Home » VintageKustom.com » Repairing Kustom Amps » C795 Frankie (big resistor wired into speakers)
icon7.gif  C795 Frankie [message #23067] Sun, 07 June 2015 00:22 Go to next message
bluezebra is currently offline  bluezebra
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Opened up the new Frankie 2 X 15 cab and found a 4 ohm 50 watt resistor wired into the speakers at the bottom of the cabinet. Both 15" speakers measure about 8 ohms on the meter. This one doesn't have a horn...so what's the heavy resistor in there for...or has someone removed the horn. The cab looks original.
Re: C795 Frankie [message #23068 is a reply to message #23067] Sun, 07 June 2015 06:01 Go to previous messageGo to next message
stevem is currently offline  stevem
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I can not say there are a couple of possible reasons why someone would add a resistor to the output circiut but in terms of what would be in there stock if it had a horn then the only thing would be the in line cap used for the crossover!
Re: C795 Frankie [message #23071 is a reply to message #23067] Sun, 07 June 2015 11:59 Go to previous messageGo to next message
Iowa Boy is currently offline  Iowa Boy
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Could it possibly be an inline fuse of some kind? Also was wondering if at sometime or other that maybe one of the speakers might have been a siren and they forgot to remove the cap but that should have been at the top of the cabinet, not the bottom. Of course after 40 some years, who knows what's been done to this cabinet. Thinking it might help if we knew what speakers are in it now; if it has CTS its possible the guy wanted to use it for guitar and was wanting more high end and put a siren in there.....who knows.

By any chance is it orange..........they are in my siren cabinets.

[Updated on: Sun, 07 June 2015 12:12]

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Re: C795 Frankie [message #23072 is a reply to message #23067] Sun, 07 June 2015 14:07 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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Thanks for the responses.
The resistor is brown and was wired at the bottom between the input and the speakers.
THe speakers are about 8 ohms each and wired in parallell and the resistor is 4 ohm.
The speakers are CTS with the big magnets dated Feb 1966 and are matched.

This thing looks to be untouched on the inside. No modifications at all.
Re: C795 Frankie [message #23073 is a reply to message #23067] Sun, 07 June 2015 14:14 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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A pic is a thousand words

http://i571.photobucket.com/albums/ss154/bluezebra1/Cab%20Resistor_zpssrdwvtru.jpg
Re: C795 Frankie [message #23074 is a reply to message #23067] Sun, 07 June 2015 14:19 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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What does a Frankie expect to see as far as impedance?
Re: C795 Frankie [message #23075 is a reply to message #23067] Sun, 07 June 2015 14:29 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
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This has come up before. I can't remember if there was ever a final answer, maybe Pleat remembers.

Try searching the board and see if you can find the old post. I think that the one theory that made the most sense was that when the amp was sold with two cabinets, each cabinet needed to be 8 ohms to keep the load seen by the head at 4 ohms. In the early days if they didn't have 16 ohm speakers, this was one way to fix the problem.
Re: C795 Frankie [message #23077 is a reply to message #23072] Sun, 07 June 2015 14:44 Go to previous messageGo to next message
Iowa Boy is currently offline  Iowa Boy
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I'm wondering if this was used to change the ohm output on the cabinet. I'm not sure but Kustom was one of the few companies that their amps were designed for 4 ohm total load. Just guessing here, but is it possible that these 15's are 16 ohms each and not 8 ohms? I still think this was put in as speaker protection. Bill, Steve and Pleat as well as Bart are the electronic experts here....I'm just taking some shots in the dark. Pleat is the one with the memory of an elephant, maybe he can shed some light on this thing.

Just saw Bills post.......looks like my guess was right then.

