New DIY amp - Nelson Pass design

[magma]

anilva

superb

see if you can get it brush finished and anodised

powder coating has only 1 up side ( hides the flaws/scratches on the surface of the raw matl)
the other are downsides for a higher power high heat amp chasis

PCoat however well its done, chips ( unless ofcourse you have access to those heavy double coat process with pre and post heat furnaces)
Also Pcoat on heatsinks would not be optimal

i hope your/our offer still stands
electronics for the cab
ill get around to doing it soon ( right now im a bit tied down)

currently im working on someones cab order
though im hoping he will agree to a delay because im awaiting some prototype AL extruded sections ive ordered from abroad
if hes willing to wait he will have the first prototype of my first modular cab design.
(one of the sections actually allows you to slide off the side panels without even opening the top cover)

later i will see to mfg of these sections locally

anyway
gettin back to your thread
i wanted to ask the PCBs
why did you have to use Pdaniel
arent those PCBs on group order anyway ( i mean the exact nelson copy?)

 

[dragonxwas]

amp looks good, but why toshiba mosfets, they are 99% fakes, the only originals are brought by OEM's themselves...Came to know of it only when one of the pair blew up the very next week..

Get the ones from Vishay.but keep in mind that they are from same batch..

Also its better off to do a spray job rather than getting it powder coated which comes off as the amp heats and cools off... You could do something more cosmetic about the faceplate, maybe smoked acryl sheet.. with indicator led's glowing subtly behind it..

Edit:

P.S: Try to use some heavier gauge wire for wiring the internals and bind them as close to the chassis as possible..Get a DB dressing kit from local electrical shop, once you see it you will get 1000's of ideas on how to do cable management..

 

[t.antony]

Congrats on another excellent build! Waiting to see pics after finishing.

Regards...

 

[anilva]

anilva

superb

see if you can get it brush finished and anodised

powder coating has only 1 up side ( hides the flaws/scratches on the surface of the raw matl)
the other are downsides for a higher power high heat amp chasis

PCoat however well its done, chips ( unless ofcourse you have access to those heavy double coat process with pre and post heat furnaces)
Also Pcoat on heatsinks would not be optimal

i hope your/our offer still stands
electronics for the cab
ill get around to doing it soon ( right now im a bit tied down)

currently im working on someones cab order
though im hoping he will agree to a delay because im awaiting some prototype AL extruded sections ive ordered from abroad
if hes willing to wait he will have the first prototype of my first modular cab design.
(one of the sections actually allows you to slide off the side panels without even opening the top cover)

later i will see to mfg of these sections locally

anyway
gettin back to your thread
i wanted to ask the PCBs
why did you have to use Pdaniel
arent those PCBs on group order anyway ( i mean the exact nelson copy?)

Thanks. Will keep your advice in mind when I get the cabinet finished.

Yes, the offer stands, but has a time validity ;-) Need to move to next set of projects....

I think if you offer some decent DIY type cabinet for F5, lots of people on this forum will benefit. Don't wait for the most perfectly finished professional looking cabinet! Becomes expensive and takes time to make I guess.

As far as PCBs are concerned, there are two (in fact 3) officially NP approved boards. One is from Peter Daniel and is available as group buy/direct from Peter and the other is CViller board, which is available from DIYA store and the third from Sudhir. I would recommend any of the first two options. For the third option, getting around to the seller to respond to you would be the first challenge....There is no exact copy of Nelson PCB. It has not been ever on offer...

Cheers.

 

[anilva]

amp looks good, but why toshiba mosfets, they are 99% fakes, the only originals are brought by OEM's themselves...Came to know of it only when one of the pair blew up the very next week..

Get the ones from Vishay.but keep in mind that they are from same batch..

Also its better off to do a spray job rather than getting it powder coated which comes off as the amp heats and cools off... You could do something more cosmetic about the faceplate, maybe smoked acryl sheet.. with indicator led's glowing subtly behind it..

Edit:

P.S: Try to use some heavier gauge wire for wiring the internals and bind them as close to the chassis as possible..Get a DB dressing kit from local electrical shop, once you see it you will get 1000's of ideas on how to do cable management..

Thanks for the tips. My Toshiba MOSFETs are from a very reliable source and come completely matched N-P across 4 pairs, to 0.01V at operating current of 1.3A. I have no problem on that front. Of-course costs lot more for that genuine/matched parts. My earlier F5 is stock type with IR/Vishay outputs.

