J M O N Posted March 1, 2003 Share Posted March 1, 2003 I recently purchased one of these and thought I'd forward some early impressions. I was going to just add on to the H/K 430 thread that is currently running, but that one took off in another direction and I quickly got tired of reading it. First off, here is some background information. I am using this receiver to power an older pair of Thiel 04a speakers (early 1980's). Several weeks ago I posted a question about inexpensive speaker recommendations and these are the speakers I ended up with. I wanted to put together a simple and inexpensive sound system to keep me satisfied while I am away from home for the next several months. I selected the 730 instead of the 430 because of the additional power. I thought I might need that extra power with the Thiels as they tend to be fairly power hungry. However, in this case, the 40 wpc 730 powers the Thiels with no problem at all. It turns out, I probably could have gotten away with the lower powered 430. I believe these speakers have a sensitivity of 89 dB. I purchased the 730 from eBay. I got it for $104 with shipping from Canada. The receiver worked fine, but there was a little bit of noise from the pots. I am working on cleaning those up. Upon opening the box up, I found some burned out light bulbs as well. The inside looked fairly clean considering this thing is almost 30 years old. The exterior is also in pretty good shape. Since I haven't heard either the speakers or the receiver with anything else, it's tough to give feedback on their individual performance. What I can say is that I am getting pretty good sound from this combination. The sound is pretty clean. I have heard others mention the bass impact with the h/k. It does seem like there is a fair about of bass there. However, I'm not sure if the bass is a result of "better" bass or deeper bass, or if it is just a result of the h/k having a bit of a "bass boost" via some kind of internal equalization. I'm unsure yet if I like this. I do have to play around with speaker placement though to fine tune the sound. Of course I can compensate for this by reducing the bass control just a touch. As far as the tuner performance goes, I can say it does a good job. I haven't connected an antenna to it yet, but still can tune in some stations cleanly. It's been several years since I've owned a tuner, but the tuner in this receiver does seem to do a very good job and sound quite good as well. Overall, I am quite happy with this setup. With the addition of a DVD/CD player from Sam's Club, I think I have succeeded in putting together an inexpensive, pleasing system. It should keep me satisfied until I can return home. When I do return home, I will likely still use it in a secondary system. As for the HK 730 receiver, I can highly recommend it at its price point. I'm sure the same could be said about the 430. Thanks goes out to HDBR for letting us know about this audio bargain. Quote Link to comment Share on other sites More sharing options...
mace Posted March 2, 2003 Share Posted March 2, 2003 As I've learnd from HDBRbuilder, when you turn the thing on, do it in this order. Make sure volume is at zero and no speakers are on. 1) Power on unit, let sit about 45 seconds 2) Turn on speaker button, let sit a few seconds 3) Turn up yer volume When powering down, do so in reverse order. I got a 430 and had some pretty bad static/popping in volume knob. I cleaned it with some radio shack lube/cleaner, spray right into the little holes on top of the pots, use a gentle trigger finger, turn knob rapidly after squirting, wipe excess with Q-tips. The volume knob still had a whooshing static (like brushing sound). I cleaned and cleaned and cleaned to get rid of this. I was then informed that if you turn knobs and such right after powering up (without letting it sit for 45 seconds or so) then you get this noise. If I follow the above all knobs and buttons are as quiet as a church mouse. All of the above was pretty much HDBRbuilders tips he passed onto me! I'm sure you'll like your 730. Mace Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted March 2, 2003 Share Posted March 2, 2003 Jmon, Glad you are enjoying your little combo. Depending on the material and source I play with my H/K 430, I usually either leave the bass control "flat" or back it off just a tad...but I normally leave the treble control setting "flat". You are right..the bass punch from these takes a bit of "getting-used-to"...I find that I get a bit more bass bottom-end performance with these units, though. Mace, Although I have always used this power-up and power-down sequence...there is also always the possibility that the volume pots on many of these receivers may well have quite a bit of wear on them contributing to noise, too..I tend to think of this as possibly being due to them being used alot by previous owners who may have just not seen a need to clean controls regularly on them...or maybe...because they have been in continual regular use ever since new? What I mean is...if one of these almost 30-year-old receivers can hold its on with...or out-perform so many others that have come along in the decades following its original manufacture...isn't it highly likely that previous owners have been using many of these pretty much continually since the original purchase? After almost 30 years...there outta be a decent amount of wear in a volume pot, and in some cases, a new replacement volume pot could be a good idea. Quote Link to comment Share on other sites More sharing options...
