The Amp Garage

Could you use your 7.5V tap off of the 15V regulator as an input to your L7805? Might be able to scrap a few components that way. L7815s will regulate up to 34V and can handle 1A, so you can give them a little extra. I've used 7815/7915 regulators in a 15V split rail supply drawing 300mA from a 500m...

Guys, after experimenting with different LEDs for a few days now, I gotta say I really like them. I tried unbypassed, partially bypassed, and fully bypassed cathodes with Rk/Ck on several of my tubes, and 1.7V red LEDs (center bias), 2.7V blue LEDs (cold bias), one 1N4007 at 0.6V (very hot bias), an...

I bought them off eBay from China to avoid shipping charges and they worked great. Wound up costing about $10 for 50 turrets, and I bought a board that was already loaded with 60 turrets. Never had an issue soldering to them. Edit: If you're having trouble getting solder to stick to a metal and flux...

Reducing R234 from 4.7k to 2k should give a bump a little over 6dB. Again, this is assuming you're not already close to your rails. You should be able to get around 12 Vpp out of a TL072 with 15V and ground for supply rails. If you have more headroom and the reverb is still quiet, go ahead and reduc...

If you're not already near rail-to-rail on the output of the recovery op-amp, you could try increasing that 10k resistor or reducing the 39k resistor to get more gain from it. Failing that, I'm not sure where you mixed your reverb back into the signal path (you might have said, but I've forgotten), ...

Update 2: The blue LEDs were dropping about 2.6V, so I switched to 1.7V red LEDs to bias the tubes warmer. Not too much of a difference noticed. I also did an unbypassed gain stage and the phase inverter. Now, I had those stages biased really warm, so putting LEDs in them moved them closer to center...

Gentlemen, checking in. I replaced the V1a and V1b cathode resistors and bypass caps with blue LEDs in my amp, and took some video for you to decide the differences yourselves. You'll probably come to the same conclusion I did, which is that it makes little to no difference. Maybe a slight mid boost...

At least you didn't call your utility to have them check your transformer because mains was reading at 165V! That was an embarrassing call back. :oops: I'm relieved it was just the multi meter. That Hammond transformer is for my attempt at this same project, only it's rated for 250mA. Would have had...

Whew! You'd have to draw all that current through your whole power supply if you wanted to get those voltages from your B+ string. You'd need a pretty fat PT and high power resistors to handle all that. If your PT has a fixed bias tap, maybe you could use that instead and save some VA. Are the batte...

375mA? Damn! And the datasheet said a maximum of 100mA. Would it be too much effort to buy a small PC mount transformer like a Hammond 229 series and put a small split-rail power supply on a perfboard inside the amp? I've attached a picture of one of the 6VA transformers I have as a reference for th...

I have a pile of 3mm LEDs left over from another project, and I'm still tweaking my first tube amp almost every day, so I'll also give this a shot and add my two cents to the pile. Although, it's two cents Canadian, so it's worth half that south of the border. And we completely phased out pennies, s...

Leave yourself the option of trying each one individually once the build is done, and see what's quieter. In my last build I found the real CT quieter than an artificial tap, but there really was barely a difference. I went with the real CT out of convenience.

Here's a datasheet that I found: http://amptone.pl/templates/images/file ... btdr-3.pdf

The datasheet says that the inputs and outputs are already AC coupled.

I'd like to add to Martin's post that that cathode followers can be AC coupled or DC coupled to the previous gain stage. AC coupled cathode followers (hopefully) serve as a "transparent" impedance buffer in the circuit - that is, they have a high input impedance and a low output impedance due to the...

For my own interest, Xtian (or anyone else who knows), can you tell me what the differences are between the BTDR-2 and BTDR-3 as far as reverb tone and functionality go? I'm about to start a 12W build using one of the two, and NE5532 op-amps (I prefer them to TL072). As far as protoboard choices go,...