My_Ref Fremen Edition RC - Build thread

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Well I've been listening to this amp on and off for a few days now and I have to say I like it a lot.For some reason I was expecting it to not be as good as my F5 clone but it has proven me wrong in fact in some respects it improves on it being extremely dynamic and detailed;I'm sure I am hearing certain things that aren't quite revealed with the class A amp.The only down side if it can be called that is that I only need 6 clicks on the volume control for things to go loud.I guess I could go back to using the TVC but my VTA valve pre just sounds so good.
A big thank you to Dario for this and the excellent pcb's and every one for their enthusiastic posts which inspired me to build this amp.I think the class A will be retired although if we have the cold winter there predicting I might have to fire it up again to aid with heating.Back to listening.
If you do another group buy Dario I'll take a pair of boards as I think my brother would like one of these.
 
Marra, you are messing me up and costing me money. :D I just ordered two class A kits just because I wanted to make the same comparisons you describe in your posts. For years I have heard people raving about the fine sound from F5 and other class A amps. I just told Dario in an email about my efforts so he didn't think I was a turn coat, and I mentioned I really thought the FEs would come out on top. Your comments are very encouraging and reflect the growing reports that the Fremen Edition has put many power amps up on the shelf to collect dust.

I'll still build the two kits, but suspect I will come to the same conclusion as you.

AmpCamp #1 Got the bare PBCs from the DiyAudio store yesterdey.

JFET-BJT Cascode Probably 4 -5 weeks to cross the pond.

Happy Listening. :hphones:

P.S. Dario has already volunteered some suggestions to upgrade the JFET-BJT, what a guy !!!
 
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Sorry about that Bob;this bug when it bites won't let go.The F5 is a lovely amp easy to build and does sound good.I built mine with over specced heatsinks as there is a set of Aleph J pcb's waiting in the wings and I've just taken delivery of Teabags F5 turbo boards but as the FE is resolving music in such a natural;dynamic and untiring way it could well be a good while before they get built.
By the way the problem board was sorted by replacing the LM318 and diodes D1/2 and 3.All smd components were removed checked and resoldered[not by me I hasten to add.I need to practice soldering these little critters.]All thats left to do is wire up the led's.
 
Well I've been listening to this amp on and off for a few days now and I have to say I like it a lot.For some reason I was expecting it to not be as good as my F5 clone but it has proven me wrong in fact in some respects it improves on it being extremely dynamic and detailed;I'm sure I am hearing certain things that aren't quite revealed with the class A amp.

Very interesting... thanks for the report. :)

The only down side if it can be called that is that I only need 6 clicks on the volume control for things to go loud.

Yes, all My_Refs don't need a preamplifier with gain.

A big thank you to Dario for this and the excellent pcb's and every one for their enthusiastic posts which inspired me to build this amp.

You're welcome. :)

If you do another group buy Dario I'll take a pair of boards as I think my brother would like one of these.

Fine, it will be in the first quarter of 2013.

But stick more to the BOM next time... ;)

the FE is resolving music in such a natural;dynamic and untiring way it could well be a good while before they get built.

The nice thing is that you can improve further swapping some parts...
 
a quick update from me and my wife :)

FE - very detailed, analytical, pleasant and soft sounding amp
Restek - considerably more dynamic and punchy, militant and unpleasant for my wife :D but kind of reference for me.

the difference was quite obvious and common for both of us (though it wasn't like comparing 192kbp mp3 and then flac), however none of us could say where and which drum or bass guitar was more articulated and better placed on the sounstage... It seems to me that swapping the caps (C9) would bring very trivial difference if compared to different amps, hence I'm kind of scared in case I found no difference at all :D as it would take time to get up from the sofa, turn off the FE, swap the caps, turn it on and sit again already in slightly different position...:confused:

Few more pics in chrome.
All in all, I very happy with both amps:hohoho:
 

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I understand your skepticism. However, I started at the same place and was actually astounded how much component orientation changed the personality of the amps. If you followed Dario's labeling on the PBC you are probably very close to optimum.

If a builder is going to engage in the process it is recommended before placing the amp in a chassis. My RC build seems to continue the sweetening even after weeks from removing the sockets.

The chrome looks super!
 
FE - very detailed, analytical, pleasant and soft sounding amp
Restek - considerably more dynamic and punchy, militant and unpleasant for my wife :D but kind of reference for me.

I still think you should replace R3 and particularly the current settings resistors R101/R201 with Caddocks.

They make a HUGE difference.

In general, IMHO, any variation to the BOM makes sense only if you compare the alternate part with BOM's one.

Otherwise how can you say the alternate parts is better/worse/different than the specced one?

