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Official Ampeg Portaflex Club
- Thread starter JimmyM
- Start date
I'd love to know how many working Fliptops are in Australia- particularly bass amps. I'd be guessing less than 10.
..also.... what's the deal with extension cabs on these things?
I was experimenting with different cabs @ the Basscentre (thx Mr Dave!) and found that adding a second cab results in a huge volume DROP.
[mines a '65]
"hmmmm... I have a really small and quiet gig tonight so I'd better take my extension cab"
I was experimenting with different cabs @ the Basscentre (thx Mr Dave!) and found that adding a second cab results in a huge volume DROP.
[mines a '65]"hmmmm... I have a really small and quiet gig tonight so I'd better take my extension cab"
Ya, that's why I abandoned the idea of ever using an ext cab with mine. It actually splits the 25 watts into two cabs, which could easily be perceived as a volume drop...also.... what's the deal with extension cabs on these things?
I was experimenting with different cabs @ the Basscentre (thx Mr Dave!) and found that adding a second cab results in a huge volume DROP.
"hmmmm... I have a really small and quiet gig tonight so I'd better take my extension cab"
Most of the 60's era schematics I've looked at seem to indicate that the internal speaker is 16 ohms and the extention should be 16 ohms also. Plugging in the extention speaker jack switches the OT tap to 8 ohms.
ReallY? Because I've never seen one that didn't have an 8 ohm internal speaker. Why would they use 8 ohm speakers if the tap was made for 16 ohms?
He's right about that 16 ohm tap off the transformer.
I was wondering why also.
Unless the external speaker jack is wired in series.
It switches the tranny to the 16 ohm tap to match up to the two 8 ohm loads when you run the extention cab..
I'm just saying.
I was wondering why also.
Unless the external speaker jack is wired in series.
It switches the tranny to the 16 ohm tap to match up to the two 8 ohm loads when you run the extention cab..
I'm just saying.
The external speaker is wired in series. 8 ohm internal + 8 ohm external = 16 ohms. I guess that Portaflexes don't like 4 ohm loads.
BTW, I got my JJ tubes in yesterday, retubed my B15N and turned it on (after 25 years of sitting untubed in someone's basement). I turned the power on and watched all the tubes light up, waited a couple of minutes and switched the standby off. No sound, but no noisy pots either. I plugged my ol'Jazz and wow, I can't describe it yet. Smooth, creamy...ah no adjectives fit. It was like my strings changed their tension and were so beautiful to play.
I silence I heard when I fired up the amp was just that; silence. No hiss, no hum, no nothing but angelic tone. I guess there is no need for a cap job at this point. Quite crazy that it just sat with no apparent deterioration to the components. I was certainly expecting to have some work to do getting it up and running. I got dealt a lucky hand this time I guess.
BTW, I got my JJ tubes in yesterday, retubed my B15N and turned it on (after 25 years of sitting untubed in someone's basement). I turned the power on and watched all the tubes light up, waited a couple of minutes and switched the standby off. No sound, but no noisy pots either. I plugged my ol'Jazz and wow, I can't describe it yet. Smooth, creamy...ah no adjectives fit. It was like my strings changed their tension and were so beautiful to play.
I silence I heard when I fired up the amp was just that; silence. No hiss, no hum, no nothing but angelic tone. I guess there is no need for a cap job at this point. Quite crazy that it just sat with no apparent deterioration to the components. I was certainly expecting to have some work to do getting it up and running. I got dealt a lucky hand this time I guess.
I just recently plugged my 77 head up to my SVT cab, which is 4 ohms, and it worked just fine. Jess Oliver says that you can run 4 ohms safely with it. So I wouldn't say it rejects 4 ohm loads. Might not be the optimum way to use it, though.
hey guys,#32 here,
two quickies here.
does ampeg (ie,whoever owns them now) have a ironclad patent on the fliptop design ?
i'm really surprised no other amp mfg has "copied" the portaflex idea.
lately i've been using a sansamp bass driver d/i for a little extra kick w/ my old B-15
i can make that baby sound like an svt w/ just the push of a button.
two quickies here.
does ampeg (ie,whoever owns them now) have a ironclad patent on the fliptop design ?
i'm really surprised no other amp mfg has "copied" the portaflex idea.
lately i've been using a sansamp bass driver d/i for a little extra kick w/ my old B-15
i can make that baby sound like an svt w/ just the push of a button.
Ampeg owns all patents on the fliptop. It's patented in Jess' name, but Ampeg owns it. When Jess left Ampeg in 1966, he wasn't permitted to make fliptops anymore, so his Oliver Powerflex amps have a sewing machine motor that lifts the head in and out of the cab. Vintage Blue has a couple pics of his Oliver on the first page of this thread.
