Transformer details
I received a question about transformer specifications - The transformer is specified with dual 115V primaries for 115 or 230/240V operation, 50 or 60 Hz, and dual 15V secondaries. It is now a 600VA transformer and two are required per complete FX5.
Once I have a PM with the information from all of those currently on the transformer list, I will get final price with shipping and will send it on to the individuals to get payment comming for transformers. SumR will ship directly once the product is built.
This first purchase is for those developers and early adopters who have already committed to purchasing transformers. We can't add a large number of people at this time because it will add considerable leadtimes for the materials.
For everyone else interested in building one later on, we can do a larger group buy for transformers if there is enough interest.
Best regards,
Dave
I received a question about transformer specifications - The transformer is specified with dual 115V primaries for 115 or 230/240V operation, 50 or 60 Hz, and dual 15V secondaries. It is now a 600VA transformer and two are required per complete FX5.
Once I have a PM with the information from all of those currently on the transformer list, I will get final price with shipping and will send it on to the individuals to get payment comming for transformers. SumR will ship directly once the product is built.
This first purchase is for those developers and early adopters who have already committed to purchasing transformers. We can't add a large number of people at this time because it will add considerable leadtimes for the materials.
For everyone else interested in building one later on, we can do a larger group buy for transformers if there is enough interest.
Best regards,
Dave
I looked and couldn't find real reference but.... I have two sets of Peter Daniel F5 PCB's yet to be populated and would like to know if a Balanced version is still possible with his PCB's. I don't see any real reason why not and this may be one of those moments I'll laugh at later but I just wanted to be sure.... Take care.
You can in principle, except :
a) it might be a bit tricky with the wiring if you want to using floating X instead of grounded;
b) you are not using the advantage of near constant current draw of a Class A balanced circuit on the power supply properly, unless you can placed the +Vs and -Vs of the two halves closed to eachg other (which is possible if you put the 2 boards back to back).
But maybe the best solution is to sell the PD boards and buy new F5X boards in January 2011.
Patrick
a) it might be a bit tricky with the wiring if you want to using floating X instead of grounded;
b) you are not using the advantage of near constant current draw of a Class A balanced circuit on the power supply properly, unless you can placed the +Vs and -Vs of the two halves closed to eachg other (which is possible if you put the 2 boards back to back).
But maybe the best solution is to sell the PD boards and buy new F5X boards in January 2011.
Patrick
Patrick:
I've been following this thread with great interest but limited comprehension; you guys are miles above my head. But, hubris notwithstanding, the allure of building a pair of F5X monoblocks (and perhaps a second pair for a friend) is awfully tempting. I have a few questions, which I hope you won't mind answering:
Thank you for indulging me.
Regards,
Scott
I've been following this thread with great interest but limited comprehension; you guys are miles above my head. But, hubris notwithstanding, the allure of building a pair of F5X monoblocks (and perhaps a second pair for a friend) is awfully tempting. I have a few questions, which I hope you won't mind answering:
First, am I right in assuming that the expected power output of an F5X amp with the 600 VA transformers will be in the vicinity of 100 watts at 8 ohms?
Second, perhaps I missed it earlier in the thread, but is your chassis design intended as a monoblock or stereo housing?
And finally, I have only single-ended sources (are balanced sources largely limited to professional or highly specialized digital players?) and would be pairing the amps with Egglestonworks Andra loudspeakers (87 dB). I realize this question begs for a hard slap, but would the F5X be any less suitable for me than, say, an F5 or Aleph J?
Second, perhaps I missed it earlier in the thread, but is your chassis design intended as a monoblock or stereo housing?
And finally, I have only single-ended sources (are balanced sources largely limited to professional or highly specialized digital players?) and would be pairing the amps with Egglestonworks Andra loudspeakers (87 dB). I realize this question begs for a hard slap, but would the F5X be any less suitable for me than, say, an F5 or Aleph J?
Thank you for indulging me.
Regards,
Scott
The F5X as is will have about 48W output into 6 ohm, probably similar figure into 8 ohm, as there is some voltage headroom.
The case discussed here is for dual mono, i.e. one case for a stereo amp even though the power supply is totally separate for the two channels.
And no the F5X is no use for you if you only have a single ended source. You should build a single ended amp, like e.g. F5 standard.
Patrick
The case discussed here is for dual mono, i.e. one case for a stereo amp even though the power supply is totally separate for the two channels.
And no the F5X is no use for you if you only have a single ended source. You should build a single ended amp, like e.g. F5 standard.
Patrick
Single- ended to balanced conversion
If you want to use single-ended sources on a F5X, you need to employ a phase-splitting transformer between the input and the amp driver stages, (just like a push-pull tube amp).
Jensen makes some good ones as does Lundahl. Check with Kevin at K&K Audio for more information.
If you want to use single-ended sources on a F5X, you need to employ a phase-splitting transformer between the input and the amp driver stages, (just like a push-pull tube amp).
Jensen makes some good ones as does Lundahl. Check with Kevin at K&K Audio for more information.
To be precise, you need a SE to Balanced converter, of which transformer is one method.
You can also use what I used at the start, a phase splitter from JLH. 4 resistors, 1 BJT and 4 coupling caps.
I am sure there are many other options as well.
But you should really get a proper balanced source if you want a balanced system.
Otherwise better stick to single ended throughout.
Patrick
You can also use what I used at the start, a phase splitter from JLH. 4 resistors, 1 BJT and 4 coupling caps.
I am sure there are many other options as well.
But you should really get a proper balanced source if you want a balanced system.
Otherwise better stick to single ended throughout.
Patrick
Advantages of Amorphous Core Input Transformers
A good wideband center- tapped amorphous core transformer has a lot of advantages as a phase splitter for this application. First it is simple to implement. Second it provides a very high quality Rf / EMI filter for the input, which these amps NEED.
If anyone hadn't noticed, there is next to NO inductance in the F5 circuit and every FET in this thing is pretty wideband. That means these babies can ring at very high frequencies (1-2 Mhz) when excited, if your shielding or layout isn't pristine. A good input transformer which begins to roll-off at ~ 100 kHz has a lot of merit by protecting the amp at it's most vulnerable spot - where a leaky DAC can cause no end of grief.
Finally, I defy anyone to build an active phase splitter that intrudes less on the input signal than a very high quality amorphous core split transformer. It may be possible, but certainly not as easy, and it inevitably induces asymmetry in the signal paths, defeating the whole purpose of balanced common mode cancellation.
A good wideband center- tapped amorphous core transformer has a lot of advantages as a phase splitter for this application. First it is simple to implement. Second it provides a very high quality Rf / EMI filter for the input, which these amps NEED.
If anyone hadn't noticed, there is next to NO inductance in the F5 circuit and every FET in this thing is pretty wideband. That means these babies can ring at very high frequencies (1-2 Mhz) when excited, if your shielding or layout isn't pristine. A good input transformer which begins to roll-off at ~ 100 kHz has a lot of merit by protecting the amp at it's most vulnerable spot - where a leaky DAC can cause no end of grief.
Finally, I defy anyone to build an active phase splitter that intrudes less on the input signal than a very high quality amorphous core split transformer. It may be possible, but certainly not as easy, and it inevitably induces asymmetry in the signal paths, defeating the whole purpose of balanced common mode cancellation.
Best Value Transformation
If you talk to my friend, Kevin at K & K Audio, he will take good care of you - trust me !! K & K Audio - Lundahl Transformers, audio DIY kits and more
If you talk to my friend, Kevin at K & K Audio, he will take good care of you - trust me !! K & K Audio - Lundahl Transformers, audio DIY kits and more
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