I have an 80W/80Ohm 12” speaker I want to pair to a 20W/8Ohm 12” in a pre-amped cabinet with output from a 100W tube valve. What do I need to include to manage the output to these speakers?
Riff-in-Thyme said:
I have an 80W/80Ohm 12” speaker I want to pair to a 20W/8Ohm 12” in a pre-amped cabinet with output from a 100W tube valve. What do I need to include to manage the output to these speakers?
What resistance is the amp expecting?
Carmen_Sandiego said:
Riff-in-Thyme said:
I have an 80W/80Ohm 12” speaker I want to pair to a 20W/8Ohm 12” in a pre-amped cabinet with output from a 100W tube valve. What do I need to include to manage the output to these speakers?
What resistance is the amp expecting?
Futile.
Carmen_Sandiego said:
Riff-in-Thyme said:
I have an 80W/80Ohm 12” speaker I want to pair to a 20W/8Ohm 12” in a pre-amped cabinet with output from a 100W tube valve. What do I need to include to manage the output to these speakers?
What resistance is the amp expecting?
How do I identify this?
do you measure the resistance of the two speakers by connecting in parallel?
then add an appropriate crossover?
Dropbear said:
Carmen_Sandiego said:
Riff-in-Thyme said:
I have an 80W/80Ohm 12” speaker I want to pair to a 20W/8Ohm 12” in a pre-amped cabinet with output from a 100W tube valve. What do I need to include to manage the output to these speakers?
What resistance is the amp expecting?
Futile.
So <1ohm?
Riff-in-Thyme said:
Carmen_Sandiego said:
Riff-in-Thyme said:
I have an 80W/80Ohm 12” speaker I want to pair to a 20W/8Ohm 12” in a pre-amped cabinet with output from a 100W tube valve. What do I need to include to manage the output to these speakers?
What resistance is the amp expecting?
How do I identify this?
ohm meter?
Riff-in-Thyme said:
Carmen_Sandiego said:
Riff-in-Thyme said:
I have an 80W/80Ohm 12” speaker I want to pair to a 20W/8Ohm 12” in a pre-amped cabinet with output from a 100W tube valve. What do I need to include to manage the output to these speakers?
What resistance is the amp expecting?
How do I identify this?
The amp specs will state “100W to 8ohm load” or something similar. It’ll probably be 8, so no worries.
So you need two pre-amp signals – one to your 20W speakers, and one to your amp driving your 100W speakers. (Do either specify if it is “W” or “WRMS”?
Just don’t turn it up past about 7.
you have 80w and a 20w speakers both 8ohm. to drive them safely with a 100w amp you’ll need them in series i believe, and if you do this then the input impedance to them will be 16ohms. if they’re in parallel then the max input wattage would be 20w and the input impedance would be 8ohms.
willing to be corrected.
JudgeMental said:
you have 80w and a 20w speakers both 8ohm. to drive them safely with a 100w amp you’ll need them in series i believe, and if you do this then the input impedance to them will be 16ohms. if they’re in parallel then the max input wattage would be 20w and the input impedance would be 8ohms.willing to be corrected.
80W 80 Ohm + 20W 8 Ohm
looking at up to 4 by 6550 valves wired to compliment the speakers
80ohm speaker???
JudgeMental said:
80ohm speaker???
that is what it says on the back- Impedance 80 ohms-Max. Power 80 watts
JudgeMental said:
80ohm speaker???
I assumed that was a typo…
BTW, the 20W speakers, you were saying they have a pre-amp input, implying they have an amp built in and a power cord?
Carmen_Sandiego said:
JudgeMental said:
80ohm speaker???
I assumed that was a typo…
BTW, the 20W speakers, you were saying they have a pre-amp input, implying they have an amp built in and a power cord?
I am going to build in a circuit to the cabinet that includes 4 6550 valves, transformer and output circuitry compliant with the speakers
Riff-in-Thyme said:
Carmen_Sandiego said:
JudgeMental said:
80ohm speaker???
I assumed that was a typo…
BTW, the 20W speakers, you were saying they have a pre-amp input, implying they have an amp built in and a power cord?
