Recent Posts

1

Tube Amp Building - Tweaks - Repairs / Re: IS there a reason to build another AMP

« Last post by TIMBO on March 12, 2026, 04:46:02 am »

A bit more progress...

2

Tube Amp Building - Tweaks - Repairs / Re: Revisiting Sears Silvertone 1484/85 Piezo Tanks.

« Last post by SoundmasterG on March 11, 2026, 11:16:06 pm »

...I can post pictures later if you like...
Greg

Would love to see that work. On that note, I did same when experimenting, if the tank return was closer to the PT, the hum was fairly pronounced, rotated away it was better, but to me, still unacceptable. You resolved that issue with a some added space and fabrication; I'd rather not walk that path, as this amp has the original speaker cabinet, and the head stows in the bottom of speaker cabinet. I suppose that I could modify the cabinet's back panel to accommodate a taller head cabinet, but I'd rather keep as much stock as possible.

--Pete

I was going to upload some pics, but I remembered I had already done that on the amp garage forum, so here's some pictures and a link explaining some of the things I did to it. The pictures and my comments are on page 2.


https://ampgarage.com/forum/viewtopic.php?f=6&t=37885


Greg

3

Tube Amp Building - Tweaks - Repairs / Re: 5879 amp favorites?

« Last post by SoundmasterG on March 11, 2026, 11:09:58 pm »

Use the 5879 as the second stage instead of the first stage. You get more of the good pentode effects without all the microphonic instability that pentodes often give. Merlin has a lot about it in his books and he's right.

Greg

4

Tube Amp Building - Tweaks - Repairs / Re: Adding an LED or neon lamp to tremolo

« Last post by dickjonesify on March 11, 2026, 11:07:08 pm »

Just checking: Could I add a neon lamp in the exact same way?

5

Tube Amp Building - Tweaks - Repairs / Re: Adding an LED or neon lamp to tremolo

« Last post by dickjonesify on March 11, 2026, 09:16:11 pm »

The voltage drop across the LED is the same regardless of the input voltage. The current limiter is the triode, approx 1mA or so.

Perfectly safe with no extra resistors needed.

See bottom of this page: https://www.valvewizard.co.uk/trem1.html

That’s awesome! Thanks.

Valve Wizard is a site I have bookmarked and have read a lot but I don’t think I’ve seen that page.

6

Tube Amp Building - Tweaks - Repairs / Re: Adding an LED or neon lamp to tremolo

« Last post by stratomaster on March 11, 2026, 08:28:46 pm »

The voltage drop across the LED is the same regardless of the input voltage. The current limiter is the triode, approx 1mA or so.

Perfectly safe with no extra resistors needed.

See bottom of this page: https://www.valvewizard.co.uk/trem1.html

7

Tube Amp Building - Tweaks - Repairs / Re: Adding an LED or neon lamp to tremolo

« Last post by dickjonesify on March 11, 2026, 07:31:15 pm »

I have the LED calculator bookmarked but all the schematics and current limiter resistor calculations show it then connecting to ground, which would require a high wattage resistor and a whole lotta heat. I can’t find any clear instruction about putting it in series with high voltage.

8

Tube Amp Building - Tweaks - Repairs / Re: Adding an LED or neon lamp to tremolo

« Last post by dickjonesify on March 11, 2026, 06:55:44 pm »

Just put the indicator LED between the plate resistor and plate.

You can also put the LED in the plate circuit

Just in series? And nothing will catch fire? Haha

But I also prefer the look of the neon

I may order one.

9

Tube Amp Building - Tweaks - Repairs / Re: Adding an LED or neon lamp to tremolo

« Last post by stratomaster on March 11, 2026, 06:49:38 pm »

Just put the indicator LED between the plate resistor and plate.

Putting it where you did will impact performance of the opto-coupler/trem sound.

The cathode voltage is determined by the forward voltage of the LED in the opto-coupler.

10

Tube Amp Building - Tweaks - Repairs / Re: Adding an LED or neon lamp to tremolo

« Last post by passaloutre on March 11, 2026, 06:47:29 pm »

You can also put the LED in the plate circuit. But I also prefer the look of the neon