Oh build a new cross feed amp. I think I will enjoy the amp as is for a while. Although simple to make another one.
No, you build a passive cross feed module on a small PCB.
Place it between your current RCA inputs and the stereo pot (or F5HA inputs).
That' it. Not even power supply required.
If you find out you don't like it, then take it out again, and you have your original F5-HA back.
Patrick
Place it between your current RCA inputs and the stereo pot (or F5HA inputs).
That' it. Not even power supply required.
If you find out you don't like it, then take it out again, and you have your original F5-HA back.
Patrick
Absolutely same impressions here. I also try my favourite piano pieces first with any new piece of equipment. 😉
F5 HA is a great amp at that... it's bigger brother (father? 😀) is king of the hill though.
And regarding the Crossfeed: I don't use it yet with the F5 HA (in the process of recasing) but just tried the active one with my DAO.
For testing I have used it with potis connected in place of the resistors R5 (Crossfeed amount). Very interesting effect but very worthwhile.
Seems as if the stage goes from collapsed to really wide. Need to play with it some more.
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> it's bigger brother (father? ) is king of the hill though.
You meant the DAO SE ?
It is a much more complicated project though.
If you are a balanced guy then F5X-HA is one step up.
But that is only my opinion, and that of the alpha tester.
Patrick
You meant the DAO SE ?
It is a much more complicated project though.
If you are a balanced guy then F5X-HA is one step up.
But that is only my opinion, and that of the alpha tester.
Patrick
Patrick: With the F5X-HA will you sell PCB's with only the amplifier circuit, or will there be some kind of complete impementation like F5-HA? Also, approx what size are the PCBs?
My remark was not meant as a recommendation, just an experience.
Also to shed some light on the Crossfeed @xrk971
60mm x 65mm for one channel.
Attached a photo of the PCB, to fuel some interests into this nice amp 😛
Attachments
What is cost of just HA amp PCB ?
*warning about connecting or disconnecting inputs while powered*
I damaged one channel plugging in the DAC RCA connector while powered on - right channel is all clipped and distorted now. Be sure to power off before doing so. I fried the IRF610/9610 I think as I replaced the SK/SJ and problem remains. 🙁
*warning about connecting or disconnecting inputs while powered*
I damaged one channel plugging in the DAC RCA connector while powered on - right channel is all clipped and distorted now. Be sure to power off before doing so. I fried the IRF610/9610 I think as I replaced the SK/SJ and problem remains. 🙁
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Looks nice!
Will first try to get time and stuff to finish F5-HA before thinking about the balanced one - but i will of course buy the boards as soon as they are ready.
I unfortunately(?) have too many hobbies, and also two small kids on that - but one can at least plan future projects 🙂
We shall only run the F5X-HA as a complete project (PCB set) if there is sufficient interest.
Anything else is too much effort and no motivation for my guys who have all the donkey work.
Just for the amp you can easily do Vero P2P, as in the F5-HA.
Patrick
Anything else is too much effort and no motivation for my guys who have all the donkey work.
Just for the amp you can easily do Vero P2P, as in the F5-HA.
Patrick
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Made the same mistake and damaged the mosfet, jfet are still good. Is there anyway to protect those mosfet?
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> Be sure to power off before doing so.
Those who has a pot only need to turn it down to minimum.
That is assuming your source has a DC output and not capacitor coupled.
It is just good practice, for any FET input amps.
Patrick
Those who has a pot only need to turn it down to minimum.
That is assuming your source has a DC output and not capacitor coupled.
It is just good practice, for any FET input amps.
Patrick
> Is there anyway to protect those mosfet ?
Current limiter as in the F5 power amp.
But it interferes with the sound during normal operation.
None of the XEN PCB builders have used that till now.
Patrick
Current limiter as in the F5 power amp.
But it interferes with the sound during normal operation.
None of the XEN PCB builders have used that till now.
Patrick
I use hexFETs on other amp designs and they are very robust but I have 12v Zener and 1n4148 to protect the gate with respect to the Source. Would that detract the sound quality?
Anything that has a (even) minute leakage current at normal operating bias voltage will affect SQ.
Why is it so difficult to turn down the inout to the amp before switching power or source ?
I do this all the time and it is just good practice.
Patrick
Why is it so difficult to turn down the inout to the amp before switching power or source ?
I do this all the time and it is just good practice.
Patrick
It's not hard - just trying to make it idiot proof for times I might loan it to a friend. But certainly right about keeping things minimal. Probably why it sounds so good - nothing extraneous in the signal path. I was thinking of adding usual 330pF to ground in inputs to block RF - but so far seems to be immune from it. Also, I am running it minimal like the veroboard drawing : no 100k to ground and no 100R series between input to the two 100R's in front of JFET gates (those do have the 100R SMTs). I wonder if I need the 100k inpedance loading resistor?
> no 100k to ground and no 100R series between input to the two 100R's in front of JFET gates
They might have saved your MOSFETs.
In fact, reducing the 100k to 10k will be even more effective in tying the input to Gnd when source RCA is open circuit.
So not circuit design fault from me.
Patrick
They might have saved your MOSFETs.
In fact, reducing the 100k to 10k will be even more effective in tying the input to Gnd when source RCA is open circuit.
So not circuit design fault from me.
Patrick
And to me subjectively at least, Fairchilds sound better than IRFs.
Toshiba even a touch better, if you can find them.
Cloud85 has matched Fairchilds.
Patrick
Toshiba even a touch better, if you can find them.
Cloud85 has matched Fairchilds.
Patrick
I will order few pairs of Fairchild to try, already got 4 pairs of 2013/313 in the pipeline. Start to get used to turn down the volume before powering off.
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Would be a pity to burn your 2013/313, wouldn't it ? 😉
Matched-pair yield of Fairchild is quite bad, as published before.
Patrick
Matched-pair yield of Fairchild is quite bad, as published before.
Patrick