DIY FirstWatt F4 and McIntosh C48?

[Rosewind]

http://www.diyaudio.com/forums/diyaudio-store/279556-back-panel-parts-2.html
Thanks. Just found this thread and will try to order one directly from the Italian hifi2000 store.
Peter

 

[2 picoDumbs]

http://www.diyaudio.com/forums/diyaudio-store/279556-back-panel-parts-2.htmlThanks. Just found this thread and will try to order one directly from the Italian hifi2000 store. :

I don't think they sell the back panel kit. I'm fairly certain you have to order through the diyaudio store.

 

[Rosewind]

I don't think they sell the back panel kit. I'm fairly certain you have to order through the diyaudio store.

Right you are
Hello Peter, We don’t have any back panel kit for the Deluxe 4U. You will have to buy the kit directly from the DIYAudio Store. Kind regards

 

[Rosewind]

For My BA-2 front end, I am struggling a bit with the resistor /capacitor brands and values:

4 10K R201, R202
4 47,5K R203, R204
2 1K R205
2 221R R206
2 100R R207
4 750R, 3wR208, R209
4 47,5R R210, R211
2 150R R215
2 5K P201
4 20pF C201, C202
2 10uF, 35v C203
4 1000uF, 35vC205, C206, C208

​

I would appreciate if anyone could point me to a good brand.
Would Audio Note 0.5 watt resistors be overkill?
Would a 47K resistor be alright to use in place of the 47,5 k one specified for R203 and R204?

Does anyone have a photo of a fully stuffed BA-2 board?

Otherwise I have almost all the "big" parts in the house. I still need to buy the last components to stuff the BA-2 board, buy internal wires, M3 screws, nut, washers, spacers and so on.

Thanks,
Peter

 

[KevinHeem]

Resistors

You want Vishay/Dale RN60D where it's specified 1/4 watt resistor. The part number for your 10k ohm resistor would be RN60D1002FB14. They're available at Mouser.

 

[Rosewind]

Thanks, Kevin. Much appreciated!

 

[KevinHeem]

For R208 and 209 3w resistors you want Panasonic part number ERG-3SJ751. Also available at Mouser.

 

[KevinHeem]

For the 1000 uf 25v this would work - ECA-1EM102.

 

[KevinHeem]

I'm using ClarityCap PX for the output caps in my BA-3FE but you have a plethora of choices ranging greatly in price. You can find a selection of caps at Madisound. The ClarityCap PX 10uf is here:

https://www.madisoundspeakerstore.com/claritycap-px-capacitor-250vdc/

 

[KevinHeem]

I'm not sure about the 20pf and 1n film caps.

 

[KevinHeem]

For R208 and 209 3w resistors you want Panasonic part number ERG-3SJ751. Also available at Mouser.

I'm second guessing myself on this recommendation. The BA-2 article says "The point between R208 and R209 is “bootstrapped” from the output of the amplifier through C208". You may want a metal film resistor there. In that case something like this:

http://http://www.mouser.com/ProductDetail/Vishay-BC-Components/PR03000207500JAC00/?qs=sGAEpiMZZMu61qfTUdNhG%2f4r7Iw6CIkyG7zviBZagDQ%3d

Hopefully someone else will chime in!

 

[Rosewind]

I have problems finding these parts still:

4 x 20pF C201, C202
2 x 5K P201

Kevin: You have helped me a lot, although I have used a different series Vishay/Dale resistors (CMF55). Those were recommended to me by a friend in Denmark. But the Vishay 3w 750R PR03000207500JAC00 looks right.
Elna Electrolytic Capacitors (10uF 35v + 1000uF 35v). Right too?


Still on the to get-list:
Board mounting standoffs, w/ bolts and washers
Mounting bolts for fets w/washers
Speaker Terminals and RCA Jacks
IEC power connector/Power switch (Schurter type)
Wires: audio and power

+ heatsinks for some of these:

SJ109V+2SK170+IRF610 (I have bought these).

 

[Rosewind]

Just ordered scews, wire, rca back panel connectors online at Tube Town (Germay)

Possible Schurter IEC inlet with on/offs witch:
(1) 6765 - IEC Appliance Inlet C14 or C18 with Line Switch 2 pole and Fuseholder 1- or 2-pole
(2) 6762 - IEC Appliance Inlet C14 or C18 with Line Switch 1- or 2-pole and Fuseholder 1-pole

Are these alright? Elna Electrolytic Capacitors (10uF 35v + 1000uF 35v).

