Did a low wattage 5E3

[printer2]

I did a quick build of a 5E3 amp with a couple of changes. The main one is the 6AK6 instead of 6V6's for a big 2-3W. I also included a switch to change the 5E3 interactive volume and tone controls to a regular resistive divider volume controls. I also put in a switch to disconnect the cap on the second stage cathode resistor. I jumpered out the 4.7k resistor after the voltage doubler and went to a 360 ohm resistor for the output cathodes.





Used a Hammond flat pack transformer for the 6V heaters and used one of the 115V primaries as the high voltage. A 70V line PA transformer for the output transformer.



Did a strip board build.



A quick chassis out of aluminum.



One of my empty cabinets, old 10" console stereo speaker to round it out.





So I did mp3 of a work buddy trying out the 6AK6 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

[stratele52]

Not to much hum or white noise ?

[printer2]

At 2W max output? Heck no. I do have a problem with my 12AY7 input tube, sometimes it decides to start crackling which is a shame as it is a nice old tube otherwise.

[TeslaRect5150]

I like your board layout. Fun to wire things up on a perf board, can be a pain sometimes though. Seems like mounting resistors in this way could help fit a lot of amp in a small chassis. Maybe possible in a board with a small eyelet for the bottom resistor lead and then a tall turret next to it to wrap the other lead around. Makes for nice spot to connect a wire too. 
Planning on covering the cab?
Sounds good!  I like the cleaner sounds towards the end.
Peace
Aaron

[stratele52]

I like your board layout. Fun to wire things up on a perf board, can be a pain sometimes though.
Aaron

I' don't like it myself , pain to replace parts , to unsoldered and to work on  .

[sluckey]

Not to much hum or white noise ?

I' don't like it myself , pain to replace parts , to unsoldered and to work on  .

DO YOU HAVE ANYTHING POSITIVE TO SAY!!!

[Willabe]

Used a Hammond flat pack transformer for the 6V heaters and used one of the 115V primaries as the high voltage.

That's very dangerous.


              Brad   

[stratele52]

Used a Hammond flat pack transformer for the 6V heaters and used one of the 115V primaries as the high voltage.

That's very dangerous.


              Brad   

DO YOU HAVE ANYTHING POSITIVE TO SAY!!! 

[stratele52]

Not to much hum or white noise ?

I' don't like it myself , pain to replace parts , to unsoldered and to work on  .

DO YOU HAVE ANYTHING POSITIVE TO SAY!!!

You prefer that I not be honest?


I think it is useful and constructive Printer2 knowing

[sluckey]

You prefer that I not be honest?

I think it is useful and constructive Printer2 knowing

My Momma always said "if you can't say something nice, don't say anything at all".

I personally don't find your opinions useful or constructive.

[tubenit]

I think it is useful and constructive Printer2 knowing

Useful to know about the challenges with a perf board?  He built the thing, I think he can effectively evaluate that for himself.

Or are you thinking it's useful that he know your personal opinion? 

I personally think it is a fantastic and somewhat innovative build.  And I thought the sound clip was good also. I liked it. 

I think one of the things about this forum that makes it fantastic and with so many innovative ideas is the abundance of positive feedback and encouragement and help from the members.  It inspires people to try new approaches.

I think it is useful to give constructive feedback when 1) someone is doing something that is dangerous,  2) they have voiced a problem and are seeking a solution and/or 3) if they are about to make a decision that could create a significant or irretrievable consequence  (ex: like burning up a PT from miswiring).

I am not sure it's all that useful to offer a negative viewpoint to a project that someone is enjoying as a success IF it doesn't fall into one of those categories.  Just my 2 cents worth.

With respect, Tubenit

[g-man]

Deleted

[stratele52]

Brad write it is very dangerous  ! 


Open you eyes gentlemen .

[kagliostro]

If the transformer has two independent 0-115v windings, to use one of this winding as B+ winding isn't dangerous


if the transformer has only one winding with 115v intake, to use one intake as B+ intake IS DANGEROUS


K

[stratele52]

I'm sure printer 2 will experience the difficulties I mentioned.


