So I built a 2W 5E3.

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printer2
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So I built a 2W 5E3.

Post by printer2 »

I was half way through building another amp and someone was asking about a low powered 5E3. Automatically I thought of using the cute little 6AK6 as an output tube. I just had to try it and dropped the other build. Just got all the little bugs worked out. Never heard a real 5E3 in person so I can not say how much it compares, but it sure does sound nice for a low volume amp.

[IMG:1024:768]http://i406.photobucket.com/albums/pp14 ... 31a8f7.jpg[/img]


[IMG:1024:768]http://i406.photobucket.com/albums/pp14 ... 63302e.jpg[/img]

Jumpered out the first 4.7k resistor in the power supply and I have around 230V on the plates of the output tubes. Also the cathode resistor for them is somewhere around 360 ohms I think. Used a 70V line transformer for the OT. A 120V - 120V to 6V - 6V transformer with one of the 120V transformer windings for the HV supply.

[img:1024:597]http://i406.photobucket.com/albums/pp14 ... 5775a3.jpg[/img]

There is a switch on the right side to disconnect the cathode cap on the second stage and I will have the other position for adding some NFB. The switch on the left flips the 5E3 controls to a regular voltage divider volume circuit.
Last edited by printer2 on Mon May 26, 2014 10:36 pm, edited 1 time in total.
Regan
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Re: So I built a 2W 5E3.

Post by Regan »

Very cool! Nice cabinet too!
I have almost all the parts, right down to the same speaker :D
Good classic tone out of it?
I'm gonna dig around and see if I have any more 6ak6s, this looks like a fun little amp
Regan
Stevem
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Re: So I built a 2W 5E3.

Post by Stevem »

sweet little bugger ya got there!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!

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dorrisant
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Re: So I built a 2W 5E3.

Post by dorrisant »

Nice! This has got me to thinking about some of the little power tubes and OTs I have just sitting around here.

Tony
"Education is what you're left with after you have forgotten what you have learned" - Enzo
printer2
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Joined: Sat Jun 26, 2010 5:14 am
Location: Canada

Re: So I built a 2W 5E3.

Post by printer2 »

Do not know about classic tone but sounds pretty good. Because there is not a lot of information out there on using the 6AK6 in P-P I put a high value cathode resistor in and paralleled up resistance with it until I was happy with the sound clean and dirty. I watched the waveform (sine wave) on the scope and dc on the resistor with a meter. When overdriving the output the cathode voltages rises biasing the tubes colder and you can see the crossover distortion in the sine wave.

I found running the tubes too hot lost some edge when playing through the amp. Sounded best with some crossover distortion when you really hit them hard, otherwise it sounded too smooth. At least to my ears, could see it also depending on your speaker. I did try it through a WGS ET-65 and liked it also. With a speaker where you have more emphasis on the top end less crossover distortion might be the ticket.

I calculated the power dissipation and it is about 2W which is pretty much what the tube is rated for. One thing that I set the amp up for is to use 6AQ5's for the output. The tubes share some pins and a switch to shift the remaining ones and lower the cathode resistor would be easy enough. Might have to change the transformer impedance, maybe not. I'll leave that for when I am feeling bored.
Regan
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Re: So I built a 2W 5E3.

Post by Regan »

Most of the time when i have seen people running 6ak6's they have found they sound best down around 180v to 200v. Maybe try el95's too, they are a nice sounding tube.
Regan
printer2
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Re: So I built a 2W 5E3.

Post by printer2 »

Tried them at 180V, that is what the 4.7k resistor after the voltage doubler was for. I just kept reducing that value until I took it right out.

Runs them at a higher voltage than me. Sounds pretty fine.

http://www.bluetone.fi/en/jcm-800-jr/

http://www.bluetone.fi/en/lead-jr/
Regan
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Re: So I built a 2W 5E3.

Post by Regan »

Proof's in the pudding, if it sounds good it is good :)
Those Bluetone's do sound great!
Regan
printer2
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Re: So I built a 2W 5E3.

Post by printer2 »

A few pics to show the build process. The board with Fender styled hi low input, 1M on the jack, common cathode resistor and cap then plate resistor and blocking caps for the first tube. Next triode`s plate resistor and coupling cap with big grid stopper up top, beside the filter cap is the cathode resistor and cap. Next the cathodyne components and grid leak resistors for the output tubes. Just one screen resistor in sight and the output cathode resistor and cap along with the rest of the power supply components.

I have done a couple of low output amps using perf strips and as long as you do not put unrelated sections beside each other they generally play nice as long as it is not a high gain amp. I think part of the reason I have got away with it is the chassis have been cramped and I did not have a lot of wire running from the board to the tubes. I also try to cross wires at right angles and will run wires across open space, no need for them all to be tight up against the chassis. Sometime distance is your friend.

[img:1008:756]http://i406.photobucket.com/albums/pp14 ... eefc39.jpg[/img]

The switch to flip the volume controls to act like voltage divider volume controls.

[img:1024:559]http://i406.photobucket.com/albums/pp14 ... ce49c0.jpg[/img]

The power transformer that was only intended to be a split 12V supply with two windings for use on 120v or 240v. The 70V line transformer used as a output transformer, at 2W I doubt I am stressing it. I still have to make a cover to keep curious fingers out.

[img:864:490]http://i406.photobucket.com/albums/pp14 ... 46ca79.jpg[/img]

Not pretty but it works.

[img:929:1024]http://i406.photobucket.com/albums/pp14 ... 151b29.jpg[/img]

The chassis is aluminum, here is me bending a steel one.

[img:1024:768]http://i406.photobucket.com/albums/pp14 ... bnet12.jpg[/img]

[img:1024:768]http://i406.photobucket.com/albums/pp14 ... bnet13.jpg[/img]

[img:1024:768]http://i406.photobucket.com/albums/pp14 ... bnet14.jpg[/img]

[img:1024:768]http://i406.photobucket.com/albums/pp14 ... bnet11.jpg[/img]

Router attached to my table saw. Made a sled to ride in the table saw channel (what the heck was it called).

[img:1024:768]http://i406.photobucket.com/albums/pp14 ... _9377a.jpg[/img]

I got carried away and now I have to fill them up.

[img:1024:656]http://i406.photobucket.com/albums/pp14 ... family.jpg[/img]
Regan
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Re: So I built a 2W 5E3.

Post by Regan »

Thanks for all the photo's, really enjoyed it!
Tht amp really looks like fun, would be great for basement playing.
I love the stack of cabs!!! I'm hoping to do that very thing this summer, I have the wood set aside and just have to set up outside one nice day and make some dust.
Regan
printer2
Posts: 146
Joined: Sat Jun 26, 2010 5:14 am
Location: Canada

Sound file of amp

Post by printer2 »

So I did mp3 of a work buddy trying out the amp. He has never played a 5E3 so he didn't know how to get the most of the controls. Please be kind to him as this is his first time playing it. I put it on a Microsoft sharing file place, first time I used it also. If you want to hear the amp you can download it.

http://1drv.ms/1hDNpt3
Regan
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Re: So I built a 2W 5E3.

Post by Regan »

I think the amp sounds great, sounds really touch sensitive!
Regan
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Structo
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Re: So I built a 2W 5E3.

Post by Structo »

Sounds good!

Is that just the amp or was there a dirt pedal in use?
Tom

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printer2
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Re: So I built a 2W 5E3.

Post by printer2 »

Just the amp. He did have a delay/reverb on it for the first bit.
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electrochimp
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Re: So I built a 2W 5E3.

Post by electrochimp »

love those 6AK6's !
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