Restoring the VE 9-55 and VE 9-25 Amplifiers

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Victrola-Monkey
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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by Victrola-Monkey »

Thanks Earl.

RESOLVED ISSUE:
The volume switch turned out ok. The knob was caught between the stops on the short range side of 7 o’clock and 10 o’clock. I just pushed past the stop to get it on the larger range side and it works smoothly and without noise when adjusting the volume when listening to a record. The backside of the volume has measurements of a 3” diameter cylinder that is 2” long. I thought that was big but the Brunswick’s must be a monster.

PREVIOUS ISSUE ON PRE-SOLD VE 9-55:
My radio/phono switch is noisy, so I have removed the radio to gain access to the switch’s back side to spray clean and lubricate.

NEW CHALLENGE:
Since the radio was out I thought I do the resistance checks on the radio/catacomb as defined in the Service Notes. I’m getting lots of opens where there should be closed (meaning some continuity). If tube sockets go from 1 to 7 as you look at the radio and the terminal strip goes 1 to 22 where its #1 is on the same side as the tube #1, then things are very bad. I did do the same test on a spare Radiola 28 and got the same results, so I suspect I’m doing something wrong but I don’t know what. I know I got the socket’s pins understood as far as which pin is the grid, plate, plus, and minus filaments.

PREVIOUS ISSUE ON SPARE VE 9-25 AMP:
I have reverified every wire connection and retested all component values. All good except one thing. As mentioned before, I replaced every wire except for the wires coming from the transformers. I notice on my other three rebuilt good amps I get around one ohm of resistance between the plus and minus filaments on the 81 tube sockets. I suspect that mostly comes from the use of resistance wires coming from the transformer, where there is about a half ohm on each wire. On my one rebuilt amp that is not working, I get point one ohms between the plus and minus filaments. On closer inspection, I see that those leads have been cut and spliced with regular (non-resistance) wire to those socket pins. Could not having resistance wire there be causing no audio and just a hum? All the tubes light up as they otherwise should on both the amp and radio (when in phono mode).

victor 15-1
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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by victor 15-1 »

EarlH wrote:2. The VE 9-55 Owners Manual says that the seven 99 tubes that were supplied with the Electrola have white labels on six of them and one had a red label which is to be installed in the second from the right socket (2nd detector). What was the difference of that tube when compared to the others?


That tube probably sounded best to whoever was installing the tubes at the factory. That's the detector tube for the amplifier if I remember right. Those 99 and 199 tubes are are not terribly consistent and it seems like they will "come to life" and sound better after they've been in use for awhile. And the speaker will sound better after it's been played awhile as well. Those things have sat silent for a long, long time now. Some of those old radio owners manuals will even tell you to swap the tubes around until the set sounds the best to you.

Those volume controls can drive a person nuts. And the one that Victor used is smaller than the one's Brunswick used for whatever reason. The one in my 10-70 has one dead position, but it's up where I'd never have the volume anyway. Those things are really loud at full volume.

They look good Wayne. Those things are a lot of work to go through, there's no way around that one! Earl.
The '99 marked for electrola use was pre selected for the most gain and the least microphonic tendencies at the factory

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startgroove
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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by startgroove »

To answer a previous question, the reason for offering two difference ballast tubes back then has to do with the line frequency and line voltage. UV876 is for a range of frequencies a little above and below 60 Hz, while the UV886 is for line frequencies below 50 Hz. (45 Hz was a line frequency that was infrequently employed in parts of the country back in the day. The lower line frequencies, when applied to a transformer that is wound for 60 Hz, don't allow as efficient a transfer of energy, hence the lower resistance of the UV876.) It was also used in areas where the line voltage would have been different than normal.
Alternative (on other amplifiers) to choosing which ballast according to line voltage, a switch would allow the user to choose between 110 and 120 Volts.
You can use either ballast, just be sure the plate voltage on the #10 tube does not exceed its rating. If it does, you will need to take additional corrective measures. Cheers, Russie

Edit: Oops, typos on that one... I meant UV876 not UV776. I've corrected that above.
Last edited by startgroove on Sat May 25, 2019 9:14 am, edited 5 times in total.

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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by Victrola-Monkey »

Thank you Russie for the explanation of the difference between the 876 and 776 tubes. However, I was asking about using a 876 in the amplifiers that call for a 886 tube. Going by your explanation, it sounds like any of the 3 tubes will work.

VE 9-55 #766:
Well, Raphael’s client’s VE 9-55 works, radio, phono, changer, and all 3 lights. The radio comes in real clear, but there’s only a couple stations. I had to pull the Radiola out a second time. The first time was to spray clean/lubricate the radio/phono switch which resulted excellent. The second time because when the radio played it blasted and had no adjustment. Turned out that it’s volume switch was a mess. The wire wound tube on it was all coming apart. I swapped it with a spare (115 ohm) and did a spray on it and the filament control switch (63 ohm). The result was excellent. I don’t however get much volumn adjustment in sound on the phono volume switch. I’m gonna have to test it out with an ohmmeter and compare it to another. Will likely have to swap it out. I pulled the #10 tube out and with power I took a voltage reading of the plate pin of the tube #10 socket. It reads 580 VDC with reference to the amp’s chassis. Is that bad?

