Official Ampeg Portaflex Club Part III: Don't Stop 'Til You Get Enough

[bassybill]

This is turning into a bit of an epic.

Link to Part II here:

http://www.talkbass.com/forum/showth...70#post9629870

Bill

[JimmyM]

thank you bill! good title, btw!

here's the current roster:

#1 JimmyM
#2 Caca de Kick
#3 Vin_tone
#4 Vintage-Blue
#5 Jazzman
#6 coreyfyfe
#7 jmcgliss
#8 Membranophone
#9 knarleybass
#10 markjazzbassist
#11 ducknturtle
#12 tarzanalog
#13 Main Sale
#14 Swamp Ash
#15 morebass!
#16 sedan_dad
#17 bebop1
#18 BluesDawg
#19 bobyoung53
#20 X Wolf
#21 salcott
#22 esoxhntr
#23 jnewmark
#24 RP50
#25 Chebass88
#26 terlewine
#27 fretlessman71
#28 SWRGonzo
#29 DaveProulx
#30 JoanG
#31 Loudthud
#32 Mike Ranger
#33 Aragorn35016
#34 jimbobv
#35 stingray56funk
#36 Sonic Skip
#37 4bassman4
#38 markjazzbassist
#39 riotriot
#40 McGoo
#41 etinsley
#42 gpmonkey
#43 wallybill
#44 IronRadio
#45 gdthomas
#46 nickyn99
#47 krall
#48 elgato
#49 joplin
#50 vintageampeg
#51 Tom Domino
#52 tilehilder
#53 kaputsport
#54 dlmarquez
#55 mindwell
#56 LittleTed
#57 johnnyt
#58 wellshuxley
#59 randy1kenobi
#60 jvdb
#61 dk123123dk
#62 GGJaguar
#63 baddog
#64 garmenteros
#65 Frank Tuesday
#66 BloozBass
#67 led baron
#68 adbass
#69 nysbob
#70 SteveD
#71 davelowell2
#72 Thomas Peasley
#73 chipshot44
#74 RocketGuy
#75 bluesfan216
#76 stiles72
#77 Etingi
#78 marsbel
#79 catalinbread
#80 cripula
#81 johnk_10
#82 rawdogg
#83 Jamie Bishop
#84 Rickenbackerman
#85 Big John
#86 pgk
#87 Scarvin1
#88 kcmoe
#89 beans-on-toast
#90 shrinkskull
#91 citrone
#92 caseycash
#93 DeluxeRed
#94 rubato
#95 the mad daddy
#96 gcordez
#97 UnDx3 bassist
#98 JMarkD
#99 mrbeezroom
#100 lucien
#101 Kirk Bryant
#102 barrister
#103 jacotosh
#104 gmacc
#105 woodyng
#106 buddyellis
#107 jeefberky
#108 bassgasser
#109 Washishimi
#110 Standalone
#111 brekfustuvluzer
#112 edadmartin
#113 eb2
#114 f64
#115 braydensharrar
#116 Bluesbob
#117 tombowlus
#118 tifftunes
#119 Jocelyn-B15N
#120 tubetone
#121 TwoGearGeeks
#122 Wannabass
#123 audiolux
#124 nalapit13
#125 Music Man Dan
#126 4bassman4
#127 Kindness
#128 iceboxbass
#129 softsupply
#130 Aussie Mark
#131 timmarks
#132 RD
#133 Crackpot
#134 derridiandrift
#135 superreverb
#136 CB3000
#137 drasticDUB
#138 originalscottyg
#139 Tonedeaf Hack
#140 hennessybass
#141 joshwilkesbooth
#142 MR PC
#143 fusoid
#144 shadi
#145 sliderbass
#146 Yisrael
#147 Farfetched
#148 Craig_S
#149 JayAmel
#150 Nighttrain1127
#151 John D
#152 infiniteposse

i wonder how many yards of blue checker tolex that encompasses...

[sedan_dad]

"This is a single baffle cab like the type that Corey mentioned (http://www.postimage.org/image.php?v=gx_Cy40). I think that they moved from the double baffle to the single baffle to save money in production.

Old cabinets tend to be funky and it is best to measure the baffle size directly from your cabinet. The inner double baffle has 8 oblong ports, 3/4" X 6" positioned around the speaker. There are 4 spacers, about 1" X 2 1/2" X 3/8" deep separating the inner and outer baffle. Mark has an image of the inside of the double baffle on his site (http://www.vintage-blue.us/).
"

So there were 3 designs before the Theil design.

(1) The double baffel with oblong ports and spacers.

(2) A totally sealed design with no ports what so ever.
( this is my new project and the one I have questions about)

(3) A single baffel with ports at the lower corners like I have in my 67 cabinets.
(The ports are in seperated chamber from the rest of the cab. like a internal port)

Is this correct?

[JMarkD]

Okay Jimmy, here's an old friend. Very sweet.

[Vintage-Blue]

Originally Posted by beans-on-toast

This is a single baffle cab like the type that Corey mentioned (http://www.postimage.org/image.php?v=gx_Cy40). I think that they moved from the double baffle to the single baffle to save money in production.

