Aug 12, 201715394 views

The Massdrop x Alex Cavalli Tube Hybrid: In With the New

The new Cavalli Tube Hybrid is an evolution of the original Compact Tube Hybrid DIY project.
The new “CTH” has significant improvements to the original design: Higher power output, approximately 1W into 50 ohms. The new CTH has some global negative feedback reducing the gain from the mu of the triode to a more manageable gain of 8x. By reducing the gain, we are able to make the amp work with the widest array of headphones through a very simple design to operate. The unity gain, discrete output buffers on the new CTH are updated versions of the buffers used in the Cavalli Audio Liquid Glass amplifier and provide the same or better performance.


The original CTH used a 24VAC wall wart power supply. This is suitable for a DIY project, but this type of power supply is uncommon and introduces raw power line AC and rectifier noise into the power supply circuit and the amp. The new CTH uses a 28VDC external power supply which is quieter than the original 24VAC supply. The power supply has no rectifier noise at 120Hz. The power supply also handles universal voltage (100-240V) for a single power supply version (use with plug adapters for your country if needed).
Anything the same? The original CTH has an auto-bias adjustment circuit on the tube so that no manual adjustments are needed. The new CTH does too.
PLEASE NOTE: The original CTH was designed to roll many different types of tubes. The new CTH is designed around the 6922 for simplicity of use. Owners can roll different types of 6922 or equivalent tubes, but they cannot roll other tube types into this new amp.

You’ll hear the differences in the new Massdrop x Cavalli Tube Hybrid.
Quieter, more powerful, easier to operate, higher resolution while maintaining that touch of tube warmth.

Massdrop 101: What Is An Amp?
Massdrop 101: What Is A DAC?
gorian2222, Scott Makeig, and 28 others

It works very well as a preamp using the 4 pin out to a pair of Mackie HR824 MK1's. more musical with NOS 7308's, and more detailed with Sovtek 6922's, it replaced my Musical Fidelity X-Can V8P, which uses two 7308's and now I'm Shopping for a Schiit Valhalla 2 in order to try an OTL amp for the first time. The best thing about these new amps is their affordability. LOL
It would be great to see a version of this product with Balanced XLR outputs for use with monitor speakers. Any chance of that happening?
Hello. I have my CTH on order :-) My favourite tube in my current amp is an E288CC. I understand from the above description that the CTH is designed only for 6922 (E88CC) and equivalent tubes. The E288CC, strictly speaking, isn't equivalent to the E88CC (for example, it requires 475mA heater current as opposed to 300mA for the E88CC) but it is often used as a drop-in replacement. What I would like to know is the E288CC compatible with the CTH (I would not want to damage the amp)? Many thanks for your time. Looking forward to February 2018!
Load 2 more comments
I haven’t... is it a viable option?
It would be if the filament power supply can handle it; 0.6A @ 6.3V. I popped the question to Cee-Tee and never heard back. I don't own a CTH, as an owner you could perhaps better elicit a response.
I own Fostex and HIFIMAN headphones. Can someone explain why I would need an amp? My volume output out of my PC is more than adequate--more than I could even handle in fact.
Load 12 more comments
hello sir - so far I have had very good exeprience with AudioGD. The shipping was a bit slow (4weeks) but my unit arrived in the US safely (no dents on the box, no scratches on the unit). The build quality is superb. All the buttons have smooth movment, the volume knob is nice and heavy, the amp itself is pretty well constructed. The input / output connectors are pretty soild. My Amp came with a nice silver remote, and I use mine with headphones and a speaker amp (pre-amp to control volume) - Its a very powerful amp delivering 9900mw @ 16 ohms via XLR, and 3500mw @ 16 ohms single ended. It has no channel imbalance. I am quite happy with it :)
see I'm in a weird state with cables, because my logical brain wants to tell me no there is no difference, yet when i tried different cables on my hd600 i could definitely notice a difference, mainly in the presence area, one cable seem to have a more forward upper mid range than the other cable which actually made the hd600s sound worse than with the stock cable. but again without being able to blind test this, im kind of skeptical as to whether i heard a difference.
I'm really interested...but am also quite dubious when sellers highlight the words "entry level". I also feel weird about the words "entry level end game". Why under-sell, or under-value a product before it is even for sale? The sellers confidence in the product seems low.
Load 3 more comments
If you have enough confidence to say End game w/ Entry level, that says something. End game is the best you will ever need for entry level? I guess if you want advanced you should think of spending more?
Sorry, I don't understand your questions. Maybe rephrase them
THIS IS A HYBRID DUE TO THE COMBO OF BOTH TUBE- & CLASS A(A/B?) POWER. THIS IS OBVIOUSLY 100% BALANCED, DUE TO THE FACT THAT THE ONE &ONLY OUTPUT I am ABLE TO SEE IS A 4-PIN XLR (never heard rumours about unbalanced 4-pin xlr outputs - It´s the new high-end balanced output because you don´t need TWO 3-pin xlr outputs. Finally but last.
You didn't see the 6.3mm socket next to it?
Your post couldn't be more naive or wrong in this case unfortunately. Read the specs, please. It is SE only, 2 of the 4 pins are to ground. There is no balanced input, so even if it was push-pull it wouldn't be balanced because the entire chain needs to be differential, from a balanced DAC chip onward.
Besides that fact, the included tube is a 2 cathode, 2 grid, 2 plate tube, meaning it can handle up to two independent channels. A balanced amp needs 4.
It has a little R2 unit on board.
haha it really does look like theres a mini R2D2 sitting in your amp xD
I'm not familiar with the old DIY versions topology/design. Is the power delivery rating the same for XLR output vs TRS? It's obviously not fully balanced due to the lack of associated inputs but was curious about more detail on the power delivery.
no - the XLR is single ended, no double voltage
Why is this hybrid? is it transister out with tube pre amp ?
My guess is two output stages.
Does this have a true balanced-drive?
Nice job! Curious to see what dacs will be coming up to integrate this into a stack!