Jlaa

Hi all,

So my C2 has an aesthetically lovely CR-210 in it --- it controls a CD changer and has a pristine tape deck. The car also has 4-tape-holder in the center console --- indeed quite quaint. There's just one problem. The sound quality is terrible. Atrocious. Speakers, head unit, the whole lot of it is terrible (non hi-fi car).

That said, I thoroughly enjoy the aesthetics of the CR-210 --- the straight lines, the non-bling-display, and the inscrutable user-interface with impossibly cryptic controls. I find this to be part of the charm of the car --- there is a sense of occasion driving the car on a weekend drive --- the 993 smell, the archaic dashboard layout, the metallic rasp of the engine ---- and yes, putting in cassettes and listening to them.

So ideally I would like to have my 993 do the following with OE head unit looks and much improved sound quality (I will be upgrading speakers as well):

• bluetooth streaming audio
• control CDC3 changer in frunk (would be a travesty to remove this!)
• play cassettes (sense of occasion!)

My first thought was to contact Becker to graft on an additional line-in jack that would interrupt the FM tuner for the CR-210, as in the below photo:



I would ensure that the mini plug goes out the back, add some kind of switch to enable/disable the mini plug, and use an aftermarket bluetooth device that would jack into the mini plug and bury all this in the dashboard. However, in speaking with Rod Birch @ Car Audio Innovations, has has convinced me that the CR-210 sound quality is only slightly better than listening to music through a hand crank telephone while standing under the elevated subway lines in a prohibition-era Chicago bar.

And so Rod (a great guy!!!) has convinced me that using a CR-220 is tolerable, albeit in a begrudging way [tongue in cheek], but at least will bring me into marginal reasonableness as far as sound quality goes. Actually he's promoting the CDR-220 (CDs!) but I just can't bring myself to eliminate the ability to play cassettes in my car. The 993 is a week toy that is all about the celebration of a collection of anachronistic neanderthal technologies that somehow combine to delight one's senses on a Sunday drive.

So next my thought was --- what if I do the following with the CR-220 -

• bluetooth streaming audio --- via direct-connect FM modulation -
  http://www.amazon.com/iSimple-ISFM21-Universal-Bluetooth-Transmitter/dp/B005XUEMK6
  http://www.amazon.com/iSimple-ISFM21-Universal-Bluetooth-Transmitter/dp/B005XUEMK6
• control CDC3 changer in frunk (would be a travesty to remove this!)
• play cassettes

There are those that question the wisdom of running your phone via bluetooth via FM modulation. I'm no audiophile by any stretch of the imagination (I just want the 993 to sound as good as, say, my Volvo V70R. Or even my Toyota Prius) .... and I wonder about the FM modulation. I will make a note that :

• This is direct FM modulation --- not the wireless transmitters of yore that plugged into the cigarette lighter socket.
• The CR-220 manual shows a frequency response of the CD section to be 20 HZ - 20KHZ. The FM specs are 50 HZ - 15 KHZ. Will I even really hear a difference considering that I will be upgrading the speakers to nicer speakers in the doors, but no subwoofer (ie.... keep the stock look). Is this noise floor for direct FM modulation that much worse than CDs?
• This is a car environment. Heck, it is a 993 environment. With Fister Stage IIs. With motorsound airbox. Am I REALLY going to hear any difference?

Part of me says "this technique will be good enough."

Another part of me wants to buy a shell of a CR-220 and try to find the preamp stage on the internal circuit board and with a bit of luck, solder on a connector to create another line-in for the CR-220 --- similar to this link below as was done on a CR-210 by theRossinator : https://rennlist.com/forums/993-foru...ux-in-diy.html

Opinions and Observations highly welcome (just please don't tell me to get rid of tapes!!!

therossinator

Have you looked at my aux in DIY? It's linked in my sig. It wires directly into your tape inputs. It would do everything you want and you could keep your 210 or go to a 220. You would still be able to play cassettes and you could hook up the aux in to a bluetooth receiver. It's actually quite simple, only three solder points.

Also, the 220 series is very hard to view without a $100 mod from Becker NA.

Also, you may find this thread useful.
https://rennlist.com/forums/993-foru...tegration.html

Jlaa

Thanks theRossinator, yes I have studied your DIY write up extensively! Thank you. I believe, though, that your write up applies only to the cr-210 correct? It does not apply to the cr-220?

What i wanted to do is to change out my cr-210 and move to the cr-220 because the 220 is supposed to have much better sonic qualities and have a volume **** AND add an aux-in to the headunit without losing cd changer control capability.

If anyone has looked into this, I would love to hear their experiences. In the meantime, I have purchased two used cr-220s to experiment with..... I will post my findings if they are at all not indicative of spectacular failure....

therossinator

My DIY will theoretically work with any cassette radio. The 220, being the closest brother to the 210 should be pretty straightforward with my DIY.

The 220 will cause you to lose the CD changer capability if you want a direct aux in. It uses the same port as the CD changer (there is only one) but what makes the 220 different from the 210 is that the 210 couldn't recognize an aux in using this port, it could only recognize a CD changer. The 220 is capable of recognizing either, not both.

As I mentioned above, I have a CDR-220 and I just could not read the display.
With a quick bit of research just now I found this:
https://rennlist.com/forums/928-foru...at-a-time.html

Jlaa

So it looks like I will be disassembling my 220s to see, hopefully, that the family resemblance is clear and that I can find R L and G markings.

Thanks, and this is exactly why I would like to add another aux in to the 220. So that I can drive the cd changer AND have an bluetooth aux-in.

Thanks, yes, I saw that really clever thread on the 928 forum as well. Also, Becker autosound is still offering non angle faceplates as of 6-2014 ... $200 for a new one and $100 to modify an existing one. This is not exactly a value oriented exercise ... But that's not really the goal ... Up until a certain absurd point I guess ....