mace Posted March 2, 2003 Share Posted March 2, 2003 HDBRbuilder, What source would you recommend for volume pots? Digikey or something? Thanks, Mace Quote Link to comment Share on other sites More sharing options...
djk Posted March 3, 2003 Share Posted March 3, 2003 "or if it is just a result of the h/k having a bit of a "bass boost" via some kind of internal equalization." Measures dead flat with test equipment. "What source would you recommend for volume pots?" I don't know of any that fit. "I was then informed that if you turn knobs and such right after powering up (without letting it sit for 45 seconds or so) then you get this noise." The electrolytic coupling caps are leaky and could stand to be replaced. Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted March 3, 2003 Share Posted March 3, 2003 Mace, I really can't give a recommendation for a source for volume pots for these...simply because I haven't so far had a need to get one, myself. Both of my H/K 430's are as quiet as a mouse...even when initially powering-up. I would imagine that as long as the pot is basically the same design and configuration, and of high quality manufacture, it probably doesn't make alot of difference WHERE you source it from. H/K MAY have some of these...but I am not even sure of that! At any rate, if H/K does have them, they MAY be found less expensively elsewhere...you know how it often is when you order replacement parts for old stuff from a manufacturer...if they DO have them...they normally cost an arm and a leg! LOL! Also, since these items are electro-mechanical, it may be possible to rebuild them if one has a clue as to how to go about it. I certainly don't. Anybody out there reading this have any ideas on a source for these potentiometers? If so, will you please throw in your "two-cents' worth" on the subject? Thanks! Quote Link to comment Share on other sites More sharing options...
J M O N Posted March 10, 2003 Author Share Posted March 10, 2003 I do turn the volume all the way down when powering up or down. However, I tend to leave it powered on at all times. Not only will it increase the lifespan, but it does sound better when it's warmed up. I still have a little bit of noise from the volume pot, but none anywhere else. I'll try cleaning it some more. Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted March 10, 2003 Share Posted March 10, 2003 JMON...those older S/S items from back in the mid-70's are NOT supposed to be left powered-on at all times...they are NOT modern stuff...and unless they have a standby switch(and these DON'T)), then they need to be powered-down at the end of each listening session. They are S/S, but not the same as the S/S made today...not the IC chip thingies that you can just leave on all the time nowadays! Keeping that 730 powered on at all times will NOT extend its life...it will SHORTEN IT! Quote Link to comment Share on other sites More sharing options...
Johnny dB Posted March 11, 2003 Share Posted March 11, 2003 I'll just to have to see for myself what all the fuss is over the HK x30. I just bought a 630 off ebay today. I'll give a full report when I get mine. Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted March 11, 2003 Share Posted March 11, 2003 JohnnydB, The twin-powered "X"30 series of H/K solid-state receivers began life in 1972 with the initial entry of the 630(30wpc) and 930(45wpc) models. In 1976, two more models were added to the line-up, the 430(25wpc), and the 730(35wpc), and the 630 was dropped from the line-up at that time. There is NO INDICATION that the 630 was dropped from the line-up for any other reason than the fact that it just was NOT economically feasible to retain it since it fell so closely between the new 430(25wpc) and 730(35wpc) models with its 30wpc power-rating. The 930 went through a bit of upgrade for the 1976 model year, but was left basically unchanged. The new 430 and 730 models had a much different power amp heat-sink/transistor configuration than the 630 had, though. On the 630, that portion of the amplifier section was cooled through a vented protective "cage" located on the rear panel of the receiver, whereas on the new 430 and 730, that portion of the amplifier section was completely retained within the unit and cooled from larger vents in the upper case of the receivers. Of all of the twin-powered "X"30 models in production in this series, the 430 and 730 seem to be in a "tie" among vintage enthusiasts' opinions as to which one is the "best of the bunch" overall...with the 930 getting the nod for highest power and best tuner, and the 630 holding the "last place" in the vote with a VERY honorable mention. By no means is the 630 a "slouch", tho...it was just not as modern and "refined" a version as the newer 430 and 730 models were...but it has the same "basic sound" as they do. Let us know how your 630 performs when you get it...be sure to check and replace all the fuses in and on it, and give all the switches and controls a good cleaning BEFORE powering it up with speakers, when you get it! Also give the "under the hood" area a good blowing out and general cleaning before powering it up with speakers. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 11, 2003 Share Posted March 11, 2003 Here is a trick for cleaning stubborn pots first drown the pot in WD-40 while turning it for a good 5 minutes. Now the important part get some contact cleaner that completely evaporates and drown it again while turning the pot the idea here is to wash ALL the WD-40 out of the pot. Let it dry. Then use Caig Dexoit for the final cleaning and lubrication. Works almost everytime on some of the worst pots in vintage tube gear !! Craig Quote Link to comment Share on other sites More sharing options...
