4 Ohm Speaker OR use 8 Ohm with Weber Speaker Motor

[dragonfly66]

I want to try out a 15" speaker in my Custom Vibrolux Reverb, but I am having a hard time finding a 4 Ohm speaker for it. The CVR is 40 watts and I heard a good rule of thumb is to find a speaker rating of twice the watts. I see plenty of high watt 4 Ohm 15" for Bass application.

Here is what I can find on the shelf for guitar.

• Eminence Legend 151 (150 watts, only 8 Ohm and 16 Ohm)
• Jensen C15N (4 Ohm, only 50 watts)
• WGS G15C (75 watts, only 8 or 16 Ohms)
• Weber has 5 ceramic 15" but all seem to be for Tweed Pro applications and none over 60watts

Does the speaker have to be custom made or is there someone out there that has an Fender/American sounding 4 Ohm 15" at at least 80 watts?

P.S.
I contacted WGS about a 4 Ohm version of there G15C and they said it would be $19.99 upcharge to make the speaker 4 Ohm. Currently it is the closest to what I need at 75 watts. I doubt I'll ever dime the CVR. I didn't ask about extra watts though maybe they could do that too for a fee. I like WGS speakers. I have the Veteran 10s in my CVR now. To get the 4 Ohm G15C it would cost $129 for the speaker + $22 shipping. So a total of $151

I haven't checked with Eminence to see if I could get a 4 Ohm of the Legend, but I will do that today.

---------------------------------

Another option I thought of would be to use the Legend 1518 I already have which is 150 watts 8 ohms and build in a 8 Ohm 100 Watt Weber speaker motor (https://amptechtools.powweb.com/truload.htm bottom of page). This would provide the 4 Ohms the amp wants to see. This would limit the watts to 100 which is perfectly fine in this 40 watts amp.

This would cost me $45 plus whatever the shipping cost would be, which you don't find out with Weber until your card is charged. Let's guess $12. So this option is $57.

I don't know what the ramifications are of using this option.

Any words of wisdom would be appreciated here.

 

[homesick345]

8ohms will work just fine

 

[muchxs]

Lotta text here with multiple questions.

Weber or WGS can build you 4 ohm speakers. It's worth the extra $20 if it solves a "problem".

Changing your output transformer would be another way to solve your "problem". Stick an upgraded Allen in there wqith 4, and 8 taps. I'd have to make a quick search to suggest a specific model. 8 ohm transformer, 8 ohm speaker. Done deal!

Just because a speaker is supposed to be a "tweed" amp speaker doesn't mean you can't use it in another amp.

While we're at it the original Jensen speaker in a tweed Pro was approsimately a 25 watt speaker when it was new. Due to aging components is more like a 15 watt speaker now. Comparing apples to oranges but your costom Vibrolux puts out about the same power. Draw your own conclusions.

If you have an 8 ohm Legend try that! If you don't like it at least you can cross that off your list.


If you don't find what you're after then broaden your search. New speakers represent what's available in current production. We're comin' up on the 100th anniversary of the loudspeaker. That means old speakers are about as common as old tires. As commone as used computer monitors, maybe? I have a big ol' CTS that came outta some old electronic organ. It's 4 ohms, ribbed cone... great speaker for a 40 watt guitar amp. Nicely broken in, too.

 

[bluemoon]

Check out the Weber Z matcher

 

[dragonfly66]

Changing your output transformer would be another way to solve your "problem". Stick an upgraded Allen in there wqith 4, and 8 taps. I'd have to make a quick search to suggest a specific model. 8 ohm transformer, 8 ohm speaker. Done deal!

I thought about this too, but swapping speakers seemed easier.

I have a big ol' CTS that came outta some old electronic organ. It's 4 ohms, ribbed cone... great speaker for a 40 watt guitar amp. Nicely broken in, too.

So are you offering to sell it?

Check out the Weber Z matcher

I actually have one of these. Great device but not my first choice to have carry this around with the amp.

 

[dragonfly66]

8ohms will work just fine

Will it?

The back plate says, 2 Ohms Minimum Total

The manual says,

R. MAIN SPEAKER  -  Primary connection for
(internal or external) speakers.  A speaker must
always be connected here when the amp is on
to prevent damage to the unit.

S. EXTERNAL SPEAKER  - Connection for an
external speaker.  This jack is wired in parallel
with the MAIN SPEAKER JACK, and must only
be used with a speaker plugged into the MAIN
SPEAKER jack.  The amplifier is optimized for a
4 ohm speaker load, and the speakers in the
cabinet are wired for 4 ohms.  Should a total
load of more or less than 4 ohms be used, the
amplifier will not put out its maximum power
output before distortion occurs and tube life
span will be reduced.

At 8 Ohms the "amp will not put out maximum power" I guess I can try the Legend without the Z Matcher and see what it sounds like, but I am guessing it may not sound like the amp should sound if this mismatch occurs.

At 8 Ohms "tube life span will be reduced" so don't use very expensive power tubes in this amp.

What else could possibly happen using an 8 Ohm speaker long term?

 

[trancedental]

I'm sure you can set the Weber to the amp output impedance, 4ohms & just attach a 8ohm or 16ohm speaker. I've done this before without problems.

Here's a post from TGP about this issue http://www.thegearpage.net/board/showthread.php?t=1107829

 

[muchxs]

At 8 Ohms the "amp will not put out maximum power" I guess I can try the Legend without the Z Matcher and see what it sounds like, but I am guessing it may not sound like the amp should sound if this mismatch occurs.

