This set now sounds simply the best it's sounded since I brought it home from Chicago on Feb. 1. The volume level on both phono and FM is nearly DOUBLE what it was before. I mentioned to Doug VanCleave about a month ago that this set didn't seem as loud to me as Golden Throat 15's 6-HF-2 sounded when I restored his amp and tuner a little over one year ago. Now I know why it wasn't as loud... it was this yellow Chinese cap!!!!@!

Basically, we restore these sets that are 55 to 60 years old, recap them, leave all the old tubes in them, and expect them to continue performing like a million bucks after continual use. Parts can break down, tubes can fail, resistors can shoot the craps, anything can happen. I think all the bugs that happen usually happen within the first 90 days of restoration. This set shot the craps after about 2 1/2 months.

Larry,

Matt is giving it to you straight, a shorted tube is not going to take out a good 630 volt capacitor but a shorted coupling capacitor can easily damage a tube. You would have to exceed the 630 volt rating of the capacitor to put it at risk. The power supply in this amp puts out less than 400 volts.

Don't look at it as wasted time, you gained more experience. A professional would have hooked this amp up on the audio bench, run a 1 kHz signal through it and seen immediately that the amp was not running on all four. It would have been repaired in minutes. The hobbyist has to figure out what’s wrong in the blind.

I would expect that a leaky coupling capacitor would elevate the DC voltage on pin 1, the control grid of the 6AU6 and that it would have been caught with voltage checks.

At any rate, the amp was pushing and not pulling or vice versa. Half of the power output stage was not doing its job. There would be a phenomenal increase in performance and now you are hearing what a 6-HF-1 really sounds like. Time to snug up the cross bracing on the floor joists.

Matt,
The ETR brand ?
I have a new bag of 25.

Yeah, and that professional would have presented me with a bill for $300, what a price to pay for 10 minutes worth of work.

I need to check into the floor joist cross bracing companies out there...also companies that make windows that don't rattle. The 6-HF-1 is now rattling both!!!

I know I really like what I'm hearing coming out of that big speaker enclosure today!!!

There is a college girl who bought the place next door, and she was over visiting with me the other evening on the front deck, and I asked her if playing my hi-fi gear loud bothered her. She said she keeps the windows facing my place open most of the time, and that she occasionally hears the music but it doesn't bother her. She said it's a lot better than hearing all the sirens that go down the nearby freeway!!! (We're one block off I-30)

I like my music loud! You can't appreciate the true high fidelity of a console radio-phonograph unless you play it loud!!!

Let's break that $300 bill down.
Parts and labor for replacing defective component - $25.
Knowing which part to replace - $275.

Servicing consumer electronics has always been a hard buck to make. If you have a shop and all of the necessary equipment, there is overhead. I have never met a rich service man or independent shop owner. I left consumer electronics in the early '80s making $20 grand per year. That was about tops for a bench technician. Three years later I was in industrial electronics and had doubled my income. I actually got to use income averaging on my federal income tax. That was 28 years ago and I’m still not a rich man.

Doug, I'm not quite sure of who the manufacturer is, but I did hear of the situation somewhere recently.
I tend to stay away from those yellow crappers anyway and use the epoxy-dipped caps.
And I always test caps before installing them - as well as doing voltage checks on plates, grids and cathodes during break-in testing.
It eliminates any issues later on, I don't need customers hauling the stuff back to me because I didn't feel like being a worthy technician.

Doug,
Do you mean that professional diagnostic equipment and knowledge don't fall like manna from heaven?

Larry, I'm glad that you found the problem. When we do a full recap on a large set like a radio-phono, changing 15-20 capacitors, the odds are reasonably high that one of the new capacitors will be bad or will fail early on. Sometimes there is no alternative to troubleshooting.

