Advice to choose first vintage SS

[Blue Shadow]

Typically an increase of 3db is perceived to be twice as loud

Actually a 10dB change is twice as loud.

A 3dB change requires twice the power from the amp.

There are so many different dB types for all types of things, here is a link to one concerning audio:
https://www.gcaudio.com/tips-tricks/the-relationship-of-voltage-loudness-power-and-decibels/
It has the 3dB as being 1.4x in voltage, 2x in power and 1.23x in volume

The 3db change it generally considered a noticeable increase on volume, not a doubling of volume.

 

[Gustercc]

So, is there a shortcut or easy way to help a person be able to match a pair(s) of speakers to the receiver or amp or both? For example, if you have "Superpower Happy Joy Receiver Model XXX w/ YZ wtts, then any any speaker that is rated at ABC would work nicely with it" ??? If that makes any sense.

 

[wmgwizard]

As stated in the article Blue Shadow linked to, it's almost impossible to have too much power and potentially damaging to have too little.

 

[Blue Shadow]

So, is there a shortcut or easy way to help a person be able to match a pair(s) of speakers to the receiver or amp or both? For example, if you have "Superpower Happy Joy Receiver Model XXX w/ YZ wtts, then any any speaker that is rated at ABC would work nicely with it" ??? If that makes any sense.

Yes, it is easy. How loud do you want to listen? Most use a watt or three most of the time and all the rest of the watts are just there if needed. Like a car, you're not using all the HP all the time. Just a few hp most of the time.

If you have to listen LOUD, you need speakers that will play over 95dB with 1 watt input and a desire to have poor hearing in later years. Otherwise, most anything will work fine to decent listening levels. Most receivers are on the lower middle of the power spectrum, 35-70 watts. Most folks are more than happy with that.

 

[Gustercc]

Yes, it is easy. How loud do you want to listen?

As stated in the article Blue Shadow linked to, it's almost impossible to have too much power and potentially damaging to have too little.

I’m going to go audition the H/K this afternoon. This going to be my first time auditioning a vintage receiver, so for some reason, I’m nervous. Common sense tells me of course to make sure all the output are working. Check tuner, AM/FM strength and accuracy, listen for cracks, static, pops. Listen for balance between both speakers. Ask if it’s ever been serviced and if so, if he knows what was done to it and by whom. Etc.... but my question is: aside from the phone stage being underwhelming (as previously mentioned) what else are specific to this model that I need to look for?
I did read in a few posts that the FM Chip is difficult to find if it goes out. Gotta admit, that raised an eyebrow. Is there a substitute? I live in Austin and there are a respectable amount of vintage techs here.
Any other tips for checking this unit out, are greatly appreciated by you all.

 

[wmgwizard]

The phono stage is easily "fixed" with a minimal investment of time and money.

There are enough parts/ parts units on eBay that worries about spare parts shouldn't be much of a concern either.

Don't worry too much about burned out bulbs or scratchy controls either, there is a wealth of information and assistance here at AK to get you through a cleaning and re lamp.

 

[Blue Shadow]

The phono stage...(yada, yada, yada)

Lemme translate, We can rebuild it. Almost doesn't matter what is wrong or missing.


But at what cost? That depends. Buy a good one and then the rebuild is a lot easier and yields nice results.

 

[Gustercc]

Lemme translate, We can rebuild it. Almost doesn't matter what is wrong or missing.


But at what cost? That depends. Buy a good one and then the rebuild is a lot easier and yields nice results.

That’s definitely reassuring. So, I picked up the 730. Looking over the unit: cosmetically it is in really good condition. I’d probably say an 8 or 7 at the least. There’s some very minor faint static when adjusting the volume in the first minute of turning the unit on, then it disappears. Buttons function properly and with a sturdiness that breathes “quality”. Dials move smoothly and evenly. The inputs are all functioning.
The biggest problem I’ve found ( and I’m guessing it’s a big one) is the entire left side speakers are not working. I hooked up some very old minimus 7’s to speaker set 1 and only got sound from the right side. Same for speaker set 2. My worry is that one of the power transformers is out. But I’m probably guessing there are about a hundred other things it could be as well. Is there a way I could test the transformers to see if they’ve gone bad? Troubleshooting?
My wires are correct and I’ve used a properly functioning speakers to test speaker connection and yield the same result. i will say : when twisting the balance to the left side, I get a faint transmission occasionally. When I hook up both speakers to right side speaker set 1 and right side speakers set 2 and press both buttons, I get a great sound, but of course this is not utilizing it to it’s full potential considering it’s two power capability.
any suggestions? I’ve got a multimeter, if that’s any help. Not much, I know.

 

[wmgwizard]

Check the fuses inside the unit on the power supply boards. There are 4 fuses total, 1 by each of the large capacitors.

https://audiokarma.org/forums/index.php?threads/fuses-on-a-harman-kardon-730c.243090/

Clean ALL of the controls and switches inside the unit with DeOxit or CRC QD Electronics parts cleaner.

https://audiokarma.org/forums/index.php?threads/the-idiots-guide-to-using-deoxit-revisited.207005/

Some other helpful hints:

https://audiokarma.org/forums/index...bleshooting-flowchart-is-the-solution.108218/

 

[Blue Shadow]

Frequently the HK units can lose a channel to the switches. Ecercise them between now and when you get a chance to clean them per the above link.

