I finally got to documenting the design of the 50 watt hybrid amp design I've been playing with for some time. It uses the Korg Nutube as a gain stage in front of a Monolithic Power MP7770 self-oscillating class-D amp chip (as well as a few JFETs).
You can find details here: NuClassD 50W Nutube hybrid amp
Pete
You can find details here: NuClassD 50W Nutube hybrid amp
Pete
Very nice!!! Kudos once again. How do you think this new hybrid might sound compared to your Nutube buffer (which I purchased but have yet to solder up) leading into a Hypex amp? I currently have multiple Hypex amps, but miss the sound of my old EL34 that has been in sick bay for a few years. So I purchased your buffer. I may have to purchases this one as well in order to compare the two.
Man Pete! This sounds awesome, but I already have too many projects in the cue! Looks like I'm going to have to add another.
Just wanted to take the opportunity to thank you for all your great designs and for sharing them with the DIY community. I really enjoyed building and listening to your SSMH and a couple versions of the Millet Hybrid Maxed, one of which I'm listening to as I type.
Cheers!
Just wanted to take the opportunity to thank you for all your great designs and for sharing them with the DIY community. I really enjoyed building and listening to your SSMH and a couple versions of the Millet Hybrid Maxed, one of which I'm listening to as I type.
Cheers!
I'm very excited to get mine built Pete, love the idea of a super efficient tube amp 🙂
512-P6KE30A was all sold out at Mouser, assuming this is a good sub? 625-P6KE30A-E3
Also, are 2% resistors okay, or do they need to be 1% on the amp boards?
TIA.
512-P6KE30A was all sold out at Mouser, assuming this is a good sub? 625-P6KE30A-E3
Also, are 2% resistors okay, or do they need to be 1% on the amp boards?
TIA.
Yeah, sorry about that - in Japan for a week then Europe for two, so I shut down the store until I get back.
No problem Pete, have a great journey.
Does the board need any additional heatsinking?
Not for normal music applications. If you run a 50W sine wave, though, it will hit a thermal limit and shut down after some time.
I haven't tried adding any external heatsinks.
Pete
I haven't tried adding any external heatsinks.
Pete
Hi Pete,
Can this amp push 2 ohm load? And what's the output at 2ohm it is capable of?
Nice design !!
Can this amp push 2 ohm load? And what's the output at 2ohm it is capable of?
Nice design !!
Pete will answer, but it is already in "bridged output" mode, so pushing 2 Ω is asking for trouble. Internally it has a self-protection-on-thermal-overload circuit, so you could safely try it, but don't expect great results. At least that's from y review of the circuit schematic and Class-D power amplifier module docs. GoatGuy
Speaker protection?
This amplifier looks rather interesting. I really like the idea of it and also that it fits in a rather small chassis. Would I need to add a speaker protection circuit to it?
This amplifier looks rather interesting. I really like the idea of it and also that it fits in a rather small chassis. Would I need to add a speaker protection circuit to it?
You shouldn't need to. Assuming you use a power supply with lots of cap (like a linear supply), the amp powers up and down gracefully. If you power it from a generic SMPS with small output caps, the rise and fall times are so fast you may get a thunk.
Pete
Pete
As was mentioned... it can drive 2 ohms but the current will be high, so the IC will heat up at fairly low power outputs. I^2*R, you know...
Pete
Thank you, Pete, for the prompt reply. It is great to ask a question and get an answer from the designer!
Looks like this will become my "Summer amplifier". I'm hopeful that with a little tweaking it will sound close enough to my 845 SE that heats the house through other seasons.
Thank you Pete, for publishing your design and making the build practical by supplying the PCB with SMT components already attached🙂
Thank you Pete, for publishing your design and making the build practical by supplying the PCB with SMT components already attached🙂