cheers 
I've been planning to build myRev since almost the beginning of the year by reading aboundance of topics and looking for a small enclosure to match my DAC/ Preamp. At last I have found a decent toroid and good to my mind enclosure. Just few questions to be clarified:
- is it possible to use one toroid for both channels?! this has already been asked here, has anybody done it that way? Were there any problems with virtual ground/ hum?
Alternatively I could use 2x 80-100VA toroids and put one on another, though that makes me looking for a higher case...And I'm not sure if that is a good solution in accodance to hum?!
- are FE latest boards available to acquire?
Reading profusion of comments regarding MyRevC and further mods, I guess it's not the best idea to buy some initial versions or even a clone of MyRev like this one...Thus probably will stay with two boards.
I've been planning to build myRev since almost the beginning of the year
by reading aboundance of topics and looking for a small enclosure to match my DAC/ Preamp. At last I have found a decent toroid and good to my mind enclosure. Just few questions to be clarified:- is it possible to use one toroid for both channels?! this has already been asked here, has anybody done it that way? Were there any problems with virtual ground/ hum?
Alternatively I could use 2x 80-100VA toroids and put one on another, though that makes me looking for a higher case...And I'm not sure if that is a good solution in accodance to hum?!
- are FE latest boards available to acquire?
Reading profusion of comments regarding MyRevC and further mods, I guess it's not the best idea to buy some initial versions or even a clone of MyRev like this one...Thus probably will stay with two boards.
With the My_Ref, yes,
With the My_Ref Fremen Edition, no.
You can parallel two transformers (pay attention to hot/phase) but, IMHO, it should be used only as an interim solution.
Yes, more later.
Said I’d do it and did – finally.
After months of teasing forum members, I did catch up with my friend John (all the way back to High School) to compare an LM3886 amp to a high quality tube design. The problem seems to have been him and his wife saved their money so they could travel in retirement, while I spent all mine on silly DIY projects and can’t afford to leave the house. Anyway, a little salt on the bird’s tail did the trick.
The tube amp is a Cary Audio Design CAD-300SEI integrated amplifier. His system includes some other very nice equipment including a Cary PH-301 moving coil phono preamplifier, top end turntable and cartridge and a Cambridge CD player with the ability to feed a separate DAC or other digital boxes.
Again, the source was flac files fed from a Samsung Galaxy S II. It was connected directly to the tube amp and the FEs via standard RCA interconnects. I tried to collect a wide variety of music – some being native uncompressed, and others reformatted to the flac format. We didn’t try any standard CDs.
The music flowed from a pair of ProAc Response 2.5 loudspeaker bass reflex speakers through some $600 + cables in a bi-wire configuration. To keep things simple we didn’t do any double blind stuff. Just played the selections on the Cary first and then the FEs.
In general, the Cary is probably the cleanest and most accurate amp I have had the pleasure of hearing over an extended period. As I expressed to John, my intention was not to do a critique of the Cary – more correctly a chance to detail the similarities and differences between the tube and the LM3886 approaches. (Though it would have been fun to thump Mr. Cary)
1. “Chega De Saudade (No More Blues)” – a small jazz/Brazilian combo. Much like a brass choir with lots of active rolling percussion. As with all the music, the Cary was super clean and defined. The instruments were spread well across the stage with noticeable separation between the instruments. The entire spectrum was fully represented and sounded balanced. On the FEs a slightly more “juicy” character could be heard (IMO - a good thing) and a more forward image appeared.
2. “I’ll Be Seeing You” – New York Voices – Long standing world quality vocal group specializing in close harmonies and interpretations of instrumental jazz classics. This is where some sibilance started to show. Johns comment “there is something around the voices”. My impression was less space between the voices. While still maintaining the placement across the stage, there was a slightly more “homogenized” presentation. The trade-off was the “In-the-room” character the FEs added. We agreed on the word “forward” as descriptive and both felt it to be a positive for the FE.