Check speaker circuit breaker and fuses as mentioned above.

Verify you have both jumpers on the rear panel, then pull them and replace with RCA cable and verify issuing channel. Then swap one side (in or out) and verify missing channel. If the channel changes it is missing in the preamp section. If the bad channel remains the same it is in the power amp.

Did you test b4 purchase? Missing channel, oh well, maybe some work to do.

 

[Gustercc]

Frequently the HK units can lose a channel to the switches. Exercise them between now

Did you test b4 purchase? Missing channel, oh well, maybe some work to do.

So, just a quick update, I got both speakers working. Looks like it's a dirty Tape Mon 2 switch. After working it a few times, both speakers turned on, evenly and brightly. It was like when my Little League team won the city tourney. I did not have the time to open 'er up, but I plan to later on this week.
I bought a can of CRC and plan on cleaning the TM2 and Volume dials (pots?) as the Vol pot seams to have a tiny bit of static on the low end.
If all those respond to a good cleaning, that still leaves the problem of light replacement. Pointer, VU, and Dial. I saw a vid on YT that worked on a H/K 330, so I imagine it will be relatively similar.
I'm anticipating the VU meter bulb will be the challenge, per the vid.
I'll send more updates once I crack the top and sides.
YES, I did test it, but obviously not that closely. It was my first vintage buy and I was a little nervous.
It did strike me odd that he had both speakers hooked up to both right sided plugs on Speaker Set 1 and 2, respectively. But I guess I go tunnel vision. All aux inputs and phono inputs work well and fine. Tuner pulls in nicely. And Like i said, it's very nice cosmetically.

Thanks

 

[Blue Shadow]

The smooth silky knob rotation of an HK receiver is washed away with the use of flushing cleaners. It removes some of the lubricant in the control. Can't really prevent this unless using a dropper of cleaner works. I haven't tried this. But be aware of the fact that just hosing out the controls and the silky smooth will be gone and the control will operate much more easily, too easily.

 

[quiet]

I'm apprehensive about the CRC brand electronic cleaner.

 

[432HzBob]

The smooth silky knob rotation of an HK receiver is washed away with the use of flushing cleaners. It removes some of the lubricant in the control. Can't really prevent this unless using a dropper of cleaner works. I haven't tried this. But be aware of the fact that just hosing out the controls and the silky smooth will be gone and the control will operate much more easily, too easily.

A small dose of Caig fader lube can works wonders too after using cleaner.

 

[wmgwizard]

Congrats !!!!!

Glad to hear all is working well.

CRC QD Electronics parts cleaner is a safe and effective chemical for cleaning the various pots and switches. Be sure to squirt the cleaner into the openings of the pots, either from the top(circles) or bottom(arrows). The flex straw makes this easier. Work the switch / pot and spray again.






They will loose some of their silky smooth motion that can be restored with a few drops of fader lube as 432hzBob mentioned. Use sparingly, a few drops is all you need and be sure to work the switch / pot during the application to spread the lube around evenly.

Replacing the lamps is fairly easy. Take your time and be patient.

The manuals etc should be available at HiFiengine.com. You will have to register but its free and they don't spam you or sell your info.

Keep us posted on your progress.

 

[quiet]

I've had bad results with CRC. It wiped the whatever out of the control. The control went full on.

 

[Blue Shadow]

CRC QD Electronics parts cleaner is a safe and effective chemical for cleaning the various pots and switches.

yup a good product for a first cleaning and then follow up with correct deoxit. I keep both on the bench, ah dining room table. Deoxit makes some greases that might be good to refresh the controls but I haven't tried that. Nye lubricants work, too but those are designed for the initial build not stuffing back into the gap between the shaft and the bushing.

So just be careful with the cleaner and don't flood the control over and over. A quick shot to get some juice in there then operate the control full range 126 times then a short shot to wash out the control. Let Dry. The CRC will dry quickly the deoxit leaves behind a lubricant that doesn't dry so you don't want to flood the control and hence the circuit board with the stuff. That is why it is available in a drop applicator in addition to the higher volume sprays.

 

[wmgwizard]

I've had bad results with CRC. It wiped the whatever out of the control. The control went full on.

I would be more inclined to believe the particular part was damaged prior to the application of the CRC product. Also be sure you were using the QD electronics parts cleaner. They do make other cleaners that are listed as Parts/Electronic cleaner that is not recommended.

 

[Oerets]

Always when purchasing a product check to make sure it is "plastic safe" not "safe on most plastics" also zero residue.

 

[quiet]

I would be more inclined to believe the particular part was damaged prior to the application of the CRC product. Also be sure you were using the QD electronics parts cleaner. They do make other cleaners that are listed as Parts/Electronic cleaner that is not recommended.

Always when purchasing a product check to make sure it is "plastic safe" not "safe on most plastics" also zero residue.

This is what wiped out the control. The control had a minor tick at one spot before application. After disassembling the control it was clear "all" of the what I think was graphite "stuff" was removed from the contact perimeter board.
Great for metal to metal contact cleaning, not great for "everything". Wonderful on auto plugins, headlights,,,,,,,,,,,,.
I wouldn't use it on "any" enclosed control. We're never ever getting back together.