Help Identifying/Understanding 1960 5f11 replacement caps

redhouse_ca

TDPRI Member
Joined
May 13, 2022
Posts
57
Age
54
Location
USA
Hi all, I have a 1960 F511 that was stored for a bunch of years at my moms house while I moved around a lot. I bought it in 93 or so and there we some updates (or down-dates, not sure) made in 92. I am by no means proficient with amp circuits but I’d like to learn more. I found the schematic on the forum and I’m trying to orient the circuit layout with the schematic but I’m a bit of a knucklehead with such things and figured I’d ask for help. The amp seems to have the original speaker and transformers, but clearly some caps (and possibly other complaints) have been replaced. It sounds amazing and I pulled the tubes and they are a combo of vintage RCA and possibly NOS Sovtek, but I’m not sure.

Could someone help me identify, left to right, what looks to have been replaced and what the impact to tone might be because of these replacements? I can send more pics if you need them. Thank you, and my apologies in advance if this is not the right place to post this.
 

Attachments

  • FE4C1532-29F6-4E22-A73C-F4738B341032.jpeg
    FE4C1532-29F6-4E22-A73C-F4738B341032.jpeg
    154 KB · Views: 47
  • 30041A43-AE24-495A-82E3-DE58215221B3.jpeg
    30041A43-AE24-495A-82E3-DE58215221B3.jpeg
    268.8 KB · Views: 44
  • D7E568DF-4707-4653-867C-B3FFB20E4244.jpeg
    D7E568DF-4707-4653-867C-B3FFB20E4244.jpeg
    187.6 KB · Views: 44
  • 937F51B0-F306-4998-AB50-D346D20B43DC.jpeg
    937F51B0-F306-4998-AB50-D346D20B43DC.jpeg
    187.3 KB · Views: 40
  • E7B6875F-6F07-49A6-83C9-4858B81BB908.jpeg
    E7B6875F-6F07-49A6-83C9-4858B81BB908.jpeg
    164.2 KB · Views: 43
  • 2E4A148F-A50C-4045-AF52-D1C36940A230.jpeg
    2E4A148F-A50C-4045-AF52-D1C36940A230.jpeg
    215.3 KB · Views: 45
Last edited:

redhouse_ca

TDPRI Member
Joined
May 13, 2022
Posts
57
Age
54
Location
USA
Did you mean 5F11?
Yes, typo, sorry. I am very new to this forum and this is clearly a 101 level post and if it’s not appropriate, please let me know and I’ll ask to have it removed. I have read through a bunch of posts and I am trying to figure this out myself but I also thought maybe someone could fast-track this for me. Again, my apologies if this is too pedestrian for the forum.
 

Wally

Telefied
Ad Free Member
Joined
Mar 17, 2003
Posts
41,727
Location
Lubbock, TX
The filter caps, the bias cap, and two bypass caps, one on the input gain stage and one in the tremolo circuit triode…. have been replaced. Theseare all electrolytics. It appears that someone has added a 1/4” Jack to the speaker out circuit.
Beyond that, it looks to be original from what we can see.
 

redhouse_ca

TDPRI Member
Joined
May 13, 2022
Posts
57
Age
54
Location
USA
The filter caps, the bias cap, and two bypass caps, one on the input gain stage and one in the tremolo circuit triode…. have been replaced. Theseare all electrolytics. It appears that someone has added a 1/4” Jack to the speaker out circuit.
Beyond that, it looks to be original from what we can see.
Thank you, this is super helpful. If you don't mind me asking, are the replacement parts quality? Do you feel that the replacement parts would have had a meaningful impact on tone (I know this is subjective)? Thank you!
 

redhouse_ca

TDPRI Member
Joined
May 13, 2022
Posts
57
Age
54
Location
USA
With the dates on those parts, it's due to get serviced again.
Thanks. It's basically been in storage for the past 20 years (I know that's a shame, but life sometimes gets in the way of enjoyment of things like this). That said, would the lack of use impact the interval of service or is it just a smart move to get it checked out? Thanks!
 

Wally

Telefied
Ad Free Member
Joined
Mar 17, 2003
Posts
41,727
Location
Lubbock, TX
Thank you, this is super helpful. If you don't mind me asking, are the replacement parts quality? Do you feel that the replacement parts would have had a meaningful impact on tone (I know this is subjective)? Thank you!

I am not familiar with those caps. The original selenium rectifier diode is there. Most would have changed that out when the recap was done. I think I see the original brown two-wire Ac power cord. That needs to be changed with a 3 wire AC cord wired in the best and safest manner.
if I read the dates on those large silver filter caps, they are fr9m 1991. That is 31 years……with 20 of those years being without current running through them. That is not an ideal way to treat an amp. It would have been better to have run some current through the amp occassionally….once a month at a minimum. But…done is done. Many would advise recapping again. I don’t have the amp in front of me, so I Don’t know what I th8nk…except those caps have been ignored for too long. IF I had some electrolytic caps that were 30-year old NOS….never used; then I would have some 30 year old NOS electrolytic caps that I would never put in an amp.
USA is a big place. Got a tech??
I like a 5F11 a great deal…..if you are going to use it, it needs work. If not, sell it while it is working.
 

King Fan

Poster Extraordinaire
Ad Free Member
Joined
Jan 1, 2013
Posts
8,184
Location
Salt Lake City
That is a superb amp in overall very nice shape. A gem.

What the smart guys are saying is e-caps go bad, especially if not used. Replacing all the e-caps can’t hurt tone, in fact may help — but is key for reliability. Your 1992 caps have no vintage mojo *or* modern quality.

As for signal caps, yours are desirable. A good tech will try hard to preserve the blue 'Ajax' caps and might evaluate the yellow Astrons to keep if possible.

A general checkup for reliability and safety is smart. And a 2-prong cord can kill you, or somebody else, or your amp. Tech time.
 

redhouse_ca

TDPRI Member
Joined
May 13, 2022
Posts
57
Age
54
Location
USA
That is a superb amp in overall very nice shape. A gem.

What the smart guys are saying is e-caps go bad, especially if not used. Replacing all the e-caps can’t hurt tone, in fact may help — but is key for reliability. Your 1992 caps have no vintage mojo *or* modern quality.

As for signal caps, yours are desirable. A good tech will try hard to preserve the blue 'Ajax' caps and might evaluate the yellow Astrons to keep if possible.

A general checkup for reliability and safety is smart. And a 2-prong cord can kill you, or somebody else, or your amp. Tech time.
Thank you very much. Super helpful. It sounds glorious. A little hum, but I don’t mind that too much. The harmonic overtones at low, clean volume sound beyond rich. I’m super lucky to have it and I appreciate the feedback.
 




Top