6aq5 amp

[Berger]

Been a while since I finished my last amp. Eagle Supre. So I figured its time for another build.

I needed something low wattage and low voltage. I already have a couple ax84 fireflys so I figured I'd build a 5e3 with 6aq5 for power tubes. The plan being that after I get that working to rework it into something more fun as I already have a 5e3.

Plan right now is
190-0-190 120ma transformer
classictone output transformer
Mallory Cap Can that I've had but never found a use for yet
5y3 rectifier

Attached pic is my trying to figure out a layout.
I got the chassis drilled out over the weekend and got the transformer wired up and the rectifier working.

Will try to get the heaters wired up and the board filled.

Aaron

[Phil_S]

The 6AQ5 is identical to the 6V6 but in a small 7 pin bottle. Because of the size, I would not want to run it at something over 300V. Your 190 PT should give you mid 250-260 -ish B+ and that is probably a good spot.

Here's the problem, though. At that voltage, I doubt it will behave or sound like a 5E3. I suggest it is appropriate to adjust expectations or find another amp to build. I'm just sayin....not trying to discourage your sense of innovation.

[Berger]

Yup, i'm sure it won't sound the same. My thought for building it is that I have done 1 already and know the layout etc.

So my goal is to get it running and then take it apart and make a different amp.
So its a round about way, but I figured I'd build something I know and then mess with it.

Aaron

[Berger]

got the heaters wired up. Found out that one of my 9 pin sockets is faulty. I have to wiggly the tube a certain way to make it fully light up.

Thankfully its the last on in the chain. And I only need 2 to for my initial run.

[Phil_S]

Nice. It's giving me the jones for another build. I still have to finish the last one. I went the whole 9 yards doing a head cab. Almost there.

Anyone know how to get this monkey off my back?
<no answer>
Yeah, that's what I thought, I'm not asking in the right place.

[Berger]

don't worry i'm already planning another build.
and a couple speaker cab builds.
and some head cab builds.
yeah this place doesn't help things

[Tone Lover]

Phil_S I hate to tell you, it was to late after the first amp. The monkey grows up and becomes a gorilla then you have 2 or 3 amp stands like me, and there always full, and you day dream about 2 amps ahead of those (LOL).
Bill

[randalp3000]

I put this together a couple weeks ago. I first had a 5v4 in it because I couldn't find my 5y3's and had about 345v on the plates. The screens were also higher than the plates but it sounded ferocious. I added the 1.5K behind the choke and 1k's on the screens to get them lower than the plates. Now I have 295v on the plates and 294 on the screens. The amp still sounds good but I might put it back for a little more balls.

I wonder how much voltage these tubes will take, I might put the 5v4 back in and see how long they last. I would like to do another one with 4 6aq5's.

Good luck on your build, look forward to seeing it finished.

[Berger]

I put this together a couple weeks ago. I first had a 5v4 in it because I couldn't find my 5y3's and had about 345v on the plates. The screens were also higher than the plates but it sounded ferocious. I added the 1.5K behind the choke and 1k's on the screens to get them lower than the plates. Now I have 295v on the plates and 294 on the screens. The amp still sounds good but I might put it back for a little more balls.

I wonder how much voltage these tubes will take, I might put the 5v4 back in and see how long they last. I would like to do another one with 4 6aq5's.

Good luck on your build, look forward to seeing it finished.

Thanks for the schematic, that is a lot of what I'm looking to end with on the build. we'll see if I get there and what changes I make a long the way.

Aaron

[Phil_S]

Phil_S I hate to tell you, it was to late after the first amp. The monkey grows up and becomes a gorilla then you have 2 or 3 amp stands like me, and there always full, and you day dream about 2 amps ahead of those (LOL).
Bill

Oh, I've built over a dozen in the last 10 years or so. I know exactly what you mean. I have a tube collection now, too. And wire, caps, undrilled chassis, bunch of transformers, who knows what else! I think I've got enough projects on the shelf to last until I can't do it any more.

[Berger]

I don't have a lot of time to work on the amp tonight. So i'm going to charge the cap can.
never done this before. not sure if I believe in it, but I've had the thing sitting on my desk for at least 3 years. So I'm following the instructions from metro amp.

Oh and I found a bad heater solder joint on the socket that didn't work correctly.

So maybe that fixed it. If not I ordered more sockets today.

Aaron

[Berger]

got the board populated tonight. The caps are huge this board and hide the resistors.

I'm missing the cathode bypass caps at the moment.
they are in the mail.

Aaron

[Phil_S]

When using that style of terminal, I'll flatten the inside lugs so I can get the full width to the outer lugs. You should still have enough space in the hole for a hookup wire. If not, if you use a bent nose pliers, you can thread the wire into the inner terminal and leave it flat. I wouldn't undo anything, but you may want to think about the rest of whatever you are putting on that board. Just my 2 cents. Enjoy the build.

[David Root]

The 6AQ5 is a good tube but so is the advice to go easy on the plate voltage. 300V is about it and they don't cost a lot so if you fry one it's not like doing in an RCA blackplate 6L6GC.

Ten years ago I built a tweed Harvard using all 7-pin tubes. I used two 6X4 rectifiers in parallel, if you pull one it sags like an old lady's boobs. And if you play around between 6AT6, 6AV6 and 6BF6 with their different mu you can get some considerable tonal variations and feel.

[Berger]

I've been collecting some good RCA,GE,etc 6aq5 tubes. probably more than I will never needs. But they are fun.

I'm tempted to build a SE amp next as well. I've picked up some 6au6 as well.

I got my needed cathode bypass caps today, so I finished the board and started cutting/running the wires to the tubes. Nothing soldered to the tubes yet, mainly just getting the initial lengths.

Aaron