[Updated on: Sun, 07 June 2015 14:46]

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Re: C795 Frankie [message #23078 is a reply to message #23067] Sun, 07 June 2015 16:10 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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When I got the cabinet I metered the input jack at 8 ohms. Then I opened it up and saw the resistor. The two 16's are 7.9 ohms each. I'm thinking that in parallel it brought them to 4 ohms and then the resistor was added to get it back to 8 ohms? But I'm speculating here.
Re: C795 Frankie [message #23079 is a reply to message #23067] Sun, 07 June 2015 16:59 Go to previous messageGo to next message
stevem is currently offline  stevem
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That 4 ohm resistor is in series so the total dc resistance would be 12 ohms and two of such cabinets in parallel would make for a very safe 6 ohm load on the amp so what Bill posted makes sence and the resistor would need to be 50 watts.
Re: C795 Frankie [message #23080 is a reply to message #23067] Sun, 07 June 2015 17:04 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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Good Lord....The place where I bought this had another red 11 pleat cabinet next to it with a Red Kustom 200 on it (a mismatch of course).
What you're saying is....I left the second cabinet behind...?

So if I just run one cabinet as is...should the resistor stay or go?
Re: C795 Frankie [message #23082 is a reply to message #23080] Sun, 07 June 2015 21:03 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
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If you read the dc resistance of a speaker with your ohm meter, the reading will always be slightly less than the rated impedance of the voice coil. You have two 8 ohm speakers in there.

If you are only using the one cabinet, I would rewire it as a 4 ohm without the resistor. Save the resistor in case you ever want to return it to original.
Re: C795 Frankie [message #23083 is a reply to message #23067] Sun, 07 June 2015 22:39 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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That's what I'm leaning to for now....unless I come into the other cabinet.

Thanks!
Re: C795 Frankie [message #23084 is a reply to message #23067] Mon, 08 June 2015 06:12 Go to previous messageGo to next message
stevem is currently offline  stevem
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Ok, I am confused now!
Early in this string of post you said the drivers where 8 ohms each which would not make sence with having that 4 ohm resistor in there and now your saying each driver measures over 7 ohms which would make them the needed 16 ohm drivers for running two such cabinets on one head?
Re: C795 Frankie [message #23087 is a reply to message #23067] Mon, 08 June 2015 09:13 Go to previous messageGo to next message
Iowa Boy is currently offline  Iowa Boy
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I noticed that also but thought that Bill had the answer. What do you bet those are not the original speakers and they got switched out and the resistor was not removed? Either that or someone was trying to be creative......hard to follow the logic but who knows.

[Updated on: Mon, 08 June 2015 09:16]

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Re: C795 Frankie [message #23089 is a reply to message #23067] Mon, 08 June 2015 11:23 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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I know it's confusing but I'm just reporting what I found. Before I opened up the
cab I measured 8 ohms at the jack. When I opened up the cabinet I saw the resistor.
Cleaned it off and found it was a 50 watt 4 ohm. It was wired in between the positive
and negative side of the speakers. Each speaker was removed and measured at about 8 ohms
and they were wired in parallel.

I now have the speakers in parallel without the resistor and the cab is at 4 ohms.

The location I found the amp had another 11 pleat cabinet with a K200 head on it and
I never realized that the other cab went with this head. So a two cab setup was
very possible. The drivers appeared to be original. The insulation on the brown speaker
was wire was falling apart as I touched it.
Re: C795 Frankie [message #23090 is a reply to message #23067] Mon, 08 June 2015 12:55 Go to previous messageGo to next message
carlc is currently offline  carlc
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The Frankenstein heads are looking for a 4 ohm load.
Re: C795 Frankie [message #23091 is a reply to message #23090] Mon, 08 June 2015 13:24 Go to previous messageGo to next message
pleat is currently offline  pleat
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Reading the posts is very interesting. First off, the resistor is something that someone added to bring the cabinet back to 8 ohms.
Kustom never added resistors to any cabinet in the T&R series. First give a way is all black wiring.

Kustom only used 16 ohm speakers in their cabinets for guitar and bass cabs. Since the replacement speakers are 8 ohms each wired in parallel gives a 4 load, adding the 4 ohm 50 watt resistor in series, bring the cab back to 8 ohms. You mentioned there was another 11 T&R cab where you bought the first cab and Frankie head, I'd guess the second cab may have the same situation going on in the cabinet, so running both cabs on the Frankie head would get the impedance to 4 ohms.

