Hello.
On my desk I have Blaupunkt BEA80 car eq with 4ch amplifier.
I did the recap and it sounds much better than it did before (2 channels, other 2 have bad ICs).
I want this unit in my 91 Camaro because it fits it's time period nicely by the look.
I have some scenarios planned, final will be decided based on your anwsers and further testings.
Now I'm deciding between:
1.) Using this unit only for looks and feeding input signal in just for the vu meters.
2.) Using this unit only as eq, just feeding signal thru the eq part.
3.) Replacing TA7270P ics to get all channels working.
4.) Removing all amplifier components from the PCB and modify with different IC. There isn't much space so I was thinking about using single car hifi 4ch ic, something from the early 2000s, on it's own pcb.
Now my questions are:
1.) Did anyone had such unit and can tell me what it's sound quality should be?
2.) Can anyone tell me about TA7270P sound quality?
3.) Do TA7270P tend to get bad like STK for example?
4.) Are there TA7270P chinesse knockoffs online like for STK?
5.) Can anyone tell me about the quality of eq section?
My plan would be to use it only for the looks, but I don't want to feel like idiot when someone will try to move the faders and nothing will change 🤣😗😗
I'm leaning the most towards using this unit only as eq and to use another amplifier to power the speakers... but again I don't know if it will harm sound quality.
I'm attaching the schematic and photo of the unit:
On my desk I have Blaupunkt BEA80 car eq with 4ch amplifier.
I did the recap and it sounds much better than it did before (2 channels, other 2 have bad ICs).
I want this unit in my 91 Camaro because it fits it's time period nicely by the look.
I have some scenarios planned, final will be decided based on your anwsers and further testings.
Now I'm deciding between:
1.) Using this unit only for looks and feeding input signal in just for the vu meters.
2.) Using this unit only as eq, just feeding signal thru the eq part.
3.) Replacing TA7270P ics to get all channels working.
4.) Removing all amplifier components from the PCB and modify with different IC. There isn't much space so I was thinking about using single car hifi 4ch ic, something from the early 2000s, on it's own pcb.
Now my questions are:
1.) Did anyone had such unit and can tell me what it's sound quality should be?
2.) Can anyone tell me about TA7270P sound quality?
3.) Do TA7270P tend to get bad like STK for example?
4.) Are there TA7270P chinesse knockoffs online like for STK?
5.) Can anyone tell me about the quality of eq section?
My plan would be to use it only for the looks, but I don't want to feel like idiot when someone will try to move the faders and nothing will change 🤣😗😗
I'm leaning the most towards using this unit only as eq and to use another amplifier to power the speakers... but again I don't know if it will harm sound quality.
I'm attaching the schematic and photo of the unit:
Any electrical change in the signal path will modify sound. It depends on Physics Laws. Each device, from the humblest resistor to the most complex IC has its own L, C, R parameters and its own distortion. The way you perceive it will depend on personal taste, ears condition and the amount of change in those parameters.
Several years ago I read an Argentine author who said that those people that always listen severely distorted sounds, past some time they loss the hability of distinguish between good and bad audio qualities. ITOH those who regularly listen good audio sources, dislike distorted sounds.
Several years ago I read an Argentine author who said that those people that always listen severely distorted sounds, past some time they loss the hability of distinguish between good and bad audio qualities. ITOH those who regularly listen good audio sources, dislike distorted sounds.
I'm aware. I'm in big dilema as I recapped it and it still does not deliver the sound I expect. For example when bassline starts first fraction of it sounds distorted, then it clears up.
Also some sounds like whooshes sounds distorted aswell.
Maybee it's the working two ics starting to go bad aswell.
Then I don't want to do the work of changing ICs just to find out it sounds the same... or to install chinesse knockoff.
I'm going to wire it up in the car later to see how it sounds there.
Will try in the car to exclude possibility of my speaker playing tricks and do as suggested if problem presists.
Sincerely don't believe upon a speaker problem. Or it is open, shorcircuited or become noisy because of metallic particles in the magnet's gap or cone/coil with deformation. All them aren't time dependent issues. Your problem makes me thing that it is a semiconductor taking too long to stabilize its operating point: an althered resistor, an excesively large or leacky cap or a thermal fault in the semicon itself. Check a coupling cap reversed. Once I had a lytic with the polarity reversed in the shrink tube it covers.
