 watt wideband drivers with an efficiecy of 94 dB/1 W...so I believe the final results will be decent...at least.
Thank you again for your kindness Abraxalito.
Best regards
Surpassing the 0.5% of total harmonic distortion, you can't qualify any amplifier as "hi-fi" or at least as a well sounding advice: for this reason, in my case, I'm satisfied with 7 or at maximum with 8 watt.
Moreover I'll use two good 12 watt wideband drivers with an efficiecy of 94 dB/1 W...so I believe the final results will be decent...at least.
Thank you again for your kindness Abraxalito.
Best regards
Ok Abraxalito, it's a little difficult to understand all that to me.
Please tell me just a last concrete reply in order to be serene: using just 7 watt of the 10 watt from the TCA940...can I get a decent sound?
Please I ask you only this question and then I'll go to bed (here in Italy is deep night!)
Please let me know!
Please tell me just a last concrete reply in order to be serene: using just 7 watt of the 10 watt from the TCA940...can I get a decent sound?
Please I ask you only this question and then I'll go to bed (here in Italy is deep night!)
Please let me know!
A TCA940 is a drop-in "on steroids" upgrade for TBA810AS and "sounds" similar, too. It was used in cheap home vinyl turntables, radios of the 80's etc. It has high Zin and could be driven directly from a cheap hi-z cartridge. It is somewhat sturdy, ... but I replaced a few of them in my younger years. (I suppose home parties killed a few of them). How come you still have this chip? These are "very retro". Rare.
Hi Anti!...you're right: in fact I've a vintage turntable of the '70 (it belonged to my mother) with an amp based on two TBA810.
So I've decided to have some fun with an upgrade by replacing the TBA810 with the more robust TCA940.
In this way, I'll get 7 or 8 "real" watt instead of the 4 or 5 watt of the TBA810.
By the way, Anti...I've a curiosity: what do yo mean when in your previous message you say cheap hi-z cartridge and high Zin?...sorry but I'm a newbie and I'd like to learn new stuff.
Thank you so much!
Regards
So I've decided to have some fun with an upgrade by replacing the TBA810 with the more robust TCA940.
In this way, I'll get 7 or 8 "real" watt instead of the 4 or 5 watt of the TBA810.
By the way, Anti...I've a curiosity: what do yo mean when in your previous message you say cheap hi-z cartridge and high Zin?...sorry but I'm a newbie and I'd like to learn new stuff.
Thank you so much!
Regards
The frequency range of the chip under discussion begins only from 40 Hz.
And the distortion value of the old TCA940 chip is 0.3% only up to 5 watts.
If you have suitable power supply with a voltage of 22 V, you might want to use TDA 2009. Its characteristics are much better.
TDA2009 Datasheet(PDF) - STMicroelectronics
Or build both amplifiers and compare them.
And the distortion value of the old TCA940 chip is 0.3% only up to 5 watts.
If you have suitable power supply with a voltage of 22 V, you might want to use TDA 2009. Its characteristics are much better.
TDA2009 Datasheet(PDF) - STMicroelectronics
Or build both amplifiers and compare them.
Attachments
Thank you very much, but I don't want modern amp like the 2009 even if they sound better, as you said correctly.
However, the distortion of the TCA940 is 0.3% up to 5 wat at 18 V as the schematic says, but with 22 or 23 volt are you sure that you can't get 7 or 8 watt with "only" 0.6% of distortion?
Thank you for your reply.
Best regards
A 2009 isn't "modern" amp, it's a "vintage proper" oldtimer as well.
With TCA940, if memory serves well, you shoud take care of proper cooling. It will dissipate more heat compared to a TBA810. So make sure before you jump to higher voltage supply that you have enough "cooling power". These chips get hot quick, small fins they have don't cool the chip as good as "better" power packages (like TO220) do, etc.
Once they heat up, their built-in protection circuitry stops being as effective as it is when chips are cooler. This results in chips blowing up. So if you plan to pump them with a muscular PSU, better stock up on them, because you could end up replacing them often if you push them too far.
Bottom line: big enough heatsinks and bolt them tight to ensure good thermal contact.
With TCA940, if memory serves well, you shoud take care of proper cooling. It will dissipate more heat compared to a TBA810. So make sure before you jump to higher voltage supply that you have enough "cooling power". These chips get hot quick, small fins they have don't cool the chip as good as "better" power packages (like TO220) do, etc.