In the early days of Kustom, Kustom did include a choke inside the cabs to correct for a motorboating issue that the very early Frankies had. I've only seen two cabinets that included the choke, one was a 2x15 cab and the other was a self contained 2x15 Frankie amp and speakers in the same cabinet.
pleat
Re: C795 Frankie [message #23092 is a reply to message #23067] Mon, 08 June 2015 13:59 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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Thank you pleat for those details...it brings closure to some of the questions.
I couldn't figure out why the speakers were 8 ohms. They are both marked Feb 66 and
do not appear to have been reconed. I see no modifications to the cab or the
chassis (with exception of the resistor). I just wish I would have gotten the
second cab but I didn't think the store would want to split the cab and the K200
on it.

Also, carlc..thanks...that's where the cabinet is now...at 4 ohms!
Re: C795 Frankie [message #23093 is a reply to message #23092] Mon, 08 June 2015 15:35 Go to previous messageGo to next message
pleat is currently offline  pleat
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What color is the K200 head that is sitting on top of the cab you didn't buy? There is a collector in GA that might be interested if it's a -5 PA amp.
pleat
Re: C795 Frankie [message #23094 is a reply to message #23067] Mon, 08 June 2015 16:44 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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No, it's a K200 B and the red tuck and roll is faded and rough.
Not a collector item.
Re: C795 Frankie [message #23095 is a reply to message #23067] Mon, 08 June 2015 18:51 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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Well I swung a deal on a trade and got the second red 11 pleat cabinet.
It'll be interesting to see what I find when I open that one up....
Stay tuned...!!
Re: C795 Frankie [message #23097 is a reply to message #23067] Tue, 09 June 2015 06:28 Go to previous messageGo to next message
stevem is currently offline  stevem
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So are we!
Re: C795 Frankie [message #23098 is a reply to message #23067] Thu, 11 June 2015 19:02 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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OK, got the second cabinet in. I took off the back and Voila!
It's identical to the first. Two 8 ohm 15 inch CTS speakers
wired with a 50 watt 4 ohm resistor to bring back to 8 ohms.
It does not appear to be have had a speaker change out.
No marks on the speaker nuts. Similar bracket and wiring to
the first one.
The only thing of interest is the speaker code shows Feb of 1960...?

[Updated on: Thu, 11 June 2015 19:03]

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Re: C795 Frankie [message #23099 is a reply to message #23067] Thu, 11 June 2015 19:36 Go to previous messageGo to next message
stevem is currently offline  stevem
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Thanks for the report on the second cabinet and I would have to say that this confirms that this is the way Kustom handled placing two cabinets on one amp and duriving the near 4 ohm load!
It's not odd to turn up a speaker that old, it just means it sat in the CTS warehouse a few years
Re: C795 Frankie [message #23100 is a reply to message #23067] Thu, 11 June 2015 20:22 Go to previous messageGo to next message
Iowa Boy is currently offline  Iowa Boy
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So with this new revelation, imagine a 400 head with eight 2-15's cabinets with 16 ohm speakers in it. That would be a roadies worst nightmare. lol
Re: C795 Frankie [message #23101 is a reply to message #23067] Thu, 11 June 2015 21:06 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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You think they could have added a 4 ohm tweeter or mid range speaker
into the mix rather than just a resistor but then again there's not
much room left in that smaller cab.

