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SFDR questions

 
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Muttcaster



Joined: 03 Sep 2006
Posts: 130
Location: New Mexico

PostPosted: Tue May 01, 2007 1:55 pm    Post subject: SFDR questions Reply with quote

Amp is a '75 SFDR w/ Philips tubes, fresh caps (chocolate), Weber Cali speaker. I leave the pull boost off. This is my first "big" amp (the others being a '57 Champ and '62 Princeton) and I have some newbie questions.

1) At what volume number should it start breaking up? This one sounds clean up to 3 and starts breaking up at 4. By 6 it's rock 'n roll and by 8, it's Hendrix. I've been playing the amp down at the barn and folks, this thing is LOUD.

2) Noise- I can't believe how noisy my guitars are. Once you get up to 5-6, every switch click, finger squeak, and strap-lock shift goes thru the amp. Is this normal or do I need to do some shielding?

3) Past 5, the bass notes get so strong that they're unbalanced. The low E, in particularly, will immediately make the sound totally distorted. The Princeton doesn't do get this "loose", even at full blast (it's also recapped, retubed, with a blue Weber speaker)

I suspect a lot of this is just learning to control the amp, but if you have any comments, been-there/done-that, suggestions, I'm open.
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Silverface



Joined: 23 Aug 2006
Posts: 324
Location: Hermosa Beach CA

PostPosted: Fri May 04, 2007 2:15 pm    Post subject: Reply with quote

A few things:

Quote:
fresh caps (chocolate)


??
Fresh caps means a cap job - which is replacement of the electrolytic filter caps under the "doghouse" on the other side of the chassis, plus the bias cap. The "chocolate" caps affect tone, but are not normally replaced unless you're aiming for a different sound. They're not a maintenance item, and if you were sold an amp with a "cap job" and the electrolytics were not replaced, you were mislead IMO - plus, are you saying you have NEW chocolate caps now? I wasn't aware of anyone making them - they are considered the worst amp caps ever used by Fender, and often are replaced with orange drops or others.

If bass notes are breaking up it sounds like it needs a cap job - catch 22. If it's breaking up at "4" - same thing (although the numbers on the knobs are pretty meaningless, as different components in the amp circuit can make those numbers irrelevant as a guideline). You should check the bias as well - it may be biased too hot, common with DR's. Anything over 20-22ma is danger zone, and some people will bias them like 6L6 amps at 30-40ma...very bad for tubes, transformers, tone. After the cap job the amp would need to be rebiased as well.

Another question concerns tubes - what is your V2 preamp tube, what power tubes are in it, and what rectifier?

Anyway - first things to check are the "doghouse" and bias caps - if they are not replacements it's way overdue, and that needs to be done - you shouldn't even be playing it if it hasn't been done. Second, I'd check the bias and rebias if necessary.

Then re-post and let's see where you are.
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Muttcaster



Joined: 03 Sep 2006
Posts: 130
Location: New Mexico

PostPosted: Sat May 05, 2007 1:20 am    Post subject: Reply with quote

Silverface wrote:

Quote:
fresh caps (chocolate)


??


Just ignore me.... Very Happy I don't know anything about amps other than those glass things in the back are called "tubes", there's some "knobs" on the front, and I think there's a speaker involved.

I sent pictures of it to Drake before I bought and he approved. Somewhere on my hard drive are those same pictures but I can't find 'em right now. When I do, I'll show 'em to you.

EDIT: I just checked the bias of the amp and it said it was "radically liberal". I did my best to re-bias it, but the top end only got tight and shrill, so I just shut it down, came up to the house, and plugged the Champ in. The Champ is about as unbiased as you can get, I guess.
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Drake



Joined: 22 Aug 2006
Posts: 89
Location: California

PostPosted: Sat May 05, 2007 4:28 am    Post subject: Reply with quote

Quote:
EDIT: I just checked the bias of the amp and it said it was "radically liberal". I did my best to re-bias it, but the top end only got tight and shrill, so I just shut it down, came up to the house, and plugged the Champ in. The Champ is about as unbiased as you can get, I guess.


Laughing Laughing Laughing
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Silverface



Joined: 23 Aug 2006
Posts: 324
Location: Hermosa Beach CA

PostPosted: Sat May 05, 2007 4:09 pm    Post subject: Reply with quote

OK, now that we have all THAT out of the way -

Has the amp ever had a cap job? If not, it needs to go to a tech for service immediately. You are in danger of losing a transformer and other critical parts if a cap blows, and if it still has originals it's WAY overdue.

I can give you some advice - but not without knowing exactly what you have. And if you are using a tube amp I strongly suggest getting a bit educated about them. Gerald Weber's Hip Reference to Tube Guitar Amps ( or something like that) is a decent introduction. But tube amps are finicky and need "tuning" regularly, plus you don't just plug-'n-play; there are different ways of setting one up depending on what sound you are aiming for. If you don't know how to do basics - discharge filter caps to avoid electrocution, change/bias tubes, recognize bad parts, know how & why to use a multimeter, know how to solder - you'll be spending an ever-flowing pile of money at your tech's shop.

Classic tube amps are outstanding tonal tools, but they are not for everyone - so unless you plan on learning how to work on it or have a tech who can do the work for you (and the funds to pay him), IMO it's not the right tool to have.