Johnny_law

I'm on the road right now but I did something that meets your requirements except the sound quality. My criteria was not messing with my stock car so my solution is plug and play with the exception of running power. I will elaborate later when I get a chance to be at my PC. Johnny

Jlaa

Doh! I just realized something. One possible solution is staring me in the face. The CD changer uses RCA out! So I could hook up an aftermarket Bluetooth device via those RCAs into the HU. I could mount the aftermarket Bluetooth device next to the changer.

Then I could figure out a way to switch the RCAs from within the cockpit between the changer and the Bluetooth device ..... And whenever I wanted to use the Bluetooth device, I would load a CD with 1 track that is pure silence for 74 minutes.....

So now I would just need to figure out how to do the switch .... If I was particularly ambitious maybe I could resilkscreen a rear window wiper switch with a Bluetooth icon for that .... Don't know if that switch is quadruple pole single throw or what....

therossinator

You'd need a QPDT switch. I looked down that road. Good luck finding one of those. Apparently alibaba has some but I've never ordered from them and I don't wait a month for it to get here. You could do a pyramid with two DPDT relays controled by a single SPDT relay, but it just seemed to get messy to me, additionally switches like that aren't well shielded from interference because they aren't designed for audio applications.
The tape solution makes it elegant because its so simple, plus tapes with no ribbon in them can play forever with no added noise.

M. Schneider

OP -
Is your 993 equipped with the #490 HiFi speaker option? External amplifier module under the passenger seat, Speaker enclosure's mounted to the doors, etc.

The AUX in scheme from Therossinator is a solid piece of the HiFi enhancement puzzle.

Sonically speaking the CDR-220 has OK sonic's, its not great, however for the 964/993s there's the AUX. For decades a huge functionality draw if nothing else. The 220 is every bit a vintage radio as the Becker/Porsche CR-210, CDR-210 or the Alpine/Porsche CR-1. The same or similarly positioned OP amps.

Another piece of the puzzle is an aftermarket DSP module - these work well with any of our OEM 993 radio's. There's I/Os for a Bluetooth module, simple AUX, etc or opt for a SP-DIF module.

There are many mouse traps out there. A starting point: CD-210 w/AUX mod, frunk mounted CD-changer, aftermarket DSP for an active 2way set-up, aftermarket amplifier, correct speaker replacements, 1/3rd octave tune, DONE. (Way over simplified, but you get the idea.)

Jlaa

Hi M. Schneider,

I do not have the HiFi option - no amplifier under the seat, no door panels with 3 drivers.....

therossinator

I'm not sure what the importance of being hi-fi is. If you want to patch an aux-in between the head unit and the amp you will need to take care of the rear channels somehow. You need to patch in somewhere before the rear channels are decoded. From there you've got three options: radio, tape, and cd changer.

If you want to go through the radio, send it to Becker and shell out $100. It works and you don't have to do it yourself, however, the display still shows the radio stuff and at low line in volumes the radio station can be heard. I do not know where they patch in or I would add it to my DIY.

If you want to go through the tape you can follow the DIY, its quite cheap and you can still play tapes. The audio quality is low with a lot of clipping when playing from my phone, however, when I use a bluetooth adapter the audio is what would be expected. My bluetooth adapter receives interference from the engine and you can hear a whine that is directly proportional to the RMP when you are playing a low line in signal. When a song is playing the whine cannot be heard. This would likely be the same with all bluetooth receivers designed for home use connected to any of the mentioned methods to patch in an aux-in.
Also don't use tapes and the bluetooth is always connected, so selecting the tape source is now selecting the aux-in. I like how my aux-in has it's own separate source, not piggybacking off an input that I regularly use.

Patching into the CD changer seems easy and it would be a great idea. It seems like an obvious solution to purchase a relay designed to switch between 2 separate 2 channel audio sources and could be triggered by a button in the cockpit. But oddly enough, none exist, despite a ton of potential uses. Perhaps the relay coils cause interference. You could make one, but none are designed for audio/shielded and would receive a lot of electrical interference as well.

Obviously if you have the amp you could patch into the lines between that and the head unit, and copy the front channels to the rears as well.

Beyond those four options I don't think theres another way to add an aux and keep all the functionality you desire.

Jlaa

It seems that if one converts the RCAs to 1/8" audio headphone jacks, the selection of A/B audio switches is much larger. This might be because 1/8" audio jacks use a common ground for both channels?

I've been thinking about perhaps using this switch in the ashtray: http://www.markertek.com/Audio-Equip...B-SWITCH.xhtml
It is 2 1/4"L x 3 1/2"W x 1"H.

It might work ---

therossinator

OOh! I like that! you could disassemble it and relocate the switch. I've never seen one of those before. It would also be great for side by side audio quality comparisons.

This looks more suited for the application:

Johnny_law

Now your thinking. What I did is I built a box with a bluetooth dongle and auto RCA A/B switch and a relay. The system works just like it does out of the factory. When I begin streaming Audio the Auto RCA switch automatically switches input to source B. I hear my streaming audio. When stopped about 10 seconds later the CD begins playing. I only have a project box that I decorated with Porsche Emblem sitting in my boot. I could unplug it in 1min and you wouldn't know I had it and still have a fully functional stereo with Tape and CD Changer.

No other input is required. I haven't played with it enough to see how functional or not it is especially at very low output on the bluetooth or long pauses but at first tryouts it seems to work well.

Once again I'm on my phone and not willing to type too much. Will try to lead you to the equipment I used and tell you lessons learned when I can get to my PC.

Johnny

therossinator

Looking forward to hear what you used to auto switch to your aux in.