VE 9-25 Amp #2:
I’m going to order some resistance wire for the #81 tubes’ filament wires coming from the transformer of the one VE 9-25 amp that does not work.

VE 9-55 #2061:
I swapped my newly and verified good rebuilt amp and Condenser Bank from this machine with those that were rebuilt by ChuckA from the VE 9-55 I am keeping (#1360). Phono plays at a low volume and its volume control does not provide any change in volume. May have to open up the phono volume to see what’s going on, but I’ll do some ohmmeter testing first. The radio plays decently loud and clear but it’s volume control seems not to provide any changes in volume level. Will have to pull out this Radiola as well to see what’s going on. By the way, the plate voltage of the #10 tube socket is 575 VDC.

VE 9-55 #1360 (mine):
With my newly rebuilt amp and Condenser Bank, the phono part played great. Now need to test the radio side.
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Last edited by Victrola-Monkey on Fri May 24, 2019 7:56 pm, edited 3 times in total.

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ChuckA
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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by ChuckA »

startgroove wrote:To answer a previous question, the reason for offering two difference ballast tubes back then has to do with the line frequency and line voltage. UV876 is for a range of frequencies a little above and below 60 Hz, while the UV776 is for line frequencies below 50 Hz. (45 Hz was a line frequency that was infrequently employed in parts of the country back in the day. The lower line frequencies, when applied to a transformer that is wound for 60 Hz, don't allow as efficient a transfer of energy, hence the lower resistance of the UV776.)
Russie,

Can you post or point to the data sheet you are using to explain the function of the ballast tube in regards to its frequency characteristics?

As far as I know it's a simple current regulator that regulates the output voltage based on current draw, nothing in regards to the frequency of the incoming voltage.


Chuck

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startgroove
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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by startgroove »

Chuck,
At the moment, it escapes me where I read that. Probably in the RCA Victor Service Notes. However, with a quick search there I didn't find it. I'll have more time tomorrow afternoon to find it, and if I do, I'll post it for you.

Meanwhile, I did find a reference to it on ARF. Here is the link: https://www.antiqueradios.com/forums/vi ... &view=next
"The UV-876 is rated lower current than UV-886. UV-876 drops 40-60 volts @ 1675-1725 ma. UV-886 drops 40-60 volts @ 2025-2075 ma. RCA used the UV-876 for equipment operating on 60 cycles. UV-886 was originally designed for the same equipment but on 25 cycles." By Norm Leal.


BTW, I'm still enjoying the Brunswick Model 42 that I got from you, or through you, a couple of years ago. It has been fully restored and performs well still to this day. Thank you for help on that. Cheers, Russie

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startgroove
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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by startgroove »

Chuck,
Got up a little early this AM with a quest to find the source of the information I gave above.

It came from "RCA Service Notes For 1923-1928", pages 22 and 23. See the pics below.

I hope that helps to clear it up. Cheers, Russie
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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by ChuckA »

startgroove wrote:Chuck,
Got up a little early this AM with a quest to find the source of the information I gave above.

It came from "RCA Service Notes For 1923-1928", pages 22 and 23. See the pics below.

I hope that helps to clear it up. Cheers, Russie

I see your information and have actually read that a long time ago, but I still can't figure out what a purely resistive device has to do with input frequency range.
Time to do some investigation.

Chuck

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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by startgroove »

Wayne,
The plate voltage on the #10 tube should be read while the tube is plugged in and fully warmed up (it takes a few minutes). You have confirmed that the voltage output of the filtered DC supply will read high, as Chuck correctly pointed out previously. Once the #10 tube is installed, it becomes a load on the circuit and the plate voltage should be under 425 VDC. If it is close to that limit, the tube will suffer a short life. I like to run it under 400 volts, not less than 375. If it gets too low, there would be an increase in the likelihood of overdriving (clipping) at loud volumes, or even an increase in tonal distortion.
BTW, that voltage is not to be read referenced to chassis ground (which will read abnormally high), but read between the filaments and the plate.
It looks like you are learning a lot in this project, as I am as well. Sometime in the near future, I will be going through a couple more of these amplifiers. Yet, it is too bad we can't do them at the same time, and compare notes and results.
Cheers, Russie

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Re: Restoring the VE 9-55 and VE 9-25 Amplifiers

Post by Victrola-Monkey »

Thank you Russie and Chuck for your information and discussions. I am learning a lot and it is mostly due to you folks. I will take proper readings soon. Oh, don’t worry Russie, I’ll be rebuilding the amp’s and associated electronics of my 10-70s, 8-60s, 9-25s, 9-40/Borgias, 9-18, 9-16, 9-54s, and 15-1, plus all the RAEs. So I’m sure we will be working on them at the same time.

Below is a picture of the VE 9-55 Volume Switch and is next to the VE 9-40 (Borgia 2) and Panatrope for visual and electrical comparisons. The VE 9-55’s is 21K ohms and both the 9-40’s and Panatrope’s are 19K ohms. Fortunately the wiper and contacts are external and accessible. So I’m hoping cleaning and adjustment will resolve my Volume switches’ problems.
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