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Official Ampeg Portaflex Club

#13,101
jdub, sure the extra row of cones is helping and I have no trouble hearing every note with the 810/SVT match up. Granted my band is not super loud. But I also don't have a problem with the 610/800rb combo and I'm a tall dude, well over 6 foot. I do have trouble with single 15 and 4 10 cabs sitting on the floor, they must be elevated. So I think it's just a matter of the ported 610 not letting the SVT do it's thing.

OK I just did a-b the 610, 810 and 2-15's with my V4BH and 1) I don't have the V4b that you have, and 2) my 810 is late '70's and cones may be quite different from what you end up with. 3) I did this at pretty low volume since my whole family was in the house. So for what it's worth here's what I found.

610hlf vs. '77 810 fridg.
The 610hlf, even with the tweeter off is a brighter sound than my 810. The 810 is like reducing the treble by a quarter turn. A newer 810 I suspect may have a brighter cone tone but that's just a guess. The 610 also goes deeper so it's a fuller range modern sound compared to my 810. The 610 is also a tiny bit louder at a given volume setting. (may be perceived due the brighter top) The V4BH/610hlf and a P bass actually sounds quite nice with the "Ultra-Lo" switch on. I would like to do this at much higher volume to see if that changes my impression, but with the V4BH at this level I kind of prefer the 610 to the 810 because you can get a much wider freq range.

15e's (2) vs....
The SVT15e, a pair of them is rated at only 400 watts. They don't seem worthy of an SVT's raw power. But they work great with a 100 watt V4BH. The pair of 15e's is the brightest, clearest and loudest cab of the 3. They will go low and stay tight. I know from actually trying it that I can eq a very B25ish tone from the V4BH with 15's. And it will go a good bit louder than an actual B25b.

However I didn't bring the B25 into this test and now that jdub asked and JimmyM replied, I am curious and will have to see how the V4BH compares with the B25b, through the different cabs.
 
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#13,102
vistacruiser said:
jdub, sure the extra row of cones is helping and I have no trouble hearing every note with the 810/SVT match up. Granted my band is not super loud. But I also don't have a problem with the 610/800rb combo and I'm a tall dude, well over 6 foot. I do have trouble with single 15 and 4 10 cabs sitting on the floor, they must be elevated. So I think it's just a matter of the ported 610 not letting the SVT do it's thing.

OK I just did a-b the 610, 810 and 2-15's with my V4BH and 1) I don't have the V4b that you have, and 2) my 810 is late '70's and cones may be quite different from what you end up with. 3) I did this at pretty low volume since my whole family was in the house. So for what it's worth here's what I found.

610hlf vs. '77 810 fridg.
The 610hlf, even with the tweeter off is a brighter sound than my 810. The 810 is like reducing the treble by a quarter turn. A newer 810 I suspect may have a brighter cone tone but that's just a guess. The 610 also goes deeper so it's a fuller range modern sound compared to my 810. The 610 is also a tiny bit louder at a given volume setting. (may be perceived due the brighter top) The V4BH/610hlf and a P bass actually sounds quite nice with the "Ultra-Lo" switch on. I would like to do this at much higher volume to see if that changes my impression, but with the V4BH at this level I kind of prefer the 610 to the 810 because you can get a much wider freq range.

15e's (2) vs....
The SVT15e, a pair of them is rated at only 400 watts. They don't seem worthy of an SVT's raw power. But they work great with a 100 watt V4BH. The pair of 15e's is the brightest, clearest and loudest cab of the 3. They will go low and stay tight. I know from actually trying it that I can eq a very B25ish tone from the V4BH with 15's. And it will go a good bit louder than an actual B25b.

However I didn't bring the B25 into this test and now that jdub asked and JimmyM replied, I am curious and will have to see how the V4BH compares with the B25b, through the different
cabs.
Click to expand...

JimmyM and vistacruiser, thanks for the feed back. This is great stuff, I am tempted to try the v4b thru my b25b cabinet as well to see how it sounds compared to the 70's b25b head. Looks like an 810 will be in my future ; ).
 
