first watt f5

[John Caswell]

Philiphifi wrote

On various forums, the F5 seems more popular than the F6. Is there a reason for that or is it just that it is new?

I don't know really.
Perhaps it is personal - maybe people don't like transformers - perhaps the F6 is too simple - whatever. Either way both give excellent results, even though I am a "died on the wool" valve/tube man, and my lady wife prefers the "valve/tube sound" whatever that is.

John

 

[eastone]

Thank you very much. On various forums, the F5 seems more popular than the F6. Is there a reason for that or is it just that it is new?

Pass described the F5 as ruthlessly revealing. The F6 is just on the sweet side of neutral. It all depends on the rest of your system and what you’re looking for.

Have a read of the various manuals on the First Watt site, they describe the different circuits in a very clear, concise manner.

 

[laverda]

I've built a few FW amps and started on the F5t at 25watts (stereo) then moved to 50watts (stereo) and then 100watts (monos) and found the originally 25watts in 2 x mono form was quite adequate driving various speakers. 4-8ohms. But can seem a bit bass light ( In my systems) I have also built the Alpha J and F6 both of 25watts. I've yet to build the M2 though. There's never enough hours in the day!! The Alpha J I like over the F5t its a more musical presentation. (Not so ruthless) They are all very reviling of the source. As they say rubbish in rubbish out...As a starter though, if you fancy a go with the FW (Nelson Pass) experience the Amp Camp Amp is a single ended amp and can be tweaked to 10-12 watts, no ground shaker but will give a taste of what can be had. Loads of info over at DIyaudio...

The only issue is (may be) the heat they generate, they run quite hot, heat sinks temps:- 50-55deg C will heat a average sized room here in the UK quite nicely.

 

[Arkless Electronics]

F5 all the way for me. Based on the design etc. I haven't heard it. Transformers in the audio path are a no no here...

I hope to have a 10W ish SS class A amp of my own design available to try at some point later this year.... or not... time will tell! I fear that people will not be willing to pay the postage to try out a heavy class A power amp...

Loads of promising designs at the simulation stage here! A hybrid is looking quite interesting in the measurements. The valve in it is there purely because it has highly suitable electrical characteristics for the job BTW and there is no intention that it impart any "valve sound" to it. It can all get rather confusing when you have designed maybe 12 10W class A amps, all eminently "doable", but you've heard non of them 'cos they are just simulations... which to actually build? Why? Go for the easiest to make? or the cheapest in parts? or the best measuring? or the hybrid and simply because some people will think it having a valve makes it intrinsically better?

 

[laverda]

I hope to have a 10W ish SS class A amp of my own design available to try at some point later this year.... or not... time will tell! I fear that people will not be willing to pay the postage to try out a heavy class A power amp...

Loads of promising designs at the simulation stage here! A hybrid is looking quite interesting in the measurements. The valve in it is there purely because it has highly suitable electrical characteristics for the job BTW and there is no intention that it impart any "valve sound" to it. It can all get rather confusing when you have designed maybe 12 10W class A amps, all eminently "doable", but you've heard non of them 'cos they are just simulations... which to actually build? Why? Go for the easiest to make? or the cheapest in parts? or the best measuring? or the hybrid and simply because some people will think it having a valve makes it intrinsically better?

Easiest, cheapest, or the best measured that's the rub ..a bit of all three? N Pass and others state 'run of the mill' quality components to start, if you fancy spending your money on exotics please feel free to do so. It'll sound OK with just quality parts. For the DIY market easiest always sounds good. You can always upgrade later but as a finished product you have to build in all three, not easy. Looking forward to hearing more on this.

 

[Arkless Electronics]

Easiest, cheapest, or the best measured that's the rub ..a bit of all three? N Pass and others state 'run of the mill' quality components to start, if you fancy spending your money on exotics please feel free to do so. It'll sound OK with just quality parts. For the DIY market easiest always sounds good. You can always upgrade later but as a finished product you have to build in all three, no easy. Looking forward to hearing more on this.

Yep that's the rub alright! Personally I don't believe that "component quality" is responsible for any more than Nth degree differences but something I have been doing is avoiding the somewhat difficult to obtain and expensive fet's etc that Pass likes to use... and certainly no SIT's or anything like that! It's awkward and time consuming enough to match devices for use in low feedback, short signal path amps without those devices being obsolete, £7 each, fakes all over the place etc! It's got to the ridiculous point where it's easier, cheaper and more predictable to use triode valves instead of the likes of 2SK170!

