Hi,
Please excuse a total newbie question;
I sometimes use my low watt Bottlehead SEx as a preamp for my 3e Audio Class D amp. I find it softens the midrange and general tone.
If I did it the other way and used my 50w/ch amp as a pre amp for the SET, would I damage the SET amp?
Cheers,
Ade
Please excuse a total newbie question;
I sometimes use my low watt Bottlehead SEx as a preamp for my 3e Audio Class D amp. I find it softens the midrange and general tone.
If I did it the other way and used my 50w/ch amp as a pre amp for the SET, would I damage the SET amp?
Cheers,
Ade
Do you use a volume control? If so then just turn it down. BUT there could be an issue with the poweramp as it now does not see a correct load. It likes to see something like 8Ohm, right?
adejacko,
Wow!
You are very creative. But . .
Do not do either of those!
1. Most amplifiers do not like to be used without a proper load.
A Bottlehead SEX amp input jack has a very high impedance input, it is not a proper load for a 50 Watt amp.
A 50 Watt amp input jack is not a good load for a SEX amp. Same principle.
Using the wrong load on either amplifier can potentially destroy the amplifier.
And, depending on the 50 Watt amplifier, the SEX amp may have enough output to destroy the 50 Watt amplifier.
2. I bet the input tube self bias voltage on the SEX amp is about 2 or 3 Volts.
Any input signal larger than 2 or 3V peak will cause the SEX amp to draw grid current.
There may be a volume control before the input tube grid.
Can the volume control take 28.8V input?
3. 50 Watts into an 8 Ohm load is 28.8V peak.
4. Are you loading the 50 Watt amp with a 50 Watt 8 Ohm load resistor (will get real hot, unless you only occasionally get short 50 Watt music passages (so use a 100W 8 Ohm resistor)?
Are you loading the SEX amp with a 10 Watt 8 Ohm load (or the 50 / 100 Watt 8 Ohm load)?
As you can see, there is no good match for a 50 Watt amp driving a SEX amp input, nor the other way around either.
I am only guessing, but I think it might be time for you consider building another amplifier kit.
If you like bottlehead amps, try the 2A3 or 300B models.
There are many other good kit amplifiers out there too.
Some are excellent simple push pull designs too.
Perhaps you can build an amplifier from schematics, with some help from this forum (but that is Much more challenging).
And, you need to pick a simpler one, not a complex one to do from scratch.
Question for you:
What is / or are your loudspeaker model(s).
Wow!
You are very creative. But . .
Do not do either of those!
1. Most amplifiers do not like to be used without a proper load.
A Bottlehead SEX amp input jack has a very high impedance input, it is not a proper load for a 50 Watt amp.
A 50 Watt amp input jack is not a good load for a SEX amp. Same principle.
Using the wrong load on either amplifier can potentially destroy the amplifier.
And, depending on the 50 Watt amplifier, the SEX amp may have enough output to destroy the 50 Watt amplifier.
2. I bet the input tube self bias voltage on the SEX amp is about 2 or 3 Volts.
Any input signal larger than 2 or 3V peak will cause the SEX amp to draw grid current.
There may be a volume control before the input tube grid.
Can the volume control take 28.8V input?
3. 50 Watts into an 8 Ohm load is 28.8V peak.
4. Are you loading the 50 Watt amp with a 50 Watt 8 Ohm load resistor (will get real hot, unless you only occasionally get short 50 Watt music passages (so use a 100W 8 Ohm resistor)?
Are you loading the SEX amp with a 10 Watt 8 Ohm load (or the 50 / 100 Watt 8 Ohm load)?
As you can see, there is no good match for a 50 Watt amp driving a SEX amp input, nor the other way around either.
I am only guessing, but I think it might be time for you consider building another amplifier kit.
If you like bottlehead amps, try the 2A3 or 300B models.
There are many other good kit amplifiers out there too.
Some are excellent simple push pull designs too.
Perhaps you can build an amplifier from schematics, with some help from this forum (but that is Much more challenging).
And, you need to pick a simpler one, not a complex one to do from scratch.
Question for you:
What is / or are your loudspeaker model(s).
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A Class D amp shouldn’t be damaged driving your SET, but depending on it’s output filter design it may require a nominal 8 Ohm load to have a flat frequency response. If you use it as a preamp it might therefore, have a non-flat response with a big peak somewhere in the treble.
The input of your SET will surely clip if you over-drive it. If the input is dc-coupled you could drive damaging positive grid current into the first tube. If the grid is protected by a large enough resistor it may survive but it may not. If you keep the input signal to the Bottlehead amp low enough not to drive it into heavy distortion then you should be OK. Just keep the volume down low.
I can’t see any reason why you’d throw a cheap class d amp in front of a tube amp, it won’t make the tube amp any louder as the output of the tube amp is limited by the design of it’s output stage and not by the input signal.
The input of your SET will surely clip if you over-drive it. If the input is dc-coupled you could drive damaging positive grid current into the first tube. If the grid is protected by a large enough resistor it may survive but it may not. If you keep the input signal to the Bottlehead amp low enough not to drive it into heavy distortion then you should be OK. Just keep the volume down low.
I can’t see any reason why you’d throw a cheap class d amp in front of a tube amp, it won’t make the tube amp any louder as the output of the tube amp is limited by the design of it’s output stage and not by the input signal.
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