Double Bass Bandmates love my...B15N?!?!

[Uncletoad]

I like the solid state sound better. My AI Clarus just seemed to respond more quickly, it was almost like there was a delay with the tube amp.

It's a different thing. I prefer my Woods and Vl208's for string bass and SVT for Fenders. I'll double check the magnet thing. I was always under the impression they were alnico.

 

[macmrkt]

fwiw, I have an early B15 (like around '63) and a later one around '66. I have a '67 B18 and two 70 or 71 SVT 810's. All are stock and original. All have square magnet alnico speakers. The modern drivers by eminence are ceramic.

If you ever feel like posting photos of the B15's and B18, I'd sure love to see them. I used to have a bunch but they are long gone...

 

[Ric Vice]

A few days ago I was at my bass teacher's house and we were just sort of messing with head/cabinet combinations. Near the end he pulled out the head from his old B15 and hooked it up to an 8ohm Bag End 1x12. It sounded very nice and warm. The only thing is, I like the solid state sound better. My AI Clarus just seemed to respond more quickly, it was almost like there was a delay with the tube amp.

Well, I can only speak from my experience. I never tried to use the head
to drive another cabinet. IMHO the system was designed as a combination, so the B-15 head and the portaflex cabinet compliment each other. I have used the cabinets with a Walter Woods MI 100 and the sound was nice. It's a low volume rig. I'll second Uncletoad on the EA Cabinets there
the greatest!!! I just have a real fondness for the B-15, within it's parameters it's a good amp.


Ric

PS: This thread has taken on a life of its own

 

[Doug Ring]

Yeah well... can't compete here

I only use small rigs these days - a 100W solid state head and either a 12 or a 15 home brew cab according to venue size.

But in the attic I have a Marshall 100W bass head and a ridiculous Jimmy Bean 4x12 cab, which was aimed at the country and western market, obviously, because it's covered in blue denim and has leather corner protectors...

I don't know why I don't get rid of them, because I never use them - in fact, I'm sure the Marshall would catch fire if I switched it on again, and the cab's been in the attic 11 years and I was much younger and fitter when I hauled it up the stairs to put it there! But somehow I can't bear to part with them.

I used to think this was a great sounding combination until I was listening to a very old recording of an early band of mine. The cab had been miked, I think, but the Marshall was clearly running out of steam and the distortion was awful. It sounded grungier than Jack Bruce! With the rest of the band it sounded just about okay, but there was one number I used to kick off on bass and it was ... ordure.

So I wonder if any of these old rigs were crowd-pleasers but wouldn't be entertained near a recording studio these days?

 

[robgrow]

All this old amp nostalgia made me get out my 1983 Polytone Mini Brute last week. I've used it on a few jobs now, including an outdoor show, and it sounds great. Recently, I'd heard an excellent bassist, who had played with Woody Herman and other well known orchestras, and he was using a Polytone and had a wonderful sound. Although I'm definitely not planning to sell my AI amp or any my other newer gear, I'm having fun with the Polytone for now. I'm glad I kept it, and I doubt if I'll ever sell it.

 

[Ric Vice]

So I wonder if any of these old rigs were crowd-pleasers but wouldn't be entertained near a recording studio these days?

Well, interestingly enough there are quite a few studios that
list an Ampeg B-15 as part of their amplifier compliment. I think
that they use them mostly as a EB recording amp, though.

Ric

 

[bikerbassplayer]

Hi everybody. This is my first post and also a question.
Yesterday I got a call from a retired drummer asking
if I wanted an old amplifier. It turned out to be this
BT-15C . Its got the old paperwork with it and it says
its a 100watt amp with 2 - 15" speakers. Is this the amp
you guys are talking about or is this something different ?
The paper work says its a "solid state portaflex amp".
Any info would be appreciated and also , how do I send
my personal info to the web site ? Thanks and so far I
am really enjoying all the great info on this forum. By the
way my name is Tom .

 

[JimmyM]

Different amp. The B-15N has only one 15" and is only 25 watts.

BTW, Doug, those old B-15's are indeed crowd pleasers, and are still very much in use in studios. Not everyone likes solid state amps or DI. And the B-15 is a very much in-demand amp for studios, used for everything from electric to upright bass. I have a beaten up old B-15N that engineers and soundmen have raved about, even recently. I don't bring it out often because it's not really roadworthy, but I do bring it out sometimes and it never fails to kick ass.