3. “Freedom Is A Word” – Bobby McFerin – Vocal magician with full operatic capabilities. This song begins with some clean and delicate interplay between Bobby and some hand percussion. It transitions to include a wonderful pedal pad that has some of the best low end resonances I have heard for testing. The tubes produced a wonderful combination of physical and sonic balance on those notes. The FEs were more powerful there, but showed a ”blooming” that made the sound a little more like something coming from a good amp as opposed to hearing a natural reproduction of a real world instrument. Not a lot but clearly heard by both of us. This was probably the most interesting difference of the entire session for me. Just the day before I installed the new GB F caps. The change was exactly the same as with the character of the two amps – more/tighter control of the sonic elements of the low end when compared to the BG Standard caps. It is also a lot of what the Mundorf AG caps do in comparison to the standard 10,000 uF caps at C101/201. More builders will address this as we progress, but there is still some work needed to dial in on this part of the FE design. I do believe it is also going to be related to the speakers the FEs play through.
4. “Back On The Block” - ICE-T/Quincy Jones – Though I own many more, this is one of only three rap songs I allow into my snobbish little musical world. It also has that deep room shaking synth sound but balanced for musicality as opposed to rattling the windows in all the cars at a stop light. The results were about the same though this is one place my Sunflowers clearly beat out the ProAc speakers. I don’t think the Cary can produce that thump (nor were they designed to) that the FEs are capable of if and when one chooses to play that type of music.
5. “Pines Of Rome” A. Respigh – A glorious finale that builds from an almost silent state with one instrument and some natural forest sounds to an almost crushing full orchestra – sometimes incorporating a large pipe organ. This is where the FEs dominated the tubes. It is also where builders musical preferences come back into play. When John did his multi-year search for his optimal system, he knowingly sacrificed the ability to create that totally engulfing, furniture moving SPL in his home setting while playing full classical pieces. The FEs combined with the right speakers can easily create that aura without a sign of stress.
There was more music played but that covers what came across as most significant. I came away extremely happy and encouraged with all the comparisons. When I got home I called John back and asked this question:
“As someone who has been living with a top quality tube amp for years, considering the Cary as 100%, how much of that did the FEs cover?” His answer – “I can’t really do that. It wasn’t so much a better or worse type of thing – there were just differences”. He started to explain and I interrupted with – “Stop bloviating and limit your answer to my question”. Answer – “O.K., If I have to it’s somewhere around 80 to 85%, but that’s not the full story.”
Later today I will put the examples that were used in the BoxNet Test folder for those who may be interested.
After months of teasing forum members, I did catch up with my friend John (all the way back to High School) to compare an LM3886 amp to a high quality tube design. The problem seems to have been him and his wife saved their money so they could travel in retirement, while I spent all mine on silly DIY projects and can’t afford to leave the house. Anyway, a little salt on the bird’s tail did the trick.
The tube amp is a Cary Audio Design CAD-300SEI integrated amplifier. His system includes some other very nice equipment including a Cary PH-301 moving coil phono preamplifier, top end turntable and cartridge and a Cambridge CD player with the ability to feed a separate DAC or other digital boxes.
Again, the source was flac files fed from a Samsung Galaxy S II. It was connected directly to the tube amp and the FEs via standard RCA interconnects. I tried to collect a wide variety of music – some being native uncompressed, and others reformatted to the flac format. We didn’t try any standard CDs.
The music flowed from a pair of ProAc Response 2.5 loudspeaker bass reflex speakers through some $600 + cables in a bi-wire configuration. To keep things simple we didn’t do any double blind stuff. Just played the selections on the Cary first and then the FEs.