With only one input on the head I have no choice other than using a
quarter inch Siamese to connect the two cabs...?
Re: C795 Frankie [message #23102 is a reply to message #23101] Thu, 11 June 2015 23:52 Go to previous messageGo to next message
pleat is currently offline  pleat
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With a date code of 1960, that should tell you the speakers are not original to the cabinet. Kustom did not use 8 ohm speakers in the 15" size speakers.

pleat
Re: C795 Frankie [message #23103 is a reply to message #23067] Thu, 11 June 2015 23:57 Go to previous messageGo to next message
Iowa Boy is currently offline  Iowa Boy
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You could always add another speaker jack to the cabinet and wire it in parallel like they do on monitors and just plug one cabinet into the other.
Re: C795 Frankie [message #23104 is a reply to message #23067] Fri, 12 June 2015 02:16 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
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Exactly what is the EIA code on the speakers? The first photo shows the 2nd week of 1966.

My horizontal 2X15 Ross and Myers cabinet has no ports or holes and has 2 15" CTS, 8 ohm speakers that are wired for 4 ohms.
Re: C795 Frankie [message #23105 is a reply to message #23067] Fri, 12 June 2015 06:15 Go to previous messageGo to next message
stevem is currently offline  stevem
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My horizontal 2-15 cabinet is the same deal, two 8 ohm drivers!

I have worked on 3 all orignal Ampeg Fliptop B15 amps who's speaker was dated 1 to 3 years earlier than the manufacture date of the amp!
Re: C795 Frankie [message #23106 is a reply to message #23105] Fri, 12 June 2015 08:35 Go to previous messageGo to next message
pleat is currently offline  pleat
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I sent Bud the photo and asked him if he can shed some light on the resistor in the cabs.

I really can't believe that CTS or any other speaker company would have speakers stocked in their warehouse for a few years before selling them to an amp manufacturer.
I would imagine a speaker company would be out of business if they sold speakers that slowly. I think the opposite, especially after the British Invasion in the early 60's and everyone took up playing musical instruments.
pleat
Re: C795 Frankie [message #23107 is a reply to message #23067] Fri, 12 June 2015 08:45 Go to previous messageGo to next message
stevem is currently offline  stevem
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Yeah, but you got to remember not many USA made amps in the early 60s used 15" drivers but for Ampegs and the Fender showman or duel showman line!
Even Plush amps that used a lot of 15" drivers in there model line did not come about until 1968.

[Updated on: Fri, 12 June 2015 08:47]

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Re: C795 Frankie [message #23108 is a reply to message #23067] Fri, 12 June 2015 14:01 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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Bill,
The speaker code showing on the both speakers in the second cab is 137 602

[Updated on: Fri, 12 June 2015 14:06]

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Re: C795 Frankie [message #23109 is a reply to message #23067] Fri, 12 June 2015 14:04 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
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I searched back in my archives and I found a message that Pleat posted regarding a choke that was added to some of the early cabinets. Bud noted that some amps would oscillate at a very low frequency, causing the speaker cones to slowly move in and out. He also noted that JBL speakers did this more than the other types.

He attributed the cause to the change in the power amp design, removing the driver/phase inverter transformer. If this was the case, then we're talking about the K200A series amps and not the Frankie heads.

We need to find out the correct date codes that are on the speakers. As I posted earlier, the photo shows a EIA code of 137 602. 137 is the code number for CTS, 6 is for the year 1966 and 02 is for the 2nd week of the year. If in fact the date code is for Feb of 1960 it would have to be something like 137 005.
Re: C795 Frankie [message #23110 is a reply to message #23108] Fri, 12 June 2015 14:09 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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I'm probably reading the date code wrong (brain fart)....02...second week of 6...1966...
if so all four speakers match. Unfortunately one is doa.

[Updated on: Fri, 12 June 2015 14:10]

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Re: C795 Frankie [message #23111 is a reply to message #23067] Fri, 12 June 2015 14:20 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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I also find the wheels are different on both of the cabinets as are the Handles..
they are solid black plastic (3 of the 4 broken). The head Serial No. is 2172

http://i571.photobucket.com/albums/ss154/bluezebra1/Wheel%20small_zpsp0v8izf5.jpg


http://i571.photobucket.com/albums/ss154/bluezebra1/314015_435984989767491_522548133_n_zpszjsaxpyk.jpg

[Updated on: Fri, 12 June 2015 14:35]

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Re: C795 Frankie [message #23112 is a reply to message #23067] Fri, 12 June 2015 15:18 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
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Nice looking rig. It'll look even better with both cabs.

