Roender's FC-100 Rev.1 Group-Buy

[jszjsz]

Gentlemen,

Do you know any good source for R-Core transformers for the FC-100? I would like to build two monoblocks.

Thanks!

Janos

 

[tagheuer]

Ferry: I received your PAYPAL transfer. Thank you.

Find enclosed the current order list.

Best regards - Rudi_Ratlos

Hi Rudi,

I would like to add a few things for spare, just in case I screw up during my prototype build:

2x AMP PCB
2x Shunt PCB
2x Soft Power-on PCB
2x 0R1 resistors
2x capacitor MKP 1839

What would be the total for the above additional items, including paypal fee and additional shipping cost if any ?

Thanks again.

 

[Rudi_Ratlos]

Find enclosed the current order list.
If you want, you can do your PAYPAL-transfers. I would appreciate this.

Gentlemen: Mihai's FC-100 is a real "gem".
I like your enthusiasm and anticipation to build this amplifier.

As any gem, the FC-100 will not be finished on a weekend.
But once it is finished, the FC-100 will delight your ears for a very long time!

Take your time and plan your build carefully.
Be sure that you have all the tools needed at hand!

This "tap" for example:



http://www.abload.de/img/gewinde00612s0x.jpg

Either think about buying a cabinet with integrated heatsinks or fasten your FC-100 PCBs to a 10mm ALU-plate - I did it this way -
and mount one (several) heatsink(s) on the opposite side of the ALU-plate.

I will close this group-buy on Saturday morning.
I hope (keep your fingers crossed!) that my distributors (MOUSER, FARNELL, BUERKLIN) have enough components
(transistors, capacitors, emitter-resistors) on stock for you all.

I myself have ordered several PCBs and components for late-comers as well.

Best regards - Rudi_Ratlos

P.S. @TAGHEUER: Your last post "crossed" this one.

 

[tagheuer]

P.S. @TAGHEUER: Your last post "crossed" this one.

Hi Rudi,

I'm sorry that I made a mistake. I need 2 x LS protect PCB instead of 2 x Shunt PCB.

So the list of additional items is below. I'll send you a PM regarding this mixup.

2x AMP PCB
2x LS Protect
2x Soft Power-on PCB
2x 0R1 resistors
2x capacitor MKP 1839

Cheers...

 

[Rudi_Ratlos]

@JSZJSZ:

I remember that this company:

Résultats de recherche pour : 'R-core'

has been recommended for producing "nice" R-Cores.

Best regards - Rudi_Ratlos

 

[Rudi_Ratlos]

Gentlemen,

the PAYPAL transfers are "dropping in".
Thank you very much - Rudi_Ratlos

 

[AndrewT]

.........the PAYPAL transfers are "dropping in".
...........

Have we been told to pay?

 

[zsaudio]

I remember that this company:

Résultats de recherche pour : 'R-core'

I use their R-Core trafos. Those trafos look marvellous.

 

[Rudi_Ratlos]

No, Andrew!
You have not yet been told to pay. I will tell you on the weekend, Saturday morning, after I have closed this round.

Best regards - Rudi

 

[joshvi]

Hi Rudi,
I have 10 pair of NJL0302/NJL 0281 & NJL 1302/NJL3281 each with me.But not matched pair. what type of matching is required? VBE and Hfe? Matching between N-N ,P-P or N-P?

joshvi

 

[rellum]

Hi Rudi,

Count me in for:

4 x Shunt psu PCBs
4 x 0.1R resistors
2 x NJLs matched transistors

Thanks,
Francis

 

[Rudi_Ratlos]

Joshvi,

I prefer the NJL0 to the NJL1/3 due to their lower COB (400pF vs. 600pF).

I have attached an image showing the result of the values of the transistors that Mihai used after having matched them.
Mihai matched his transistors at 100mA Ic and 20Vce.
I will match the transistors at 350mA Ic and 12Vce. (OnSemi does at 1A Ic and 5Vce, ...)
I will not measure Vbe nor will I do "cross-matching", but I will measure Vf of the integrated diodes and group the NPN- and PNP - triples in a way
that I "combine" the NPN- and PNP triples according to their Hfe values.

For example: I will take the NPN- and PNP-triple with the lowest Hfe values and mark the transistor whose TT-diode has the highest Vf.
These 6 transistors shall be soldered on a PCB and the TT-diode of the marked transistor shall be bypassed by means of the on-board jumper.

Find enclosed the current order EXCEL sheet.

Best regards - Rudi_Ratlos

P.S. @JethroTull: can you please give me your address (by PM)? I did not find it in your PAYPAL transfer sheet.

 

[AndrewT]

You don't need to match the transistors at 350mA.

You do need to match the outputs at the operating quiescent bias, i.e. 170 to 180mA.

 

[roender]

You don't need to match the transistors at 350mA.

You do need to match the outputs at the operating quiescent bias, i.e. 170 to 180mA.

It's enough at 100mA, even lower at 50mA, because beta is constant after this point till over 2A.

 

[Rudi_Ratlos]

Thank you Andrew, Mihai.
I will decrease Ic to about 140mA (arithmetic mean of your advices ) then.

Best regards - Rudi_Ratlos

 

[jszjsz]

I use their R-Core trafos. Those trafos look marvellous.

I know them but
- what about small transformer with the 2*34V secunder? They do not have it.
- the 120W-size seems to be small and do not have mounting plate,
- the 300W-size is big and expensive.

(Again: I`m to build two monoblocks.)

 

[Rudi_Ratlos]

Fabrizio: I received your PAYPAL transfer! It was easy, wasn't it?

JSZJSZ: some of the German DIYers of round 1 and I ordered a "customer specific wound toroidal" rated at 4 x 34VAC, 50W from BADEL:

produkte der badel gmbh, ringskerntransformatoren

The price was <20€; the lead-time was about 4 weeks. Minimum amount to order is 5, as I remember.
You can even ask BADEL to shield the transformers, put them into a case, ...

Maybe there is some interest of the EUROPEAN participants and you can arrange a "transformer - group-buy"?

Best regards - Rudi_Ratlos

 

[jszjsz]

Thank you, Rudi, the toroidal is not a problem. I would like to stay with the R-core. If I find a good source then I will post it to the list.

 

[zsaudio]

- what about small transformer with the 2*34V secunder?

I connect two small ones in serial.

 

[joshvi]

Rudi,

please change my count as follows

AMP - 4Nos.
shunt - 4Nos.
LS Pro - 2Nos.
Soft PO- 2Nos.
0R1 Res- 4Nos.
NJL Pair- 0
Mkp1839-4Nos.

Best regards
Joshvi