At 8 Ohms "tube life span will be reduced" so don't use very expensive power tubes in this amp.

What else could possibly happen using an 8 Ohm speaker long term?

Back in the day we just did it and didn't worry about it.

You're not going to hurt your amp with an 8 ohm load. You might not notice a difference between an 8 ohm 15' speaker and a 4 ohm 15" speaker.


When I mod an amp I chase down all the little things that aren't exactly right and could be better. "Exactly right" usually means "sounds better". Impedance match is what it is because it usually sounds better.


We get into the classic internet "which speaker, which tubes... all the way down to which capacitors and resistors." It would be great if some things clearly sucked and some things didn't. It's all about the combination. You might chase this all the way to its conclucion... a 4 ohm speaker "perfectly matched" to your amp and still not like it.


Not too thrilled about the Z matcher. There ain't no such thing as a free lunch. There's usually some sacrifice whenever you stick something else in your signal path.

 

[dragonfly66]

Thanks for the input guys.

I'll try the Legend with the Z-Matcher and then on its own and see if there is a big difference in tone.

If using the 8 Ohm speaker won't hurt the amp (just shorten the life fo the tubes) then there is no need to spend more money for this experiment unless I end up hating the Legend.

It seems some people think an 8 Ohm speaker into 4 Ohm tap won't do any damage to the amp and others think it will. I found these other threads.

Good lord, my head was hurting after reading this thread, http://www.tdpri.com/forum/shock-brothers-diy-amps/314473-8ohm-speaker-4ohm-fender-reverb-amp-i-know-its-overdone-but-lets-hear.html

This one was a little better - http://gretschpages.com/forum/other-amps/can-i-run-an-8-ohm-speaker-on-a-4-ohm-amp/9425/page1/

 

[homesick345]

Will it?

The back plate says, 2 Ohms Minimum Total

The manual says,

R. MAIN SPEAKER - Primary connection for
(internal or external) speakers. A speaker must
always be connected here when the amp is on
to prevent damage to the unit.

S. EXTERNAL SPEAKER - Connection for an
external speaker. This jack is wired in parallel
with the MAIN SPEAKER JACK, and must only
be used with a speaker plugged into the MAIN
SPEAKER jack. The amplifier is optimized for a
4 ohm speaker load, and the speakers in the
cabinet are wired for 4 ohms. Should a total
load of more or less than 4 ohms be used, the
amplifier will not put out its maximum power
output before distortion occurs and tube life
span will be reduced.

At 8 Ohms the "amp will not put out maximum power" I guess I can try the Legend without the Z Matcher and see what it sounds like, but I am guessing it may not sound like the amp should sound if this mismatch occurs.

At 8 Ohms "tube life span will be reduced" so don't use very expensive power tubes in this amp.

What else could possibly happen using an 8 Ohm speaker long term?

I thought your amp was 4 ohms, sorry about that. At two ohms, no it wont work and will sound tubby. But 4 to 8 works just fine. Actually it might sound better. I use an eminence legend 15 , great speaker, especially with tweed. Fits like a glove. Muchxs is right, do try it. It corrects tweed shortcomings, rolls off the middle a bit, adds nice highs and lows.

 

[BigDaddyLH]

I think the Jensen Neo 15-150 comes in 4, 8 and 16 ohms.

 

[homesick345]

I think the Jensen Neo 15-150 comes in 4, 8 and 16 ohms.

Good idea

 

[dragonfly66]

I think the Jensen Neo 15-150 comes in 4, 8 and 16 ohms.

I saw this one, but didn't know if was American voice liked the Legend and C15N. I just listened to the (link removed) and the even the clean seemed to have a little fuzz. I will investigate this speaker further though. Oh wait... wow it is $170!

 

[fauxsuper]

I think I'd take the "double your amp's wattage" rule with a grain of salt. Unless you often run your amp at very high volumes with high levels of distortion you should do fine with a speaker rated at 50 watts or so. That said, Jensen makes a 120 watt rated 15" in the Mod series that's available in 4 ohm form for a little over $120. I have a 50 watt 4 ohm Weber Blue Dog that lives happily in a 40 watt amp (Bandmaster Reverb) and it will play louder than I need it to, but I don't play heavy metal or play with lots of gain.

 

[birddog01]

A few years back after I got a Bassman head, did a recap and a few mods to it I was inquiring about a speaker on the vintage amp board. Mostly what was mentioned was a Weber Califonia or Michigan.
At the time I wound up going with a 2-10 Ragin Cagin set up.
Then I started reading all these 15" speaker threads here a couple years ago.
I was watching ebay for a while & came across this 4ohm speaker for a resonable bid and after playin it for a while decided it will be with me for as long as I have this amp.

 

[dragonfly66]

I think I'd take the "double your amp's wattage" rule with a grain of salt. Unless you often run your amp at very high volumes with high levels of distortion you should do fine with a speaker rated at 50 watts or so... I have a 50 watt 4 ohm Weber Blue Dog that lives happily in a 40 watt amp (Bandmaster Reverb) and it will play louder than I need it to, but I don't play heavy metal or play with lots of gain.

This is good to know. I do recall hearing that speakers are rated lower than what they actually can handle. I usually have the CVR at 6 and control the volume through my guitar.

...Then I started reading all these 15" speaker threads here a couple years ago. I was watching ebay for a while & came across this 4ohm speaker for a resonable bid and after playin it for a while decided it will be with me for as long as I have this amp.

Thanks for this, it hadn't dawned on me to try to find a used speaker on ebay.