I think that low power, low feedback class A amps are the way forward JLH was on to something back in 1969!

 

[laverda]

Yep that's the rub alright! Personally I don't believe that "component quality" is responsible for any more than Nth degree differences but something I have been doing is avoiding the somewhat difficult to obtain and expensive fet's etc that Pass likes to use... and certainly no SIT's or anything like that! It's awkward and time consuming enough to match devices for use in low feedback, short signal path amps without those devices being obsolete, £7 each, fakes all over the place etc! It's got to the ridiculous point where it's easier, cheaper and more predictable to use triode valves instead of the likes of 2SK170!

I think that low power, low feedback class A amps are the way forward JLH was on to something back in 1969!

Agreed. I've (in the past) bought the 'genuine' matched LT 170/74 jfets from the USA store to avoid fakes and their now + £10 each by the time their landed here in the UK after duties taxes and postage. The JLH amp is at the top of my to build next list.

 

[martin clark]

Thanks Graham for the honest views from wide and comparitive experience.

I've built a few FW amps
... They are all very reviling of the source. As they say rubbish in rubbish out...

(it's unfair to pic on an honest typo - heaven knows I supply many - but) this had me tickled.
A more apposite mispelling on the context of 'revealing amps' I could not imagine : )

 

[chiily]

laverda's old F5T that I re-homed I wouldn't say is ruthless just very honest with music. Driving a pair of ESL57s makes a perfect match, nothing clouds the mid and treble ranges. I'm impressed with the Pass Labs stuff.

 

[Arkless Electronics]

I have problems with this "too revealing/open/transparent" thang that some go on about... what is hi fi for or about if maximum transparency and openness are not our goals? Even more so when some folk read revealing/open /transparent/detailed as actually meaning "clinical, bright, harsh"... "No, that's not what I said" YMMV

 

[eastone]

I have problems with this "too revealing/open/transparent" thang that some go on about... what is hi fi for or about if maximum transparency and openness are not our goals? Even more so when some folk read revealing/open /transparent/detailed as actually meaning "clinical, bright, harsh"... "No, that's not what I said" YMMV

Yawn.

Not everyone aims to be a scholar of the history of record mastering.

If a home music system renders a large percentage of its owners music unlistenable then it doesn’t really serve its purpose does it. This has always been the case for me - I’m sensitive to prominence in the treble region, so I tend to enjoy amps that are a little softer there. I also tend to enjoy amps (and systems) that are open, insightful, quick and dynamic. These things don’t have to be mutually exclusive. And not dogmatically pursuing the most ruthlessly transparent amp doesn’t make one ignorant.

Perhaps the OP is a scholar of the history of record mastering. The F5 may be just what he’s looking for. Who knows?

Either way, surely it’s still worth pointing out that there is a range of FW designs he might want to consider.

I doubt any of them suffer for lack of transparency, in the grand scheme of things.

 

[laverda]

Thanks Graham for the honest views from wide and comparitive experience.


(it's unfair to pic on an honest typo - heaven knows I supply many - but) this had me tickled.
A more apposite mispelling on the context of 'revealing amps' I could not imagine : )

He He, made me smile too...auto correction is a lode off creep.

 

[laverda]

hi - i just been on the diyaudio and read reviews on the FW F5. Is it true that the sound is that good? It is easy to build and doesn't cost that much

Yes it does sound good...and maybe revealing/accurate and all the other descriptions of its presentation are over exaggerated. Its a stunningly good amp. Maybe not so easy to build? there are lots of beginners who have lots of problems getting the F5 (and any other project) to work straight of the bench. DIYA have a huge 'lets get it working' ethos and most get it driving speakers in the end. Cost would be around £1200, if you buy in the ready made chassis, not sure if that's cheap. I don't look at the cost of a project so much these days (but I should). And am going too work on it, SWMBO has never mentioned any cost issue with this hobby but is always concerned over the amount of time I spend in the workshop or at the bench under a plume of solder fumes. (Love it...)

I mentioned the NP designed AKAmp , that's not cheap for 4 watts if go down the DIYaudio 'buy it all from us' route, right down to the last nut and bolt. (a one stop shop) Strange thing is this little 4 watt amp sounds wonderful and apart from being a bit light in the bottom end (which can be address to some extent) Is what I use to drive a pair of JR149s and they have never sounded better.

