Factory premium amp PN 65 121 375 983 info please

[parkerbink]

Finished my radio replacement yesterday, didn't know I had an amp, it's this one on the driver side trunk wall:

65 121 375 983
[IMG]s-l1600 by phled1, on Flickr[/IMG]

Anyone know the specs? and also since the output is speaker level, is it getting the HU's power plus the amps?

[bobdavisnpf]

This amp replaces the HU speaker-line power with its own. It takes speaker-level input and puts out 25 wpc x4. At 0.1% THD its output is 10-12 wpc x4. Not very much oomph, and like any small amp is prone to clipping at speaker-damaging levels when driven too hard. The stock 8-ohm speaker coils & crossovers may be tanky enough to withstand the clipping but if you upgrade to 4-ohm or even 3-ohm speakers I'd say all bets are off.

Looks just like the amp I pulled from my e30 when I replaced the original cassette deck with a CD43. The CD43 is "high power" using the same amp chip onboard as is used in this amp, so I basically did not upgrade the main amp in my build. I added a couple Kenwood powered bass boxes, upped their gain a little, and lowered bass at the HU. That saves the HU amp more for mids & highs which take far less power and 10 wpc is plenty.

[parkerbink]

Thanks

[george graves]

Looks just like the amp I pulled from my e30 when I replaced the original cassette deck with a CD43. The CD43 is "high power" using the same amp chip onboard as is used in this amp

Really? Wow - same IC?

[bobdavisnpf]

Really? Wow - same IC?

No! I was wrong.

The amp in question - Blaupunkt BMW pn 7 607 395 140

I'm gonna go with 8 wpc at 1% THD, with clipping at 9 wpc and 10% THD.

This amp has 8 ST2003 amp chips. The 1-channel ST2003 can't do 0.1% THD, but at 0.11% it's good for 4wpc to 4 ohms. At 1% THD it's 5 wpc to 4 ohms. I guess each channel has 2 amp chips, with a crossover separating lower and upper frequency ranges, then post-processing to gang the 2 amplified signals. This would net a theoretical max of 10wpc into 4 ohms at 1% THD, but if the bass signal is only gonna get 5 wpc then your effective max is probably more like 8 wpc.

Link to TDA2003 spec pdf:

http://www.st.com/content/ccc/resource/technical/document/datasheet/43/57/41/42/e4/e8/43/42/CD00000123.pdf/files/CD00000123.pdf/jcr:content/translations/en.CD00000123.pdf

It does have decent thermal management, imo. Those 8 little phillips-head screws between the fins are the heat-sink mounting screws for the amp chips.

The CD43 uses 2x TDA7376B amp chips. The 2-channel TDA7376B can do 0.03% THD at 10 wpc into 4 ohms; it's still at just 0.08% THD at 15 wpc into 4 ohms. (Or, it hits 1% THD at 11 wpc, depending on if you read the summary chart or the THD chart)

The CD43 packs its 2 amp chips in on one side of its enclosure, with a narrow air channel for heat dissipation. Still, I've got the impression now that the CD43 alone is an upgrade to the E30 outboard amp -- and that almost any modern head unit on its own will also be a significant improvement over the E30 outboard amp.

Link to TDA7376B spec pdf:

http://www.st.com/content/ccc/resource/technical/document/datasheet/45/b7/f0/65/c3/86/46/8a/CD00000161.pdf/files/CD00000161.pdf/jcr:content/translations/en.CD00000161.pdf