harman/kardon "Twin Power" Receivers

[juncers]

Thanks Ray. I think these receivers have more constant current as well vs. some newer ones that are peak power ratings. Is that fair to say? I like this receiver and if anyone has a minty 730 twin I would be interested, prefer shipping within Canada. Thanks. Bill.

What you're referring to is how they measure the power output. In the 70s, after a few ridiculous marketing claims, the US congress required any amps sold in the US to publish continuous RMS power ratings ( google for details). Since the US was the largest market, it became a global standard. Today's manufacturers don't bother anymore as the law either expired or isn't enforced.
What makes the HK special is the twin-mono amps ( as opposed to one stereo amp). I own a 430 and a 930, so I can't comment personally on the 730.

Good luck with the search,
Ray

 

[Gudstufshevy]

double post of stupid question...

Yes, I took too many cold pills, and my brain is in full oscillation.

 

[Gudstufshevy]

stupid question deleted by poster...

 

[wyaldbill]

gear to run with "the twins"??

I just set up my "NEW" 930 twin in walnut case, to go with my 430 twin. Sweet shape and sweet sound. Everything works beauty! I have a 330A arriving tomorrow, and a 630 shipping Friday to arrive next week. A 730 shipping on Feb 5th. I'll have the whole line-up! When I get them all set up on one rack I'll post some pics. What speakers and TT's or equip are any of you running with your HKs. I han some Klipsch HeresyIIs but sold them before I got going on the twins, so before I shop I thought I'd get some 'expert' speaker opinions. Thanks and nothin like a good scotch with some twin tunes on HAPPY ROBBIE BURNS DAY.:thmbsp:

 

[MudSlideSlim]

Homage to HK twin power!

The HK 430 was my first receiver I bought. Looking at it now it really is such a chrome beauty.

I traded it in for a NAD1020, at that time every audio reviewer was having a wet dream about this integrated amp. The NAD was in battleship gray ( and don’t open it to look inside it’s so... your mother saying clean up your room) although not a bad product it could not hold a candle in beauty, sound and quality of the HK 430.

A lesson well learned a few years later I bought a HK 730, I used it for years, the amp section was very noteworthy. I still have it. As a badge of pride. If only to show it to my friends as evidence of the quality and beauty of our golden age.

Even audiophiles today question my veracity. It had two transformers?

As if how could a mid fi reliever could have such a thing because their way to expensive amp but one!

Are you sure?. Let’s open it up the inside is as good as the outside. This is so Steve Jobs; the idea of quality, ie, things should look good on the inside as well as the out side. Maybe he owned a a HK?. I just smile.

 

[wyaldbill]

How can you not like these! I don't think I can pull in the images but here are the attachments...930 before shipped to me..

 

[Gudstufshevy]

Wow, she looks great! Nice collection.

As to speaker selection, if you have the space and budget, K-horns are the obvious choice. Cornwalls or Fortes are also amazing. I've been using KG-4's with the Crites upgrades. I've also run my twins with Boston A-70's & A100's, both were very easy to listen to.

While I've run the 430 with the KG-4's for years, I only recently tried it with the A-70's and a Definitive sub. I can hardly believe how good the combo is. I run the Boston's on speaker 1, and run the sub on 2. Keeping the Boston's full range, and crossing the sub pretty low 40-60 hz (guesstimate).

While the Klipsch sound is almost ubiquitous with HK, I'm really enjoying the smooth sound of the Boston's. They do a lot of things well, and nothing to offend.

 

[MudSlideSlim]

Dr Fulton of Fulton Speaker fame had a cult following in the late 1970’s.
A San Diego doctor even opened up a boutique audio shop by Mission Bay.
Close to where I lived at the time.

With this group anything Dr Fulton said was considered a divine revelation.
His recommendation for unwashed masses (that was me) was the HK 430
(and not the HK 730 I never knew why). I did buy the HK 430 that was
my entry-level drug.

 

[saunadog]

Hi, I'm glad to find this resurrected thread as I just joined the HK twin power club. I picked up an HK 680i for peanuts the other day ($9). It's really in beautiful shape and I hope audition it soon to see how I like the sound. I was hoping that there was someone familiar with this receiver as the one issue it seems to have is that it will lose station presets a short time after it is powered off. I heard that there might be a replaceable battery on the board, but can't find the schematics.

I know that the later series styling is polarizing. Talk about a lot of buttons! Definitely has that 80's vibe for better or worse. BTW, I also picked up a matching HK 400xm cassette deck for an extra $7.

 

[geph0007]

The battery is on the bottom. You have to turn the unit over. It looks like a nicad AA BE CAREFUL I changed mine out and then the tuner no longer worked. I screwed something up. KG

 

[saunadog]

The battery is on the bottom. You have to turn the unit over. It looks like a nicad AA BE CAREFUL I changed mine out and then the tuner no longer worked. I screwed something up. KG

Thanks for the info :thmbsp: I might just leave well enough alone!

 

[wyaldbill]

hk tuner bulb

In the old twins does anyone know if you can still find the fuse looking tuner signal bulb, or are they and their replacements obsolete? I've got a 330 A, the predecessor to the twins that I thought was a close enough relative I could ask in the twin thread, bulb is burnt out so either standard or replace with LED I guess. I just received this receiver today and it still had the blue plastic wrap on all the chrome around the front face plate. From over 40 years ago!! I'll post some pics of the pristine chrome once I clean the rest of it up this weekend. Cheers.