I was thinking more of a resonating cabinet or something loose inside rather then a driver itself.
But your theory makes much more sense...
It does sound to me like a bad cap, I will take another look if I had missed any while recapping. Polarity is 100% on all I replaced, realy hard to miss as there is white dot on the pcb on the negative side for each cap.
New caps don't warranty that anyone may be faulty 😳.
https://www.diyaudio.com/community/...ar-cb15-hopelessly-blown.393082/#post-7199819
https://www.diyaudio.com/community/...ar-cb15-hopelessly-blown.393082/#post-7199819
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Wow, that was unfurtunate.
Looks like I'm up to something.
Signal at the IC input looks clean thru the range, even with eq set to +12dB.
But check the speaker output:
This deformation happens after about a second of feeding signal, it is also really audible on speaker.
Will try on second channel to see if it's the same.
Edit:
Second channel does the same...
It only happens when eq is more than +8db tho...
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Yep, it is also logical from the layout / thermal view. The middle two are dead, those two that are still working are at the edges of the heatsink.
I would replace them if I could get original parts, but I have a feeling that they suffer and fail same as stk ics... same time period, same problem...
Will check...
EDIT:
Nope, it's way too low.
0.35vpp vs 1.10vpp directly from the cell phone...
But I think that the unit expects the higher signal input level...
Out of the factory it was paired with Blaupunkt radio and connected with DIN connector...
Vu meter suggest that input voltage is way lower than expected, I had to set it's pots way up in order to get activity of all LEDs...
Will try to find input specs, but Blaupunkt was short with the info.
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Thats exactly what happened...
Bracket that goes over ics is bent on both corners.
I'm really leaning towards removing the amplifier section...
I would like to use it as pre-eq and use car amplifier in the trunk... I have a few...
What do you think about preamp and eq section?
Preamp seems ok to me, 6458 dip8 are now in there. Do those get bad? If they have problems I would replace with 4558.
I need to find out expected input level, but if I won't be able to solve it with adjusting gain / resistors, I can still made a preamp from single 4558 or similar.
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A classicsl problem. There came to me the following solutions:
1.- Replace with same ICs but keeping less torque to the screws.
2.- Replace with another kind of IC. Perhaps thinking in TDA2004 or the like with lots of work to adapt.
3.- Use with an external amp.
IMHO the best is the first, minimum effort. The second may need to add-on some pieces of extra PCB which over being ugly, in a car will be a sources of more problems (we say in spanish kilombos).
The third is still worse because now you have to interconnect two quasi-independent devices, again, in a car I see it complex because of extra wiring and the less space available in newer cars.
The desicion is your. Take a dialog with your pillow. It is a good counselor. Almost mine two are.
1.- Replace with same ICs but keeping less torque to the screws.
2.- Replace with another kind of IC. Perhaps thinking in TDA2004 or the like with lots of work to adapt.
3.- Use with an external amp.
IMHO the best is the first, minimum effort. The second may need to add-on some pieces of extra PCB which over being ugly, in a car will be a sources of more problems (we say in spanish kilombos).
The third is still worse because now you have to interconnect two quasi-independent devices, again, in a car I see it complex because of extra wiring and the less space available in newer cars.
The desicion is your. Take a dialog with your pillow. It is a good counselor. Almost mine two are.
1.) Worries me, because I don't know if I will source oem or chinesse ICs, also I would like a bit more power as I have 6x9 75wrms JBLs in the car.
2.) This is the option that I was thinking of alot. I know that some 4ch ics can sound really good. Once I sourced one (cant remember the model right not) from old JVC car radio and I still cannot believe to this day how well it performs, strong sound and doesn't clip easily.
3.) This seems the good option for me as I have few good amps that I could use (2 JBLs, 1 Pioneer from 1989 that sounds really nice).
I have space in car and using more wiring doesn't hold me back. I had used amplifiers in trunk in 3 cars without any problem as long as I used quality signal cables.
I will have small subwoofer in the trunk (nothing serious, just to enrich sound a bit), so wiring will be there anyway.
What is holding me back is how amplifier will affect on the eq.
But I can try it without much work and see...
Will sleep it over and see.