Denon PRA-1200 PRe Amplifier low sound and crackling...

codycatalist

I was gifted a Denon PRA-1200 Pre amp yesterday with a Kenwood KM-208. I would love to have these take over for my Yammy, however whenever I use the Denon as the Pre the sound would be VERY low and when it comes through it sounds like straight distorted noise.

I can make out the music but it seems like it is constantly coming and going (I know hard to describe). Opened it up yesterday but I don't see any signs of damage on the internals, what are the areas I can check (with multi meter) that might be the cause of this issue?

I can plug a variable volume device in the kenwood and the sound is fine so I am sure it is the Denon. I can always take it to a repair shop to diagnose and repair but I figured if I can diagnose it that will save me $50 some odd dollars.

JPete

Spray down the pots with some deoxit and get 'em all cleaned up. inputs too.

Did you try both pre-outs and multiple inputs with the same results? I have a Carver C-1 that I haven't used in quite a few years. Plugged it in the other day and sounded like you're description of the Denon. DeOxit to the rescue.

codycatalist

Detoxit was on my mind. Haven't had a chance to do much beyond opening it up really. Did try both pre outs and all inputs but same results. I'll try and clean it today and see what happens.

boston1450

^^^^ +1 I had that same preamp & had issues with it also. I did as stated & it came out of it. Nice preamp

skrol

Check the PCB for bad solder joints. I had several in one of my Denon receivers also in my Parasound.

codycatalist

Thinking it is the pots. Cleaned it with 91% isopropyl alcohol (didn't have time to buy deoxit online) and it cleared up the issue for a couple minutes. Started coming back then only playing from left channel, then only from right channel.

Everytime I cleaned it the issue cleared for a small time frame. Will just have to be patient and get deoxit.

JPete

Did you sweep all of the pots after you cleaned? You can snag some deoxit at Radio Shack if there is one close by you. I'm sure some other places carry it too, but I usually just grab it at the Shack.

tonyb

Thought all the Radio shacks are gone now. Amazon.....and have a drone drop it in your lap as your outside pulling weeds.

codycatalist

Yeah on my coast all the stand alone stores are gone. They do have some sprint/radio shack combos but not sure if they will have deoxit. Worth checking though.

codycatalist

Which deoxit should I get? D5?

JPete

I think D5 is just the regular one, right? Nothing fancy. That's all I've ever used and works great for me.

Radio Shack/Sprint combos carry it. At least the ones in GA and TN do.

codycatalist

Yeah I'm going to give them a call here on my lunch break.

Question though, when it did work I had to turn the dial up to around 1 o clock to get the power to really come through. Is that normal with a sep pre amp and amplifier. I always figured to not turn it past 12 o clock, however this amp is supposed to be 150 watts and is quite han my 100 watt Yammy.

JPete

That sounds WAY too high to me, but I've never owned one of those Denons or Kenwoods(I've had some Kenwood amps but not that model). Not sure if impedance of either one of those in coming into play, but I doubt it should be that high to get sound. I can't get any of my preamps in any system to 1'oclock before my ears start to bleed.

Any relays inside that preamp? Does it just kick on all of a sudden when you're cranking it up or is it just really quiet until that position on the potentiometer?

Clean it again with the DeOxit, see if it helps, and write back. Good luck man.

codycatalist

Yeah it's once I get it to about 11 it starts getting louder 12 o clock roughly matches my Yammy.

Will clean and report back later today. Thanks guys.

codycatalist

Hopefully the cleaning will resolve having to turn the pre amp up so much. The Kenwood has gauges for the wattage they are putting out, even at 1 o clock it isn't hitting the 150w RMS indicated on the front.

The US version of the amp is 8-16 ohm but the EU of the same model has a switch for 6 ohm speakers. I know the SDA 2Bs are 6 ohm, I honestly don't believe I will have an issue running them. If I fry the amp oh well I have back ups.

heiney9

That amp is borderline junk, the wattage gauges are peak averages and in no way indicate how much the actual wattage is.