I have wired the amp with adequately provisioned gauge of Teflon insulated wires. I do not want to go overboard on this. I did not feel the need to increase the wire gauges so far. Will enter the zone of diminishing returns I guess.

I do not know what DB dressing kit is. Will check that out.

Cheers.

 

[GeorgeO]

I got a chance to visit and audition Anil's amps yesterday and in a word they were "awesome". I have too many amps lying around my house (5-6 at last count) but am sorely tempted to off load one and jump into the Pass bandwagon.

The fit, finish and aesthetics were outstanding as is the simplicity of the design. I have seen an original Pass Labs amp, and Anil's craftmanship stands very favourable comparison.

Highly recommended.

Peter Daniel is an excellent vendor, I have dealt with him in the past when I bought a NOS DAC, and his after sales support is very good.

 

[shershah]

amazing - the velvety intimacy of anilva's Nelson Pass class A amps paired with his fostex back-loaded horn.

aspirational - a peak that must be scaled by those who know!

 

[neeraj]

Great Work anilva.:thumbsup::thumbsup:

 

[longshanks]

Great work! Nelson Pass DIY is a great way to experience true high end audio.

 

[GeorgeO]

This is also an interesting view. Many commercial vendors tomtom their high power amps, but one has to try and see what works best for oneself. For example with my Scanspeak 2 ways(87db), I always assumed that I need a lot of power(50wpc+) to get decent performance.

Imagine my utter surprise when I connected them to a 28 wpc pp valve amp and they sound better than I have ever heard them before! I dont plan to change this combo for some time. Anil's point of using high efficiency speakers with an amp that is not a "flea powered" amp echoes what I have read elsewhere.

My personal preference is BOZ, but many are happy with B1 using a hi output dac/cd. Also one needs to look at high to mid efficiency speakers when using a F5 instead of very low efficiency speakers. I personally use a high efficiency fostex full range and higher efficiency Altecs.

 

[Kannan_madhu]

Does it consume a large quantity of electricity ?

 

[anilva]

Does it consume a large quantity of electricity ?

Around 250VA is a safe assumption of what it consumes.

 

[ravi_d]

Hi Anil,

Nice build there. I have few questions I would like to get clarified from you.

Looks like there are three possibilities which can be implemented with cviller pcb version 2.
1. Stock F5
2. Double Ouput Mosfets
3. Cascode and Double Output

Can you please explain the difference between the three options in terms of power output and transformer requirements?
what option have you implemented 2 or 3? Are the heat sinks you using enough options 2 and 3?

 

[anilva]

I have made a F5 with standard single output pair and another one with a dual output pair. I have not used the cascoded front end. I did both IRF and Toshiba outputs.

I have used 600VA toroids, which are a bit of overkill, but then allows me to experiment different combinations.

Cheers.

 

[madbullram]

Great work Anilva. Reminds me of my Threshold S150 and S300. Would love hear this

 

[GeorgeO]

Does this mean that you plan a visit here, or is it just wishful thinking? I can vouch for the sound.

I've been planning a visit to Madras for the past year to meet and do some auditions just havent had the time to do it, except for one brief session with Venkat and Rajesh.

 

[captrajesh]

I've been planning a visit to Madras for the past year to meet and do some auditions just havent had the time to do it, except for one brief session with Venkat and Rajesh.

Why don't you plan a trip on 29th which is most probably the date for Chennai meet.

 

[GeorgeO]

Thanks for the invite, have some travel to Delhi and Kerala over the next 2-3 weeks, so not too sure about 29th.

 

[pdhanwada]

anilva,

I am tempted to think about this nelson pass F5 design. I would want to know the details about the stuff needed. Prices and total manhours spent on it.

I would not want to worry about the manhours but money and complexity in implementing is more important to me. I am not an electronics guy just yesterday bought a soldering iron and soldered an electrical equipment and got it working. Beyond that I am an engineer can spend time to learn.

My preamp is B&K Ref 30 I am not sure about the specifications. Will need to check it.

Thanks
Pandu

 

[omishra]

anilva,
I am tempted to think about this nelson pass F5 design.

Good work :clapping:
I am tempted too! Please keep the information flowing. Now I want peace for some time and listen completed projects.

After PASS B1 success, I feel this is next candidate for DIY. People there, what do you say?