-David

I don't think any amount of testing when parts are first installed eliminates the possibility of said parts from failing 3 months, 6 months or a year later. The truth is, these sets are dormant, for the most part, in somebody's closet, storage facility or basement and haven't been in use for years. New capacitors are then installed in them, and the set becomes somebody's daily player. A set that hasn't been fired up in 35 or so years is now used for hours a day listening to FM radio or playing records. Gee, all of the parts in the set other than the new capacitors are over 50 years old, and they are prone to failure with heavy daily use.

So, know-how is why pro technicians charge so much. They're doctors of electronics.

I guess I've been too trusting of the new yellow metal film caps. I always test the old ones in a crude way as I replace them, just to get an idea of their condition. I don't have a capacitor checker so I put the capacitor in series with a DC voltage and check for leakage. I always do voltage checks on control grids afterward, mainly to check for vacuum tube grid leakage but a leaky capacitor would be detected as well.

Brian,
Oy vey, Of course they do, didn't you know that? Just ask any customer, they'll tell you.

We're more like experienced surgeons.
And you know how high hospital bills are.

Bottom line - who can do what a surgeon does?

You cannot put blind faith in any new component. About 10 years ago, when I was chief technician for a manufacturer of vacuum tube amps, I ran into such things as; major brand electolytics with the plastic sleeve installed backwards, indicating the wrong end as negative; rotary switches with short contacts where long ones should be, and vice-versa; major American brand (Made in Mexico) dual volume controls that tracked more than 7 db apart at some point, switching the high and low channels at some point (they were made to order, and there was no recourse); and toroidal audio inductors (also custom wound) with some having different inductance than the rest.
The only film caps (custom made) that I found bad, were overheated by the assembler's soldering iron.

Now that had to be an interesting job, with a set of headaches all its own I'm sure.

Headaches?
Headaches you say?

You don't want to hear my foul tongue those weeks I spent custom-cutting 3/4 inch pine panels and measuring to within a millimeter each and every facet of re-doing that console in 2010.
I didn't have an extra fraction of an inch to play with for the most part - cramming the guts into that smaller cabinet.
Cursing all the way.....
Considering air-flow, later-on serviceability, vibration elimination, and of course how it would ulimately look.
Drawings on paper, on the PC.... it was maddening!

But, I didn't give up.
I'm a stubborn bastard.
Davey Sarnoff would have loved it.

I reinstalled the amp and tuner in the cabinet tonight. It had been out so long I forgot what it looked like in the cabinet.

Listening to some good FM tonight...my, that sound is sweet!!!!

Congratulations Larry on your second save of the 6HF1. Sets of that complexity might be like TV's which, after you get them working perfectly, on average need to be hauled out of the cabinet 4 times in two years and then they work OK for a while. They needed a lot of service when they were new, so it shouldn't be any surprise. You just kept moving forward , trying new things, though not everyone agreed with them, until it worked. Good radio men out in Arkansas.

I guess this was my "second save" of this set. I hope this isn't like one of those early TVs.... hopefully it will work quite well now for years to come. But, if it develops any more problems, I'll be back getting ohm readings and checking voltages again.

I'm not a radio man, but I'm learning. I'm an RCA record player and changer man. I can do those things in my sleep.

I put the set back in the cabinet yesterday and soon noticed I had some significant hum in phono mode. I could touch the record stabilizer arm or motor board and the hum would go away. I pulled the changer and couldn't see any problems except that the phono plug looked a little suspect. Today I pulled the changer again and replaced the muting switch and phono cord/plug and it works perfectly now with no hum. Everything is now buttoned up in the cabinet except for the reel to reel Magnecord tape deck. It won't start on its own in horizontal mode without giving the capstan a "boost" to get it started. I have to replace the idler springs in the machine.

I have a question for you experts on here. Since I've had this set it has had a "pop" in the speaker when the set is turned on, and also a slight pop when it is turned off. I haven't been able to figure out what is the cause. Could it be that I need to replace the rectifier tube, which is the only original tube in the set?

Give me some guidance, guys.

Put a .047uf 630V across any AC switch terminals.