#13,104
vistacruiser said:
"I am tempted to try the v4b thru my b25b cabinet"

jdub, that sounds like a great idea. But the B25b cab, if I'm not mistaken, is two 8 ohm speakers wired in series to equal 16 ohms. In that case you will need to re-wire the cab to parallel and bring it to 4 ohms for the V4b. Right?
Click to expand...

After the first year of the B25 they added a series/parallel switch for 4 or 16 ohm operation.
 
#13,106
coreyfyfe said:
After the first year of the B25 they added a series/parallel switch for 4 or 16 ohm operation.
Click to expand...
jdubbass38 said:
Correct my cabinet is a late 70's with a 16 and 4ohm switch.
Click to expand...

Now I'm learnin' somethin'. That's cool, my B25b is a '69 and doesn't feature that convenient switch.


Disclaimer/discloser or whatever, I have played around with 12ax7's in my pre-amps, the B25b runs with a Tung-Sol in channel 2. And either old RCA or Sovtek "LPS" are whats in the V4BH, they both sounded really good to me and I can't really tell them apart. That said, the V4BH is surprisingly good at reproducing the B25 sound, with all 3 of my cabs. I assume the V4b is as good or better. For the sake of this comparison I will consider the pair of SVT15e's as one cab. I used a fender 4 string in standard tuning with DiMarzio model P and laBella deep talkin' flats. My vol knob is about 3/4 up on the bass to keep the signal from over driving the amps.

First off, I set up my B25b this way, bass plugged into channel 2.
B25b settings with orig 2-15 cab: V-9:30 to 10:00, T-10:30, B-1:30 and if vol goes up much, bass will come down to keep it somewhat clean.

So first I dialed in the svt15e's. The 15's captured the B25 character better, I think, than the 10's did. I guess that, and the convenience of using 1 or 2 cabs is why I favor them as my first choice with the 100 watt V4BH. But they also required the use of "ultra lo" to scoop out the very present mids, and as you know these cabs have no tweeters but still I cut Treble quite a bit to tame the brightness of these speakers.

V4BH settings with svt15e's:
Gain and Master at Noon, B-12:00, M-12:00, T-9:00, "ultra-lo" ON

Next I went to the '77 vintage 810. Not sure how this cab compares to a newer 810e, but it strikes me as a dark sounding cab, especially compared to my newer Ampeg cabs. Still it does the B25 sound, with authority.

V4BH settings with SVT810:
Gain and master at Noon, B-9:00, M-12:00, T-12:00, "lo and hi" off.

Finally, the 610hlf. (tweeter OFF) This being the first time I've put the 610 side by side with a B25b, I was a little surprised by the 610. Setting were all very similar to the 810 but volume included, all needing to be cut slightly. The 610 again, was noticeably louder than the others. It still sounds B25ish but with deeper lows and clearer upper mids and highs. Kind of a modern, if you will, B25 tone. I guess that's what the Ampeg sound is all about. You really have to watch the Bass setting tho, or the tone tends to go too deep and get muddy. Not as much of a problem though as I've had with my SVT head on this cab.

V4BH settings with svt610hlf:
Gain-Noon, Master just a tad under 12:00, B-8:30, M-11:00, T-11:00, Mid freq centered, "lo and hi" off.

Summary, I could get a satisfying vintage B25b sound with the V4BH and either the 2-15e's or the 810, the 610 sounded very good also, but not quite what I'd call "vintage" B25.
 
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#13,107
jdubbass38 said:
This is great stuff, I am tempted to try the v4b thru my b25b cabinet as well to see how it sounds compared to the 70's b25b head .
Click to expand...

Please do, and let us know how the two heads compare through the same 2-15 cabinet!

jdub, are you or have you ever tried using a solid state rectifier in place of the 5ar4 tube in your B25b?
I like the effect it gives. More punch and stronger attack, it actually feels like it adds headroom. It's a simple as pulling the tube and putting the ss recto in it's place. When I put the ss recto in my B25b I saw a voltage increase of 3% at pins 3 and 4 of the 7027A's. From 505 and 499 up to 520 and 514. I took it back out after a while when I noticed my old Sylvania power tubes were not well matched. But plan to re-install it at some point when I re-tube with a matched pair of Sovtek 7027's that are stashed away. :)
 
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#13,110
After the brutal winter that some of us experienced this year, perhaps it's the nice weather.

