KRC-2001 stuff

[negusm]

I have been playing with the KRC-2001 radio in my car.

I picked up some front and rear Kenwood speakers and hooked it up. The fronts WAY overpowered the rear. The newer rear speakers simply are rated too high I think and need some oomph to make them louder. Even if the backs are faded to the max, the fronts are still too loud. Both front and rear speakers have a response of 92db.

So I figured I'd do what asc did and tossed on one of those small Alpine Amps (3505). The 3505 is a tiny little guy and 18w/channel. The original amp was a 3516 and about the same size and also 18w/channel (per the box or 16w/channel if you go by Alpine's web site). I have a new, in the box 3516 also.

The 3505 or 3516 are about the only amps Alpine has made that will fit in the space the old Ford stock premium sound amp went.

The Kenwood Brochure I have says the radio is 10w/channel so I figured the 3505 at 18w/channel should be an improvement.

Got it all hooked up, used the preout from the Kenwood to the amp and got only the right speaker. SO I pulled the new 3516 out and hooked it up. Same deal.

I got out my KRC-2001 repair manual (glad I have it) and the pinouts on the preamp are NOT the same as what Alpine used. So, I happened to have an AT computer keyboard extension cord which will NEVER be used again as I have all new keyboards. The plug on the extension cord is EXACTLY the same as the preout plugs for both the amp and the radio (cool, huh?).

So I raped that extension cord and swapped the speaker inputs to the right pins.

Hooked it up and got left and right but not any louder. So I looked at the radio box and it says 15w/channel and in the manual it says 20w/channel max. Sooooo....its definitely no improvement if I'm hooking up an 18 w/channel amp in place of a 20w/channel radio.

I happen to have an alpine amp I got from Hank. I don't know where he got it....its not an amp that anyone has said they had in their car. It is a 3522 Alpine. It is twice the size so it won't fit under the dash pad....but its small enough it will fit between the console and the heater box. It is 30-40w/channel but uses RCA line inputs so I have to rape that keyboard connector again and wire in some RCA plugs.

BTW, the Kenwood speaker outputs on this radio are kind of funky too. The fronts and rears of each side share a ground. So the Front and Back Left speakers share a ground and the Front and Back Right speakers share a different ground. You are not to tie the grounds together as per a warning in the manual. Looking at the schematic of those grounds, I would not tie them together either.

The implications of this is that if you want to hook up an amp using the wires that would normally go to the rear speakers (not the preout), the amp needs to accept separate gounds. An amp like the 3505 does not. It has a left and right "+" wire and a single "-" (signal ground) wire input.

For the schematic on the radio's preout, there is a circuit to resolve this problem and output a single ground for both left and right.

So anyways...that's my adventure in KRC-2001 land.

-Mike

[Sandy]

> Which McLaren and what year came with KRC-2001 as standard installed equipment ? <

[negusm]

> Which McLaren and what year came with KRC-2001 as standard installed equipment ? <

85 ascMcLaren Coupes

Some 85 verts may have gotten it from a few people that have spoken up about them in the past.

One final note that I meant to ask but forgot....if anyone had a car with the KRC-2001, was there an amp anywhere in the car with it?

-Mike

[Tom S.]

> Which McLaren and what year came with KRC-2001 as standard installed equipment ? <

85 ascMcLaren Coupes

Some 85 verts may have gotten it from a few people that have spoken up about them in the past.

One final note that I meant to ask but forgot....if anyone had a car with the KRC-2001, was there an amp anywhere in the car with it?

-Mike

Mine didn't have one. The Pre-amp cable was just hanging behind the radio. I did put some sort of amp in the car eventually but the radio still wasn't all that good.

[negusm]

FINISHED! DONE! FINITO! But not exactly the way I expected. Here's the story.

I hooked up that amp I got from Hank for $45 and it powered up once and then blew its fuse. I removed all connections and it blew 2 more fuses. I disassembled it and there was some "oil" in it....I figure the amp is TOAST. Oh well. So much for trying to boost the rears to match the loudness of the fronts.

So I picked up this device on ebay (PAC-OEM2) and its a pretty cool device IF you are installing an amplifier (crap). It will take the signal from your radio, convert it to RCA output or low level speaker outputs for easy connection to your amp. You can adjust the levels of each speaker separately. It won't adjust high level speaker signals directly from the head unit. Since the amp is shot, I needed to get another amp or the idea of using the PAC is a bust.

I guess it pays to read the manual first.

SO....back to the drawing board...with a little more research I found that there are ways to "quiet" speakers namely using:

One Resistor in series and one in parallel with the speaker. These resistors can be calculated to drop a certain db level and retain the impedance of the speaker (4 ohms). But I don't have a sound meter to determine the db I need and you need resistors that can handle the wattage of the amp, etc and it seems Radio Shack is pretty thin these days on basic electronics parts.

SO...Enter the "L Pad". This is a variable version! Dial in the db drop you need! I could not find a 4 ohm L Pad (It needs to be 4 ohm to match the 4 ohm speakers). It seems ALL that are sold out there are 8 ohms...and 4 ohm versions can be like $60. I finally read (thank you google) that you can use two 8 ohm L pads in parallel to get a 4 ohm L pad (duh!) and it doubles their power handling! I drew the schematics and did a few calcs just to be sure.

