Recent Posts

31

Other Topics / Re: Anybody watching Gold?

« Last post by EL34 on January 23, 2026, 07:00:01 am »

Silver is $99 and should be $100 soon
Gold is going to 5k

32

Tube Amp Building - Tweaks - Repairs / Re: Adding FX loop

« Last post by Auke Jolman on January 23, 2026, 03:43:05 am »

You can get away with it because the tonestack is driven by a cathode follower getting the impedence right. There will be some volume loss depending on the pedals you use in the loop.

33

Tube Amp Building - Tweaks - Repairs / Re: Champ-ish "pocket"-amp

« Last post by Banjan73 on January 22, 2026, 08:58:42 pm »

Printer2:
Thats an interresting project!
Can you tell more about the DC booster? Is that an DC-DC converter? Doesn`t those make a lot of noise for audio?
Do you have the full schematics?

34

Tube Amp Building - Tweaks - Repairs / 5E3 build troubleshooting

« Last post by dsones on January 22, 2026, 08:24:55 pm »

I just finished a 5E3 build and tested voltages with no tubes.  Voltages were good.  I plugged in the rectifier tube and the first 25uf 25v capacitor blew up.  I can't see anything wrong.  However, when I was checking components for continuity to ground I noticed the 6.3v heater pins have continuity to ground.  I checked the lamp holder and the two lugs on the lamp holder have continuity to ground.  Is that normal for a 5E3 circuit.  Any ideas why the cap would blow up?  I checked the orientation of the cap and that was correct.  I tried attaching photos but got error message file was to large.  The wiring diagram and schematic I used are the ones from Fender.  Thanks

35

Solid State / Re: Ashdown MAG 600 VU meter bulb

« Last post by dpm309 on January 22, 2026, 06:18:58 pm »

Yes I did. Got back to me after the third try and will send me what I need.

36

Tube Amp Building - Tweaks - Repairs / Re: Ampeg B15, I still the bass when the standby is on

« Last post by pbman1953 on January 22, 2026, 03:57:51 pm »

By chance has a high value resistor been wired across the standby switch, as explained in this link https://www.valvewizard.co.uk/standby.html

no resisitor

37

Tube Amp Building - Tweaks - Repairs / Re: Ampeg B15, I still the bass when the standby is on

« Last post by mresistor on January 22, 2026, 02:58:46 pm »

By chance has a high value resistor been wired across the standby switch, as explained in this link https://www.valvewizard.co.uk/standby.html

38

Video Clips / 2025 Fails

« Last post by EL34 on January 22, 2026, 02:45:43 pm »

Here's some crazy sheet

39

Tube Amp Building - Tweaks - Repairs / Re: Testing Bad Filter Cap with a scope for 120HZ hum

« Last post by wsscott on January 22, 2026, 02:32:16 pm »

I thought I would upload an image of the Output signal from the ReVibe.  I injected a 1khz/150mVRMS signal into the input, and the image is the output of that signal with the Output Level being at "parity" (I know that's not the correct term, but I can't remember what the proper term is) with the Input signal.

It's pretty smooth, but you can see some "blurring" on the edges of the sine wave.  I'm assuming that's the 120hz hum that I've been dealing with.

Is there some way that I can use the scope to identify the reason for the blurring, ie. if it is the hum how can I get the scope to "dissect" the signal into its components?

40

Tube Amp Building - Tweaks - Repairs / Adding FX loop

« Last post by RoadShow on January 22, 2026, 01:29:01 pm »

Before I ask my question, I did read this thread and others:
https://el34world.com/Forum/index.php?topic=10208.0

and when I built the dual JTM45/2203 amp 3 or so years ago I included the Metropolous FX loop board.

So, here's my question.  The Ceriatone FX loop just has jacks, intercepting the MV output to the PI .022uF cap.  Can that be problematic, or can you get away with it.  See attachment.