Once they heat up, their built-in protection circuitry stops being as effective as it is when chips are cooler. This results in chips blowing up. So if you plan to pump them with a muscular PSU, better stock up on them, because you could end up replacing them often if you push them too far.
Bottom line: big enough heatsinks and bolt them tight to ensure good thermal contact.
I mean in early 80's I did tose things that I think you plan to do now: beef up the supply and pump up the volume.
So from memory: One thing that can help with that is to replace all the 100uF lytics with 220uF and the 1000uF lytic with a 2200uF. This is going to provide a little better bass and a better tonality at lower volumes.
Personally I wouldn't even try to go above 22V supply.
So from memory: One thing that can help with that is to replace all the 100uF lytics with 220uF and the 1000uF lytic with a 2200uF. This is going to provide a little better bass and a better tonality at lower volumes.
Personally I wouldn't even try to go above 22V supply.
Hi Anti, you're very kind!
You can't imagine how I apreciate this precious this kind of tips and tricks in order to get some sound improvements.
Even the smallest advice is really welcome to me: so dear Anti, if you see other components or other stuff in this amp circuit board (based on the TCA940 of course) please let me know...your electronic knowledge is precious and very interesting!
Thank you one again
Best regards from Italy
You're funny pimping up the relics, hahaha. Myself and some of my friends did that with what we got when London Calling (the clash) for me and Deep Purple for the others were "it things", so we naturally squeezed a little bit more oomph from what we got back then. You never forget those things, haha. And all of the pissed-off neighbours who failed to appreciate our efforts.
If your board has axial lytics by chance, I'd recommend to consider FT-Cap brand 'lytics FTCAP Fischer and Tausche Capacitors - FTCAP GmbH - not associated with them, but used these in a somewhat recent refurb I did and they seem ok and look good visually.
Also recently I had to makeover an old TBA810 board I had like "forever" as a small bench-amp; I killed it with a new switching wallwart psu that had different polarity than my old one. What a PITA it was!
So much for the blast-from-the-past moments.
If your board has axial lytics by chance, I'd recommend to consider FT-Cap brand 'lytics FTCAP Fischer and Tausche Capacitors - FTCAP GmbH - not associated with them, but used these in a somewhat recent refurb I did and they seem ok and look good visually.
Also recently I had to makeover an old TBA810 board I had like "forever" as a small bench-amp; I killed it with a new switching wallwart psu that had different polarity than my old one. What a PITA it was!
So much for the blast-from-the-past moments.
Hi Anti!!!...London calling the faraway towns...What a fantastic song!!!..and this one?: Rudy can't fail no no no no...!!!
That said, yes I love the elctronic relics...I think they deserve respect and love!!!.
Thank you for your tips about the caps that I'll follow surely.
By the way, Anti, please could you give me the last advice for this restoration and improvement of my project?
I'd like to if the few passive components on the tone and volume control circuit board are upgradable?...you can see all the picture of this circuit board and you can read the description of every picture here:
vintage amplifier circuit board with TDA2010 with this tone/volume control circuit
Please click on each single photo in order to get them bigger and clearer...The upgrade I'm referring to is for all the ceramic capacitors and resistors that you can see between the two pair of sliders.
Please ignore the whole initial project of replacing the original amp circuit board with the other one based on the two TDA2010: as you know at the end I've preferred to replace only the TBA810 with the TCA940.
Thank you Anti...you can't imagine how your support is helping me
Please let me say you're a great electronic expert but above of all, you're a very nice person.
Best regards!
That said, yes I love the elctronic relics...I think they deserve respect and love!!!.
Thank you for your tips about the caps that I'll follow surely.
By the way, Anti, please could you give me the last advice for this restoration and improvement of my project?
I'd like to if the few passive components on the tone and volume control circuit board are upgradable?...you can see all the picture of this circuit board and you can read the description of every picture here:
vintage amplifier circuit board with TDA2010 with this tone/volume control circuit
Please click on each single photo in order to get them bigger and clearer...The upgrade I'm referring to is for all the ceramic capacitors and resistors that you can see between the two pair of sliders.
Please ignore the whole initial project of replacing the original amp circuit board with the other one based on the two TDA2010: as you know at the end I've preferred to replace only the TBA810 with the TCA940.
Thank you Anti...you can't imagine how your support is helping me
Please let me say you're a great electronic expert but above of all, you're a very nice person.
Best regards!
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.