SFDR...new reverb tank & parts....

44deluxe · March 14th, 2006, 07:54 PM

My SFDR is coming along nicely...it sounds pretty good, although I've ordered a new Weber 12F150 speaker to see if it improves things.....

Anyway...the reverb is pretty bad and I'm thinking about changing over the tank....is that a simple job? Also I think the phono type leads that connect the reverb tank are shot...do I just need to get a new set of phono leads, or is there more to it than that?

Thanks in advance :)

milocj · March 14th, 2006, 08:01 PM

Changing the tank out is a pretty straightforward job. Take off the back panel, remove the strain relief from the cables if there is one screwed into the side of the cabinet, and then unscrew the two Phillips head screws that hold the reverb bag to the bottom of the cabinet.

There may be a cardboard bottom that you have to swap off of the old tank before you put the new one back in the bag and make sure to mark which reverb lead went where.

You can buy audio RCA leads if you want to, or you could check out www.tonecraftamprepair.com and have Vintage Jon make you up a set that looks and fits exactly like the BF and early '70s SFDRs original leads with the braided, shielded wire. I believe he's the cheapest around on repro reverb leads and he's great to deal with.

Ringo · March 14th, 2006, 10:03 PM

Just a couple thoughts, check your tubes before you go swapping tanks out, different 12AT7's can dramatically change the tone of the reverb, I think there are some other circuit tweaks too. Short of one of the really small wires breaking on one of the reverb tank inductors I don't think that there really is a lot to go bad on the tanks.
If you have access to another Fender amp with reverb, you can easily try the tank from that amp to see if it's the tank or something else that doesn't sound right.

alotas123 · March 14th, 2006, 10:13 PM

Quote:

Originally Posted by milocj

You can buy audio RCA leads if you want to, or you could check out www.tonecraftamprepair.com and have Vintage Jon make you up a set that looks and fits exactly like the BF and early '70s SFDRs original leads with the braided, shielded wire. I believe he's the cheapest around on repro reverb leads and he's great to deal with.

He's also an ace tube amp tech and a really nice guy. He works on my BFDR and gets it sounding incredible. Let's keep him in business! He also designs and makes Austone pedals. I have serious GAS for his trem/vibrato pedal.

Of course, my only affiliation with him is as my amp tech.

-alotas

radarman · March 14th, 2006, 10:15 PM

how does your reverb sound? what is it you find unfavorable about the sound, could you describe it a little more...I have to agree with replacing the 12AT7 driver and 12AX7 recovery tubes first then there are more things to look at doing besides replacing the tank right off...your tank could be just fine...you can get some vintage cable and rca connectors pretty cheap at

http://www.hoffmanamps.com/index.html
or you could buy a set already made up. I like the vintage style cable and connectors myself. take a little time to read this link it's not about SFDR's but he talks a little about the DR reverb circuit and there is lots of great info and links
http://aga.rru.com/Events/MM-DRRI-rebuild/

44deluxe · March 15th, 2006, 04:52 AM

Thanks guys...well the reverb is pretty noisy...it also crackles a bit.

I just got the amp back from an smp tech who said the tubes were ok....so it led me to think it may be the tank and/or leads. Having said that, it is a little microphonic when you turn it up past 7 or so.....

If I were to replace the reverb valve(s) which would I need? I'm a pretty busy so to spend £30/$50 on a few parts is not a problem as it saves me the time when I could be working and earning. Also do reverb/trem valves need biasing?

The amp was in a pretty bad state when I got it, I think it had got damp in a garage and hadn't been used for a while. This made me think maybe the reverb springs had got rusty, also a new reverb tank is cheap if it turns out not to be that.

It's good to know I can check the lead by swapping it over with a normal phono lead...I have plenty of them kicking about to try.

Thanks again...you're a real help dudes ;)

blue metalflake · March 15th, 2006, 04:37 PM

Quote:

Originally Posted by 44deluxe

Thanks guys...well the reverb is pretty noisy...it also crackles a bit.

I had this problem and it was cured by changing the tubes.