dougdrake Posted March 11, 2003 Share Posted March 11, 2003 Craig - Dumb question: Would you remove the pot from the unit (and remove the wires as well), or just "drown it in place" with a good heavy spraying (using the high-tech new fangled red straw-thingy that comes taped to the side of the can)? DD Quote Link to comment Share on other sites More sharing options...
justin_tx_16 Posted March 11, 2003 Share Posted March 11, 2003 I would think that you would have to take it out completely, remember where the wires go, otherwise you could have WD-40 all over your case. Oil and electronics DON'T MIX. Quote Link to comment Share on other sites More sharing options...
J M O N Posted March 14, 2003 Author Share Posted March 14, 2003 HDBR: Aside from the lightbulbs inside the receiver, what will wear out / burn out from leaving this thing on? I'm not sure there is anyting else in there that will wear out. Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted March 15, 2003 Share Posted March 15, 2003 You'll end up frying the amplifier section on it...THERE IS NO STANDBY SWITCH...so it will burn up your amp over time! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted March 15, 2003 Share Posted March 15, 2003 Doug, Sorry for not responding I missed your question. No you don't have to remove it just spray the mess you make with the WD-40 with the second cheap evaporating contact cleaner and on the final spray with Dexoit try not to make a mess and all will be good. Craig Quote Link to comment Share on other sites More sharing options...
djk Posted March 15, 2003 Share Posted March 15, 2003 If your coupling caps are leaky, your pots are going to be noisey. Cleaning will at best be temporary. If you screw up a pot no replacements are available. It would be a good idea to replace all the coupling caps. Due to the number of people that favor the 430 it might be worth your while to get up a repair kit of all the required values. Digi-Key or Mouser would be the best bet. Quote Link to comment Share on other sites More sharing options...
J M O N Posted March 27, 2003 Author Share Posted March 27, 2003 HDBR: Although there is some wear on an amp (or any electronic device) simply by being left powered on, there is significant wear and tear on these devices by the simple act of powering them up. Many of the more expensive gear don't even have power switches -- you plug 'em in and leave them on all the time. Most expensive electronic equipment that you find in labs and manufacturing facilities are left powered on 24/7. Unless you are not going to use it for long periods of time between uses, the amp will typically last longer if left powered on all the time. When powering up electronics, there is the electrical wear from the electronics going from an uncharged / unpowered state to a charged up / powered state. Think of lightbulbs burning out -- this usually happens when you turn on a light switch, rarely do they burn out when they are already on. In addition, a friend of mine who used to work in the semiconductor field informed me of the thermal stresses involved that I had not previously considered. Different material expand and contract with changes in temperature. Electrical components will typically experience higher temperatures when they are powered up than when they are unpowered. Everytime you power up or down the equipment, there are expansions and contractions going on. My friend told me that semiconductors are designed so that when the semiconductor is powered up, it has the least amount of mechanical stress. Power them down, and there is stress applied as the units cool off and their physical dimensions change, and in the case of these semiconductors, the stress is still there when left powered off as they were designed to have the least amount of mechanical stress when powered up. From an electrical component point-of-view, think of the mechanical stresses involved at the solder joint of say a simple resistor on a pc board. You have expansions/contractions on the board itself, the solder joint, and the lead from the resistor. Of course these changes are more prevalent with those components that get the hottest (look for those components that have heat sinks!). Pretty intersting information. I'm sure there is a certain length of time, where unless you are not going to use your electronics for X-amount of time, then go ahead and turn them off. However, I would think that that length of time is on the order of weeks or even months for most solid-state equipment rather than hours. I used to have some older solid state Harman / Kardon separates that I powered up and down, probably an average of once or twice a day. Both the power amp and preamp ended up giving me problems after several years. I'm sure had I left them powered up all the time, they would still be working fine to this day. Unless your electronics have vacuum tubes or electrical motors running (tape decks), it's usually best to leave it powered up all the time. For the past several years I have been leaving all my solid-state electronics on all the time (some of them don't even have power switches) and haven't had a single problem. Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted March 30, 2003 Share Posted March 30, 2003 JMON, I gave you good advice...it is up to you whether or not you follow it...your choice! Quote Link to comment Share on other sites More sharing options...
mace Posted March 30, 2003 Share Posted March 30, 2003 does anyone know what type and how many coupling caps the 430 uses? i.e. what would I order from Digi-key if I wanted to replace them in my 430? Mace Quote Link to comment Share on other sites More sharing options...
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