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My_Ref Fremen Edition Interest/Group Buy

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Officially, the answer is you should have one tranny per board for the FE. Because of the double diode bridge, there is more risk of hum if you power two boards with one tranny.

Unofficially, I have tried powering two boards with one transformer. I measured no difference in hum (nearly unmeasurable in my boards) and couldn't hear any problems, but that is no guarantee for everyone. The official answer is probably the best one as each situation and build is different.

The final answer is the standard DIY answer. If you want to use an active crossover and independently amplify individual drivers, go ahead and try it with 2 boards on one transformer. Just be careful of your grounding design and be aware that you may have better results with individual transformers.

Jac
 
Sorry for misleading question. I was generalising :)
I mean IF let's say I have pre board and want to add source selector and let's say remote and boards have different ratings is there only one option of multiple transformers ?
When I open commercial amp(or any electronic device), it has got single board running off single transformer. Board has multiple functions.
I can imagine it is actual limitation (and advantage altogether) of diy - to use step by step integration of boards but nevertheless adding more and more transformers ?
Again sorry for not clear question.
 
Not a problem - but actually I don't know the answer. They are the Sunflowers and Paul has never answered that question. I have been planning to do a bunch of tests on my builds but have held off till I get my upgrade to the Redux crossovers completed. Parts have been sitting here for months but I've been distracted by all these silly amp projects.:rolleyes:

I'm assuming the efficiency is in the low to mid 80s - maybe a little higher. For reference, the FEs (with the big Mundorf AG caps) and being driven from a computer (through the Mini2496 DAC - no pre) can rattle the coffee cups three rooms away in the Kitchen with these speakers:D

Edit - On pipe organ pedal notes in Copeland Organ Symphony.
 

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MyRef does not like inefficient speakers and i had some bad experiences in this matter. The worst experience was the combination with Spendor SA1. Now i have XTZ 99.26 wich are rated at 87db and is driving the speaker quite good but sometimes i trigger Spike protection.
 
Hey Ivan,

Probably my oldest unfinished project is a set of monitors quite similar to your Mark Ks. I've had the drivers on hand for about two years but not completed because the plan is to bi-amp them with electronic crossovers and four separate amps - at least two being MyRefs.

Both madisonears and lehmanhill have been doing work in this area and I've been watching. I'm suspecting a combination of FEs and MyRef V1.3 might work, but I've been hanging on to a pair of BPA-150s and a Carver M-1.0t for possible use on the bottom.

I see several builders bought multiple boards so there may be more developments in bi-amping with the Fremen Edition.

FIY - I made the front baffles (1.25" thick) by laminating scraps of oak, maple and walnut from the dumpster at a local cabinet shop. :D
 

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I can confirm I like the sound of my speakers. Still fine tuning them, but they are very easy on the ear. My arcam is not capable of adequate amplification of er18. That s why I am looking forward to build FE... Unlike my lighter note (I made mistake while soldering) I am really anxtious about my usual distraction which can mess up things again :(
 
Sorry for misleading question. I was generalising :)
I mean IF let's say I have pre board and want to add source selector and let's say remote and boards have different ratings is there only one option of multiple transformers ?
When I open commercial amp(or any electronic device), it has got single board running off single transformer. Board has multiple functions.
I can imagine it is actual limitation (and advantage altogether) of diy - to use step by step integration of boards but nevertheless adding more and more transformers ?
Again sorry for not clear question.

Now I get the question!

Here are two ways of looking at this.

If you think about it, the MyRef (FE included) combines several "power supplies" in one device sharing transformer, diode bridges, and even reservoir caps. MyRef has an unregulated power supply for the high power section of the amp, a regulated power supply at a different voltage and much lower power for the op amp, and a separate unregulated power supply for the speaker protection circuit. So it is feasible to combine different voltages and power levels from a single transformer.

That said, in my limited experience, I usually use a separate transformer for my low and high power sections of an amp. Typically, the high power, unregulated power supply can provide large transient currents and sees the voltage vary some with music demand. The low power section is usually powered by a regulated power supply and I am more comfortable having it independent of the high power supply voltage ripple. Also, depending on what kind of regulator you use, it is often better to have the transformer voltage closer to the regulated voltage, so that the amount of voltage drop in the regulator is smaller and often has lower cooling requirements.

As usual, there is more than one way to skin a cat. Have fun figuring out the way you like best.

Jac
 
Hey Ivan,


Both madisonears and lehmanhill have been doing work in this area and I've been watching. I'm suspecting a combination of FEs and MyRef V1.3 might work, but I've been hanging on to a pair of BPA-150s and a Carver M-1.0t for possible use on the bottom.

I see several builders bought multiple boards so there may be more developments in bi-amping with the Fremen Edition.

Hi Bob,

as you suggest me, I write a PM to Madisonears about bi-amp with 2 My-ref. He told me that if I want to use 10" or 12" woofer in 3 ways speaker, or a subwoofer, I will need much power than My-ref. So I start to look around and I have find the TA3020 Audio Amplifier v4b by Connexeletronic, it has an output power of 211W for channel at 8ohm, 0,1%THD+N. Do you think it will work good in bi-amp with My-ref ? It costs less than UCD400...
My configuration is 2 ways + subwoofer, passive XO between Mid and Tw, active XO for subwoofer 10".
 
Kreisky,

My idea of the best path is to build the FEs first and try them with your speakers. As reported earlier, I built a sub using a driver with an 66 lb magnet and a 500 W Bash amp (Carver Sunfire Clone). Haven't even turned it on for stereo since the beta FE build. I only keep it for the occasional block-buster movie - but even then it's connected to a separate Denon HT receiver. You might not need a sub at all. I'm using 8" woofers and am quite happy with how it fills the room with these amps.

IMHO, the heart of the MyRef series and the FEs in particular, is the emphasis on "refinement" more than power or high output. Potential builders should keep that in mind while considering system configurations. My personal interest in biamping is sound quality and definition, not necessarily higher SPL.
 
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