But its not about the money so much over there its all about, Lets make it easy to get people involved in our hobby and make it work first time so we keep them in the hobby. The same applies here at PFM (could we do more?) and most other forums I lurk around at. A very good thing IMO. I must stop banging on.....

 

[philiphifi]

thanks for this info. Does it really cost £1200? i have not looked at the price for the transformer and the power supply but the other parts including the chassis are c. £500

 

[laverda]

thanks for this info. Does it really cost £1200? i have not looked at the price for the transformer and the power supply but the other parts including the chassis are c. £500

Ok, so £1200 is a worse case ...I think the average is about 1k or there abouts dependant on what you have on hand. ? Don't skimp on the power supply though. A good 600VA transformer is regarded as a min. 750 -1000VA is common and 60,000uF per rail. I would only use named genuine 105c capacitors. You might want a soft start module too.

Build it, you will not be disappointed. You cant get anything as good for 3-4 times the price. If you like it you can use the existing case and power supply for other interesting FW amp projects as most use the same/similar PSU config.

 

[Arkless Electronics]

Yawn.

Not everyone aims to be a scholar of the history of record mastering.

If a home music system renders a large percentage of its owners music unlistenable then it doesn’t really serve its purpose does it. This has always been the case for me - I’m sensitive to prominence in the treble region, so I tend to enjoy amps that are a little softer there. I also tend to enjoy amps (and systems) that are open, insightful, quick and dynamic. These things don’t have to be mutually exclusive. And not dogmatically pursuing the most ruthlessly transparent amp doesn’t make one ignorant.

Perhaps the OP is a scholar of the history of record mastering. The F5 may be just what he’s looking for. Who knows?

Either way, surely it’s still worth pointing out that there is a range of FW designs he might want to consider.

I doubt any of them suffer for lack of transparency, in the grand scheme of things.

OOOoooo my post was intended as a rhetorical one.... and certainly not intended to cause any offence....
But, if we were to debate it, then on this I disagree with you. Who said anything about prominence in the treble? This is one of the things I have some issue with ie that subjective description of total transparency etc is so often turned into "ah so it's bright and edgy then!?" when it should not mean anything of the sort. Transparent should not mean ruthless in my book!
Each to their own.

 

[Arkless Electronics]

Ok, so £1200 is a worse case ...I think the average is about 1k or there abouts dependant on what you have on hand. ? Don't skimp on the power supply though. A good 600VA transformer is regarded as a min. 750 -1000VA is common and 60,000uF per rail. I would only use named genuine 105c capacitors. You might want a soft start module too.

Build it, you will not be disappointed. You cant get anything as good for 3-4 times the price. If you like it you can use the existing case and power supply for other interesting FW amp projects as most use the same/similar PSU config.

Personally I would do it rather different.... Smaller transformer and more capacitance. I'm not a fan of big transformers at all. Regulated supplies are another possibility for ultra low mains hum but another kettle of fish altogether...

 

[Stunsworth]

If a home music system renders a large percentage of its owners music unlistenable then it doesn’t really serve its purpose does it. This has always been the case for me - I’m sensitive to prominence in the treble region, so I tend to enjoy amps that are a little softer there.

I've found the opposite, that the better my system the more I've enjoyed the music - I started with a BSR autochanger, so that wasn't difficult. Personally I've always found transducers - cartridge and speakers in particular - to have much more influence on the sound than amplifiers.

 

[philiphifi]

Ok, so £1200 is a worse case ...I think the average is about 1k or there abouts dependant on what you have on hand. ? Don't skimp on the power supply though. A good 600VA transformer is regarded as a min. 750 -1000VA is common and 60,000uF per rail. I would only use named genuine 105c capacitors. You might want a soft start module too.

Build it, you will not be disappointed. You cant get anything as good for 3-4 times the price. If you like it you can use the existing case and power supply for other interesting FW amp projects as most use the same/similar PSU config.

ok - got it. In case things go wrong (i.e. switch on and nothing happens, then how much would it cost to get it fixed?)

 

[Arkless Electronics]

I've found the opposite, that the better my system the more I've enjoyed the music - I started with a BSR autochanger, so that wasn't difficult. Personally I've always found transducers - cartridge and speakers in particular - to have much more influence on the sound than amplifiers.

Now there's a can of worms ripe for debate! I reckon I'll start that one in the main section!