Silvertone 1472 Had Issues - Better Now

[Blackburn]

Hey everybody, just got back from vacation in Louisville, KY and came home to a new '62 Silvertone 1472 I got from Ebay. Unfortunately, this thing is not doing well...

This is what the listing stated:

Sears Silvertone 1472. Good overall condition. There are some minor stains to grill cloth and tolex but very presentable. Amplifier was just serviced and got a new 15' grounded cable, new Arco can capacitor for the power supply and a new Sprague bypass cap for the output tubes. Also one Sprague capacitor for the tremolo. All the original Sangamo tone caps tested great and where left alone. All the replacement parts are Made in the USA accept the power cord. This amp has always been kept in a nice dry location. There is no rust or corrosion. All the knobs turn freely with no noises. Tremolo works great. Original Fisher speaker has no damage and sounds good. Ready to enjoy straight out the box. All tubes are vintage USA GE and RCA. I have installed a solid state rectifier but will also supply a good used 6x4. You can swap them around for different distortion/loudness. Also you can jump channels on these with a pedal cable. Great blues/classic rock tones. Great size for practice/recording or playing out miked.

It sounds like it's got a major filtering issue and doing some readings today, I find that every cap is leaking hundreds of mVs. The output is shameful. The trem is not functioning correctly either. Before I put down the cash, I asked for a gut shot which was provided. The work looked well done and the amp is almost completely original. I decided to take their word for it and here we are. The bullshit alone is enough to make me send it back and give some bad feedback. There's a 14 day money back on it, of which I have a week from today left on. I'd love a reason to keep her, but the cap leakage is not at all a favorable repair. That, among any other possible repairs needed.

I'd love any thoughts on this situation, despite being fairly certain of what the outcome will be.

DK

[Cliff Schecht]

You sure the caps are actually leaky and you aren't reading some voltage from the next stage tube grids?

I assume this was shipped meaning all sorts of bad things could have happened. Post some pics of the amp as you received it, maybe we can spot something? Doesn't sound like the seller is trying to pull one over on you. Have you contacted him about the issues? If the seller is worth a piss he will do whatever he can to rectify the situation. Usually in my case I offer a partial refund or full refund upon receipt of the amp. Since he probably got insurance on the shipment he won't be out any money and since he sold it to you as working, eBay will be on your side. If it wasn't shipped then did you test it before taking it home?

[Blackburn]

Cliff, I actually spoke a little too soon about all the caps. I should have said the caps to and from the PI. I was just assuming for the caps on the first two channel's plates. Here are a couple pics...

Edit: The first two caps don't seem to have any DC leakage. Both volume and both tone controls are dead quiet during rotation. Just slipped my mind.

[Blackburn]

I did a recording with both volume and tone full up and in the middle I turn the trem controls all the way up. Guitar's controls full up as well.

https://soundcloud.com/snapdragon58/unh ... ertone1472

[eniam rognab]

dang man, you were SO excited for this!!! sorry to hear about the troubles...

"if dat shits whack, send it back!" trademarked

ewwww, that sounds poopy....

[Cliff Schecht]

First thing I'd check is that 220Ohm cathode resistor. Those sand cast resistors are infamous for failing either intermittently or completely even if they look OK.

Also could be a speaker issue. I fucked up a little bit recently and thought a similar sound was the yellow Astron caps in an old tweed Fender. After removing a few (luckily in a manner that made them easy to reinstall!) and troubleshooting for quite a while, I discovered my beloved SRO was blown and was causing my issues. Try another speaker, you have a very similar sound to what I was chasing.. FWIW I think blown speakers are actually pretty easy to mistake for a bad signal cap in some cases.

[vibratoking]

That sucks when you expect what you paid for and it ain't happenin'. Now you enter the realm of fix it or ship it. I'm sure it occurred to you to check the tubes in addition to the speaker. The thing looks pretty clean FWIW, which ain't much at this time.

[Blackburn]

Thanks for the responses, guys. At this point, I've pulled all tubes except for the 6X4, 6AU6 and the first 12AX7 and I'm measuring definite leakage from the first stage, second stage and PI. Can't understand why I don't hear the pots scratching with rotation. The tone pots? With no 6V6s in, I'm seeing around 9vdc on one socket and 13vdc on the other. Looking at the schem, there's no direct path for DC from the Intensity pot to the 6V6 grids, unless the .05uf cap is leaking as well. I'm just trying to be thorough and hopefully learn some more in the process, but this isn't looking positive with regard to whether the amp will stay. And Cliff, I measure 14vdc across the 220R cathode resistor and with a plate voltage of about 280vdc, it's a very cool 8.9w a piece. The amp is stable, just poopy.

http://www.silvertoneworld.net/schemati ... e_1472.pdf

Edit: Forgot to mention that I played my Ipod through the speaker and it sounds alright, but I do think trying another would be good practice. As far as tubes go, I'll probably hook up my scope and signal generator just to see what da hell is going on in the pre, if anything.

[Blackburn]

That sucks when you expect what you paid for and it ain't happenin'. Now you enter the realm of fix it or ship it. I'm sure it occurred to you to check the tubes in addition to the speaker. The thing looks pretty clean FWIW, which ain't much at this time.