And if nobody mentions him he asked how is it that people on the forum are not warned him . Maybe they are not as competent as I thought?

[sluckey]

Brad write it is very dangerous  ! 


Open you eyes gentlemen .

Using one of the dual primaries as a secondary is not dangerous. Look it up.

[sluckey]

Maybe they are not as competent as I thought?

That's your opinion. I'm struggling right now to express one of mine. Hopefully someone will come along and save me the trouble.

[Willabe]

Using one of the dual primaries as a secondary is not dangerous.

That's my mistake, I missed the dual primary part.


              Brad   

[tubenit]

StratTele52,

Brad expressed a concern out of good will and a concern for safety.  That was Brad's comments not yours.

Brad has a history of good will, positive remarks, encouraging others and helpful information.  If he believed there was a legitimate concern for safety, I am grateful that he brought it up.  Others can look at his comment and those with expertise can voice their opinion and/or concerns.

In stark contrast ....................

What was the constructive purpose behind your comments ?:

Not to much hum or white noise ?   I' don't like it myself , pain to replace parts , to unsoldered and to work on  .

Maybe they are not as competent as I thought?

Tubenit

[printer2]

OK everyone take a deep breath and say Ohmmmmm.... 

Yes doing an amp on a perf board is a pain to make changes to. I offset the board to the front of the amp so that when I had to do some work on it I could at least unbolt the controls and had enough wire to flip it over to get to the copper. I had to do this as the first time I powered it up I found I forgot to run a ground from the lower resistor in the cathodyne. The inconvenience served me right for leaving a part hanging out not doing anything.

When I had to put the final resistance in for the output cathodes I just looped one end of the resistor across one lead of the 1k resistor in the circuit and the other lead to one of the ground jumpers. I can appreciate amp builds that are a work of art but this one was more of a look-see at what the 6AK6's can do, also if they would like the 70V line transformer. Happy on both counts.

The power transformer is safe as any other transformer made, better than PT's that have their windings stacked on each other with some fish paper between the windings. Each winding is physically separated from each other and has a good chunk of plastic between them. I picked this transformer to fit in a low profile case with all the tubes mounted horizontally inside the case. Was going to do a 5F6a Bassman with the 6AK6's. Might still do it with this transformer. As said before, this was not really intended to be something to keep for a long time. Might even strip the board for the caps.

I was in the middle of a different build when someone was asking about a low powered 5E3, I am bad for getting distracted by shiny objects and found I had to give this amp a try. And now that it is done, do you think I would get back to the amp I was making? Noooo... I just had to try another build that might be questionable. Anyone up for a 1W Plexi running on 30V? Being the realist that I am, I am not against using a doubler to get in the 60V range if the amp needs it. But that is as high as I will go. Any more and I end up loosing the initial concept. A tube amp even those that should not mess with electricity can build. Would have worked on it yesterday but I just had to edit down the recording my buddy made and find somewhere to post it. Glad some of you liked it.

[printer2]

Forgot to mention but was brought up in another forum.

The filter caps were scrounged from electronic ballasts that were defective (from work), the wire was cast offs from building cabling (from work), the knobs were from equipment being replaced (from work), the 70V transformer (from a demolition done at work). I did buy the jacks switches sockets and the cabinet material (although the grill cloth is a place mat that has an open weave design, bought at a dollar store for $2), IEC power connector from an old computer, found the aluminum for the chassis somewhere.

Didn't cost me much.

[HotBluePlates]

That's a pretty rockin' little amp! I really enjoyed the mp3!

I might even need to look into scrounging some 6AK6's for output tubes. Or maybe I should use up the tubes I have... 

[Willabe]

I might even need to look into scrounging some 6AK6's for output tubes. Or maybe I should use up the tubes I have... 

    More Tubes, More Tubes!


           Brad     

[SILVERGUN]

So I did mp3 of a work buddy trying out the 6AK6 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.

I think you guys did a good job of running the amp through some different settings....nice demo and nice build. 

[printer2]

Thanks again.

