I don't have investigated so accurately, but at the moment after just 24h hours, the sound is very enjoyable. More detail tone balance and bass control than GC
I'm very satisfied!!It's exactly what happened, now I can measure 1.5mV for one and 4.8mV for the other channel.
I'll listen for some days than I'll measure the ambient with my budget phonometer.
Wow Jac, much more than I expected. Hope you are taking pictures along the way. It will be interesting to see such a sophisticated system.
So I'll throw out the obvious question to you and others - is there an advantage, possibility or reasonable method to feed the FE from a balanced source? Would that require a complete redesign?
So I'll throw out the obvious question to you and others - is there an advantage, possibility or reasonable method to feed the FE from a balanced source? Would that require a complete redesign?
Two possible interpretations to your question.
1. I am doing just that with my balanced line receiver. That is, I bring the balanced signal to the FE and convert it to single ended just before the input of the FE.
Below is a picture of an unpopulated board. I called the boards "differential line receivers" which is the same as balanced. The pair of boards are about 2.4 x 4 inches (60 x 100 mm). They are larger than needed and not as pretty as Dario's boards, but it was my first attempt.
Madisonears has commented privately on the difficulty of working with the AD797 chip. I recognize the danger, so copied a design from Analog Devices, including dimensional limits. The good news is that the board should work with other chips if the AD797 proves too fast and unstable.
2. Your other option is to do like Twisted Pear (Russ White) has done on the Sympatico amp which is essentially two parallel MyRef style amps fed by a balanced, out of phase signal.
It would be like taking 2 FE, running the plus through one side and output to the plus speaker terminal, then taking the 2nd FE and feeding it the minus signal (out of phase from the plus) with it's output on the negative speaker terminal. It is theoretically possible, but it is better if you the internal balanced references similar to what Russ did with Sympatico.
Anyway, none of us should get too carried away with this balanced stuff. Single ended systems sound great and if you don't have a noise problem to solve is a lot of work for maybe no gain. I'm just one of those guys that enjoys learning and doing, even if it hurts.
Sorry if I highjacked the thread.
Jac
Thanks Jac, I don't think Dario minds if we wander a bit as long as we get back to business ASAP.
For my part I'm quite happy with the straight forward input we have now, but am always interested in squeezing all we can from MyRefs and in particular the FEs. What you have developed appears to be a good approach to the age old question of "long interconnects vs. long speaker cables". It is a step or two beyond the RC phase but a subject that will eventually impose itself on some FE users. If there are no simple changes to Dario's current design that give the option of balanced input, then "If it ain't broke - don't fix it" will answer my question quite well
Please keep us informed of you progress.
For my part I'm quite happy with the straight forward input we have now, but am always interested in squeezing all we can from MyRefs and in particular the FEs. What you have developed appears to be a good approach to the age old question of "long interconnects vs. long speaker cables". It is a step or two beyond the RC phase but a subject that will eventually impose itself on some FE users. If there are no simple changes to Dario's current design that give the option of balanced input, then "If it ain't broke - don't fix it" will answer my question quite well
Please keep us informed of you progress.
Hi,
running a pair of amplifiers out of phase is effectively the same as bridging. Each amplifier sees an effective load that is half the impedance of the actual speaker you use.
If you had 16ohms speakers then you two out of phase amplifiers would be just great.
BTW.
Much of my listening is done with amplifiers and sometimes pre-amps without any chassis.
I used twisted pairs. and no balanced.
I have my mobile phone sitting by my keyboard ~400mm from my FM tuner (in chassis), ~ 500mm from Mesmerize (in chassis), ~1200mm from my speakers, ~1300mm from my amplifiers. I get no interference from my mobile even though it repeatedly transmits to keep in touch with the cell aerial.
I get no interference from my fridge, nor dishwasher, nor washing machine, nor heating boiler, nor lighting, not even from CFLs and LEDs.
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Funny that you should ask as this morning I am ordering this inlet (see data sheet) that combines the socket and the fuse in one unit. I am moving to a non- filtered socket as that feature is reported good for receivers and multi-component audio systems, but of little or no benefit (possibly detrimental) for a straight forward design like the FE power amp.
Some pics of what I have been using. As Andrew said, most of what I do is still on wood. The safety/earth ground (green) must be connected properly in all cases with a metal chassis. The fourth picture is an internal fuse holder design to which a safety cover can be added. The purple wires are the extra "shield" provided with the new Antek toroids. I did a new board this weekend so the AC inlet is now at the back. It is cut to the 17 X 11 inch standard so I can see what space is available for a final chassis.
BTW: If any of you "Foreigners" need anything from Mouser, pleas send a PM and I will add it and send via USPS. Seems to be working well, and I can delay the order a day or two.
Some pics of what I have been using. As Andrew said, most of what I do is still on wood. The safety/earth ground (green) must be connected properly in all cases with a metal chassis. The fourth picture is an internal fuse holder design to which a safety cover can be added. The purple wires are the extra "shield" provided with the new Antek toroids. I did a new board this weekend so the AC inlet is now at the back. It is cut to the 17 X 11 inch standard so I can see what space is available for a final chassis.