IMO, you're better off not getting it working......... I know it was free, etc, etc. but you've already spent more time than it's worth to get it running.

I won't even come close to doing the SDA's "justice" if you are serious about the quality of sound.

Just my .02c

H9

codycatalist

I'm about as serious as my budget allows. I know someone in Tucson that has an Adcom GF5500 for $125 so I am trying to set that up.

For the time being I figured the Kenwood would be better than my Yamaha AV34, I really won't know until I get the pre amp fully working however.

Amp works fine, it's the Denon that is the issue.

codycatalist

Worst case use the Yammy as the power and have the Denon process the sound.

Either way still have to get it to push a clean signal.

dkfreebird

Just remember the gfa 5500 is not common ground.

codycatalist

I apologize @dkfreebird it is an Adcom GFA-5400 which I believe someone on this forum stated WAS common ground.

dkfreebird

Yes,I had the 5400 and ran it with my 2b's but when I got the 5500 I realized it wasn't common ground.

codycatalist

Yeah that's what I read online. How do you feel the 5400 did with your 2b's? Enough power to bring out the dynamics?

dkfreebird

I thought so at first until I got the 555. I stayed with that one for quite a while until I got the Parasound 1200ii.I think if you can find a 555 you will be happy for a long time until more funds become available.I'm running a McCormack Dna 0.5 deluxe now and couldn't be happier.

codycatalist

I need to be patient....goosefraba!

heiney9

The 5400 is 10 times that Kenwood is an then some. $125 is a decent price and it should serve you while you save up for a future piece.

H9

dkfreebird

Lol,patience is tough but it pays off in the end and saves you a bunch of money.I just upgraded as I found good deals and tried not to get attached to any equipment except for my Sda's.I don't have the 2b's anymore but replaced them with their bigger siblings.

codycatalist

Tell me about it. I got the itch now. This year alone I got my first set of vintage polks (Monitor 5s for $30) and since I have acquired RTA11TLs fixed them up for around $120 and then got my 2bs for $100. My Yammy cost me $21 so I have REALLY been lucky this year with sound. Just have to stop expecting these deals to keep coming and buy some time.

skrol

It seems to go in waves like that. A few years ago I was snagging stuff right and left until I got a basement full of speakers and amps and stuff that I fixed with the intent to sell. Problem is I never got around to selling it and it still sits there annoying my wife.

Lately I haven't seen anything worth snagging in the local CL or GW.

By the way, Deoxit makes a special fader cleaner/lube for pots (Deoxit Fader F5).

codycatalist

Gave the volume and balance pot a good cleaning tonight. Too late to test it out butt I'll be ready to see after work tomorrow.

@skrol Waves...I agree with that. I have a local Savers I go to that almost ALWAYS has some early 80s late 70s integrated amps. Problem is I need more power than almost all but the most sought after "house hold" brand vintage gear gets, I end up passing. Arizona has a good selection of gear at second hand/thrift stores.

codycatalist

Even though I never doubted you @heiney9 I still was curious to see how the sound was with my new combo. Drum roll please......and it sounds....Meh.

A little brighter than my yammy but the bass doesn't feel as detailed, separation and sound stage were muted. Will probably pass the Kenwood onto someone who could use it (I could use the Karma) or run the pre amp from my AVR to it and have the Kenwood run my RTA 11TLs for the time being.

It might be good budget power but the sound just isn't there for me. Yes I could have saved time and money ($15) but sometimes it is just best to try it for yourself and get that experience under the belt.

Won't be able to grab the Adcom after all, Wife spent the money I had put away.

Oh well I guess I can buy some RD0194s come the 1st.

skrol

I had tried using my Denon DRA-835R receiver as a preamp to my Parasound HCA-800ii and it was ... meh also. The receiver sound much better using its own amp stage and drives the RTA11TL's very well. Maybe the Denon pre pairs better with a Denon amp.

Now the Parasound HCA-800ii with a Parasound C/PT600 was a step up from the Denon receiver.