However, there are plenty of amps from those days that would fit into "crowd-pleaser but wouldn't be used often in a studio" status. Orange and Kustom come immediately to mind. But not the B-15N. Everyone loves them!

 

[Jeff Michael]

They tried to evolve the Portaflex line a lot in the late 60s and early 70s. I've seen the three more "common" solid state Portaflex offerings (though I'd consider any solid-state Portaflex a rare bird) and owned one of them. There was the 2X12 ST22L Goliath, the 2X15 ST25L Olympian, and the 4X12 ST42L Colossus. They varied by cabinet configuration, all sporting the same solid state head, which featured four channels and tremolo and reverb (and a supercool faceplate that lit up blue, with treble and bass clefs for the high and low inputs!). My first amp was a used Olympian I got for $100, and I recently bagged a fixer-upper example off of eBay for about the same bread. At what works out to about $.79 a pound, it was a real bargain.

Your BT-15C was produced between 1966 and 1968 and was among Ampeg's first solid state amps. It's a 50 watt amp, and the 'C' denotes 'column', which was applied to the 2X15 models. This is of course courtesy of Ampeg: The Story Behind The Sound, an extremely well put together document of Ampeg's history. The dope on the BT-15C can be found on page 118 of that book (which is absolutely worth having).

Hope this helps,
Jeff

 

[Jeff Michael]

I'm finding the B15, while certainly an overachiever for its size and alleged power rating, still isn't enough amp for bigger venues. At this very moment I'm eyeing up a B18X head on eBay with the intent of coupling it into the aforementioned Olympian cab. Call it a Portamix, maybe. Or maybe Clusterflex.

Right after I snipe the B18-X auction, I'm shooting off to the store where I teach to bag a nice and clean Ampeg V6B head (240 watts RMS solid state) and a Peavey 1X15 cab. I figure for just under $400, it'll keep me in Ampeg even when I need a backup. The Peavey logo still makes me want to vomit, but the gear tends to be indestructible.

Jeff

 

[Ric Vice]

I have only seen pictures of this amp. When Ampeg ventured
into Solid State amplifers they apparently had three problems.
The amps actually cost more then their tube counter parts.
So a B-15NT cost more than a B-15N of the same vintage.
There were also reliability problems, they evidently didn't hold up
very well. This is probably why there are so few of them around
these days. Aditionally, Ampeg discontinued the entire line because they didn't sell. The later black vinyl B-15's were tube amps with the ultra high and ultra low switches.

Ampeg: The Story Behind The Sound is a great book

Ric

 

[robgrow]

Hi everybody. This is my first post and also a question.
Yesterday I got a call from a retired drummer asking
if I wanted an old amplifier. It turned out to be this
BT-15C . Its got the old paperwork with it and it says
its a 100watt amp with 2 - 15" speakers. Is this the amp
you guys are talking about or is this something different ?
The paper work says its a "solid state portaflex amp".
Any info would be appreciated and also , how do I send
my personal info to the web site ? Thanks and so far I
am really enjoying all the great info on this forum. By the
way my name is Tom .

Tom,

I remember borrowing one of those amps from a friend, back in high school in the late 60's. I used it on just one gig, and it sounded terrible. I vividly remember the drummer telling me it sounded like a fog horn! My friend who owned the BT-15C didn't keep it for very long, since he had nothing but trouble with it. Hope you have better luck with yours, and welcome to the group.

-bob

 

[Wesley R]

Somebody posted this earlier ;

"Tube amplifiers emphasize even order harmonics versus
odd order, giving them a more natural sound (engineers and
techies feel free to chime in on this one) I'm going from memory. "

The IEEE had a great article abvout this. I just spent an hour in the office looking for my copy. It is great reading and explains alot.

Now I wish (once again ) that I hadn't sold my B15S, it sounded close to a F but with a little more headroom.

Best of Luck,
Wesley R.

 

[Ric Vice]

Somebody posted this earlier ;

"Tube amplifiers emphasize even order harmonics versus
odd order, giving them a more natural sound (engineers and
techies feel free to chime in on this one) I'm going from memory. "

The IEEE had a great article abvout this. I just spent an hour in the office looking for my copy. It is great reading and explains alot.

Best of Luck,
Wesley R.

