Salas hotrodded blue DCB1 build

[KatieandDad]

12V was probably too low.

RCORE shouldnt make too much difference at the low power of the B1. The rectifier / cap / regulator would make far more difference.

 

[AndrewT]

12Vac may have been interfering with the performance of the shunt regulator.

 

[schubert]

12V was probably too low.

RCORE shouldnt make too much difference at the low power of the B1. The rectifier / cap / regulator would make far more difference.

I thought the advantage of an R-core is that they were quieter - are there other advantages?

 

[Salas]

Good for minimal magnetic field.

 

[AndrewT]

Good for minimal magnetic field

Are they?

Have we seen comparative data?
Are there any experiments published or that we can repeat?

Quieter. I doubt it.

 

[Salas]

I have seen 20dB lower harmonic noise when exchanging a toroid with an R-Core in one box MC phonos. Basically its the only type it can live together in same box, save the little inaudible 50Hz you still get on FFT because of the AC wiring.

 

[AndrewT]

Have you posted your experimental details elsewhere?

 

[schubert]

I have seen 20dB lower harmonic noise when exchanging a toroid with an R-Core in one box MC phonos. Basically its the only type it can live together in same box, save the little inaudible 50Hz you still get on FFT because of the AC wiring.

Then otherwise a 100VA R-core and a 100VA toroid should be pretty indistinguishable in terms of sound? That's my impression.

 

[Salas]

Have you posted your experimental details elsewhere?

No, because I didn't think it was a particular finding since R-Core are primarily designed towards low field. Not having corners in their core shape and by carefully balancing the opposing bobbins. Some are a failure due to imprecision mind you. Have had Chinese with multiple secondaries running hot and noisy. The more windings the more difficult to fulfill the cancelling goals. ''R'' name comes from reminding the horse racing track shape by the way.

 

[AndrewT]

Good for minimal magnetic field.

I have seen 20dB lower harmonic noise when exchanging a toroid with an R-Core ...............

..............should be pretty indistinguishable in terms of sound? .............

If the second follows from the first, then surely there must be some audible benefit?
20dB (1/100th part) is a mighty big reduction in mains harmonics.

 

[Salas]

Then otherwise a 100VA R-core and a 100VA toroid should be pretty indistinguishable in terms of sound? That's my impression.

Subjectively to my ears the result is calmer and softer with R-Core. Don't know if it is the discrete bobbins, the shield, or the lower capacitance for line noise coupling from primary to secondary.

 

[Salas]

If the second follows from the first, then surely there must be some audible benefit?
20dB (1/100th part) is a mighty big reduction in mains harmonics.

MC phono is a special needy case and there it is a must if in same box. Line or power level can be made quiet enough with no positioning and wiring mistakes when using EI or toroid. Still you may remember Roender recommending R-Core for close proximity boxing up with his folded cascode amp. I think you got one of those?

 

[AndrewT]

But that is not addressing the claim

Good for minimal magnetic field

 

[Salas]

What claim?

 

[Salas]

P.S.
just found some nice description of the R-Core design and traits here by just googling:
Products - Custom Magnetics, Inc.

 

[AndrewT]

That claim in post1904 and followed up by

20dB lower harmonic noise when exchanging a toroid with an R-Core

 

[Salas]

I don't think its a claim to say I found the R-Core emitting lower field than usual transformers, its designed for that.

 

[AndrewT]

You are supporting the claim by re-expressing it.

Good for minimal magnetic field

Have you previously posted elsewhere your experimental method and/or details?

 

[KatieandDad]

My B1 is inaudibly quiet with a standard toroidal transformer.

With a Salas Shunt Reg, that gets rid of almost all residual noise.

Is it realy necessary to go the added expense for inaudible gain.

 

[Salas]

You are supporting the claim by re-expressing it.
Have you previously posted elsewhere your experimental method and/or details?

As I told you no, I haven't saved and posted before and after FFTs but I think that I had mentioned enough times in the phono thread that I use R-Core in solo MC boxes after I had found toroid unusable for hum and buzz unless separately boxed. I have no reason to pay bank transfer and shipping for R-Core from France if a locally made and instantly available toroid could cut it.