It seems to me that swapping the caps (C9) would bring very trivial difference if compared to different amps, hence I'm kind of scared in case I found no difference at all :D as it would take time to get up from the sofa, turn off the FE, swap the caps, turn it on and sit again already in slightly different position...:confused:

Don't do it then... simply use one of the recommended caps... PCX has last BG PKs...

I understand your skepticism. However, I started at the same place and was actually astounded how much component orientation changed the personality of the amps.

Bob, DTSES was talking particularly about C9 which can't be reversed, since it's polarized... ;)

Apart that I obviously agree :D
 
Dario
thanks for you advice! I would go for PKs and Caddocks as you suggest (I was about to order some stuff from PCX anyway)!

Another test was held on Sunday.
C9
Panasonic FC - slightly bright with more highs
Nichicon MUSE & Elna Tonerex - the last one is more natural with a wider soundstage than FC. I didn't like MUSE, though the difference was very negligible if compared to Elna, but the overall impression was that this cap shouldn't be placed here.

Indeed there are some differences in C9, though for me they are far less obvious and significant than comparing two different amps.

Next step would be adding copper shield, removing sockets and testing PKs.

P.S. I made it so narrow to match my DAC/Preamp but now I feel some slight disappointment and wish I chose another chassis. Perhaps it's just kind of paranoia and endless process of improving and tuning audio stuff :D I'm no sure! Moreover I'd rather prefer the look of naked components with their lids off then enjoying with finished products...
 

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Hi All,
My Amp is running for 2 days and sounds good. I still expect sound may change much better after running several hours. Now I feel like vocal is to my face. I expect it may change after few days. But I still have problem with my amp that its clipping after 35% volume increase. Any suggestions? Dario I measured the values in power supply, it is as suggested.

Thanks
Badri
 
Dario
thanks for you advice!

You're welceome :)

Panasonic FC - slightly bright with more highs
Nichicon MUSE & Elna Tonerex - the last one is more natural with a wider soundstage than FC. I didn't like MUSE, though the difference was very negligible if compared to Elna, but the overall impression was that this cap shouldn't be placed here.

Interesting... very similar impressions!

Indeed there are some differences in C9, though for me they are far less obvious and significant than comparing two different amps.

So, at the end a difference was there... ;)

I can agree with you but we compared different caps in C9 to choose the better one in that position... in such context comparing to another amp makes no sense... isn't it?

I still have problem with my amp that its clipping after 35% volume increase. Any suggestions?

Hi Badri,

some more infos are needed.... are you using which transformers (secondaries voltage rating), which loadspeakers (still the Monitor Audio?).

I ask because if you're driving your Monitor Audios with 24V/25V secondaries clipping is expected....

More... you're having clipping on both channels?
 
You're welceome :)



Interesting... very similar impressions!



So, at the end a difference was there... ;)

I can agree with you but we compared different caps in C9 to choose the better one in that position... in such context comparing to another amp makes no sense... isn't it?



Hi Badri,

some more infos are needed.... are you using which transformers (secondaries voltage rating), which loadspeakers (still the Monitor Audio?).

I ask because if you're driving your Monitor Audios with 24V/25V secondaries clipping is expected....

More... you're having clipping on both channels?

Transformers:

Secondary : 22V

I tried with Monitor Audio, kenwood which is 6ohm and with onkyo 8ohm speakers. In all the speakers it is clipping and at the same level of volume (>35%). And clipping is from both the speakers. And sound wise it is getting better and better.
 
Transformers Secondary : 22V

I tried with Monitor Audio, kenwood which is 6ohm and with onkyo 8ohm speakers. In all the speakers it is clipping and at the same level of volume (>35%). And clipping is from both the speakers.

thanks, now it's more clear.

What are you using as a pre?

At 35% volume is really loud?

Which cables are you using?

And sound wise it is getting better and better.

:)
 
No preamp used. CD -> Amplifier

So you're using a 10K volume pot?

Yes it is loud enough to my room. But I wanted to try atleast 80% volume to see how loud it is!!!!

I can understand, BTW with recent over compressed music I can hardly use more than 50% volume (no trace of distortion though)

I am using a 16 guage speaker cable.(Locally available. Dont remember the brand name)

So it's a plain copper wire... no cat5 ethernet cable or other high capacitance cables, right?
 
So you're using a 10K volume pot?
Yes, I am using Alps Blue Velvet.

So it's a plain copper wire... no cat5 ethernet cable or other high capacitance cables, right?

Yes, plain copper wire. If wire plays a vital role then I try changing the wire to DAC brand 16 guage which have in my hand or I will try monsters cable?
 
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