5E3 1/4 power switch?

Thanks for reporting back. I’m curious to here what the tube swap will do. Maybe a couple 12AX7’s will get it where it needs to be. What are your Power transformer voltages? Maybe lowering those would help too

 

I run my THD hot plate at the -12dB setting with my 5e3 build and it’s perfect level for living rooms with a 93/94dB Custom 20oz ceramic speaker, or with a Weber 12A125A Alnico.
It’s not apartment quiet, but nothing is shaking and the amp doesn’t feel like it’s suffocating.
Any quieter and I’d just get a modeler so I don’t waste my vintage tubes life. I find the sound is destroyed beyond -12dB on it. Same with a JTM45 and Boogie Mark V.
I tried opening the Hotplate up to measure what gets to their “-12” but I cannot open it. Something will break if I follow the internet instructions.

 

Oh good idea. Please report back when you finish it. Only concern I could see is it having enough heat dissipation.

 

Absolutely. Trying to tame a 5e3 right now, that's giving my Twin a run for the money. I like the idea of a 1/4 power switch. Or maybe a less efficient speaker.

 

I once had a stereo rig at home that had a power meter on the amp. I was amazed at how loud it was even at 1/2 watt, much to loud for "bedroom volume". Loud enough to interfere with normal activities in the rest of the house.

 

a friend of mine bought a massively inefficient 6" car stereo speaker which he uses when he's testing amps in his home workshop. It's small and easy to move around. He can put it in a cardboard box for less volume, or throw a pillow over it for even quieter sounds.

 

I tried the 1/4 power mid and did not like it because of the loss of some of the treble. So, I installed a pre-PI master volume. It was an easy mod and gets you to bedroom levels of you want. My circuit is a little different because my my 5E3 has the Tweedle-Dee mod, but here is a link to when I was doing it.
https://ampgarage.com/forum/viewtopic.php?t=31140

 

It takes a reduction in power by a factor of 10 to cut the volume by 50% through the same speaker/s.
A reduction of 25% in power output is maybe perceptible but not anything close to significant.

 

just ordered the 8Ω and 16Ω 25w pair.
will probably build as a hardwired cable (no switch) in a pedal box with a length of speaker cable and plug in and out and use on my 5e3 and 18w TMB builds.
Can always drill ventilation as needed.

 

Hi, did you get around to building this? How did it go?

This sounds great flexible way of doing it!!

Does anyone know the maths for this so I can work out all the possible combinations downwards in power?

I get the calculation for total ohms kept at 8r, but I can't see the method to get the resulting power left ?

 

I did; in hindsight I would have preferred to use jacks, not use the plywood and caulk to mount the components, and used the values for 10%.
the cable is a little short
It gets warm but not hot
It cuts some volume but not enough.

 

Does anyone know where the 8 series/ 16 parallel, and 16 series /12 parallel come from?

Just used the Weber lpad design tool and it shows:

6dB loss ( 1/4 power)
4 ohm series
8 ohm parallel

10dB loss (1/10 power)
5.47 ohm series
3.7 ohm parallel


Why should I choose these instead of the ones in this thread?


Thanks

 

I put Rob's pre-PI master volume in... I love it.. works great !
I can dial in what I need or go full volume.. Used the Ground/standby hole
1M audio pot,a couple of wires and no big resistors...