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Post by JohnH on Sept 21, 2019 22:51:40 GMT -5
The other place where I hang out online is the Marshall forum, and over the last year or so Ive been developing a reactive attenuator to bring down the volume of loud amps without affecting their tone. This has got to a point where it works much better than I thought it would, starting from a vey simple base. A number of others have been building them to control their loud Marshalls. So I'd like to bring it home here, and show it to the GN2 family. This is the schematic: But there's a lot to say about it, and we have a 27 page thread going on there. If you are interested, best to just read the first post which is a recent summary, and the last ( currently no. 527) www.marshallforum.com/threads/simple-attenuators-design-and-testing.98285/cheers J
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Post by JohnH on Jul 1, 2020 23:15:08 GMT -5
My Marshall forum thread is at 56 pages now with several new design variations and many build reports. Here's the latest design : It is designed to take a cranked tube amp and reduce its volume in -3.5db steps down to -31db, with no change in tone. So 50W goes down to about 35mW, which is still louder than you might think, ideal for home playing.
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Post by mullardnerd on Mar 24, 2024 8:05:48 GMT -5
The other place where I hang out online is the Marshall forum, and over the last year or so Ive been developing a reactive attenuator to bring down the volume of loud amps without affecting their tone. This has got to a point where it works much better than I thought it would, starting from a vey simple base. A number of others have been building them to control their loud Marshalls. So I'd like to bring it home here, and show it to the GN2 family. This is the schematic: But there's a lot to say about it, and we have a 27 page thread going on there. If you are interested, best to just read the first post which is a recent summary, and the last ( currently no. 527) www.marshallforum.com/threads/simple-attenuators-design-and-testing.98285/cheers J Hey there, I'm new to the forum and have read that you designed a great attenuator. I recently have been on the hunt for an attenuator design that would let me play at a volume comparable to TV volume. I live in a flat with little insulation between me and the neighbors.. I've been building Lpad attenuators bu dont trust their safety and I've toasted a few now running at super low vol.. Yours has definitely got my attention. Along with the trainwreck and robinette power brake. Would any of your designs get me down to super quiet playing? Any insight would be very appreciated!!
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Post by JohnH on Mar 25, 2024 3:56:30 GMT -5
Hi mullardnerd and thanks for replying. If you can handle a few workshop skills , our design will get you a better result for less $. The Marshall forum thread has grown enormously since I posted here , so best to follow the link back there. The basic design is now M2, which has one coil. Hundreds of these have been built. With all stages engaged, it will reduce power by a factor of 1/1400. That's enough to take a 50W amp down to moderate to low TV volume. But it’s surprising how clear and reasonably loud that is. But if you need quieter, you can add more stages based on the three resistive stages and bring it down even lower. But most find it's attenuated enough. Happy to answer questions either here on on the MF.
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Post by gckelloch on Mar 25, 2024 16:44:34 GMT -5
You can also reduce the amp power by using just one tube pair in a dual pair fixed bias amp and using a cab of 2x the Ohm of the amp output. Some high Voltage-rated 6V6 tubes can also be used in place of 6L6 tubes to cut the power in half again. JJ 6V6S tubes sound a lot like 6L6 and can take 500V. The new TAD redbase 6V6GT-STR can take 450V. They have a warmer overdrive sound than the JJ. Speakers also have different efficiency ratings that might make a difference. Someone might know better, but I think closed back cabs are less efficient than ported or semi-open. Stuffing a cab with fiberfill or a shredded thermal foam pillow should also reduce resonances. Jamming a shredded thermal foam pillow between a wall and the back of an open-back combo amp might be worth try.
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