It would be interesting to know if postings are down since the new TB software came online. Even though it is nice and all, people get put off by change. Maybe that's why most of my musical instrument amps are old. Even the newer tube amps are heavily based on the old designs.
 
#13,111
beans-on-toast said:
After the brutal winter that some of us experienced this year, perhaps it's the nice weather.

It would be interesting to know if postings are down since the new TB software came online. Even though it is nice and all, people get put off by change. Maybe that's why most of my musical instrument amps are old. Even the newer tube amps are heavily based on the old designs.
Click to expand...

I'm not sure, but it seems to me that since the new software came on line, I find myself hanging out in different sections of TB. I can't put my finger on why my habits changed, other than they changed with the new software. I probably post more now than I did before, just not in the same areas. I do like the new software, by the way.
 
#13,113
Stealth Fighter said:
I'm not sure, but it seems to me that since the new software came on line, I find myself hanging out in different sections of TB. I can't put my finger on why my habits changed, other than they changed with the new software. I probably post more now than I did before, just not in the same areas. I do like the new software, by the way.
Click to expand...

I see a panel on the right with the most recent posts on TB. It certainly makes it easier to see what is going on in different groups. For some reason this doesn't come up when I log in, just when I view as a guest.
 
#13,117
Just Signed up, This is my first post. I have what I believe to be a 1964 B15NC head with all of the original Ampeg branded tubes but without the speaker cabinet. Some pots are dated 62 and others are 63 and the FP can electrolytic is dated 6404. Even though the amp had no discernable hum, I decided that because the cap is 50 years old it was best to replace it. It is cathode biased with a 5AR4 and utilizes eyelet board wiring construction. It does not have named input jacks (Guitar, Bass, Accordion) or a serial number on the chassis under the power cord or anywhere else.
I acquired this amp back in the mid 1970's from the manager of a band I was with at the time. I traded a 1969 Plymouth AM car radio for it.
When I got it home after rehearsal I noticed that I did not have 6.3 volts as the filaments and the Lucite logo lights were not on.
I got out my voltmeter and began checking voltages. As I was probing, when I touched the filament string on the first 6L6GB the Lucite logo lights flashed. I got out my Weller gun and touched up the solder joint and it came to life. I replaced all of the caps with Orange drops. I removed the Ampeg tubes, put them away in tube boxes and replaced them with Sylvania tubes that I had laying around. Now that I have electronically restored the amp, my next project is building the speaker cabinet. I have attached a picture of my B15NC. Jimmy, I would like to join the discussion group.
 

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#13,118
#413 PapaJohnBass

And since you mentioned it...nice of you to post your pic but you do not need a pic of your Portaflex or even own a Portaflex to participate in the discussion. All are welcome...you just can't join the club unless you have one ;)
 
#13,119
JimmyM said:
#413 PapaJohnBass

And since you mentioned it...nice of you to post your pic but you do not need a pic of your Portaflex or even own a Portaflex to participate in the discussion. All are welcome...you just can't join the club unless you have one ;)
Click to expand...
Thanks. I have been reading TB for over a decade and I really wanted to rebuild the B15NC. It was through this site that I finally decided to to the jopb. I have gathered enough info from the members to build the cabinet. I have purchased an Eminence Delta 15A this week and I am gathering some of the hardware to build it. Tough to find 13 ply Baltic Birch in my neck of the woods but I will keep trying until I get a sheet. I will post pictures of the cabinet when it is complete.
 
#13,120
PapaJohnBass said:
I have what I believe to be a 1964 B15NC head with all of the original Ampeg branded tubes but without the speaker cabinet.
Click to expand...

Welcome and nice looking amp. At first glance, I thought that you traded a 69 Plymouth for it. I like old cars with AM radios.

I find baltic birch is often available at wood stores that sell high end wood, as opposed to hardware stores. They list baltic birch at this place: http://www.exoticlumberinc.com/. Some of these places will precision cut the wood for you. I like to pick out my own plywood to ensure that it isn't warped. Less of a problem if the wood is stored in a warehouse as opposed to outside in an open shed.


David
 
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