Wesley,
I think that I posted that a few weeks back. I'm glad that someone
finally found an article that confirmed what I remembered hearing years
ago. I also remember Don Underwood telling me that his pickup emphasized even order harmonics as well and that the Fishman BP-100
did just the opposite. I'm definitely no engineer so I'll defer to those who,
like Dr. Science "know now more than I do"

Ric

 

[bikerbassplayer]

Hi guys , well I did some digging, got an operators
instruction sheet and find most of you right on.
1 - it is very heavy (over110lbs)
2 - it is rated at 100 watts rms/230 watts peak
3 - it was made about 66/68
4 - it does not have tremelo or reverb
5 - it is already in need of work (has a hum)
6 - has ultra high switches for each channel (2)
7 - I love the sound
Thanks to all who gave me their input and thoughts
on this amp. It is much louder and much more
bassier (is that a word ?) than any amp I have.
Now I have another request hope you guys can
help with, does anybody know where I can get a
schematic for this thing ? I tried Ampeg and the
related web sites aimed at Ampeg info but no luck
so far. Somebody got one to copy ?

If it cant be fixed how about idea's on a good
replacement head . Thanks again

 

[robgrow]

Hi guys , well I did some digging, got an operators
instruction sheet and find most of you right on.
1 - it is very heavy (over110lbs)
2 - it is rated at 100 watts rms/230 watts peak
3 - it was made about 66/68
4 - it does not have tremelo or reverb
5 - it is already in need of work (has a hum)
6 - has ultra high switches for each channel (2)
7 - I love the sound
Thanks to all who gave me their input and thoughts
on this amp. It is much louder and much more
bassier (is that a word ?) than any amp I have.
Now I have another request hope you guys can
help with, does anybody know where I can get a
schematic for this thing ? I tried Ampeg and the
related web sites aimed at Ampeg info but no luck
so far. Somebody got one to copy ?

If it cant be fixed how about idea's on a good
replacement head . Thanks again

You can buy a copy of the original schematic here: http://www.schematicconnection.com/...=75&ph=cat&keywords=&recor=&SearchFor=&PT_ID=

Frankly, I'd be very skeptical about trying to bring this amp back to life. It could easily cost a lot of money, and prove to be a very trying experience. In the mean time, I would advise being very cautious: Anytime you turn on an old solid-state amp and hear a hum, that could be a sign that there is DC on its output, which could seriously damage your speakers very quickly. If you really want to use this amp, get it checked out by a knowledgeable tech. Good luck!

 

[bikerbassplayer]

Thanks for that info Bob. I will contact that website
and go from there. I used to work on tube amps about
30 years ago and still have most of the test equipment
so repair wont be too expensive. I'll let you know how
it all works out. I have seen some old b15 tube heads
for sale on ebay so I may buy one of those if nothing
else works. Thanks again for your help.

 

[JimmyM]

I'm finding the B15, while certainly an overachiever for its size and alleged power rating, still isn't enough amp for bigger venues. At this very moment I'm eyeing up a B18X head on eBay with the intent of coupling it into the aforementioned Olympian cab. Call it a Portamix, maybe. Or maybe Clusterflex.
Jeff

If you're using a decent PA, you can gig with the B-15. But yeah, if you need a good amount of stage volume, you're screwed. But dang, the tone of those amps...I love mine more an dmore every time I use it.

 

[robgrow]

Thanks for that info Bob. I will contact that website
and go from there. I used to work on tube amps about
30 years ago and still have most of the test equipment
so repair wont be too expensive. I'll let you know how
it all works out. I have seen some old b15 tube heads
for sale on ebay so I may buy one of those if nothing
else works. Thanks again for your help.

Keep in mind that there's a reason the BT-15 amps were only made for a short time. They were pretty much a disaster for Ampeg, and a nightmare for owners and dealers who had to service them. While vacuum tube amps had reached their zenith, the late 60's was still very early in the game for solid state musical instrument amps. Although many vacuum tube amps from that era survive today, very few solid state amps do. Most were pretty bad unfortunately.

Sorry that I sound so cynical, but I know 2 old-time repair guys who worked on the SS Ampegs when they were new, and I know neither would go anywhere near one now. They both have very bad memories of them.

 

[bikerbassplayer]

I appreciate all your feedback Bob. At least it keeps
me on the alert. I will take your advise in that I wont
put too much effort into the repair. If I cant find the
problem; from the sound of all the feedback and threads
on the BT-15 models I will probably look to Ebay to find
a tube model that I can use with these speakers. I dont
have much to lose since the unit was free. Thanks for
all your input good and bad and I will certainly think about
it as I research this project. By the way I also have a
Polytone Mini Brute and that is what I am using now and
have been since 1984. Great little amp. I emailed the
schematic site you gave me and am waiting to find out
if he has any info on the Ampeg. Talk to you later. Tom