2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
- Thread starter Jeffblue
- Start date
L
Little Pigbacon
Guest
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
1. What's the ohm rating of the speaker in the Vibro Champ?
2. What's the ohm rating of the 4x6 cab?
3. A 4x6 cab?
1. What's the ohm rating of the speaker in the Vibro Champ?
2. What's the ohm rating of the 4x6 cab?
3. A 4x6 cab?
Jeffblue
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
1. Vibro Champ speaker is a 4 Ohm 10 inch Peavey Scorpion
2. Impedance WITH the 4X6 cab is (according to my Fluke multimeter is 2.5 Ohms
3.Yep, a Quantum guitar speaker cab that is loaded with 2 vintage Jensen Alnico, an unidentified vintage Alnico and an Eminence Ceramic, all 6 inch speakers.
1. Vibro Champ speaker is a 4 Ohm 10 inch Peavey Scorpion
2. Impedance WITH the 4X6 cab is (according to my Fluke multimeter is 2.5 Ohms
3.Yep, a Quantum guitar speaker cab that is loaded with 2 vintage Jensen Alnico, an unidentified vintage Alnico and an Eminence Ceramic, all 6 inch speakers.
devastone
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
The multimeter is taking a DC reading, so the actual impedance of the cab is probably closer to 4 ohms, but no guarantees. That said, running it in parallel with a 4 ohm speaker will give a load of less than 2 ohms, so, no, not a good idea unless you order new output tubes and a transformer before you try it.
The multimeter is taking a DC reading, so the actual impedance of the cab is probably closer to 4 ohms, but no guarantees. That said, running it in parallel with a 4 ohm speaker will give a load of less than 2 ohms, so, no, not a good idea unless you order new output tubes and a transformer before you try it.
GoldenVulture
Braindeadologist
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
- https://forum.seymourduncan.com/showthread.php?322034-Replaced-OT-In-my-68-vibe-Champ - :reporter:
- https://forum.seymourduncan.com/showthread.php?322034-Replaced-OT-In-my-68-vibe-Champ - :reporter:
L
Little Pigbacon
Guest
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
A multimeter taking a D.C. resistance measurement doesn't give you a true nominal impedance for a speaker load. The ohmmeter ignores the reactive component of the load. The impedance of the load should be a little higher than the 2.5 ohms. 3? 3.2?
What are the impedances of the 6" speakers, and how do you have them connected? I'm just curious to see what it comes out to on paper. You might be okay with this, though I fear it might sound like the Mayberry Chorus with multiple Barneys.
A multimeter taking a D.C. resistance measurement doesn't give you a true nominal impedance for a speaker load. The ohmmeter ignores the reactive component of the load. The impedance of the load should be a little higher than the 2.5 ohms. 3? 3.2?
What are the impedances of the 6" speakers, and how do you have them connected? I'm just curious to see what it comes out to on paper. You might be okay with this, though I fear it might sound like the Mayberry Chorus with multiple Barneys.
Jeffblue
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
Thanks for your reply. I just replaced the OT, Mercury Magnetics 55 tweed and I don't want to replace it again.
Thanks for your reply. I just replaced the OT, Mercury Magnetics 55 tweed and I don't want to replace it again.
Jeffblue
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
The impedance of all the 6 inch speakers is nominal 4 Ohms all wired in series-parallel. I've run the 4X6 speaker cab by itself with the Vibro Champ not connected and you'd be surprised how good those speakers sound. Pushes more air than you'd think. I have run them combined with the Vibro Champ speaker in the past and it sounded fabulous. I just don't want to blow my new OT.
The speaker in my Vibro Champ is a 10 inch 4 Ohm Peavey Scorpion.
The impedance of all the 6 inch speakers is nominal 4 Ohms all wired in series-parallel. I've run the 4X6 speaker cab by itself with the Vibro Champ not connected and you'd be surprised how good those speakers sound. Pushes more air than you'd think. I have run them combined with the Vibro Champ speaker in the past and it sounded fabulous. I just don't want to blow my new OT.
The speaker in my Vibro Champ is a 10 inch 4 Ohm Peavey Scorpion.
L
Little Pigbacon
Guest
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
Isn't the 2.5 ohms you measured with the 4-ohm Jensen and the 4x6 cab? In parallel or series?
Isn't the 2.5 ohms you measured with the 4-ohm Jensen and the 4x6 cab? In parallel or series?
GoldenVulture
Braindeadologist
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
No other Ohmage taps on the OT ?
No other Ohmage taps on the OT ?
L
Little Pigbacon
Guest
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
That's a higher D.C. resistance than I would have expected for that combination. Maybe one or more drivers were rated 4 ohms just to be on the safe side.
That's a higher D.C. resistance than I would have expected for that combination. Maybe one or more drivers were rated 4 ohms just to be on the safe side.
Jeffblue
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
No, only the 4 ohm, Mercury Magnetics 55 tweed. I was told by someone at Weber that this OT will allow me to use other tube types with the same pinout. I am running an NOS 5881 tube. How does that affect my impedance?
No, only the 4 ohm, Mercury Magnetics 55 tweed. I was told by someone at Weber that this OT will allow me to use other tube types with the same pinout. I am running an NOS 5881 tube. How does that affect my impedance?
Jeffblue
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
Every driver is rated at 4 Ohms. I am running an NOS 5881 instead of a 6V6.
Every driver is rated at 4 Ohms. I am running an NOS 5881 instead of a 6V6.
L
Little Pigbacon
Guest
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
This has more to do with the speaker manufacturer and what rating they decided to put on their cones. It's not an exact science, and some amount of discretion is involved.
This has more to do with the speaker manufacturer and what rating they decided to put on their cones. It's not an exact science, and some amount of discretion is involved.
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Jeffblue
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
The total overall with all speakers connected according to my DVM reads 2.5 Ohms. The Scorpion speaker and the 4X6 cab are wired parallel. I understand that the 5881 tube will want to see half the impedance of a 6V6. Could this then be an ideal situation?
The total overall with all speakers connected according to my DVM reads 2.5 Ohms. The Scorpion speaker and the 4X6 cab are wired parallel. I understand that the 5881 tube will want to see half the impedance of a 6V6. Could this then be an ideal situation?
GoldenVulture
Braindeadologist
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
Check your OT for heat, make sure it's not getting hot.[ when in use ]
Check your OT for heat, make sure it's not getting hot.[ when in use ]
Jeffblue
Well-known member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
Hi all. Thanks for all the replies and info. I decided to relinquish the 4X6 cab because my power transformer was running warm to the touch while I'm running my air conditioning and would hate to feel the heat without the air running. My VC still sounds magnificent with the 10 inch speaker I installed.
Hi all. Thanks for all the replies and info. I decided to relinquish the 4X6 cab because my power transformer was running warm to the touch while I'm running my air conditioning and would hate to feel the heat without the air running. My VC still sounds magnificent with the 10 inch speaker I installed.
Joey Voltage
New member
Re: 2.5 Ohm Speaker Load On A 4 Ohm OT?.....................
Warm to the touch is fine, so hot it burns your skin is when you should start to worry..
Warm to the touch is fine, so hot it burns your skin is when you should start to worry..
