My_Ref Fremen Edition - Beta build/Fine tuning

[Bill_P]

Originally Posted by ClaveFremen

This is a sort of a puzzle... but I'm pretty tired now 1.00AM here.

Maybe something like this?

I was thinking more like this:

[ClaveFremen]

Originally Posted by soongsc

Dario, if you are going to swap C9 and R10, I would STRONGLY recommend you listen to it on the beta board or old MyRef first.

Originally Posted by Bill_P

I was thinking more like this:

Thanks, more clear.

Now I understand why I couldn't imagine that... you were suggesting to swap C9 and R10 in circuit, not in layout...Klaus, do you meant the same thing?

I think this thing has to be tested and it's a bit more radical than what I would like to change...

Sorry, but I'll don't swap those components departing from any My_Ref ever done (official and unofficial) in this phase.

Today I'll be busy at work so I'll check the other suggestions this evening.

[KSTR]

Originally Posted by ClaveFremen

Now I understand why I couldn't imagine that... you were suggesting to swap C9 and R10 in circuit, not in layout...Klaus, do you meant the same thing?

I think this thing has to be tested and it's a bit more radical than what I would like to change...

Yes, swap C9 and R10 in the circuit, this was suboptimal from the very beginning (no disrespect for Mauro -- his original idea was and and remains to be one of the best ideas in chip amp history --, but any designer may make some decisions that are questionable). I would consider it a minor but very necessary change (I mean, you swap to components wired in series). It does not, and can not, change the sound (you guys certainly are overreacting here, IMHO) but it will increase noise immunity by a significant marging when done right... so it may be said "to change the sound" in a certain way.

Of course I leave it up to you if you want to change it or not. That applies in general to any suggestion that I will make (and there is no guarantee that I won't make even the slightest error as well, but I have a full blown audio lab at hand where I can quantify things pretty well, also of course decent listening and comparison facilities).

[soongsc]

Originally Posted by KSTR

Yes, swap C9 and R10 in the circuit, this was suboptimal from the very beginning (no disrespect for Mauro -- his original idea was and and remains to be one of the best ideas in chip amp history --, but any designer may make some decisions that are questionable). I would consider it a minor but very necessary change (I mean, you swap to components wired in series). It does not, and can not, change the sound (you guys certainly are overreacting here, IMHO) but it will increase noise immunity by a significant marging when done right... so it may be said "to change the sound" in a certain way.

Of course I leave it up to you if you want to change it or not. That applies in general to any suggestion that I will make (and there is no guarantee that I won't make even the slightest error as well, but I have a full blown audio lab at hand where I can quantify things pretty well, also of course decent listening and comparison facilities).

In another chip amp, swapping those two components made significant difference. I do not know how significant it is in the MyRef design, so I would recommend trying it in reality to see if it makes a difference before changing it on board.

[ClaveFremen]

Originally Posted by KSTR

Yes, swap C9 and R10 in the circuit, this was suboptimal from the very beginning

OK, so it's the same thing...

I'm having a look at National datasheets and whitepapers and in fact that capacitor goes directly to ground with the resistor preceding it.

Originally Posted by KSTR

I would consider it a minor but very necessary change (I mean, you swap to components wired in series). It does not, and can not, change the sound (you guys certainly are overreacting here, IMHO) but it will increase noise immunity by a significant marging when done right... so it may be said "to change the sound" in a certain way.

Originally Posted by soongsc

In another chip amp, swapping those two components made significant difference. I do not know how significant it is in the MyRef design, so I would recommend trying it in reality to see if it makes a difference before changing it on board.

Two different opinions...

I can't be sure that Mauro did a precise choice or not.

I'll give it a try on my TP modules.

[soongsc]

Remember to move the bypass cap too.

[billo44]

Originally Posted by SoIL4x4

Whoa! Same time, same topic, different continent. Billo are you reading my mind

Spooky eh!
Truth is I have enough trouble reading my own mind... must have been a co-incidence!

Originally Posted by ClaveFremen

48 x 29 mm

It's easy since I've them at home...

Thanks Dario,
So these Russian caps are slightly smaller than the obbligatos we used in the my ref revc ultimate group buy last year.

For that build I put them in between the hot pins of the RCA input and the lightspeed input, seems to work OK to my ears. Here is a non technical build blog,
My Ref Revision C Ultimate GB (Green Mountain Edition) twiddlingmyknobs

Your up late again Dario working on the PCB design. Wish I understood and could contribute, but I know my limits...

Bill

[ClaveFremen]

I've received confirmation from Suburra that beta boards with grounded heatsink and 97dB speakers the hum is no more audible.

So, to retain a proven design, I will try to mantain RC design as similar as possible to beta boards with some mods/enhancements.

This week till saturday will be dedicated to final tests by KSTR and Suburra, finalize the boards and eventually include some minor mod.

Sunday or Monday I'll proceed with the order.

[lehmanhill]

Dario,

I support staying with the proven concept. It's just my opinion, but I also wouldn't move R3 as Klaus suggested. It is a good suggestion, but most people will only attach the heatsink once, so ease of install is of limited value, at least to me.

Jac

[ClaveFremen]

Originally Posted by lehmanhill

I support staying with the proven concept. It's just my opinion, but I also wouldn't move R3 as Klaus suggested.

Hi Jac,

I do agree, at the moment the only mods to the initial RC design I'm quite sure of are the cutout to better isolate C14 ground return and the use of a through hole part for C10.