In general, the Cary is probably the cleanest and most accurate amp I have had the pleasure of hearing over an extended period. As I expressed to John, my intention was not to do a critique of the Cary – more correctly a chance to detail the similarities and differences between the tube and the LM3886 approaches. (Though it would have been fun to thump Mr. Cary)
1. “Chega De Saudade (No More Blues)” – a small jazz/Brazilian combo. Much like a brass choir with lots of active rolling percussion. As with all the music, the Cary was super clean and defined. The instruments were spread well across the stage with noticeable separation between the instruments. The entire spectrum was fully represented and sounded balanced. On the FEs a slightly more “juicy” character could be heard (IMO - a good thing) and a more forward image appeared.
2. “I’ll Be Seeing You” – New York Voices – Long standing world quality vocal group specializing in close harmonies and interpretations of instrumental jazz classics. This is where some sibilance started to show. Johns comment “there is something around the voices”. My impression was less space between the voices. While still maintaining the placement across the stage, there was a slightly more “homogenized” presentation. The trade-off was the “In-the-room” character the FEs added. We agreed on the word “forward” as descriptive and both felt it to be a positive for the FE.
3. “Freedom Is A Word” – Bobby McFerin – Vocal magician with full operatic capabilities. This song begins with some clean and delicate interplay between Bobby and some hand percussion. It transitions to include a wonderful pedal pad that has some of the best low end resonances I have heard for testing. The tubes produced a wonderful combination of physical and sonic balance on those notes. The FEs were more powerful there, but showed a ”blooming” that made the sound a little more like something coming from a good amp as opposed to hearing a natural reproduction of a real world instrument. Not a lot but clearly heard by both of us. This was probably the most interesting difference of the entire session for me. Just the day before I installed the new GB F caps. The change was exactly the same as with the character of the two amps – more/tighter control of the sonic elements of the low end when compared to the BG Standard caps. It is also a lot of what the Mundorf AG caps do in comparison to the standard 10,000 uF caps at C101/201. More builders will address this as we progress, but there is still some work needed to dial in on this part of the FE design. I do believe it is also going to be related to the speakers the FEs play through.
4. “Back On The Block” - ICE-T/Quincy Jones – Though I own many more, this is one of only three rap songs I allow into my snobbish little musical world. It also has that deep room shaking synth sound but balanced for musicality as opposed to rattling the windows in all the cars at a stop light. The results were about the same though this is one place my Sunflowers clearly beat out the ProAc speakers. I don’t think the Cary can produce that thump (nor were they designed to) that the FEs are capable of if and when one chooses to play that type of music.
5. “Pines Of Rome” A. Respigh – A glorious finale that builds from an almost silent state with one instrument and some natural forest sounds to an almost crushing full orchestra – sometimes incorporating a large pipe organ. This is where the FEs dominated the tubes. It is also where builders musical preferences come back into play. When John did his multi-year search for his optimal system, he knowingly sacrificed the ability to create that totally engulfing, furniture moving SPL in his home setting while playing full classical pieces. The FEs combined with the right speakers can easily create that aura without a sign of stress.
There was more music played but that covers what came across as most significant. I came away extremely happy and encouraged with all the comparisons. When I got home I called John back and asked this question:
“As someone who has been living with a top quality tube amp for years, considering the Cary as 100%, how much of that did the FEs cover?” His answer – “I can’t really do that. It wasn’t so much a better or worse type of thing – there were just differences”. He started to explain and I interrupted with – “Stop bloviating and limit your answer to my question”. Answer – “O.K., If I have to it’s somewhere around 80 to 85%, but that’s not the full story.”
Later today I will put the examples that were used in the BoxNet Test folder for those who may be interested.
Attachments
Last edited:
Boards arrived!
I've boards in my hands:
Same great quality of green ones.
I'll try to start shipping tomorrow, by saturday all boards should be shipped.
Now that blue boards are here I can communicate how I intend to manage the 'excess' green ones.
I'll sell them at 20€/couple and after enough are sold all RC partecipants will receive a 10€/couple refund so that they pay their blue boards 20€/couple too.
Partecipants that want to buy green boards have precedence over all others and can have their refund immediately paying them 10€/couple (price valid for the number of blue boards buyed with the GB).
