# 2W 5E3 for apartment dwellers



## Printer2 (Apr 8, 2012)

A guy was asking about a low wattage 5E3. I did my version of one.










The 4.7k is no longer after the doubler and the cathode resistor for the output is around 360 ohms. Used a 10W 70V line transformer for the output transformer.





















Just a cheap build that did not turn out too bad. A buddy took it for a spin, here's the sound file.


http://1drv.ms/1hDNpt3


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## GuitarsCanada (Dec 30, 2005)

Nice looking unit


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## Gnobuddy (May 17, 2014)

Printer2 said:


> .. and the cathode resistor for the output is around 360 ohms.


Nice looking, and nice sounding amp! Is the 820 ohm value shown in the schematic for the output tube cathode resistor an error, then? It should really be 360 ohms?

Was 2W still too loud for an apartment? Experimenting with speaker attenuation, I found I had to cut the power output down to way below a watt before I could get distorted tone at apartment-friendly volumes. Attenuationg down an amps nominal clean power output to somewhere around 100 mW or less seemed about right. 

100 mW (0.1 W) is -20 dBW, so a 100 [email protected] speaker will still put out 80 dB sound pressure level with that tiny input power. Add another four or five dB once the amp is overdriven, and you're actually at the 85 dB threshold beyond which hearing loss starts to occur!

-Gnobuddy


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## Jim DaddyO (Mar 20, 2009)

Nice little snarling tone there. I like it!


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## Robert1950 (Jan 21, 2006)

I think that amp is neat,... even if reading that schematic and knowing what you are saying is like reading and understandomg Klingon to me.


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## Printer2 (Apr 8, 2012)

Gnobuddy said:


> Nice looking, and nice sounding amp! Is the 820 ohm value shown in the schematic for the output tube cathode resistor an error, then? It should really be 360 ohms?
> 
> Was 2W still too loud for an apartment? Experimenting with speaker attenuation, I found I had to cut the power output down to way below a watt before I could get distorted tone at apartment-friendly volumes. Attenuationg down an amps nominal clean power output to somewhere around 100 mW or less seemed about right.
> 
> ...


Sorry for not getting back sooner, forgot I posted here. The 820 ohm was what I started with as I could not find much information on biasing these tubes in Class AB. I jumpered a parallel resistor across the 820 and went down till I found a value I liked. All depends on the speaker and your neighbours I guess. A whimpy 8" goes a long way to keep the sound level down. I just picked up a 12" Yamaha speaker and tried it with this amp, it might not be a good candidate to keeping your lease. The 10" in the cabinet will put out 94dB at 1M giving all it has, the 12" about 100dB. The amp sounds much better with the 12" than the 10", just sounds smoother.


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## Gnobuddy (May 17, 2014)

Printer2 said:


> The 10" in the cabinet will put out 94dB at 1M giving all it has, the 12" about 100dB.


100 dB? Yep, definitely a lease-breaker! (And a good way to damage one's hearing.)

Thanks for getting back to us on this thread, Printer2! I really like what you did with this project, everything from the folded metal chassis to the perfboard to the cabinet. To me it's an excellent balance between pragmatism and good looks. To top it off, the amp sounds really good in those clips.

Excellent work!

-Gnobuddy


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