Jess Oliver's legacy - AMPEG PORTAFLEX CLUB part 10

[ddbassGA]

Originally Posted by beans-on-toast

The user's manual is still on the Ampeg web site under support. It wouldn't be too difficult to build.

How do these sound?

[JimmyM]

Originally Posted by beans-on-toast

Yikes! That's serious coin for that product. Why not get a REDDI for a little mo.

I did

[Apex_speed]

Here is my early '67 B-15N, one B-15R, and my B-200R. Don't worry, I have more Ampeg not in the shots.

Now here is the million dollar question...A friend and I sat down and played with all of my Ampeg 15's today in different combinations. My B-15R head sounded FAR better driving the cabinet of the B200R (fitted with the factory Eminence woofer) then driving its own cabinet fitted with a 4ohm Eminence Legend CA154.

Anyone have any thoughts? Is it the difference between the B200R ported cab v. the B-15R sealed cab or is the CA154 a turd? It was not subtle. I still need to wheel over a stock drivered B-15R cab to see how that stacks up but we ran out of time.

I have also thought about replacing the CTS square magnet driver in the B-15N with a JBL D-140F (or 130) or Altec but it sounds SO good that I'm not feeling the urge to mess with it.

Thoughts?

[Apex_speed]

Doing a full electronics update wear parts resto on my B-15N tomorrow (all caps, tubes, gaskets, leather handle, etc).

Any chance that anyone has a link to the proper wiring setup for adding a 3 prong AC cord to the B-15N? I assume this should entail disabling the AC invert switch and removing the death cap. I'm sure I can figure it out from the schematic but I would rather not reinvent the wheel and possibly make a mistake.

Thanks for any help!

[beans-on-toast]

Originally Posted by ddbassGA

How do these sound?

I test drove one and thought that it was pretty good. People that own them like them. It was a lot better than the Boss DI-1 which I was using at the time and still have here somewhere. Not hard to beat, HAHA.

There are some mods that I would perform. I've convert the heater to a DC voltage to make it even more quieter. I'd try some tube rolling. I like the RCA 12AU7 but would also want to try a 6189 or 5814A. I'd also want to try a Jensen transformer. Often these stock units are not the of the best quality. A good would cost around $75 so it is an expensive thing to try.

[JimmyM]

Originally Posted by Apex_speed

Here is my early '67 B-15N, one B-15R, and my B-200R. Don't worry, I have more Ampeg not in the shots.

Now here is the million dollar question...A friend and I sat down and played with all of my Ampeg 15's today in different combinations. My B-15R head sounded FAR better driving the cabinet of the B200R (fitted with the factory Eminence woofer) then driving its own cabinet fitted with a 4ohm Eminence Legend CA154.

Anyone have any thoughts? Is it the difference between the B200R ported cab v. the B-15R sealed cab or is the CA154 a turd? It was not subtle. I still need to wheel over a stock drivered B-15R cab to see how that stacks up but we ran out of time.

I'd totally lose the CA154. Only 3k on the top end and considerably lower lows than the stocker. Delta or Beta 15a are the ones to go with in B-15 cabs.

I have also thought about replacing the CTS square magnet driver in the B-15N with a JBL D-140F (or 130) or Altec but it sounds SO good that I'm not feeling the urge to mess with it.

Thoughts?

That's what I ended up doing. Not only did the CTS sound great but so do the Delta 15a's I have in my repro cabs. I can't tell a difference in them, to be honest. And I've considered both the JBL and a Faital 15PR400, but nah.

[beans-on-toast]

Originally Posted by Apex_speed

Doing a full electronics update wear parts resto on my B-15N tomorrow (all caps, tubes, gaskets, leather handle, etc).

Any chance that anyone has a link to the proper wiring setup for adding a 3 prong AC cord to the B-15N? I assume this should entail disabling the AC invert switch and removing the death cap. I'm sure I can figure it out from the schematic but I would rather not reinvent the wheel and possibly make a mistake.

I have some nice pics in a couple of places in this thread somewhere. I don't know which would be worse, searching through 9,000+ posts or reinventing the wheel.








This post will help but wasn't what I was looking for.

Here is one way to do it. Black hot wire from the power cable to the end of the fuse housing. The black wire goes from the other fuse terminal to the power switch. Other terminal on the power switch goes to one of the primary wires of the power transformer.





The white neutral power cord wire goes to the other PT primary wire. They are joined by a wire nut and it is secured to the chassis.






The green ground wire of the power cord is connected to a ring terminal and attached to the chassis close to where the cable enters the chassis.

