Help! Hum/Hiss in a Harman Kardon 430

[kcac]

Where did you get the caps?

Resurrecting this thread because I'm doing the same work on my H/K 430 Twin Powered. Same exact problem. I have to wait for new caps to arrive though.

Does anyone know where to get replacement transistors? I might have found a source for the 2SC1030 transistors here, but I'm not 100% certain about it being correct, or the quality of the part. Are there better quality transistors out there? Or a recommended source?

Just picked up 430 locally for $50. WOW - I've been into audio since mid 80's and owned 30 plus amps from SET tube to Class A 100 lb solid state amps and 430 is one of the best. Really amazed with Sony PS1 as source on my 2nd system...

I also have slight hiss on both channels audible when there is no source (CD or FM). Can you and others share where you bought the replacements for the 4 large capacitors next to the transformers?

Thanks

 

[JWFokker]

I got mine from Parts Connexion, specifically the Nichicon Gold Tune and Fine Gold caps, though Digikey has plenty of very good quality Nichicon and Panasonic caps, probably at a lower cost. Don't know if they have the Gold Tune (Nichicon KG) or Fine Gold (Nichicon FW) caps though. But the Panasonic FM caps are excellent too (also consideraly less expensive than the Nichicon KGs and FWs), and I've gotten them from Digikey in the past for a couple of Millet Hybrid (tube/solid state) headphone amplifiers that I built.

 

[kcac]

What spec capacitors?

I got mine from Parts Connexion, specifically the Nichicon Gold Tune and Fine Gold caps, though Digikey has plenty of very good quality Nichicon and Panasonic caps, probably at a lower cost. Don't know if they have the Gold Tune (Nichicon KG) or Fine Gold (Nichicon FW) caps though. But the Panasonic FM caps are excellent too (also consideraly less expensive than the Nichicon KGs and FWs), and I've gotten them from Digikey in the past for a couple of Millet Hybrid (tube/solid state) headphone amplifiers that I built.

Thank you very much for the info!

Can you please clarify the spec of the caps you replaced (6800 uF/50V)? These are for the 4 large caps next to the 2 output transformers right? Did it solve your hiss problem?

Do you think replacing the transistors you noted on the previous post will improve sound further?

Cheers

 

[JWFokker]

Not quite. I just received them today. Haven't had a chance to put them in yet. I personally don't have any problems with hiss. I have no output from the right channel, so hopefully it's just bad caps and not something else. I plan on replacing all of the capacitors in the amp eventually, but I figured I'd star with the power section.

The capacitors I got to replace the 6800uf 50V caps were 8200uf 50V Nichicon KG Gold Tune caps. Because the amp is so old, the capacitors are larger than today's of equivalent capacitance. So to match the dimensions, I went with 8200uf 50V caps.

EDIT: The first thing you should do if you have problems with hiss is to use DeOxit on the potentiometers and buttons. My HK 430 was kicking out a ton of noise and made the woofer on my speaker go crazy until I cleaned up the pots and buttons. To be on the safe side, I'd use the DeOxit D100 since it doesn't have any solvents like the D5. It's also recommended to follow up DeOxit with Faderlube.

 

[kcac]

Thank you very much for the info on the caps and DeOxit.

Great info about 8200uf 50V Nichicon KG with snap-in connection is good match from the overall dimension. Which other caps would you replace?

The seller told me his friend deoxed it last year and my unit's switches and knobs don't make noise when pushed or turned. This thread began with the OP's initial trouble shooting with deoxing.

You may want to check out the fuses on the bottom of the unit as hopefully your right channel issue is something simple like blown fuse.

Cheers

 

[JWFokker]

It's a good idea to replace all of the capacitors because after 30+ years, they're far from being in peak condition and capacitor technology has advanced a lot (low ESR, low ripple compared to old caps). Odds are that if you replace all of the capacitors, it will sound better than it did when it was new.

The most common recommendation I've seen for replacing capacitors (other than the four big filter caps) is to replace the capacitors in that are on the small sub-boards screwed onto the underside of the main circuit board, located along the sides of the amp. They're pretty good sized caps too. I bought 2x 4700uf 35V, 2x 2200uf 35V and 1x 1000uf 35V Nichicon FW Fine Gold caps for those boards. They match the dimensions of the stock caps pretty closely.

In all honest, I'm not sure if relatively "high end" capacitors are necessary for the power section of the amplifier. I'm probably wasting money buying "audio grade" caps for locations that aren't in the signal path. I think a good middle ground is the Panasonic FM line, which have given me excellent results for many applications in the past.

 

[kcac]

Thanks for the info

Thanks a lot for the cap info.

I'm going to check out 730 and another 430 locally this weekend. If I get 730 then open it up to see what are the differences from cap point of view.

Cheers

 

[JWFokker]

Something to keep in mind:

Comments by Todd Krieger in Vintage Asylum on June 22, 2002 at 23:50:18:

"Strengths: A good one is 90 percent of a H/K 930. Musical, almost tube-like in character. Honest 45 WPC rating. Excellent tuner section."

"Weaknesses- Has severe sample variation. Bad ones sound "dry." A little "anemic" in the bass. Needs a benign speaker load."

I'd want to test it out before buying one. But I can't say much because I bought a 930 listed on ebay that was untested except to see if it would power on. I had no idea it was fully functional and sounded great. I cleaned it up a bit and put some DeOxit on the pots and buttons and terminals, but haven't replaced a single cap yet.

 

[kcac]

730 bass too heavy

I got Harman 730 today in absolute mint condition from Goodwill eBay auction. Noticed it sounded "muddy" due to too much bass. Low cut makes it sound better and made sure Contour was not pushed in. I swapped out the pre-main U jumpers with RCA interconnect cable and ths helped - an old trick I learned from owners of Dussun V8i amp (90 lbs Chinese amp - sounded too clinical for me).

What do you think?

Sounds like what I might have might the the opposite of A little "anemic" in the bass.

Cheers

 

[JWFokker]

Odds are caps need to be replaced and resistors have probably drifted. Did you already DeOxit the pots and buttons?

 

[kcac]

Hi,

Have not Deoxed the pots and switches yet. Do you think it will help the heavy bass output?

Would replacing of the 4 output caps help? Noticed that it's same output caps as the 430.

Thanks for the help!

 

[JWFokker]

It's all going to make an improvement. I'd hit everything with plenty of DeOxit before making any decisions.

 

[MD1032]

It's been years since I posted this and got some help (props to ecluser again, he was amazing at helping me fix this). I've been using my HK 430 ever since and it's never had any problems. Hooray 1970's engineering! Yesterday afternoon, I listened to a couple albums seriously for once, which I hadn't done in a while, and it got me thinking that I should probably either buy a 730 and overhaul it (better amp, more flexibility) or just completely overhaul my current 430. I know things like the equalizer and volume controls will need to be done, obviously replacing a lot of capacitors, which seem like the electrical components that most people replace.

Problem is, I have some Klipsch Forte II's (which I also need to redo the crossovers on)...they're very sensitive speakers. What little hum and hiss is left in my receiver is still somewhat obvious when things are quiet in our dead-quiet house. I still want this receiver, but I want to take it to the next level. What's involved?