David - do you have any more photos or info on the cabinet shown in your photo? I have never seen a totally sealed B15 cabinet like that. The single baffle cabinet I'm used to seeing had a 1/4" gap between it and the sides and it was held off the back of the face frame by 1/4" spacers. Those gaps provided the porting. Your photo appears to show a permanently installed baffle (glue blocks and all) but there are no ports in the baffle. It seems like this would still have to have a second baffle to mount the grille cloth to. Perhaps it's the angle but I don't see mounting studs for a grille baffle. Actually I know there was a period where Everett Hull had them Ampeg experimenting with altering the porting on the double baffle cabinets (around 1965). There were cabinets that had foam rubber plugs stuffed in some of the ports and some that had smaller ports, similar to those on the B18.

You've really got me curious about what I'm seeing in the photo and any other info you might have on that cabinet would be appreciated.

[sedan_dad]

Let me photograph mine. I'll post here shortly.

[sedan_dad]

I just sent them to mark@vintage-blue.us

[sedan_dad]

Attachment 179125
A sealed B-15

[sedan_dad]

Attachment 179126
1967 B-15 with chambered ports.

[coreyfyfe]

@infiniteposse - definite looks like you have an early NC there. Like I said in the last thread before it was closed, the NB had the SS rec and it looks like your amp has the face/back plate of the NB (no marking for 5AR4) and the mountings for the tilt-back post which were gone by 65 I believe. I dated mine to late 64/early 65 based on the pot codes, but yours looks like it would have to be a little older.

It's kind of interesting to see the little changes they made over time...

Your amps back:


My amps back:


Odd that your tube chart doesn't list the tubes though, but from the top/bottom parts it looks like it was probably just a generalized label:


While mine has them with the 5AR4 written in (I had assumed it was leftover from the SS rec model):

[jnewmark]

Originally Posted by sedan_dad

Attachment 179126
1967 B-15 with chambered ports.

Question about this cab. I have a '67 also, but mine only has insulation on the back panel. Did you add the insulation on the sides, or was this the way the '67's came ?

[coreyfyfe]

Originally Posted by sedan_dad

Attachment 179126
1967 B-15 with chambered ports.

I thought the shelf port at the bottom was the thiele design cab?

[coreyfyfe]

Originally Posted by jnewmark

Question about this cab. I have a '67 also, but mine only has insulation on the back panel. Did you add the insulation on the sides, or was this the way the '67's came ?

As far as I know, they were just lined on the back, so that is probably added insulation.

[beans-on-toast]

Originally Posted by Vintage-Blue

David - do you have any more photos or info on the cabinet shown in your photo? I have never seen a totally sealed B15 cabinet like that. The single baffle cabinet I'm used to seeing had a 1/4" gap between it and the sides and it was held off the back of the face frame by 1/4" spacers. Those gaps provided the porting. Your photo appears to show a permanently installed baffle (glue blocks and all) but there are no ports in the baffle. It seems like this would still have to have a second baffle to mount the grille cloth to. Perhaps it's the angle but I don't see mounting studs for a grille baffle. Actually I know there was a period where Everett Hull had them Ampeg experimenting with altering the porting on the double baffle cabinets (around 1965). There were cabinets that had foam rubber plugs stuffed in some of the ports and some that had smaller ports, similar to those on the B18.

You've really got me curious about what I'm seeing in the photo and any other info you might have on that cabinet would be appreciated.

Mark,

I does look different. All the pics of other 65 cabs that I have show either those really small oblong ports or the 3/4" X 6" ones. I don't see them here either. Jess mentioned that those were Everett's idea not his. A production cost measure. He didn't like them.

I have two outside pics of this cab. No other inside ones. Here they are (http://www.postimage.org/image.php?v=Pq5RI5i) (http://www.postimage.org/image.php?v=Pq5S3xA).

One possibility is that it is ported, with the mini ports, but just on the top and bottom. The speaker would be obscuring them. I figure that it must be ported somehow.


David

[beans-on-toast]

Originally Posted by sedan_dad

Attachment 179125
A sealed B-15

This looks like the type with the 1/4" spacer between the two baffles that Mark referred to. Notice the space around the edge. You would need to remove some bolts and take off the front baffle to check.


David

[sedan_dad]

If that were the case, wouldn't you see the double thickness in this photo?

Originally Posted by sedan_dad

Attachment 179126
1967 B-15 with chambered ports.

[sedan_dad]

Originally Posted by jnewmark

Question about this cab. I have a '67 also, but mine only has insulation on the back panel. Did you add the insulation on the sides, or was this the way the '67's came ?

I didn't add anything. Thats the way this one came to me.

[sedan_dad]

Originally Posted by sedan_dad

Attachment 179126
1967 B-15 with chambered ports.

Here's the outside of this cabinet.
Attachment 179131

[sedan_dad]

Originally Posted by sedan_dad

Attachment 179125
A sealed B-15

Here's the outside of this one.
Attachment 179132

[Vintage-Blue]

Originally Posted by sedan_dad

Attachment 179125
A sealed B-15

Bill - after looking at the photos you sent yours appears to be what I have always considered to be the standard single baffle cabinet.

Your baffle is removable via the 8 mounting studs and 2 upper screws. There is a 1/4" gap at each side of the baffle.



At the front you should be able to see a 1/4" gap between the grille and the back of the face frame. If the grille is tight to the face frame then someone has removed the spacers.



The spacers are 1/4" thick and about 1/2" dia. and slip over the baffle mounting studs.


It also looks like the 4 orginal speaker mounting studs have been removed from yours. Here is what they would have looked like.



I look forward to seeing your progress on this project.