The Amp Garage

Impressive work! 8) I just wonder whether the lack of a bias resistor at the + input of the opamp may cause problems. See e.g. https://www.physicsforums.com/threads/voltage-follower-bias-current-opamp.788018/ or https://northcoastsynthesis.com/news/one-minute-op-amp-analysis/ Fair point! Thanks for...

If you don't have a Utracer and have a bunch of tubes and the ability to do some delicate soldering, then get one, the Utracer team won't let you down. Good to hear Ronald and Marie Jose are taking care of you, Rog. I'll add that some fabrication skills are needed if you want an enclosure with a so...

I'd just like to add that I've had my Utracer since around 2015. It was a tough build for me, and I had a few problems that were sorted out by Ronald and of course, Martin Manning. I have tested many tubes with it up until just before last Christmas, it started playing up. Long story short, the PCB ...

It's alive! Sounds great. The 2k drive pot indeed works well. If unity is desired, maxing out the drive is necessary in this design. I need to play more with the recovery pot values as 1M goes from grounded signal to full within the first quarter turn. I'm also thinking 1m still might be necessary ...

It's alive! Sounds great. The 2k drive pot indeed works well. If unity is desired, maxing out the drive is necessary in this design. I need to play more with the recovery pot values as 1M goes from grounded signal to full within the first quarter turn. I'm also thinking 1m still might be necessary ...

I think that would work just fine. You would need to add a voltage divider and filtering for vref at half the voltage output. Ryan's supply is +/- 15v bipolar, so it is the equivalent of a +30v design in terms of voltage headroom. -Dan Thanks, you are quite right, it's not a unipolar PS... the +/-1...

A fascinating project! One point I've thought about, would an increase from 9v to say 25vDC with a MAX1044 charge pump help with headroom, as the K-lator uses ~36vDC? Is not 15v a little low? Here's a veroboard from tagboardeffects (an RG Keen design, I believe 8) 25V Charge Pump.png with 25vDC. I'v...

Greetings from Tom (Structo) to all my Ampgarage friends! I'm still alive and kicking! I'm 66 now! :D I have missed you all. Sorry for not writing you sooner. I had a major stroke in 2016 and affected my language and also my computer broke right before the stroke. I am still working on my words, my...

Since the power amp is mainly clean anyway... how about a *gasp* Class D output section with a tube preamp? I routinely work on 500W~700W bass amps and with the master volumes, can easily be tamed down to 3:00 A.M. bedroom levels. Power scaling on tubes is cool and can definitely be useful, but I f...

Dumble things are usually played at volumes where it is 99% about the preamp and the output is damned near idlling. You will be surprised is my bet. This is a 50w amp on a Palmer PGA-04 into a 2200w Class-D stereo amp and a quad of Marshall cabs. https://www.dropbox.com/s/9hok0lymcfwmm6w/IMG_7520.M...

My setup is a vox VT40+ and a modded KLD marshall 18 clone into a stereo mosfet. Simply the best setup ive had in 40 plus years. The DIY route is always fun but there are so many good preamps available and going second hand could save you a furtune. I have an old unused peavey TGRaxx knocing around...

Reeltarded wrote: ↑Thu Jul 06, 2023 5:42 pm I like it. Probably a really good choice! Would like to know how it works out.

I will do that for sure. I'm hoping that the 2x12AX7 in the preamp and 1x 12AX7 in the Dumbleator will fool the Class D into tube like behaviour

You might be very surprised by a common class D off the shekf power section for less than the cost of tubes and an enclosure . Here is my Rever search string. https://reverb.com/marketplace?query=Mosfet%20power%20amp I used a bunch of different power amps in almost 40 years. Crest, Crown, Peavey.. ...

the marshall gut shot looks like a reasonable concept for your case. A band member used it and it sounded good. You could order a custom made toroidal PT. I'm located in Germany, whenever I need a special PT I order from polish http://www.badel.pl/, they always made whatever I nedded at a price tha...

1u is going to be a challenge. p-p is a must, so four outputs tubes, EL84 or 6V6GT, which have 40% lower heater power (0.45A vs EL84's 0.76A). There are 9-pin 6V6 lookalikes, 6973 (expensive) and TV sweep tubes like 6CZ5 (cheap). Looks like you might find a Marshall 20/20 for around $500-$600. Yes ...