Sons of VHex

Valery you can't stop,how many sons!:)
Heat shink is one of more expensive part:(

Right... In fact, even very good amplifiers modules, based on excellent topology, don't guarantee a good build. Heavy metal parts - heatsinks, transformers, cap banks, beefy quality wiring are vitally important for high-quality build, forming a significant portion of overall cost :(
 
I'll be interested to see how you get on with your testing, because if a single pair of these devices can work well at high output, it will certainly simplify the design of high power amplifiers.

Yes, if we can arrange a decent dissipation, the compact thing becomes rather universal in terms of scalability - on one hand, it can run at rather high rails (e.g. 90V), on the other hand, at lower rails it can handle low impedance loads (4 ohm, 2 ohm) - current supply capability is enormous. Bridged arrangements also look good in this case. Monoblock with two modules will be a hell of an amplifier (and welding machine at the same time :p).
 
Right... In fact, even very good amplifiers modules, based on excellent topology, don't guarantee a good build. Heavy metal parts - heatsinks, transformers, cap banks, beefy quality wiring are vitally important for high-quality build, forming a significant portion of overall cost :(

:up:

Cheap EI transformers sometime cause sibilance or distortion in high frequency. Capacitance Multiplier improve the quality of mid and high frequency in class A and AB amplifier.

Vzaichenko, I think you should design a high quality power supply for your amplifiers ;)
 
Hi Gareth.

The only BASH sub amps I've had any experience with were Klipsch, which weren't very impressive at all (disposable grenade). This would definitely be an upgrade on those, sound wise. If I can get the thermals worked out with this one it should be much more reliable. I'm not sure how this would compare to the BASH units available from such places as Parts Express. I've never had any first hand experience with them.
 
:up:

Cheap EI transformers sometime cause sibilance or distortion in high frequency. Capacitance Multiplier improve the quality of mid and high frequency in class A and AB amplifier.

Vzaichenko, I think you should design a high quality power supply for your amplifiers ;)

Hi Bimo,

In fact, we've got the PSU, developed particularly for the top-level modular designs, based on NS-OPS. That one has got a separate regulated 15V section for the front-end, protection option for the main rails, etc.

VHex - based line of amps - I'm trying to keep it simple. This approach with zener-based shunt regulation works well - no sagging, no noise issues.

Builders, who want to use some more comprehensive options, still can do it ;)

Cheers,
Valery
 
VHex+BT

OK, today I have finalized testing the new VHex+BT.

During the long term tests at high swing I have noticed that at high temperatures the drivers' tempco hardly compensates the bias of the OPS, so I have added a low-sensitivity spreader, assisting the drivers.

Now it's perfect! :up: Tested like hell :p

Double bootstrap ensures almost rail-to-rail operation, the sound is excellent - very comfortable for listening during a long time :cool:

Final schematic is attached.
 

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Yes, half of it should do the job.

Well, efficiency is already pretty good, although I had to decrease it a bit by changing the 3.3V Zeners in the drivers' emitters with 1.7V LEDs in order to arrange some headroom for the bias spreader.

Even in present setup, with +/-52V rails, it clips above 45.5Vp (32V RMS), driving more than 120W into 8 ohm.
 
Yes those LEDs are an elegant touch. Kind of like a level shifter to maximise swing. What part of the bias generator do you mount on the MOSFET - the NPN or the diode?

I like this design of yours very much. Particularly the output stage - a relatively simple but very effective way of driving these Hexfets!
 
One last question :-D

The output impedance of those bootstraps is a lot less than active current sources. Do you sacrifice much loop gain with this approach as a result of the increased load on the VAS? If its a problem you could add an active CCS in series with the bootstrap - but that would add a lot of parts.