Wheels without mounting plates and all plastic, black handles are correct for the early amps.

I wouldn't be surprised that the casters could be changed. The handles are sort of like a guitar case handle. All plastic with metal mounting pivots.

The other sign of an early version is the space between Ross and Inc. The earlier artwork said Ross and Myers, Inc. When Myers left, they removed his name from the silkscreen artwork, leaving the big gap.

Check the wiring and the wiring on the doa speaker itself. If there is a cold solder joint or something it might be fixable. If not I'd look to have the doa speaker reconed to match the originals.
icon12.gif  Re: C795 Frankie [message #23113 is a reply to message #23067] Fri, 12 June 2015 20:00 Go to previous messageGo to next message
bluezebra is currently offline  bluezebra
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Thanks Bill,
I didn't know that part about the name change. Interesting.

Also, the castors are different but one is bent and hard to roll. I have two sets
of the normal looking wheels. If these are original I'd hate to change them out
for just one (it still kinda rolls). If these have never been used...I have
replacements. I've already found some handles that match.

I was almost in shock when I walked into the store in Irving, Tx and found these.
They had been on their floor for sale for over two years....!

[Updated on: Fri, 12 June 2015 20:01]

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Re: C795 Frankie [message #23114 is a reply to message #23067] Sat, 13 June 2015 12:05 Go to previous messageGo to previous message
pleat is currently offline  pleat
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I received two emails from Bud yesterday. The first one,
"Good morning Don,
This was in the fall of 67 when we started shipping the first direct drive units. The amplifiers would motorboat, especially when we used JBL. I don't remember a choke but we did ship a few with a resistor."
The problem was fixed in a couple of days. I thought we recalled the ones that were shipped with resistors. Maybe we didn't get all of them.
Bud
The second email,
"Do say hello to everyone. You are probably right about the speakers being replaced."
Bud
I'd be interested in seeing the back panel of the amp to see how many power devices are on the back.
I've seen 3,5 and 6 power devices on Frankie heads. It looks like the cabinet in the photo has no port holes behind grill cloth, which would date the cab to a very early year. Bud told us the reason some cabs have no port holes is he broke his little hand saw that was used to cut the holes.
As ChicagoBill mentioned, the early cabinets used an all plastic handle as seen in the 65-66 catalog.
Bob Brinkman was the head tech when the company moved to Chanute. Bob told me they used the local hardware store for some items. Handles, knobs and the chrome amp glides, that also are used on the legs of furnature. About 1" in diameter and has a nail in the center. I once owned an early no port 2x15 Frankie cabinet that must have shipped from the factory without casters. I saw the remains of the nail hole follow by several different caster plate patterns. My cabinet didn't have the dividing board between the speakers, just a 1x2" slat across the middle of the back panel.
I wouldn't add a second speaker jack to either cabinet. I would want to keep the cabs original. I'd make up a simple junction box that all three ΒΌ" jacks are wired in parallel to hook the cabs to the amp head. Using a Y cable, you would want to make sure it's not a shielded audio type. Not sure if they make a speaker Y cable, but then I haven't looked for one either.
In the early days and cash flow a daily struggle, you will always find some interesting ways the early models will differ from one amp or cab to the next.
I personally have never seen a Ross & Meyer Inc. logo on a Kustom amp. I've seen the Ross MFG. logo that is narrow and the labels over the inputs are Guitar and Bass.
So the cabs may contain original speakers but as production grew and things were stabilized, Kustom used only 16 ohm speakers until the slant face era amps of 1971.

So Bud didn't recall using 8 ohm speakers, but then again in the early days, Bud was also turning over the daily production to his people and he was concentrating on the front end of building a dealer network to grow the business.
By the way Bud just celebrated his 75th birthday on May 30th.
pleat
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