Gamma Radio (golf3) + aftermarket amplifier installation

Hello!

I have a question about my car radio.
After a break-in to my car 1.5 years ago that caused almost 4000 DM in damage (because the thieves couldn't remove the radio and got angry), I abandoned my youthful carelessness and bought a genuine VW radio again (I'm not sure which model, but it's from a Golf 3).
So far, it works quite well, but it's really too quiet.
Now, the question is: Is it possible to connect an external amplifier to a car radio that doesn't have a pre-amp output? Unfortunately, I'm not very knowledgeable about that. Thank you very much for your answers!


Greetings!

Hello Capernaum,

Essentially, only a level adjustment of the output signal from the power amplifier needs to be performed to match the level of the preamplifier outputs.
In my opinion, a simple voltage divider circuit should be sufficient for this (please correct me if I'm saying something nonsensical!).
The resistors in the voltage divider circuit should not be chosen to be too high in resistance, otherwise you may experience excessive interference. Unfortunately, I cannot recall the exact ratio between the preamplifier signal and the signal from the power amplifiers. Perhaps you have some brochures or technical documentation for car audio accessories that might contain information about the technical specifications. Perhaps someone in this forum knows the answer by heart.

Regards,
Alex.

Hello!

I was looking for power amplifiers recently... I just can't remember where! I found a few that you can also connect to the speaker output. Okay, for radios without a dedicated amplifier output...
Maybe this is something for you!

Best regards, Butze.

Hello!

Sorry for the late reply, I've been really busy!
'@tdi-butze: A friend of mine also told me that there are apparently power amplifiers that can be directly connected to the speaker output... That would of course be the best (and easiest) solution...'
Unfortunately, that won't work for me, as I still have an amplifier installed (and wired) under the passenger seat. I was actually planning to use that one.

I was thinking more along the lines of what Donalexo mentioned... something like adding a circuit in between.
@donalexo: Do you have any idea where I could find such a circuit? Or, you already have a better idea of what it should look like and how it should work! It should be as minimalist and inexpensive as possible (in the Ulf style).
I could probably build one myself, although I'm not really an electronics expert, but I can solder reasonably well. Sure, I'd be happy to help.

Thank you very much for the answers so far!


Sure, here's the translation:

'cu' is a Spanish abbreviation for 'cuánto,' which means 'how much.' It's often used in online communication and text messages to ask for a price or quantity.

Hi,

What you're looking for is a level adapter.

Level adapters at Conrad

Please provide the text you would like me to translate from German to English.
Level adapter HLA-5N.
Article No.: 377515 - 13

Price: 10.95 EUR.
Piece.

For connecting amplifiers/equalizers to car radios without a built-in amplifier output, using the speaker connections. Technical specifications: 4 x insulated spade connectors, 2 x RCA output sockets, frequency response 40 Hz - 32 kHz, output impedance 10 kΩ, maximum input power 2 x 20 W, dimensions (W x H x D): 65 x 30 x 30 mm.
Please provide the text you would like me to translate from German to English.

Sure, here's the translation:

"Addendum:"
By using a voltage divider from LA+ to LA- (in the kOhm range) and an electrolytic capacitor in the outgoing signal line, you achieve the same effect, but without galvanic isolation. Under no circumstances should any of the LA connections be connected to the vehicle's ground, otherwise the radio amplifiers will quickly be damaged!

Hello!

@Bertil: WOW, thank you so much! This is exactly what I was looking for! I already checked at Conrad, but I didn't find anything because I didn't know what this part is called .
Price-wise, it's perfectly reasonable, so I'll order the adapter...


Thanks again!


Best regards,

@ bertil:
Please provide the text you would like me to translate from German to English.
Level adapter HLA-5N.
Article No.: 377515 - 13

Price: €10.95
Piece.

To connect amplifiers/equalizers to car radios that do not have a dedicated amplifier output, using the speaker connections. Technical specifications: 4 x insulated terminal blocks for input · 2 x RCA connectors for output · Frequency response: 40 Hz - 32 kHz · Output impedance: 10 kΩ · Maximum input power: 2 x 20 W · Dimensions (W x H x D): 65 x 30 x 30 mm.
Please provide the text you would like me to translate from German to English.
My question: According to the product description: 2x20W, what is the maximum RMS wattage the amplifier should have? I want to install the Magnat Cobra 200, a 2-channel amplifier.

There's also something from www.dietz.biz.
Item No. 901, €26.99.

The voltage divider allows the connection of an amplifier with...
Connects to any high-power car radio with a maximum power output of 35 watts.
This ensures that the full functionality of the crossfade control is maintained. Through.
While setting up the galvanic system, a preliminary disturbance occurs.
taken. The initial voltage is adjustable from 0 to allow for optimal adaptation.
Adjustable to 2000 mV.
Article Type
901 - 2 x 35 Watt - Cinch.

