Hi guys, I have mentioned the 1946 I.T.I AA5 that I have been restoring. Well I have one more thing to install, the electrolytic. Here is what I am confused on: The paper covering over the actual electrolytic can says three 30mfd at 150volts, all three go to the red wires.

On the schematic it states: 20mfd at 25, 30mfd at 150volts, 30mfd at 150volts. This model 546T was made by the Rauland corporation and branded Lyric, this one looks identical but says I.T.I on the dial instead of Lyric. Internally they are identical, except for this problem I have run into, the electrolytics don't match up. Now there are three red wires that were connected to the original electrolytic can that sat underneath the chassis.

My question to you: Should I go with the actual paper label that slid over the can, or the schematic that is for the Lyric (both the Lyric and I.T.I are called the model 546T). I'm thinking that it would be wise to go with what the paper label says on the can. I.T.I could stand for a technical institute, so it might of been a variation of the Lyric model, I don't know, please help if you can. Thanks.

Jon

It's a little confusing, but if there are three separate red wires on the cap, and probably one black common wire, two are power supply filters and the third is an output stage cathode bypass. It's safe to use the third 30 mfd cap as the cathode bypass; the difference in capacity won't matter much and the voltage rating is fine.

Yes, there are three red (positive) wires and one black (negative). Do you think I should go off the paper sleeve numbers or the schematic? And 10 mfd is not a huge difference? I would like it as accurate as possible to the original, but if 10 mfd off would not create a difference in performance then I am fine with that. Thanks

Jon

10mfd or even more difference here or there is often fudged with replacement capacitors, but there's no reason to use a 160 volt cap for audio cathode bypass. I would use two 33 @ 160 for the filters plus a 20 @ 25 bypass to replace the can (which I strongly suspect is itself a replacement) but that's because I have those values on hand. I don't know which values you have.

Getting parts is no problem, I have to place a order anyhow, I just want to know if it will make any difference at all perfromance wise, if there are three 30 mfd to replace (2) 30mfd and (1) 20mfd.

Jon

No there will be no performance problems. You can use them.

+1

OK, thanks fellas, I'm going with the paper label inside the chassis, and will let you know on my results. Thanks

Jon