And if you don't have a tech, you need to find one.
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Muttcaster



Joined: 03 Sep 2006
Posts: 130
Location: New Mexico

PostPosted: Sat May 05, 2007 6:04 pm    Post subject: Reply with quote

"Find a tech"?? I drive 35 miles for groceries! Very Happy Nearest good guy is probably "Lord Valve" up in Denver (300 mi) which is do-able. I sent my Champ to Drake and bought the Princeton from a fanatic, so I'm good there. I wouldn't mind shipping but the last time I sent an amp out (to a guy in TX), I had to have a friend go over and personally retrieve the amp, otherwise, I'm not sure I would've seen it again. I'll probably start learning, myself, but I've been saying that for 3-4 years now. Honestly between the ranch, the guitar business, church, and family, I'm pretty full.

Do we have recommendations for techs?

Anyway, pictures:










More:
http://www.larp.com/bakimsey/SFDR/004.JPG
http://www.larp.com/bakimsey/SFDR/005.JPG
http://www.larp.com/bakimsey/SFDR/006.JPG
http://www.larp.com/bakimsey/SFDR/007.JPG
http://www.larp.com/bakimsey/SFDR/009.JPG
http://www.larp.com/bakimsey/SFDR/011.JPG
http://www.larp.com/bakimsey/SFDR/012.JPG
http://www.larp.com/bakimsey/SFDR/013.JPG
http://www.larp.com/bakimsey/SFDR/014.JPG
http://www.larp.com/bakimsey/SFDR/015.JPG

EDIT- lunch (green chile chicken quesadilla ) was calling and I had to run... I DO have Tom Mitchell's book/video combination, just haven't had time to mess with an actual amp yet. Like I said, my Princeton and Champ are in good shape and I actually bought this DR to tinker with. Maybe when Drake comes to see me this summer, I can convince to show me around the amp? Anyway, take a look at the pictures and tell what you see.

Thanks,
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Drake



Joined: 22 Aug 2006
Posts: 89
Location: California

PostPosted: Sat May 05, 2007 6:35 pm    Post subject: Reply with quote

Play it and enjoy it.

Quote:
1) At what volume number should it start breaking up? This one sounds clean up to 3 and starts breaking up at 4. By 6 it's rock 'n roll and by 8, it's Hendrix. I've been playing the amp down at the barn and folks, this thing is LOUD.


Same as my SFDR, which is like most any other DR. Play it and enjoy it.

Quote:
2) Noise- I can't believe how noisy my guitars are. Once you get up to 5-6, every switch click, finger squeak, and strap-lock shift goes thru the amp. Is this normal or do I need to do some shielding?


The pups are microphonic, which you already know. You like them that way. Play it and enjoy it.

Quote:
3) Past 5, the bass notes get so strong that they're unbalanced. The low E, in particularly, will immediately make the sound totally distorted.


Like a DR. Turn down the bass, to like 2 or something, make the treble 6 or 7. A Weber Cali is efficient, and can thump. Play it and... Cool

Man, you're inquisitive for a cow herder.
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Silverface



Joined: 23 Aug 2006
Posts: 324
Location: Hermosa Beach CA

PostPosted: Sun May 06, 2007 2:27 am    Post subject: Reply with quote

Hey - I noticed the picture storage.

Bryan, is that you? Sheesh...I have a couple guitars coming your way as soon as I can get them packed for shipping.

Anyway - looks like you're in good shape cap-wise, except we can't see the bias cap. There have been some other parts replacements, all wiht quality stuff - and I like the date notation on the filter doghouse. Apparently, someone knew what they were doing.

If you want to play with some bias settings you can get a Bias Rite from Weber that makes it a no brainer...or email me and I'll loan you my Bias King to experiment with some settings.

As Drake said, turn down the bass when you turn up the amp - Fender's bass control needs to almost always be turned down as the amp is turned up.

I did find a shop that deals with amps in NM, but haven't looked at a map to see how far tey are from you:

Studio D
6415 Central Ave NE
Albuquerque, NM 87108

Contact: Donny Tesso

Phone: 505-256-3061

Email: dft@studio-dyp.com
Web Site: www.studio-dyp.com

Or if you want it just checked out to make sure everything is OK, you can ship me the chassis/tubes, I can use my cabinet/speakers and check it out for you for nuttin' other than shipping cost.

With the tubes in that thing, once it's set where you like it it should be pretty well dialed-in for a long time.

Email or call me if you have any questions -

Jim Sliff
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Muttcaster



Joined: 03 Sep 2006
Posts: 130
Location: New Mexico

PostPosted: Sun May 06, 2007 1:11 pm    Post subject: Reply with quote

Silverface wrote:
Bryan, is that you?


Busted! Smile

Silverface wrote:
If you want to play with some bias settings you can get a Bias Rite from Weber that makes it a no brainer...


I'll look into that. Like I said, I've been meaning to get started on tube amps for awhile- just a lack of time and work space right now. Also, as everyone noted, if you don't do it right, it's electrocution time. When Drake shows up again, I'll cajole him into showing me the right way to get rolling.

Silverface wrote:
I did find a shop that deals with amps in NM, but haven't looked at a map to see how far they are from you:


250 miles. Unless a guy comes out of the woodwork locally, it's going to be a long drive. Given gas prices, I'd just as soon ship the chassis off.

Silverface wrote:
Or if you want it just checked out to make sure everything is OK, you can ship me the chassis/tubes,


Noted and filed.

Thanks for the help.
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