Is anyone building the DIY Pass F-5

exojam · « **Reply #20 on:** 22 Aug 2010, 02:08 pm »

Russell,

When you mentioned this above "Tech-DIY store is supposed to be coming out with kits for the F-5", do you mean they are going to have everything needed for one of these? Basically a one click and order everything? Thanks.

James

sts9fan · « **Reply #21 on:** 22 Aug 2010, 02:29 pm »

I got my fets there in a F5 pack.

Russellc · « **Reply #22 on:** 22 Aug 2010, 07:57 pm »

Quote from: exojam on 22 Aug 2010, 02:08 pm

Russell,

When you mentioned this above "Tech-DIY store is supposed to be coming out with kits for the F-5", do you mean they are going to have everything needed for one of these? Basically a one click and order everything? Thanks.

James

Previously, when I ordered from them, it was a kit of all the parts that go on the amp board, including the output fets. So you still needed the power supply and heat sinks and the case. Now, he hasnt shown those kits available, but when you click on that selection there is a statement that sometime in August the kits for F-5 (and a few other F amps as well) will become available. Jack participates on the Pass forum on DIY, and there is contact info on his site. I'm waiting, I'd like to build a couple of F-4s....

This time I think they are referred to as "Clone Kits" so I dont know if its board and all, power supply, box, heatsink, I have no idea but am itching to see!

Russellc

parodielin · « **Reply #23 on:** 25 Aug 2010, 02:44 am »

I saw cviller is offering F5 boards, PSU boards and rectifier bridge boards again. What is the purpose of brectifier ridge boards and in what condition would I need them?

Should I wait for the kits? or just get the PCBs? My timeframe is very flexible...

Russellc · « **Reply #24 on:** 25 Aug 2010, 05:40 pm »

I'd get the PCB'sa just to have them. They have the option to double the number of mosfets. The rectifier boards are if you want to use the 3 legged diodes. They are not needed if you are going to use "block" style one piece rectifiers. If you go that route, I would use HEXFREDS rather than the "standard bridge rectifiers" myself.....having said that they of course will work.

Russellc

chlorofille · « **Reply #25 on:** 27 Aug 2010, 06:09 pm »

Hi Russellc,

thx for the tip. I have ordered the Jfets from Blues with matched Idss !

Boards are easily available on ebay. One such seller is Jims_audio. If you want, he even sells the kits completed with all the components as well as matched Jfets.

Power tranny - 500VA EI type with dual secondaries
Heatsink - Medium sized CPU cooling type with 12V forced cooled fan.
Enclosure - not decided yet.

Btw does anyone have any listening impressions of the F5 yet ?

wushuliu · « **Reply #26 on:** 27 Aug 2010, 07:41 pm »

Quote from: chlorofille on 27 Aug 2010, 06:09 pm

Hi Russellc,

thx for the tip. I have ordered the Jfets from Blues with matched Idss !

Boards are easily available on ebay. One such seller is Jims_audio. If you want, he even sells the kits completed with all the components as well as matched Jfets.

Power tranny - 500VA EI type with dual secondaries
Heatsink - Medium sized CPU cooling type with 12V forced cooled fan.
Enclosure - not decided yet.

Btw does anyone have any listening impressions of the F5 yet ?

jims_Audio boards are good quality, at the least the ones I've gotten. I would stay away from the kits though, I would rather get known quality parts from a vendor like digikey, mouser, etc.

Russellc · « **Reply #27 on:** 27 Aug 2010, 08:40 pm »

Quote from: chlorofille on 27 Aug 2010, 06:09 pm

Hi Russellc,

thx for the tip. I have ordered the Jfets from Blues with matched Idss !

Boards are easily available on ebay. One such seller is Jims_audio. If you want, he even sells the kits completed with all the components as well as matched Jfets.

Power tranny - 500VA EI type with dual secondaries
Heatsink - Medium sized CPU cooling type with 12V forced cooled fan.
Enclosure - not decided yet.

Btw does anyone have any listening impressions of the F5 yet ?

Sounds very nice, no suckage. Very transparent, not abrasive at all, brings out the slightest textures. The bass is killer.

Russellc

sondale · « **Reply #28 on:** 28 Aug 2010, 11:58 am »

Quote from: Russellc on 27 Aug 2010, 08:40 pm

Sounds very nice, no suckage. Very transparent, not abrasive at all, brings out the slightest textures. The bass is killer.

Russellc

What he said!! Plus in Winter they keep you nice and warm!

chlorofille · « **Reply #29 on:** 28 Aug 2010, 12:17 pm »

Quote from: wushuliu on 27 Aug 2010, 07:41 pm

I would stay away from the kits though, I would rather get known quality parts from a vendor like digikey, mouser, etc.

Noted. Initially I just wanted to get the F5 boards and a pair of matched Jfets.

Quote from: Russellc on 27 Aug 2010, 08:40 pm

The bass is killer.

Nice to hear that. I was counting on it's bass ability to drive my 8'' 2 ways. The kits would arrive on Monday; more updates to follow.