BTW: If any of you "Foreigners"
need anything from Mouser, pleas send a PM and I will add it and send via USPS. Seems to be working well, and I can delay the order a day or two.Attachments
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This is the final accommodation:
I've got a pair of leds for the front panel, but I've a little problem... they don't light up
I've tried to invert polarity and check functionality with a tester. On the socket I've 1.6V.
Now I've a doubt, do I need to remove the other one on pcb??
Yesterday I've played Miles and he was so real!
An externally hosted image should be here but it was not working when we last tested it.
I've got a pair of leds for the front panel, but I've a little problem... they don't light up
I've tried to invert polarity and check functionality with a tester. On the socket I've 1.6V.
Now I've a doubt, do I need to remove the other one on pcb??
Yesterday I've played Miles and he was so real!
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I just tried a second LED and it did not work. One polarity dims the one on the PCB and the reverse does nothing. It appears only one can be used.
For U.S builders - No True Copper yet, but Parts Express now caries some Audyn capacitors. They might be worth a try.
Agreed, I heard "Seven Steps To Heaven" by Miles with the FEs like a new recording even though I have owned it for decades. Jaco Pastorius big band offerings also come through super clean and powerful.
For U.S builders - No True Copper yet, but Parts Express now caries some Audyn capacitors. They might be worth a try.
Agreed, I heard "Seven Steps To Heaven" by Miles with the FEs like a new recording even though I have owned it for decades. Jaco Pastorius big band offerings also come through super clean and powerful.
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Each LED drops Vf.
If you have an emf, of say 10V, available and use one LED @ Vf=1.8V and a 2k2 resistor then Iled = [10-1.8]/2.2 = 3.7mA
Insert a second LED with Vf=1.85V, then Iled1 & Iled2 = [10-1.8-1.85]/2.2= 2.9mA.
This will result in a very noticeable reduction in brightness.
It's simple logic & arithmetic.
If you have an emf, of say 10V, available and use one LED @ Vf=1.8V and a 2k2 resistor then Iled = [10-1.8]/2.2 = 3.7mA
Insert a second LED with Vf=1.85V, then Iled1 & Iled2 = [10-1.8-1.85]/2.2= 2.9mA.
This will result in a very noticeable reduction in brightness.
It's simple logic & arithmetic.
I cannot equate them to incandescent bulbs, but yes, they do behave as far as ohms' law and the others expect.
Do remember to allow for the forward voltage drop Vf. That is equivalent to an emf and in the normal "lit" condition it appears as a back emf (reverse voltage or minus voltage) with respect to the driving emf.
Do remember to allow for the forward voltage drop Vf. That is equivalent to an emf and in the normal "lit" condition it appears as a back emf (reverse voltage or minus voltage) with respect to the driving emf.
I actually had a problem with one of my LEDs being brighter than the other - different values, not a voltage problem. I tested two yellow pieces to insure they match, then went about the changeover process. These have the flat so orientation was easy. Non the less, I matched things up with Dario's photo in the build instructions. Now the on-board or remote options are both available.
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Off Topic Alert!
As madisonears says, I'm stuck on wires. Months ago I ordered some fine silver to try an interconnect recipe that used clear package tape as a dielectric. They were ok but nothing special. These are much better. I won't hijack and just point here for more info on design and construction. I just twisted three strands this time instead of braiding.
With the FEs connected straight from the Mini2496 DAC, I had to switch over to "Direct Sound" from WASAPI to gain volume control. The system gained much from this experiment. The bass is noticeably better - being more "profound" and defined, not louder. The mids and highs now have a crack and sparkle that doesn't get any where near the exaggerated/overbalanced strain sound reported by some silver interconnect users. The short length may account for that.
All in all, I can only repeat - I'm hearing the best sounds I have ever owned and have to again salute Mr. Inserra
P.S. All the top choice parts have been transferred from the beta to the RC boards. Auditioning will continue.
As madisonears says, I'm stuck on wires. Months ago I ordered some fine silver to try an interconnect recipe that used clear package tape as a dielectric. They were ok but nothing special. These are much better. I won't hijack and just point here for more info on design and construction. I just twisted three strands this time instead of braiding.
With the FEs connected straight from the Mini2496 DAC, I had to switch over to "Direct Sound" from WASAPI to gain volume control. The system gained much from this experiment. The bass is noticeably better - being more "profound" and defined, not louder. The mids and highs now have a crack and sparkle that doesn't get any where near the exaggerated/overbalanced strain sound reported by some silver interconnect users. The short length may account for that.
All in all, I can only repeat - I'm hearing the best sounds I have ever owned and have to again salute Mr. Inserra
P.S. All the top choice parts have been transferred from the beta to the RC boards. Auditioning will continue.
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Hey Guys, I got a few inquiries about the interconnects and think there is enough interest to peruse the topic. In order to keep this thread centered on the RC builds, let me suggest we move the conversation over to the JA-FE Integration thread.
Feel free to post what you consider significant in terms of both interconnects and speaker cabling - Hopefully without getting into useless circular "Wire Wars".
What we want to center on is what works best with assembled FE amps from hands-on experience - and not deep metallurgical theory
Thanks.
Feel free to post what you consider significant in terms of both interconnects and speaker cabling - Hopefully without getting into useless circular "Wire Wars".
What we want to center on is what works best with assembled FE amps from hands-on experience - and not deep metallurgical theory
Thanks.
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