diy audio tube amps hi fi.

AUDIO PAGE &
DIY TIPS

CAUTION: TUBE AMPLIFIERS CONTAIN LETHAL VOLTAGES EVEN WHEN UNPLUGGED

Table of Contents

Read First-Danger High Voltage

New Soon To Come

Updated 5881 Audio Power Amp

Darling Audio Power Amp

Back to Home Page

SAFETY AND FILTER CAPACITORS


	!!CAUTION!! HIGH VOLTAGES EVEN IF UNPLUGGED! TUBE / VALVE AMPS CAN STORE VERY LARGE VOLTAGES! THESE VOLTAGES CAN KILL YOU! You have to understand how to safely work inside the chassis of a tube amp. Just reading this is not enough, but here are a few tips: Never work on a amplifier that is plugged into the wall socket, always unplug it first! Stand on a rubber mat of some sort and don't work bare foot, under the influence of alcohol or any other drug, legal or not for that matter. Here is another good tip: Only probe an amp with you're right hand and with you're left hand by you're side. So if you do happen to take a high voltage shock, the the voltage will not go across you're chest! High Voltage is stored in the electrolitic capacitors and they need to be discharged!That's what I'm doing in this pic. These are those large round can's and there usually blue or black. The discharge tool is made of 600 Volt wire with a 3-5 watt resistor of 500 to 1000 ohms. Basically you clip one side to ground then clip the other end to the Pos + side of the capacitor. Check with you're multimeter set to 600 DC volt setting and make sure the voltage has been discharged. Back to top

SE 5881 Audio Power Amp

My Single Ended 5881 Audio Power Amp

This amp was built for a first test experiment and I am very pleased with its sound and volume. It has become my main every day listening amp.

As you can see its point to point wiring like most all old tube audio amps were. I decided to make an amp that would use off the shelf common tubes and parts. The preamp tube is a 12AX7 and its two stages are wired in parallel. The power tube is a fender 5881, after comparing other compatible tubes that I had laying around such as a EL34 Tesla, 6L6 Chinese, it was fairly clear that the Fender branded 5881 had the best overall bass and sound.

My design goals were simplicity, durability, sound quality, and a semi compact size. For these reasons there are no tone controls, I got my sound and bass using large by-pass capacitors and tube selection. My only restraint was my budget, which led to one mistake and that is I can only use one side of this stereo amp. Since both sides share the power transformer it was getting a little two hot for my liking . So if you decide to do a project like this use a bigger one ore use two.

Rectification is done by my all time favorite tube the 5AR4/GZ34 and because of its inherent slow turn on I decided to use one power switch and no standby. I will be doing another one of these!

SE Darling Audio Power Amp

Soon I hope to get more info on my audio amp projects.

SE EL84/6BQ5 Audio Power Amp

A Little EL84 SE Stereo Amp is saved and it turns out to be Gem!

Here is a heads up on this one! I amp working on a little EL84 power amp that sounds really good!

Here is how it all started:
One day last year and once a year my city has heavy trash pick up day. On the side of the road was one of those large wooden consol type radio/record player. Well out of it I salvage this little ugly but neat EL84 stereo power amp! Well for a year now its been used as a head phone amp and wow what a tone that this thing has! I decided this is going to be the next project and this is where it gets interesting.

I started gathering component values, when I had to stop and scratch my head about how one particular section was wired, it just didn’t make sense to me or what I was used to seeing? So to better understand it I drew a detailed schematic of it. Turns out to be fairly interesting indeed and now it does make sense to me but its still very different. Perhaps THIS is why it sounds so good!

My goal now is to start from scratch with this unique design and bring it back from the past with all brand new shinny parts!

Check Back on This One!