Still searching for:
4 x 20pF C201, C202
2 x 5K P201
Bolts and washers
Speaker Terminals

Apart from that, I am almost good to go with:

- soldering components on the BA-2 board (heatsinks anywhere on the SJ109V+2SK170+IRF610 ?)
- checking for mistakes on the completed boards
- making up a wiring scheme for the "liberated" F4 with soft start module
- finding out how to use my C48 "xlr" outlets with the F4
- assembly
- checking everything works + adjusting bias etc.

 

[KevinHeem]

This is what I've used on three projects now: Schurter part no. KD14.1101.151

The fuse drawer is ordered separately: Schurter part no. 4303.2406

 

[Rosewind]

Kevin.

I have a pre-drilled 4U enclosure. That limits my choice.

 

[albertNL]

Still searching for:
4 x 20pF C201, C202
2 x 5K P201

5k pot
64Y-5,0K: Präzisionspoti. 25 Gänge, stehend, 5,0 K-Ohm bei reichelt elektronik

Other manufacturers shoud be available at electronic stores in Germany or Denmark. Many stores in Holland sell these.

The caps are a bit more difficult to find. Farnell has 20pF mica caps, which I assume should be fine (ask confirmation from someone with more experience, like ZenMod). Problem is that they are USA stock, and extra costs are involved.
Silver Mica Capacitors | Farnell element14
They also have the 5k trimpot, so you could order those there as well.
T93YB502KT20 - VISHAY SFERNICE - TRIMMER, 22 TURN 5K | Farnell element14

Good luck!

 

[albertNL]

Are these alright? Elna Electrolytic Capacitors (10uF 35v + 1000uF 35v).

I used these in my BA3-FE, but that was just because I had them in my drawer:
MKP1839610164 - VISHAY ROEDERSTEIN - Film Capacitor, MKP1839 Series, 10 µF, ± 5%, PP (Polypropylene), 160 V | Farnell element14

Any 10uF MKP (polyporpylene) should work.
Examples:
- Mundorf MUNDORF MCAP250, 10uF, 5% Audio Capacitor
- Clarity Cap 10.0uF ClarityCap PX

No idea if the Elna Silmic II would work here. I think someone also used them in a similar position in the BA3-FE and they sounded great. I suggest you check that thread. I think he bypassed them with a small MPK or MKC.

The 1000uF 35V Elna Silmic II should be fine. I used the same in my BA3-FE. They were slightly too big, so they lean sideways a bit. No big deal. You might find that the 25V is a better fit for the board, but I have not checked.

I am not sure how much sinking you will need, but unless you really bias it high a small heat sink should be fine for the IRF610. I used small heatsinks and standard M3 screws and nuts.

I have not used heatsinks for the JFets in my builds and do not think you need them here.

Good luck.

 

[Rosewind]

Thanks Albert.
I ordered Vishay 5k trimmer resistors, so I am almost there then - I just need confirmation of these now:

Elna Simlmic II 10 uF, 35v

Cornell Dubilier Mica Capacitors 20pF 300V +/- 5% Part: CD5EC200JO3F

+ heatsinks for IRF610?

 

[Rosewind]

I have all parts in the house or on order except:
- the two "bridges" placed between the PSU and the transformer in the build guide
- the terminal block (and how to wire it for 230v)

I am waiting for the screws and wires to arrive from Germany + an IEC power inlet with power switch to arrive from the UK.

Once everything is here, I will fit the back panel connectors and line everything up for photos.

 

[albertNL]

I have all parts in the house or on order except:
- the two "bridges" placed between the PSU and the transformer in the build guide
- the terminal block (and how to wire it for 230v)

Simple bridge rectifier: GBPC3504 or similar. See attached datasheet. I have read that discrete diodes (such as MURxxx) are better but have no experience with those as I have used GBPC bridges in the past and they work fine. I think Nelson uses similar GBPC bridges in the production FirstWatt amps.

Terminal block: I have used "barrier blocks" from Apexjr in the past, see Whats New at ApexJr about halfway down the page.

Attached a diagram of how I did my F4 and F5 psu's. My Amplimo transformer has 2 x 115V primaries. Wiring and colors will depend on your transformer. Attached is the datasheet of the transformer I used. You should be able to work it out from there.

Good luck!