I got a portaflex today! A 67-68 B15N, came with original fully functioning speaker (boxed currently has a 4 ohm carvin 15 in it original speaker part# 5815113 next line 137 6812) and is in darn near perfect cosmetic condition, not one tear in the tolex. The only non original component on it is the transformer on the right which the guy I bought it from thought it came from an SVT, but wasnt sure. Its a Foster transformer, with the #'s S5-3227-01
39477 1 or I 2
PN. 14498
The only damage to the thing is the wood bar that goes across the front of the speaker is missing. The handle is broke, but it came with a new exact replacement (though I have no idea what kind of tool fits the screws that holds it on. Has 3 original ampeg 6sl7's, 2 really old GE6L6's and one GE 5AR4. I hope to change the transformer out soon, I dont know which model the one on the right is, is it the PT or the OT? Though it doesnt shock when touched the current running through it can be felt and it kind of hums a little as well (like when you touch the magnet of a pickup). This makes me a little nervous with a toddler running around. Anyway the thing bleeds tone! Im very happy with the purchase, I got one heck of a deal on it!
John
39477 1 or I 2
PN. 14498
The only damage to the thing is the wood bar that goes across the front of the speaker is missing. The handle is broke, but it came with a new exact replacement (though I have no idea what kind of tool fits the screws that holds it on. Has 3 original ampeg 6sl7's, 2 really old GE6L6's and one GE 5AR4. I hope to change the transformer out soon, I dont know which model the one on the right is, is it the PT or the OT? Though it doesnt shock when touched the current running through it can be felt and it kind of hums a little as well (like when you touch the magnet of a pickup). This makes me a little nervous with a toddler running around. Anyway the thing bleeds tone! Im very happy with the purchase, I got one heck of a deal on it!
John
#33 Aragorn35016
Nice score, although the grillcloth is also non-original. The replaced transformer is the power transformer. The one on it does kind of look like an SVT transformer, huh? The screws holding the handle on are called clutch screws, and you can put them on and take them off with a torque driver, available at most hardware stores.
Any replacement parts you may need you can get at www.fliptops.net.
Nice score, although the grillcloth is also non-original. The replaced transformer is the power transformer. The one on it does kind of look like an SVT transformer, huh? The screws holding the handle on are called clutch screws, and you can put them on and take them off with a torque driver, available at most hardware stores.
Any replacement parts you may need you can get at www.fliptops.net.
Ah I see that now that I looked at other pics here, oh well, minor thing to me. Again for what I got in the thing its not a big deal at all! Its funny I saw two of these amps today, and they look to be identical models. The other is in much worse shape, and the guy that owns it doesnt want to get rid of it until he retires (hes 71) I was promised to be first in line to buy it when he does!
Edit: I dont think that power transformer is from an SVT, the way it mounts looks different than what an SVT transformer looks like. Oh well the thing works and has like this for many years, and will have to continue to do so until I can afford the replacement, while its down Im gonna recap it change the handle out and retube it. Needless to say, probably wont happen until next tax season! I cant get over how good this thing sounds! Never heard anything like it. However I could be wrong but I dont think there's any way it could keep up in a loud rock band, but thats nothing a mike and a good PA cant cure!
John
Edit: I dont think that power transformer is from an SVT, the way it mounts looks different than what an SVT transformer looks like. Oh well the thing works and has like this for many years, and will have to continue to do so until I can afford the replacement, while its down Im gonna recap it change the handle out and retube it. Needless to say, probably wont happen until next tax season! I cant get over how good this thing sounds! Never heard anything like it. However I could be wrong but I dont think there's any way it could keep up in a loud rock band, but thats nothing a mike and a good PA cant cure!
John
That's my philosophy, too. I use my B-15N's all the time onstage unless I need more stage volume or if I'm feeling too lazy to lift them.
Sorry, I was wrong. The internal speaker is 8 ohms, the extention is 8 ohms and when you plug in the extention the tap is switched to 16 ohms. The internal and external speaker are in series which is not the best and can give poor results.
On my B-15S the external speaker jack is wired in parallel but there is a switch on the OT taps to select 2, 4, or 8. A nice feature.
Question for you guys, I was looking at the Cap kit for the B15 on fliptops.net, and its only the caps for the power supply, is that all that needs to be recapped or do I need to replace every single cap in the thing while its open?
John
John
Well, there can't be many if Neil from Grouse Guitars has never seen one. They are all bass amps apparently. Even mine, which has "guitar" features like reverb and trem has an identical primary circuit to the ones with only "bass" features.
