Re-capping Bell Sound 3030

[nerdorama]

Some of the old integrated amps had very imprecise tone controls. Flat response may not be in the middle. You'd have to measure it, or just set it where you like it.

 

[gadget73]

if there are any fixed resistors in the tone control, or wired off the volume pot for loudness confirm their value. Some things had over-boosted loudness too.

 

[FlaCharlie]

I have the bass control down at 9 or 10 o'clock for normal sound. There are 4 ceramic disk caps attached to the bass pot, which I'm assuming have drifted a little but probably not much. What can I do to tame the bass?

I'd measure the values of any caps or resistors associated with the tone controls and replace if they aren't fairly close to the stated value. Despite their reputation for toughness, ceramic caps do drift quite a bit sometimes. Also measure the pot itself. If the problem remains you could try disabling the loudness feature (if there is one - I can't find my 3030 schematic) or bypassing the tone controls. On some amps, though, it's best to just forget about the position of the knob. Just start at minimum and turn it up till it sounds good and don't worry about.

 

[gadget73]

Some things also don't actually go flat at 50% pot travel. If you've got some means of measuring the frequency response you can figure out where flat is and just re-clock the knob as needed.

 

[EastPoint]

Resistors are all good. They're 68k and measure around 70-71k. I'll see if I can get the disk caps measured. Otherwise I may have to just leave it.

 

[Big Harry]

It's been my experience that ceramic caps are usually good unless someone has physically damaged them though if you can, it wouldn't hurt to check them. It has also been my experience that the old pots are not linear, so what is marked as flat on the front panel isn't necessarily so. Adjust the tone controls to your personal preference and enjoy the amplifier.

 

[FlaCharlie]

Yeah, more likely the pot than the ceramics although I have found some wambly ceramics on occasion. If you measure the pot and it's way off you could replace it or, if you're not getting a distorted signal, just live with it and use it in whatever position sounds best.

 

[rickknight]

Another question for the experts. I've always thought that capacitors like the Tiny Chiefs had no polarity and could be installed in any direction, but I stumbled across "Mr. Carlson's Lab" on Youtube, and he says the band on Tiny Chief and similar caps indicates the outer case of the capacitor and that that outer case shields the cap when installed correctly. He also goes into detail on how to determine which lead connects to that outer case. Any merit to this? My Orange Drops do not have any bands on them, but using Mr. Carlson's method I was able to determine that there was some sort of polarity, and it seemed to have no bearing on which side was printed. Is there any particular way I should orient these Orange Drops?

Thanks,
Rick

 

[gadget73]

It will not hurt any, some argue if it matters. I ID mine and install them as original, or the proper way if the stock is just obviously incorrect. Its one of those things that only takes a few minutes to do so why not.

If they are already installed, then the way they are is fine. I wouldn't go removing them to ID and install in any particular manner.

 

[EastPoint]

I wouldn't worry about it.

 

[primosounds]

The 716P are film and foil. I think the 715P are metallized film. The data sheets for these only mention foil for the 716P. Both will work well in tube circuits.

I think they are both film and foil type but the 715 has copper clad steel wire leads while the 716 is supposed to be solid copper wire. oops, nerdo, mentioned this previously.

 

[Brambora]

Hello,

I'm new to this site, I hope I'm asking my question correctly.

I need a replacement for the power transformer in a Bell 3030 Stereomaster Amplifier.

The Transformer that went bad has the following markings on the top lid:

32B47
138852

Contrary to the Bell 3030 schematic that I have (shown below) the 32B47 has 7 output wires. The schematic below shows 5 output wires. I'm guessing the schematic is an earlier version.

Now that the transformer is dead, I can't measure any of the output voltages to help me select a replacement and I can't find any info on the internet WRT who made the original and what the specs are.
Please let me know if you can help point me in the best direction for a replacement.

Thanks,
Cliff B

 

[knockbill]

Hello,

I'm new to this site, I hope I'm asking my question correctly.I need a replacement for the power transformer in a Bell 3030 Stereomaster Amplifier.The Transformer that went bad has the following markings on the top lid:
32B47
138852

Welcome,,, the trans EIA code is Stancor,,, you can find EIA codes in a sticky at the top of the Tube Audio forum page,,,
You will probably get more replys/help if you start a new thread,,, also the pic isn't working... Do you have a schematic for this amp?

 

[gadget73]

schematic didn't post for whatever reason

prob have to compare what you have to the schematic, draw in the changes and see what makes sense based on that. Two more wires could be a lot of things, but if we know what it connects to it gets easier to figure out what makes sense for a replacement. An exact match may not be possible but a functional sub is probably in the realm of possibility.