Russellc · « **Reply #30 on:** 31 Aug 2010, 05:52 pm »

Quote from: chlorofille on 28 Aug 2010, 12:17 pm

Noted. Initially I just wanted to get the F5 boards and a pair of matched Jfets.

Nice to hear that. I was counting on it's bass ability to drive my 8'' 2 ways. The kits would arrive on Monday; more updates to follow.

Looking forward to your build. Pleas post with pics. I am beginning to think about my next one, either another F-5, or a Aleph? We'll see. It will definitely be DIY Pass whatever it is...

Russellc

chlorofille · « **Reply #31 on:** 31 Aug 2010, 06:17 pm »

hi!

Been waiting since Monday for the boards. The beast of a transformer was custom made by a local shop.
Standard EI 8kg 500VA tranny with dual secondaries.
Will be wiring it up exactly as shown in the pass F5 service manual.

Might change out the resistors for a massive 10mH choke rated @ 10A.
One choke per channel.
Really love the classic CLC filtering.

What do you think could be a suitable choke?
I have tried chokes but only on lower wattage power supplies. (<6A)

chlorofille · « **Reply #32 on:** 2 Sep 2010, 12:26 pm »

Short update :

Boards and components arrived but was missing the trimpots!!! Seller apologizes and promtly ships them out. The other components were soldered, including the power supply. Power supply contains 13X 4700uF 35V Nichicon capacitors per channel. 60,000uF per channel. Generic breadboard used to hold the caps.

The boards are well marked, and anyone can assemble them easily. Transistor orientations are also well marked. 2 weeks ago when I did not use the boards, I tried point to point connections and made pathetic errors. The 3W 0R47 resistor turned molten red as I forgot to set the trimpots to the minimum. My dad even said "hey, the LED light is getting brighter" !

Please make sure you measure the trimpot for 0 Ohms via a multimeter before turning the unit on....

Russellc · « **Reply #33 on:** 2 Sep 2010, 06:06 pm »

Quote from: chlorofille on 2 Sep 2010, 12:26 pm

Short update :

Boards and components arrived but was missing the trimpots!!! Seller apologizes and promtly ships them out. The other components were soldered, including the power supply. Power supply contains 13X 4700uF 35V Nichicon capacitors per channel. 60,000uF per channel. Generic breadboard used to hold the caps.

The boards are well marked, and anyone can assemble them easily. Transistor orientations are also well marked. 2 weeks ago when I did not use the boards, I tried point to point connections and made pathetic errors. The 3W 0R47 resistor turned molten red as I forgot to set the trimpots to the minimum. My dad even said "hey, the LED light is getting brighter" !

Please make sure you measure the trimpot for 0 Ohms via a multimeter before turning the unit on....

I fired up with a variac. Made it much safer and quicker. Slowly turn up the voltage untill you see bias voltage starting to show. Keep going up until bias is around .40 or so. Then measure the offset.and twittle until it is zero. Now, go back to the bias and up one side, (as you do this your offset will change) and then the other until offset is 0 again. Measure bias. Repeat until you are at .59

Russellc

Russellc · « **Reply #34 on:** 2 Sep 2010, 06:08 pm »

Oh, my amp is dual mono including two transformers. I fired up 1 channel, powered it down after getting set, then did the other. A little easier than watching 2 channels at the same time.

Russellc

Russellc · « **Reply #35 on:** 2 Sep 2010, 06:12 pm »

cant help but notice there are some electro caps on your boards? The F-5 has no caps in the circuit, what are those?

Russellc

chlorofille · « **Reply #36 on:** 2 Sep 2010, 06:24 pm »

Hi,

Those are decoupling caps, which are not in the signal path. They improve transient response of the circuit. Thankfully they don't degrade the sound.

If those were the input caps, I would have burned them !! lol

Russellc · « **Reply #37 on:** 9 Sep 2010, 11:21 pm »

I dont recall seeing them on the Pass schematic. Is there somewhere I can read about this, or was it just this outfits own innovations? Glad to see you are making progress. Its a wonderful amp.

Russellc

bayman · « **Reply #38 on:** 13 Sep 2010, 03:09 pm »

Hi Chlorofille,

Where did you buy those boards? They look very nice. And what did you pay for them? I´m going to use them on the V-1 open baffle speakers

Thanks Flemming Bay

chlorofille · « **Reply #39 on:** 18 Sep 2010, 05:14 pm »

Apologies for the late reply. Things are not progressing at all for now. I still have to find a suitable enclosure and massive heatsinks.

@Russellc - Yep it's not on the Pass F5 circuit diagram. You can omit that decoupling cap. It can be though of as a smaller power supply cap. I don't worry much as it is not in the signal path. For your next amp, try considering Carlos's DX Blame ST which is hot on the diyaudio forum though the group buy is closed, but will reopen in a few months. Will report in once the heatsinks are obtained. This is OT but here is a list of SS amps that I plan to build before moving on to valve gear :

1. Rod Elliot's P3A
2. Carlos DX Blame ST and ES
3. Nelson Pass F5 !!!

@bayman - I got them from jims_audio on ebay.
A good trustworth seller who is knowledgeable about the stuff he sells.
I won't hesitate to go back to him for more DIY needs !

-Dee-