And speaking of more tubes, another thing I did was look at the pin out of the 6AK6 ans compared it to another 7 pin tube I have a few of, the 6AQ5. And guess what? With a minimum of switching you can run both tubes in the same amp. Change the output transformer impedance, cathode resistor value, and I think one pin disconnected and line moved to another pin. I worked it all out and it is on a piece of paper around here. Probably modify it to take the 6AQ5 when I get the amp back.

[zendragon63]

Those 6AK6's don't have much headroom do they.  Creative build printer2. I just love the way you guys are virtual amplifier Iron Chefs with a handful surplus parts.

Great idea to be able to switch out the Ck on the 2nd stage. Just a thought: The 5E3 does has a distinctive sag, bloom and singing quality. I am guessing that the 6V6 screens draw about at least twice the screen current under load as the 6AK6 so to get a little closer to the feel of the 5E3, you could up that screen drop R to 10k (stock 5E3 value) to 20K--it won't help the volume any but you might find it a bit more touch sensitive or expressive. OTOH you might end up running a lower preamp voltage than you want and may have to change out the 22K drop. Or not. Just a thought. 

Nice effort and congrats! Regards

dennis

[printer2]

I did have the preamp voltages lower when I had the 4.7k resistor after the voltage doubler. Decreasing it gave more output to the 6AK6's but the big difference was with the preamp tubes. They did not sound all that well with the lower voltages. I read that they want a minimum of 100V on the plates to sound good, upping the voltage to the whole amp brought them closer to that. Think they are all above 90V as is. I did try feed them directly from the screen supply but had some hum. I changed the grounding since then, might try it again when I get the amp back. I have no doubts there is more to get out of the amp by doing some tweaking, but there are so many other amps to build.
 

I probably should throw up another thread on a few more circuits that came to fruition into finished amps. I posted this one as I was getting a sound file for it. Or should I just put them in this thread?

[tubenit]

I probably should throw up another thread on a few more circuits that came to fruition into finished amps. I posted this one as I was getting a sound file for it. Or should I just put them in this thread?

By all means please post them!  I appreciate your willingness to share your innovation.  I'd suggest probably starting another thread.

With respect, Tubenit

[birt]

Just a thought: The 5E3 does has a distinctive sag, bloom and singing quality. I am guessing that the 6V6 screens draw about at least twice the screen current under load as the 6AK6 so to get a little closer to the feel of the 5E3, you could up that screen drop R to 10k (stock 5E3 value) to 20K--it won't help the volume any but you might find it a bit more touch sensitive or expressive. OTOH you might end up running a lower preamp voltage than you want and may have to change out the 22K drop. Or not. Just a thought. 

for a bit more sag he could maybe install a small tube rectifier like an EZ90, 6X5 or even lower current. i see a free spot on the chassis :p

[moonbird]

printer2 -


Great demo!! I think your friend sounds better than me    . I really like the tone of the 6AK6s very much!!. They are under appreciated IMHO. Do you know what voltages are on the 6AK6 plates? Thanks.

[printer2]

Sorry, have not been keeping up with this thread (so many other interesting ones). I had around 220-230V on the plates and idled them about 1W. Not even a hint of color on them.

[printer2]

Just a thought: The 5E3 does has a distinctive sag, bloom and singing quality. I am guessing that the 6V6 screens draw about at least twice the screen current under load as the 6AK6 so to get a little closer to the feel of the 5E3, you could up that screen drop R to 10k (stock 5E3 value) to 20K--it won't help the volume any but you might find it a bit more touch sensitive or expressive. OTOH you might end up running a lower preamp voltage than you want and may have to change out the 22K drop. Or not. Just a thought. 

for a bit more sag he could maybe install a small tube rectifier like an EZ90, 6X5 or even lower current. i see a free spot on the chassis :p

Maybe next amp. Originally I wanted to do a 5F6a Bassman with them, all in a metal case about 1 1/2" high. Use it as a preamp or a low power amp. Since then I rethought amp combinations and worked out doing a Bassman but with an extra 12AX7 I could get a 5E3 channel. I want to do a 6V6 powered amp set up that way, might be fun to have a mini-me version.