Well, I guess I've been a tinkerer...up until now.

Larry, I repeat, you've done well. Keep up the good work.

Tinkerer or no tinkerer, we've witnessed what you can accomplish...

Larry

Thanks, Larry, my tinkering continues. I had replaced all the tubes in the amp and tuner except for the 5U4 rectifier tube. Upon checking it on my Heathkit tube checker, it barely registered good (tested 60 whereas "good" is 58 to 100.) I decided to order a new Electro-Harmonix rectifier tube and that tube arrived today from AES. It registered an 86 on my tube checker!!!! I installed it in the Mark I this afternoon and the set is now more potent than ever. Good tubes do make a huge difference!!!

Larry,
When a fresh stock of tubes is readily available there is the luxury of being able to swap the old tube for new. When I worked at service shops it was standard practice. It was immediately obvious that some tubes that tested a bit on the weak side worked just fine in the set. Replacing them with new made absolutely no difference in performance. Likewise tubes that test good may show defects under actual operating conditions. In the case of a 5U4 dual diode a lot depends on how much DC current is being drawn by the equipment. A set like your HF-1 would draw quite a bit more DC current than an 8-tube console. A strong rectifier tube is essential.

Most of the 18 tubes in my RCA Victor Custom Concertmaster Deluxe are original RCA installs.
Even the 6BQ5's that are driven hard are still in the "good" range.
The original 5AS4A rectifier is fine too, pumping out near 300MA of DC to both chassis.

I often find that OEM tubes perform better in many situations, so I hesitate to change them out to modern/current/russian versions.

Where scuds or silkworms are concerned, there's no hesitation on MY part.

Simply BBM's rule of "MOX NIX."

Larry

I can guarantee you guys that this set wouldn't sound nearly as good if I reinstall all the old tubes back in it. In my honest opinion, good new tubes are just as important as quality capacitors. Now, I wouldn't replace all the tubes in an SHF-8 or 7-HF-5. However, the 6-HF-1, in order to maximize its full audio potential, is deserving of brand new tubes. The cost was definitely worth the investment.

Keep in mind that the 6-HF-1 isn't a rinky-dink record player or AC/DC radio. It is a professional piece of high powered equipment. The fact that it cost $1600 brand new in 1956 should be all you need to know about the quality of the cabinetry and equipment.

You have a Russian made tube in a console that was made back in the 1950's, in the U.S.A.? You communist!

Anyway, if this were mine...and unfortunately it's not...I'd go for a NOS RCA 5U4, instead. But that's just me. I hope this doesn't turn out to be another situation like the yellow caps, that's all.

I believe that this is nonsense. Without analyzing a circuit design, there is no basis for saying a particular phonograph is any more or less demanding of tube condition than any other model. The 6-HF-1 may be more demanding of its 5U4 rectifier tube than a lesser set is of its 5Y3, or it may be less demanding.

In fact, better quality equipment tends to be designed to be LESS demanding of tube condition. When I would (rarely) encounter a piece of equipment that would not work properly unless its tubes were new, I would know that I was dealing with a bad design. There was one tape recorder back in my college radio station that gave me fits because of this.

If someone performed a blind test on you by swapping the old tubes back into your 6-HF-1, you would not be able to hear the difference.

-David

We must have been typing at the same time, David, you beat me to the punch. A bad tube is a bad tube, and it will adversely affect an SHF-8 just as it will adversely affect a 6-HF-1. And unless all the tubes were bad, I don't see a reason to have replaced all of them, regardless of the perceived quality of the set. And this isn't like the old car analogy about old tires and brakes that everyone uses...there is no danger in keeping old tubes that test good.

Agreed in full.

Back in the days of B&W tube TV's, many circuits in many sets demanded "selected" tubes. Those were the ones with their exhaust tips painted in bright colors, usually red. They represented the top one or two percent of any representative tube sample.

When you found those, however, it was a cinch that you had a circuit hanging "on the edge." It wasn't a good design; in fact, it was a very dicey design that had to have a "selected" tube in it, or it would cause trouble. And as normal tube aging progressed, it did.

In my book, the best circuits are the ones which allow tubes to age through their normal life expectancy, at least, before performance begins to slip enough for you to notice. Maybe they won't take beauty prizes in the cutesie-pooh school of design, but you're not feeding them new tubes every other week, either.