 

[Gudstufshevy]

For audio specialty bulbs PM AK member dgwojo. Nothing like 40 yr old 'virgin' chrome huh?

 

[kenvirginia]

Hey. I have a HK 870 amp, and a HK 825 preamp, and a HK T65C turntable. I have not used them in many years; they are in boxes from my last move. Is this decent stuff, just ok, or undesireable? Any experience with these, anyone?
Thanks, -Kenny

 

[michaelhigh]

Series 2: 1976-78
Price: $325

Stereo tuner-amplifier.
Power output 25 watts rms per channel into 8 ohms with 0.5% harmonic distortion, 20-20k Hz, both channels driven.
Frequency response 4-40k Hz, power bandwidth 10-40k Hz, IM distortion 0.12%, hum and noise -65dB.
AM/FM-stereo tuner with 1.9uV FM sensitivity, S/N ratio 77dB. Selectivity 50dB, capture ratio 1.7dB channel separation 39dB with 0.7% harmonic distortion(stereo).
Signal strength meter, defeatable interstation muting, loudness switch(contour), high and low frequency filters, tape monitor circuit.
Front-panel headphone jack.
Outputs and switches for two sets of stereo speakers.


A "nude picture" is in this thread:

http://www.audiokarma.org/forums/showthread.php?s=&threadid=990&perpage=15&pagenumber=1


harman/kardon Service Manual:

http://manuals.harman.com/hk/Service Manual/hk430 sm.pdf

I just got mine back from the tech yesterday. I can tell that a good cleaning improved the bass response (none before) and the THD measured 0.4%, one tenth lower than spec. This thing was exhibiting a left channel out, and there were two fuses blown that were inside (I follow the amateur's directions on the sticker not to go inside!) It simply rocks my Fortes now! I have 3 or 4 receivers among the brood that are fighting for supremacy in my house ! Let the battle royal continue!:thmbsp:

 

[oblomov]

I'll have the whole line-up!

Actually, wyaldbill, to be a completist -- I've seen a 230 from this era! It has the toggle switches like the 330a. Don't think there are too many out there though.

myself, I luv my 630 and hk505 integrated.

 

[Spellbinder]

I just pulled the trigger on a Harman Kardon HK 730 a couple days ago. Really looking forward to hearing this. It's been gone through rather extensively as well...

From the tech's report...
* Harman Kardon 730 s/n 5679 Replaced weak and leaky electrolytic filter capacitors in the power supply, phono and amplifer driver stages as necessary.
* Replaced defective multiplex processor integrated circuit and religned 19Khz adjustments.
* Removed all output transistors and inspected mica insulators and redressed them with thermal compound.
* Cleaned and reconditioned all mechanical tuning capacitor assembly, switch wafers and control potentiometers.
* Replaced dial indicators as necessary and realigned dial scale and muting threshold.
* Realigned broken source selector shaft
* Removed front panel and cleaned dial plate and backglass, fully cleaned and detailed.
* Tested extensively driving a pair of Klipsh 5.2 loudspeakers and overall performance was outstanding.

I can't wait 'til this beauty arrives!

 

[michaelhigh]

Voltcontrol, pm AK member dgwojo regarding the bulbs you need. (I think he has a website dgwojo.com) he knows his stuff.

Hope you enjoy your 430, mine was my first vintage receiver. Still in use, still my fav. Sounds good with EVERY speaker I've hooked up to it. My favorite combo to date is the 430 running Klipsch KG4's (great on live recordings) Close second would be Boston A-100's (really nice on vocals.)

Some may scoff, but this was the rig that convinced me that music should be listened to in the format it was intended. I.E. 60's & 70's music (some 80's too) sounds best on vinyl.

Hey man! sheltiedave's getting together soon (not next weekend but the following), either the last of February or the first of March, I'm not looking at a calendar. He's debuting an awesome tube CD player he just scored, and I'm sure there will be swapping and whatnot. Check in and see and be seen! Hope all is well with you! Mike

 

[wyaldbill]

NICE 730 Mr. Spellbinder. You WON'T be dissapointed if it arrives as expected! Nothing like the green glow of that HK in a low light with the right tunes!

Hey Oblomov, I may have to look for one of those 230's! Were they twin powered or just fit in with the "X"30 theme? If I go that route then I need a 330B, 330C, and the 230. Yikes.

Incidentaly the 630 bulb (fuse type) is specified as 6V - 280MA, but the 6V 250MA works fine, and can be found online for less than a buck, or at an electr store in your are for a few bucks. They are shorter than the stock fuse bulbs but still fit well.

If anyone has or finds a spare plastic red power button I need one for an otherwise mint 730. Ha! Fat chance of that but you never know. I'm still going to post a few pics of all the twins, front, back nude, on off... Cheers Twin fans...

 

[kenvirginia]

Hello.
eThink;
Do you have any facts or opinions on my HK equipment? I have just unboxed them from my last move(10years ago)...and don't remember much about them.
Thanks, -Kenny