So, I purchased 2 of these stereo 8ohm 15w LPads ($4.25 each, but they seem to have jumped $1):
http://www.partsexpress.com/pe/showdetl ... er=260-251

Normally, one of these units would be used for speakers (left and right). Each appears to be 2 MONO 8 ohm LPads joined together to make up a single STEREO LPad.

I connect the two MONO LPads in each stereo unit together in parallel. Pin1 to pin1, pin2 to pin2, pin3 to pin3. I was left now with only TWO Mono 4 OHM LPads...I put a variable resister set at 4 ohms (to mimic the speaker impedance) accross the speaker terminals of the LPAD and measured the resistance as seem by the head unit. 4 ohms all the way, no matter what the LPad was set at. So now I had two 4 Ohm LPads rated at 30W each. PERFECT as my head unit is 20W MAX.

I set the fade to zero on the radio, hooked up the LPads to the speakers and dialed them both in (while sitting on the transmission hump) until the sound was perfectly balance, front to back and left to right.

So in short for $8.50 (plus $7 shipping ouch) and a bit of brain power and soldering, I fixed my problem and the fader on the radio will actually DO something.

I'm sure I'm just talking to myself at this point.

The KRC-2001 sounds AWESOME. Its not huge on base, but the new Kenwood 6.5" speakers do put out a decent thump and are too small to be expected to work miracles.

I can't understand why anyone would swap out a radio like this...it pulls in channels my 2002 4Runner's radio can't and sounds better too!

I haven't tried the tape player. I'm thinking to just ignore it as I don't own any real tapes.

-Mike

[negusm]

Oh yeah, I checked the values of the LPADs after dialing them in. It seems after calculating backwards, I needed to drop my front speakers 6.9db. (resister values were 2.2ohm for the series resistor and 3.6 ohm for the parallel resistor)

[Kyle]

My head hurts, seriously though, sounds cool, i need to rewire my stereo from the head unit back in my car, the last yahoo took all the wires out, at least I cant find them

[negusm]

My head hurts, seriously though, sounds cool, i need to rewire my stereo from the head unit back in my car, the last yahoo took all the wires out, at least I cant find them

Make sure you look under the padding....my wires were hidden under there.

Bottom line, if your front speakers overpower your rears. LPADs are the way to go for a simple, cheap solution.

Now I just need to take some velcro and stick the LPAD to something up and under the dash.

-Mike

[Kyle]

yeah, I had the carpet out for a while, I can see where the wires used to be and where they were cut. Good to know about the resistors as the fronts in my old capri overpowered the rears, I think it maybe a fox thing

[negusm]

yeah, I had the carpet out for a while, I can see where the wires used to be and where they were cut. Good to know about the resistors as the fronts in my old capri overpowered the rears, I think it maybe a fox thing

I never had rear speakers in this car. EVER.

When I got the car, the radio and rear speakers were yanked. My dad went to the JY and got a Premium dial radio with NO cassette. He hooked it up to the front speakers (4" kickers") and the two front door speakers (6" round)....those were REALLY hacked in there. There were TWEETERS "installed" in the top of the door too. A previous owner simply butchered the doors.

SO when I got the car, the door panels were ruined, the doors were ruined and the dash was "trimmed" to fit the oversized 4" kickers under the dash pad.

UNBELIEVABLY, he didn't hack at the rear speaker openings in the hatch to install some oh-so-common 6x9 speakers. With a new dash, new doors, new door panels and by refurbishing the original rear panels, I think I have a near factory correct sound system! MOST cars have lost their original radio and rear speakers and speaker covers.

Probably way back when, the original speakers were more balanced than what I have. The ones I got for up front, were unbelievably loud compared to the rears. If I didn't stick with Kenwood, I should have tried looking around for something in the 85db range for the fronts. Then I could have used my fader to correct things instead of needing the LPads.

Now I gotta ebay that PAC-OEM2 thingy, a set of rear 6.5" Kenwood speakers that didn't fit the speaker covers, a small alpine amp and recoupe the $50 in failed equipment.

After I balanced everything, I sat in my car for 15 minutes just enjoying the great sound.

My Probe GT with the Factory Premium Sound option (came with subwoofer) was the only car I've had that sounded better. The Ford guy who went on a test drive with me when I picked it up had gotten a 94 Probe for his wife and he was like, "DAYUM! I didn't realize that sub made so much difference!".

If that car wasn't so blasted under powered (it had 165hp and it desperately needed 200hp...which wouldn't happen because it would have been a threat to the Mustang), I wouldn't have sold it. I would have stored it away. It was fully optioned except it didn't have leather or floor matts. I'm POSITIVE it was the only fully loaded 1996 Boysenberry Blue Probe GT ordered without floor Matts or leather. I wanted the dealer to throw them in but he wouldn't budge. I found out what a great deal I got on the car and before it arrived, I had the dealer order them for me separate which I paid for.

I like to ramble...

-Mike