Larry

In Doug I trust.


I'm no communist, but the Russians' tubes are acclaimed to be the best new tubes currently being manufactured. In fact I have five Russian Electro-Harmonix tubes in this set--- four 6V6GT output tubes, and the 5U4 rectifier. They're darned good tubes!

Brain, this is the first time I've ever replaced ALL the tubes in a set. With all the problems I had with capacitors and tubes shorting out, I felt all new tubes would be a real plus for this set. I want it working right for years and years to come, not just a few months until another tube shorts out. The new tubes were, in essence, an insurance policy against future failures. Think of them as an extended warranty.

In restoring my RCA Victor console, during Multiplex alignment, I had issues with the (replaced) Electro-Harmonix 12AX7 in the tuner chassis.
Upon changing it to a GE branded NOS tube, my alignment and overall FM stereo sound was better.
So much for new russian tubes in certain instances.

I'd still much rather have them than Chinese tubes. I've had great luck with the Electro-Harmonix tubes. Another ARF member, MouseMaster, also has had great luck with them.

Hi Larry,
I read this entire thread with great interest. Like you, I got into this hobby fairly recently. I have been into vintage amps and HiFi for only the last three years. I have concentrated more on learning to repair and modify console amplifiers. I have been lucky in collecting a number of beautiful pieces of equipment including a 1959 Magnavox Imperial console in beautiful condition and a highy sought after deluxe Pilot two piece console from 1959 with the fabulous SA232 amplifier. As much as I love both of them, they don't come close to this RCA in it's absolute beauty.

I haven't spent the time documenting my efforts online like you have, my job and family keep me too tired to work at your level
In reading this thread and others you've posted I've been impressed and motivated by your fine efforts. I like the way you let snide and critical comments go like water off a ducks back. What counts in my book is action and you demonstrate it. Congratulations on your fine console and your high quality work.
Pat

Thanks, Pat, I get a lot of snide comments from time to time, but I'm not going to get into a shouting match with anyone on this thread. Everyone has their own opinions, occasionally much different from mine, and that's fine. That's what makes this forum so interesting and educational. I pick up a lot of good tips from members who know more about this stuff than I do. I'm not an expert, but I think I do a pretty dammed good job! I still haven't run into an amplifier that I couldn't fix...it may take me longer than it would a pro, but I always manage to fix it.

I'd like to see photos of your Pilot console. You should start a thread about it with lots of pictures.

Here's an ESL cartridge like the Mark I and II used. Note it sold new for $35. This eBay seller wants $399 for one. I think I'll stay with my Stanton 500.

http://www.ebay.com/itm/Electro-Sonic-L ... 0798947561

I've sold used Decca London and Fairchild cartridges for around that price. He'll probably get his price.

I never was totally satisfied with the sound of a Stanton 500. v3 magnetic cartridge in my Mark I...until tonight. The cartridge always seemed to be over-driving the amp, and I'd have to turn the bass down or there'd be some distortion in the bass.

I asked my good friend, Mr. Doug VanCleave, what he would do about this issue. He suggested an experiment-- cutting the coax between the external preamp and the RCA jack on the tuner chassis and installing a potentiometer so the output from the preamp could be adjusted. The external preamp was putting out approximately 1 volt of output, which was over-driving the amplifier. I cut the coax and installed the pot in-line with the coax for the experiment. I was able to adjust the total phono output to a level very close to the output of FM radio, but the adjustment cut the treble as well as the bass and it simply had a muffled sound. It didn't sound good at all, and I was about ready to replace the magnetic cartridge and preamp with a .5 volt Astatic 13-T ceramic stereo cartridge.

Doug then suggested that I add a .001 capacitor to the pot center (connected to the tuner bandswitch) and the pot lug connected to the external preamp. I tried it, and wow oh wow, the treble came way up and the entire phonograph sounded simply incredible!l I then installed the pot permanently on the side of the tuner chassis and adjusted its volume level very close to FM. Now, I can play records at full bass and the sound is spectacular! I've never been happier with the sound of playing records on the Mark 1.

The beauty of adding the pot is that I can adjust it to any cartridge I might want to use in the future.