The tank is go / no go usually caused by a broken wire at one of the transducers. I don't remember the cost of the tubes as I changed quite a few at the same time, but it was a fairly cheap fix.

I'd try the tank from another amp before dashing out to spend.

March 14th, 2006, 07:54 PM	#1 (permalink)
44deluxe TDPRI Member Join Date: May 2004 Location: A Brit living in the South of France Age: 37 Posts: 99	SFDR...new reverb tank & parts.... My SFDR is coming along nicely...it sounds pretty good, although I've ordered a new Weber 12F150 speaker to see if it improves things..... Anyway...the reverb is pretty bad and I'm thinking about changing over the tank....is that a simple job? Also I think the phono type leads that connect the reverb tank are shot...do I just need to get a new set of phono leads, or is there more to it than that? Thanks in advance :)

March 14th, 2006, 10:03 PM	#3 (permalink)
Ringo Tele-Afflicted Join Date: Mar 2003 Location: Memphis TN Posts: 1,925	re reverb Just a couple thoughts, check your tubes before you go swapping tanks out, different 12AT7's can dramatically change the tone of the reverb, I think there are some other circuit tweaks too. Short of one of the really small wires breaking on one of the reverb tank inductors I don't think that there really is a lot to go bad on the tanks. If you have access to another Fender amp with reverb, you can easily try the tank from that amp to see if it's the tank or something else that doesn't sound right.

March 14th, 2006, 10:15 PM	#5 (permalink)
radarman Tele-Meister Join Date: Jan 2005 Location: Colorado Posts: 319	re:verb how does your reverb sound? what is it you find unfavorable about the sound, could you describe it a little more...I have to agree with replacing the 12AT7 driver and 12AX7 recovery tubes first then there are more things to look at doing besides replacing the tank right off...your tank could be just fine...you can get some vintage cable and rca connectors pretty cheap at http://www.hoffmanamps.com/index.html or you could buy a set already made up. I like the vintage style cable and connectors myself. take a little time to read this link it's not about SFDR's but he talks a little about the DR reverb circuit and there is lots of great info and links http://aga.rru.com/Events/MM-DRRI-rebuild/ __________________ One man alone can be pretty dumb sometimes, but for real bona fide stupidity, there ain't nothin' can beat teamwork. Edward Abbey

March 14th, 2006, 08:01 PM	#2 (permalink)
milocj Tele-Meister Join Date: Aug 2005 Location: Michigan Posts: 453 3 Photos	Changing the tank out is a pretty straightforward job. Take off the back panel, remove the strain relief from the cables if there is one screwed into the side of the cabinet, and then unscrew the two Phillips head screws that hold the reverb bag to the bottom of the cabinet. There may be a cardboard bottom that you have to swap off of the old tank before you put the new one back in the bag and make sure to mark which reverb lead went where. You can buy audio RCA leads if you want to, or you could check out www.tonecraftamprepair.com and have Vintage Jon make you up a set that looks and fits exactly like the BF and early '70s SFDRs original leads with the braided, shielded wire. I believe he's the cheapest around on repro reverb leads and he's great to deal with.

March 15th, 2006, 04:52 AM	#6 (permalink)
44deluxe TDPRI Member Join Date: May 2004 Location: A Brit living in the South of France Age: 37 Posts: 99	Thanks guys...well the reverb is pretty noisy...it also crackles a bit. I just got the amp back from an smp tech who said the tubes were ok....so it led me to think it may be the tank and/or leads. Having said that, it is a little microphonic when you turn it up past 7 or so..... If I were to replace the reverb valve(s) which would I need? I'm a pretty busy so to spend £30/$50 on a few parts is not a problem as it saves me the time when I could be working and earning. Also do reverb/trem valves need biasing? The amp was in a pretty bad state when I got it, I think it had got damp in a garage and hadn't been used for a while. This made me think maybe the reverb springs had got rusty, also a new reverb tank is cheap if it turns out not to be that. It's good to know I can check the lead by swapping it over with a normal phono lead...I have plenty of them kicking about to try. Thanks again...you're a real help dudes ;)