I am going to build in a circuit to the cabinet that includes 4 6550 valves, transformer and output circuitry compliant with the speakers
Not sure if that was a “Yes” or a “No”..
BTW, I am not sure either speaker will be suitable. The 20W speakers will not be up to the task, and the others sound strange. (Do you have a model number or manufacturer?)
I asked my meditation teacher about resistance.. he just said Ohm..
Carmen_Sandiego said:
Riff-in-Thyme said:
Carmen_Sandiego said:I assumed that was a typo…
BTW, the 20W speakers, you were saying they have a pre-amp input, implying they have an amp built in and a power cord?
I am going to build in a circuit to the cabinet that includes 4 6550 valves, transformer and output circuitry compliant with the speakers
Not sure if that was a “Yes” or a “No”..
BTW, I am not sure either speaker will be suitable. The 20W speakers will not be up to the task, and the others sound strange. (Do you have a model number or manufacturer?)
80W is Southern Cross Hi fidelity sub-woofer made in Japan. Can’t find anything on it in search
20W I intended to provide a resistor
Dropbear said:
I asked my meditation teacher about resistance.. he just said Ohm..
one hand clap
when you say “speaker” do you mean the driver or a driver in an enclosure?
Dropbear said:
I asked my meditation teacher about resistance.. he just said Ohm..
10/10
JudgeMental said:
when you say “speaker” do you mean the driver or a driver in an enclosure?
I mean the driver I suppose. I intend to rebuild the two cabinets/enclosures I have in to one to house the valve circuitry and speakers
i think you’ll have problems with both the power difference and the impedance difference. putting a resister in is not the same as impedance matching.
JudgeMental said:
i think you’ll have problems with both the power difference and the impedance difference. putting a resister in is not the same as impedance matching.
can I run one 6550 to the 20W and 3 to the 80W or something similar?
i think you’d basically need two amps to do that. there is usually a matching transformer on the output of valve amps. you’d need either two, then that brings problems with impedance, or a tapped one with different taps for different impedance, and i don’t know if they exist. valve stuff isn’t as easy to get these days. anyway i’m not really an expert in this field.
JudgeMental said:
i think you’d basically need two amps to do that. there is usually a matching transformer on the output of valve amps. you’d need either two, then that brings problems with impedance, or a tapped one with different taps for different impedance, and i don’t know if they exist. valve stuff isn’t as easy to get these days. anyway i’m not really an expert in this field.
has given me some idea where to go.
http://sound.westhost.com/index2.html
might find some stuff from this guy in his articles. he’s pretty good.
CrazyNeutrino said:
Riff-in-Thyme said:
Carmen_Sandiego said:What resistance is the amp expecting?
How do I identify this?
ohm meter?
Stealth said:
CrazyNeutrino said:
Riff-in-Thyme said:How do I identify this?
ohm meter?
No, an ohm meter will not do it. You will need the amp specs.
I was looking at matching this to 6550 valves?
Are you sure it is an 80ohm speaker? Do you have an impedance meter to check it?
80ohm sounds like a 100v line impedance rather than a voice coil impedance, but then it is unlikely to be a sub-woofer.
Stealth said:
Are you sure it is an 80ohm speaker? Do you have an impedance meter to check it?
80ohm sounds like a 100v line impedance rather than a voice coil impedance, but then it is unlikely to be a sub-woofer.
it is a sub-woofer, which is why I wanted to include it in the cabinet. I intend it as final out put for a guitar amp and wanted to include both speakers to provide bass/treble balance, largely for controlling the feedback dynamics.
The 80 Ohm thing doesn’t appear correct, meter it on the low ohms range for a ball park figure, it’ll give you an idea, make sure nothing in parallel with it that messes the measurement.
Putting resistors in series with speakers reduces your damping and control, so you can get away with it a bit with maybe a midrange or sweeter, but even then it’s a bit dodgy. The amplifier is controlling (damping) a moving reactive load (cone with voice coil etc), which itself generates voltages and currents, so you need the amplifier damping. Basically the amplifer is generating a signal representaive of the music signal, when it sees something on the output that departs from this negative feedback pushes the amplifer harder the bring it back into line. Called “Q factor” maybe, which is an important rating of amplifiers. Speaker lead resistance reduces this.