I love the 5e3. Just not mine! Please help.

[JohnRose81]

Hello all!! Firstly I'm excited to be here around all of you. This is my first post but not my last. I've played guitar for 22 years and have owned a wide array of amps vintage and new. I'm currently running a '66 super reverb. Love it but I needed something smaller and not so powerful. I'm a fan of the tweed deluxe but don't have that money. So I saw the schematics and thought I could build that. Then saw kits. Mojotone was the only company to reach back to me so I bought theirs. Nice cab. Bought an original '56 Jensen for a song and found some good tubes.
Build was fun and educational. My first but TOTALLY not my last.
I did it because amp guts scare the crap out of me. I always think I'll shock myself to death. So precaution and awareness has been my motto.
I don't know abbreviations too well or the names of the wires and inside of the amp. I build this with the mojotone schematics which is very very close to the original. I used no mods. Didn't exchange the tubes for other types.

Ok, so with that, my problem:

I get sound, yay!! What I don't get is my normal channel volume knob working and the 2nd normal input doesn't work. Checked solder. It's great. Pots, perfect.
Secondly; my volume is stunningly low. Maxed out it's no louder than someone talking in conversation. Also there is a lacking low end.

I put my multimeter on the power tube prongs? 1-8 and some got reading. Same for the pre amp ones. The filter caps are working. Is there anything I can do to aid you in your feedback?

[JohnRose81]

Note: I put a bleeder resistor for each filter cap. No bueno? Should have used just one?

[eschertron]

Hey, John, welcome to the forum! I hope you had good fun with your build, and continue to enjoy the build experience! Per your questions:

I'm not sure if the schematic you have lists test points and voltages. If it doesn't probably your best bet is to start measuring AC and DC readings at each pin (that has something connected) on each pin of each tube. People can get an idea of voltages that are radically off from the norm. I hope your meter can select AC and DC so you can get separate readings at each point that you check.

Also, I see some less than stellar soldering in you pics. That's OK, absolutely to be expected at this point in the game. I want to ask what wattage soldering iron are you using? Too small or too large can have adverse results on the quality of the build. Too small an iron - say 15W or less - can force you to apply the iron for an excessively long time in one spot. One result of that is that the joint may not have gotten hot enough, and is not conducting the way it should. Another possible result is that as the iron stays on the lead of a sensitive component (capacitor, say) for longer than it should, heat can travel into the component and cause damage. Too large an iron - say 50W or more (these are my numbers, others may disagree) - and you might as well take a blowtorch to the innards of the chassis.

[JohnRose81]

Hey hey! 40watt iron. Didn't wanna go too high. My soldering does suck, but I was using wrong solder and after I changed it up? The points got much better. I'll get those readings.

[g1]

For reference, I have attached the schematic and layout from mojotone.
One simple thing I will mention, a very simple common mistake leading to very low volume is using the wrong speaker jack. I only mention this as I see evidence of the ext. spkr. jack having been used. Make sure the speaker connects to the jack with the 3 lugs, not the one with 2 lugs.

As eschertron suggested, giving DC voltages is a good place to start. To simplify a bit, how about the DC voltages at pins 3 and 8 of all tubes except the 5Y3.
List tube type, pin#, and DC voltage at that pin.

[JohnRose81]

Def using the 3 prong speaker jack.

12ay7 pins 3 and 8 = 0
12ax7 pins 3 and 8= 0
6v6 (on right) pin 8 is like 12 pin 3 is 210
6v6 by the 5y3 is the same. Pin 3 is like 210 and pin 8 is like 12.

Also, earlier I reversed the OT wires (brown and blue) to no avail. I can put em back to normal.

Pins 3 and 8 for the 12ay and 12ax are just ground pins. Should they read anything?

[g1]

210V at the 6V6 plates is quite low. What is at pin8 of the 5Y3?
Pins 3 and 8 of the preamp tubes are not ground pins. What is the DC voltage at pin 1 and 6 of the preamp tubes?

[Jazz P Bass]

12ay7 pins 3 and 8 = 0
12ax7 pins 3 and 8= 0




Also, earlier I reversed the OT wires (brown and blue) to no avail. I can put em back to normal.

Pins 3 and 8 for the 12ay and 12ax are just ground pins. Should they read anything?

According the schematic, the 12AY7 cathodes use a shared 820 ohm resistor to ground.
And the 12AX7 cathode uses a 15K on the driver & the PI uses a 15K, 56K in series to ground.

[JohnRose81]

Pin 8 on 5y3 is around 220. (Analog multimeter)
12ay7 pin 1 is 70
12ay7 pin 6 is 170
12ax7 pin 1 is 90
12ax7 pin 6 is 110

[JohnRose81]

I really need to learn the flow through this circuit so I can understand what ya mean. I know what all those are but outside of that, no.

[g1]

Are you very confident about the accuracy of that meter? Do you have another you can try? Or how about checking what it reads for AC voltage at your wall outlet.

Another thing, you said no mods, but you also said you added bleeder resistors for the filter caps (that would be a mod ). What value and wattage did you use for the bleeders?

[JohnRose81]

Yes. Calibrated.


And yes, I suppose bleeders are a mod. 220 2w bleed resistors on each filter cap.

[g1]

220 2w bleed resistors on each filter cap.

I hope you mean 220K, otherwise remove them and repost the new voltage readings.

[JohnRose81]

Haha. Yes 220k. I'm sorry.

[g1]

With 6V6 tubes removed, what is the DC voltage at pin3 of 6V6 sockets?