So, please, every partecipant should post his preference (refund or extra boards at special price).
I'll start shipping from partecipants that express their intention.
Whoever else wants green boards please express interest.
I've boards in my hands:
Same great quality of green ones.
I'll try to start shipping tomorrow, by saturday all boards should be shipped.
Now that blue boards are here I can communicate how I intend to manage the 'excess' green ones.
I'll sell them at 20€/couple and after enough are sold all RC partecipants will receive a 10€/couple refund so that they pay their blue boards 20€/couple too.
Partecipants that want to buy green boards have precedence over all others and can have their refund immediately paying them 10€/couple (price valid for the number of blue boards buyed with the GB).
So, please, every partecipant should post his preference (refund or extra boards at special price).
I'll start shipping from partecipants that express their intention.
Whoever else wants green boards please express interest.
Attachments
One significant thing I left out. John said once he understood what a chimp amp was all about, he expected to hear some of that infamous "transistor sound" - even heard from some high dollar units. He calls it the crackilies. He could not detect a trace if it and was thusly impressed.
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Well designed tube amps certainly have more advantage since most part operate in low current, and the high current to the speakers is isolated from the low current sectors. But chip based designs can perform just as well, which means clobbering lots of commercial amps of similar power rating out there.
cheers
I've been planning to build myRev since almost the beginning of the year
- is it possible to use one toroid for both channels?! this has already been asked here, has anybody done it that way? Were there any problems with virtual ground/ hum?
Alternatively I could use 2x 80-100VA toroids and put one on another, though that makes me looking for a higher case...And I'm not sure if that is a good solution in accodance to hum?!
one...Thus probably will stay with two boards.
Let me attempt a more detailed answer.
First, although successful MyRefs have been made using 160 VA transformers, both MyRefs and FEs seem to benefit sonically from larger transformers. Of course, it all depends on what your speakers need to drive them.
Both MyRef and FE use a bridge between the voltage stage output and the feedback loop. In the MyRef, the bridge is a capacitor which is more robust against hum. One of the sonic improvements of the FE is the use of a double diode bridge. Mauro, the original designer of the MyRef concept, strongly suggested that this increased the hum risk, so the FE was designed with one transformer per amplifier channel.
To my knowledge, no one has experimented with driving two FE boards with one transformer. My long term plan is to build some 3 way speakers with an FE amp driving each speaker. Naturally, I would be happier if I could drive 3 channels with on transformer. With that in mind, I will be doing some experiments, once I get my FE built.
In the end, I will use one for one, FE to transformer if needed, but I'm hoping that careful experimentation and grounding design may let me get away with a single transformer.
I hope this helps.
Jac
hi Dario and thanks for reply!
Did you mean MyRefC with your recommendations here?!
This is just to clarify whether to stay with:
RefC + one toroid + matching to my DAC compact box
or go for
FE monoblocks in two or single larger chassis
ok, the greens are the same, right?
lehmanhill,
i got it, the bigger toroid is the better dynamics would be. thanks!
Regarding the bridge cap in MyRef, could you please point me on the scheme which one is that?
Attachments
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So far I have not received any My_Ref Fremen Edition circuit boards. I paid via
PayPal some time ago but have not received my 4 circuit boards?
It's pretty normal... Didn't shipped any board yet.
We were waiting that manifacturer redo boards (first batch was the wrong color).
Please confirm if you want extra boards or not and I'll ship your package tomorrow.
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You're welcome.
Yes that (outdated) post was referred to My_Ref RevC
Yes, the only difference is color.
If want to buy PM me your paypal account and postal address and I'll send you a PayPal invoice.
I may need some back up from the experts, but here is the way I look at it. Both MyRefC and FE have C10 which acts as a bridge. FE also has D1, D2, and D3 which together form a double diode bridge.
Any of you experts want to take a crack at how the bridge changes both the FE sound and may reduce hum resistance?
Jac
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