[guest1632]

Hi Frank,

Was wondering in your investigations through the years, did you ever try making your amps as monos with 2 separate transformers? Or did you decide because of cost constraints the differences in using 2 transformers from an audio standpoint weren't that great. I've been told and what I read that you have interactions between the 2 secondaries. That is the main reason why supposedly you want separate transformers. Just thought I would ask you. Thanks for the help and info.

Ray

[avahifi_lj]

Hi:

We have looked at dual transformers.  In addition to the second transformer we would need a second power supply board(s).  Because of the physical size of the transformers used in the big amps (FetValve Ultra and OmegaStar 440EX), there is not enough room to add a second transformer and power supply boards.  It may be possible to add second transformer in the smaller OmegaStar 240EX amp, but we have not tried it.

We have toyed with putting out a mono amp for those who want a dual mono setup, but the cost to produce the mono amp is not that much cheaper than producing the stereo version.  We have sold several dual amp systems where the customer has used the stereo amp in a bridged system.  The bridged system uses two stereo amp, one for each channel.  The neat thing about bridging is the amp will produce about three times the power of the standard amp; therefore you can go with a smaller amp and still get oodles of power.  Please note that bridging is not the same as simply tying the outputs together (never do that).  Bridging requires a phase inverter / bridge.

We offer two bridging solutions.  The best is our Ultra bridge in a separate chassis; however, we also offer a solid state bridge that can be added to any preamp.  With the integrated preamp/bridge one of the line out jacks run Amp 1 and the second run Amp 2.

Thanks

Larry

[guest1632]

Hi:

We have looked at dual transformers.  In addition to the second transformer we would need a second power supply board(s).  Because of the physical size of the transformers used in the big amps (FetValve Ultra and OmegaStar 440EX), there is not enough room to add a second transformer and power supply boards.  It may be possible to add second transformer in the smaller OmegaStar 240EX amp, but we have not tried it.

We have toyed with putting out a mono amp for those who want a dual mono setup, but t ...

Hi Larry,

Ok, understood about the transformer situation. So let's say that wasn't the issue, then having 2 transformers and 2 power supplies versus the system you have now. I am surprised you're using 1 power supply for both channels? No criticism here.

Ray

[modular747]

Hi:
We have toyed with putting out a mono amp for those who want a dual mono setup, but t ...

Are you still considering a mono version of the Ultra 550 with a regulated supply for the output stage?

[avahifi_lj]

Hi:

In the FetValve Ultra amps we have separate regulators for the left and right channel audio boards.  A single transformer drives the power supply board with the regulators isolating the tube, Fet and heater supply on each board.  In addition, each audio board has a significant amount of filtering in addition to the filtering used on the regulated supply board.

Having totally isolated supplies (transformers, regulated supplies, etc.) naturally could be done, but is it cost effective?  One of the advantages of having a build to order business is that we can actually build things outside of our normal product offerings.  If you are interested in dual mono amps in a separate boxes I would be happy to build them.  I'm not sure if Frank has worked up pricing for a mono power amp, but I'm sure he would be willing to do that.

Thanks for your interest in AVA products!

Larry

[avahifi_lj]

Are you still considering a mono version of the Ultra 550 with a regulated supply for the output stage?

We have thought about offering this configuration, but at this time no work is being done with it.

Larry

[modular747]

Are you still considering a mono version of the Ultra 550 with a regulated supply for the output stage?

We have thought about offering this configuration, but at this time no work is being done with it.

Larry

I suspect that its place on the cost/benefit curve isn't too favorable... It might be more useful in conjunction with a significantly more powerful amp - 500+ watts - but that might require considerable retooling

[guest1632]

Hi:

In the FetValve Ultra amps we have separate regulators for the left and right channel audio boards.  A single transformer drives the power supply board with the regulators isolating the tube, Fet and heater supply on each board.  In addition, each audio board has a significant amount of filtering in addition to the filtering used on the regulated supply board.

Having totally isolated supplies (transformers, regulated supplies, etc.) naturally could be done, but is it cost effective?  One of the ad ...

Hi Larry,

Just wondered if you guys have done that to see just how much of an audible difference there is. You have everything there is, just add a second power transformer to the equation. Ok, besides the box constraints, how much of a difference in real world difference is there?

Ray