If you have a Type Y2 or Type Y2/X2 Safety Cap of the correct value, you can install it in place of the "death cap" and have a functioning ground switch. I usually simply remove the ground cap on the primary side of the PT and leave the ground switch with nothing connected to it.

[Apex_speed]

Originally Posted by JimmyM

I'd totally lose the CA154. Only 3k on the top end and considerably lower lows than the stocker. Delta or Beta 15a are the ones to go with in B-15 cabs.


That's what I ended up doing. Not only did the CTS sound great but so do the Delta 15a's I have in my repro cabs. I can't tell a difference in them, to be honest. And I've considered both the JBL and a Faital 15PR400, but nah.

Thanks, that's some good advice and I have heard plenty about the Delta. What is the sonic difference between the Delta and Beta?

[Apex_speed]

Originally Posted by beans-on-toast

I have some nice pics in a couple of places in this thread somewhere. I don't know which would be worse, searching through 9,000+ posts or reinventing the wheel.








This post will help but wasn't what I was looking for.

Here is one way to do it. Black hot wire from the power cable to the end of the fuse housing. The black wire goes from the other fuse terminal to the power switch. Other terminal on the power switch goes to one of the primary wires of the power transformer.





The white neutral power cord wire goes to the other PT primary wire. They are joined by a wire nut and it is secured to the chassis.






The green ground wire of the power cord is connected to a ring terminal and attached to the chassis close to where the cable enters the chassis.

If you have a Type Y2 or Type Y2/X2 Safety Cap of the correct value, you can install it in place of the "death cap" and have a functioning ground switch. I usually simply remove the ground cap on the primary side of the PT and leave the ground switch with nothing connected to it.

Awesome....thanks so much as I had started to make myself nuts sorting through ALL the posts!

What year is this? Early 60's? My PCB is the latter one with short traces and no eyelets.

What is the piggyback board with the dual caps and resistors.

If I follow this correctly....remove the death cap and ground switch completely and just wire directly around that entire circuit.

I was temped to to leave it original but if there was ever a very significant failure, it would likely save other connected gear to have the head grounded.

[ddbassGA]

Originally Posted by Apex_speed

Here is my early '67 B-15N, one B-15R, and my B-200R.

Now here is the million dollar question...A friend and I sat down and played with all of my Ampeg 15's today in different combinations. My B-15R head sounded FAR better driving the cabinet of the B200R (fitted with the factory Eminence woofer) then driving its own cabinet fitted with a 4ohm Eminence Legend CA154.

Anyone have any thoughts? Is it the difference between the B200R ported cab v. the B-15R sealed cab or is the CA154 a turd? It was not subtle. I still need to wheel over a stock drivered B-15R cab to see how that stacks up but we ran out of time.

I have also thought about replacing the CTS square magnet driver in the B-15N with a JBL D-140F (or 130) or Altec but it sounds SO good that I'm not feeling the urge to mess with it.

Thoughts?

My thoughts on the B-15R: I didn't like that sealed cab of the B-15R, or the tweeter. I think they goofed on that one. The stock driver was wimpy too (IMHO, at least on mine). So, yeah 100 watts, but an inefficient driver and sealed cab -- it didn't have the umph I expected and didnt sound like a B-15. Some guys here have put in a ported baffle or installed tuned ports. Then with a Delta it would be righteous! That's where I was headed with my R but ended up trading it (for '75 SVT head) before I modded it.

The CA154 is not the right speaker, either.

On the '67 (I'd call that one late '67, early ones were blue check), I'd keep the CTS squareback, for sure and not fool with a JBL or Altec.

[Apex_speed]

Originally Posted by ddbassGA

On the '67 (I'd call that one late '67, early ones were blue check), I'd keep the CTS squareback, for sure and not fool with a JBL or Altec.

Here is how I came up with early '67...Serial number is '67 but it has the universal knobs where late '67 units that I have seen have the later round knobs and '68 was a redo. Also, the late '66 units I have seen look just like this one with only some very early '66s having the blue diamond tolex and chicken head knobs but not many. In general, '66 and '67 were years with many cosmetic changes.

I am no expert but those have been my observations in my B-15 adventures.

Thanks for the driver advice. I had thought about porting the B-15R with B-200R ports but that seems like defacing a piece of history. If that was the ticket, I would probably buy a new cab from Fliptops and port that.

Venting the baffle would probably be reversible and invisible but an unknown to me.

[JimmyM]

Originally Posted by Apex_speed

Thanks, that's some good advice and I have heard plenty about the Delta. What is the sonic difference between the Delta and Beta?