Voltage divider / 2*30 W -> 0-2000 mV. The voltage divider allows...
connecting an amplifier with RCA inputs to any high-power device.
Device with a maximum power consumption of 35 watts. The initial voltage is adjustable.

and this part from Conrad:
Conrad High-Low-Level Converter HL-406.
Article No. 379106 - 13, Price: 12.95 EUR.

Convert the speaker connections of your car stereo into a...
Stereo preamplifier output. This allows you to easily...
Connect the additional amplifier. Adjustable level, also ideal for...
In-car radio systems! Technical specifications: High-power input up to 2 x 40 W.
sin./200 W max., Output with RCA connectors, Frequency response: 20 Hz - 35 kHz.
kHz, output impedance 10 kΩ, dimensions 90 x 28 x 65 mm.

Did those also work? What's the difference between them and a voltage divider?

Lars.

Hello,

There is no significant difference between these adapters; they all operate on the principle described by Bertil. The power rating (in watts) refers to the output power of the radio and has nothing to do with the connected amplifier or the amplifier's power output.

Regards,
Private.

PrivatBereich wrote:

Hello, There is no significant difference between these adapters; they all operate on the principle described by Bertil. The power rating (in watts) refers to the output power of the radio and has nothing to do with the connected amplifier or the amplifier's power output. Regards, Private

That's exactly how it is.

The power of the amplifier you connect to it doesn't matter.
"This adapter is available from many companies, and they all essentially perform the same function. What's important is the galvanic isolation and the absence of ground connection at the input." If a pole (terminal) of the (bridge) amplifier in a car radio is connected to ground, it can quickly lead to the amplifier overheating and failing.

I can only speak about a BMW radio, but it should be the same model.

Okay, turn up the radio. Usually, you should be able to identify a small 'amplifier' inside the radio. You'll see some transistors there. You can solder RCA cables to the wires that lead to the internal amplifiers of the radio.

alex-on-line.de wrote:

....Turn up the radio, usually, you should be able to recognize a small "amplifier" inside the radio. So, a few transistors. ...

... Bad news, the Gamma IV no longer has a transistor output stage...

However, the issue of signal separation remains, but in this case, you're fixing the tone controls instead of the power amplifier.

The adapter is the better solution.

Hello,

Quote:

Now, the question is: Is it possible to connect an external amplifier to a car radio that doesn't have a pre-amp output?

Okay, I once owned a Gamma from 1991. It had a preamplifier output.
It wasn't a Chinch connector, but it was a similar type of connector, like the others. Adapters from [something] to RCA (or "phono") are available.
Do the newer versions no longer have that issue? Doubts.

Best regards,
Albrecht.

Albrecht wrote:

...so, I once had a Gamma from 1991. It had a preamplifier output. It wasn't a Chinch connector, but it was a similar type of connector, like the others. Adapters from [something] to RCA (or "phono") are available. Do the newer versions no longer have that issue? Doubts.

Hi Albrecht,

Let me address your doubts:

The Gamma III (for the Golf 2) had a pre-amplifier output.
The Gamma IV (for Golf 3) did not have a pre-amplifier output, but it did have a changer control.
The Gamma V (for Golf 4) may or may not have a pre-out, depending on the specific equipment configuration.

My information regarding Gamma III and Gamma IV is based on insider knowledge. The radios were manufactured 5 meters away from my old workstation.
I hope you believe me – otherwise, I'll have to dig out the service manuals tomorrow.

Hmmm,
That raises some questions...

My Golf 3 has this Nokia sound system installed, which came as standard equipment in the 'GTI 20 Jahre' special edition model. This was originally driven by a Gamma radio, using the radio's preamplifier outputs, which, according to Bertil, supposedly do not exist.
Or does the special edition model have a particularly specific type of radio installed? Perhaps even a Gamma V?
I would like to check what's written on the device, but unfortunately, it's located 430 km away in a closet. I can only remember that something with 'DSP version' was written on it (I immediately removed that user-unfriendly thing after purchasing the vehicle ).

Best regards, Andy.

Andy wrote:

Or does the special model have a very specific radio installed?

That's exactly what it looks like! The candidate receives 100 points .

Quote:

Maybe even a Gamma V?

Absolutely not, the Gamma V requires different connectors. We need to bring those 100 points back .

Quote:

...I can only remember that something with "DSP version" was written on it...

That's the version for sound systems – meaning with external amplifiers.

Hello!

I have a head unit with DSP and gamma, but since I want to listen to MP3 CDs, I want to install a different radio. It should have a maximum output of 4x50 watts. If I install it now with an adapter (which seems to be the only option), will the higher power actually make a difference? Or will the adapter negate it? I saw an adapter somewhere for 69.90 euros, but I can't find the link anymore, and 99 euros is too expensive for me. Maybe one of you knows where I can find these things cheaper.


Thank you in advance, Ziby.