Yeah, it's a one or the other type of decision and I won't drop a bit of solder unless I'm keeping it. Can't risk the seller accusing me of tampering. I can simply swap tubes and speakers or probe things.

[Cameron]

Something Ive come across in some of these old Silvertone amps and other cheaper amps like it......
The type of resistors they used ....go bad ...drift way off ..or just read open. Ive even had to change almost every resistor in a few of them...allot of times its the 330ks or 220ks that Ive changed the most..but check all you can..... The first amp i had with this.... drove me crazy until I realized what was going on...
Its something I now check first when I get one like this.... I almost always have to change a few.... the caps I check next .... with that type of cap ..I do find leakage allot ....but I think you checked that...remember tho.. if the resistor is open I might look like or sound like DC leakage also.
It is a cool amp when you get it to run right....and even better through a 4x12 cab wired to 4 ohms ...it is a simple circuit ....nothing too hard to fix.

[Blackburn]

Something Ive come across in some of these old Silvertone amps and other cheaper amps like it......
The type of resistors they used ....go bad ...drift way off ..or just read open. Ive even had to change almost every resistor in a few of them...allot of times its the 330ks or 220ks that Ive changed the most..but check all you can..... The first amp i had with this.... drove me crazy until I realized what was going on...
Its something I now check first when I get one like this.... I almost always have to change a few.... the caps I check next .... with that type of cap ..I do find leakage allot ....but I think you checked that.
It is a cool amp when you get it to run right ...and it is a simple circuit ....nothing too hard to fix.

Yeah, I expected something, but this is getting extensive enough to have me send it back. I didn't pay for a project, and there are plenty of those on the bay for cheap. I paid more than would have liked, but this amp looked promising.

[Cameron]

Something Ive come across in some of these old Silvertone amps and other cheaper amps like it......
The type of resistors they used ....go bad ...drift way off ..or just read open. Ive even had to change almost every resistor in a few of them...allot of times its the 330ks or 220ks that Ive changed the most..but check all you can..... The first amp i had with this.... drove me crazy until I realized what was going on...
Its something I now check first when I get one like this.... I almost always have to change a few.... the caps I check next .... with that type of cap ..I do find leakage allot ....but I think you checked that.
It is a cool amp when you get it to run right ...and it is a simple circuit ....nothing too hard to fix.

Yeah, I expected something, but this is getting extensive enough to have me send it back. I didn't pay for a project, and there are plenty of those on the bay for cheap. I paid more than would have liked, but this amp looked promising.

That sucks.....If the price is not worth the labor to fix it.
I would check the plate resistors at least ...since you have it. It might just be a few of them ...that would be easy...but I do understand ..the situation as a whole... has made it more trouble then its worth.

[Blackburn]

Something Ive come across in some of these old Silvertone amps and other cheaper amps like it......
The type of resistors they used ....go bad ...drift way off ..or just read open. Ive even had to change almost every resistor in a few of them...allot of times its the 330ks or 220ks that Ive changed the most..but check all you can..... The first amp i had with this.... drove me crazy until I realized what was going on...
Its something I now check first when I get one like this.... I almost always have to change a few.... the caps I check next .... with that type of cap ..I do find leakage allot ....but I think you checked that.
It is a cool amp when you get it to run right ...and it is a simple circuit ....nothing too hard to fix.

Yeah, I expected something, but this is getting extensive enough to have me send it back. I didn't pay for a project, and there are plenty of those on the bay for cheap. I paid more than would have liked, but this amp looked promising.

That sucks.....If the price is not worth the labor to fix it.
I would check the plate resistors since you have it. It might just be a few of them ...that would be easy...but I do understand ..the situation as a whole... has made it more trouble then its worth.

All the plate resistors measure fine. Some drifted, some haven't. I checked them out just now, including a few others. My voltages are good and I believe filtering is an issue and there's definitely some problem with the trem, which I think my clip shows. Half way I set it to full intensity and speed. I know it's wrong because the trem circuit in the 1482 is the same and it is much stronger.

[Cameron]

Yeah, I expected something, but this is getting extensive enough to have me send it back. I didn't pay for a project, and there are plenty of those on the bay for cheap. I paid more than would have liked, but this amp looked promising.

That sucks.....If the price is not worth the labor to fix it.
I would check the plate resistors since you have it. It might just be a few of them ...that would be easy...but I do understand ..the situation as a whole... has made it more trouble then its worth.

All the plate resistors measure fine. Some drifted, some haven't. I checked them out just now, including a few others. My voltages are good and I believe filtering is an issue and there's definitely some problem with the trem, which I think my clip shows. Half way I set it to full intensity and speed. I know it's wrong because the trem circuit in the 1482 is the same and it is much stronger.

Well in some ways thats good.
Are the resistors good in the trem? Could be a weak tube also.... do you have another to try..... Sorry if you already addressed this ...

Don't get too discouraged ...just yet.. it could still be something simple. You are right about the caps...Ive always just changed them out...If you have an ...old but good.. used cap ..clip lead it in ..at different spots in the B+... if its a bad cap ....this will at least tell you if you are on the right track. The filtering could be why the trem is weak also

[Blackburn]

I don't believe the problem to be a simple one. I don't even care about testing the tubes at this point. I just contacted the seller and am going to see if they'll cover the shipping back their way. I feel that this is a very misrepresented amp and I doubt shipping was the cause.