That I'm not sure about since I've never tried the Beta. You can compare their frequency response charts and get an idea, though:

http://www.eminence.com/pdf/Beta_15A.pdf
http://www.eminence.com/pdf/Delta_15A.pdf

If I were basing it solely on these charts, I'd go Delta because it has a little more high end, but I know folks on here quite happy with the Beta, and Fliptops recommends it over the Delta. The Delta is a dead ringer for the old CTS speakers of the 60's, though.

[JimmyM]

I'd never mod a B-15R, but I might get a cab made with a port on it to replace the original cab.

[Bass 45]

Originally Posted by Apex_speed

Here is how I came up with early '67...Serial number is '67 but it has the universal knobs where late '67 units that I have seen have the later round knobs and '68 was a redo. Also, the late '66 units I have seen look just like this one with only some very early '66s having the blue diamond tolex and chicken head knobs but not many. In general, '66 and '67 were years with many cosmetic changes.

I am no expert but those have been my observations in my B-15 adventures.

Thanks for the driver advice. I had thought about porting the B-15R with B-200R ports but that seems like defacing a piece of history. If that was the ticket, I would probably buy a new cab from Fliptops and port that.

Venting the baffle would probably be reversible and invisible but an unknown to me.

I have a Beta in my Ampeg B115E cab (it had a blown stock speaker when I bought it). The B115E is a ported cab - and it also sounds superior to the B15R cab in side by side comparisons.

Many years ago I vented the baffle on my B15R using spacers between the baffle and the front cabinet frame. I also experimented with different speakers. I really could not say if it helped tonewise. It is hard for me to tell without the luxury of side by side comparisons. I did keep a high quality cast frame Eminence in there for a while. It was more for piece of mind because I was playing in a fairly loud Rockabilly band at the time and I know I would have blown the original out slapping the upright at loud volumes.

The groups I play with now are not so loud and I have had everything back to stock for quite some time now. I also have the B15E ext. cab. It has a removable rear panel, so I have considered experimenting with a new ported rear panel - but I have not decided if I should waste my time with that or just go ahead and build a B115E replica (blue check of course) with a flip top lid.

I still think using two stock B15R cabs together rocks - but I would like to get more efficiency when using a single cab

*edit - someone had a thread on here a while back about doing a double baffle mod on their B15R (which should also be totally reversible). I will have to look for that to check their findings.

[JimmyM]

Oh yeah, that's right...I believe he took out the tweeter and made it into a port, right? Or did he replace the entire baffle? Man, the mind is fuzzy these days.

[Bass 45]

Originally Posted by JimmyM

Oh yeah, that's right...I believe he took out the tweeter and made it into a port, right? Or did he replace the entire baffle? Man, the mind is fuzzy these days.

I think both have been discussed on TB at one time or another - but the one I was referring to replicated the early sixties double baffle.

[JimmyM]

Geez, my brain is fried tonight...you said that already, didn't you? Sorry...I mowed the lawn today and had a bunch of work I needed to do the rest of the day, then I had the best Italian dinner I've had in a long time. I should be in bed but I'm waiting for laundry to dry.

[Bass 45]

No worries

I think I remember someone going tweeter : port with a PF115HE - maybe.

Here are two of our brethren who documented the B15R mod:

Speaker baffle on Ampeg B15R

B15R baffle mod

[beans-on-toast]

Originally Posted by Apex_speed

What year is this? Early 60's?

What is the piggyback board with the dual caps and resistors.

If I follow this correctly....remove the death cap and ground switch completely and just wire directly around that entire circuit.

1963 B-15NA.

The board is two series caps bringing the first node capacitor to 41uF. The caps have a high ripple current spec which helps the low end. This was intended to be a temporary mod but its been there a while now.

It sounds like you got it.

[ddbassGA]

Originally Posted by Apex_speed

Here is how I came up with early '67...Serial number is '67 but it has the universal knobs where late '67 units that I have seen have the later round knobs and '68 was a redo. Also, the late '66 units I have seen look just like this one with only some very early '66s having the blue diamond tolex and chicken head knobs but not many. In general, '66 and '67 were years with many cosmetic changes.

.

From my experience I believe you're a year off, with '66 being all blue, '67 starting blue and going to black with piping mid-year which went thru mid '68.

My first B-15 was a '66 blue check I bought new in late '66. I currently have an early '67 ( by serial no) that is blue check with round knobs. Also see p. 71 in the Ampeg book.

So how many angels can dance on the head of a pin?