Pass Labs F4

For the three and more legged things
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#1 Pass Labs F4

Post by Nick »

Continuing from all over the place :-)
btw did you source Ian's Plitrons and if so can you tell me where
Nope, Ian did, but I am sure he will tell you.

I think I should create a solid state area, to give this a place to live.[/quote]

What bias have you set yours to now Ed?

I left Ians running at about 0.6w per device, as my workshop is cold, and I had no idea what temp it would run at in a normally heated room.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#2

Post by ed »

right off the top of my head I can't tell you...I will have to find my log, it seems like such a long time ago. I do remember 250mv was the last attempt(works out at 0.5 amps if memory serves) but I've noticed that after about 4 hours the temp on the trannie is worrying. The sinks are ok, its just the 300va transformer.

At 250mv it really does sing...under my normal philosophy I would leave it alone because it works, but for some reason I have the devil in me with this and I want to see if there is something beyond perfection.

Bearing in mind that it exposed the colour of your TVC, I think I understand exactly what a Li-Te DAC AH sounds like now as I've done the with and without test......Its not to be trifled with!
Last edited by ed on Mon Jan 14, 2008 7:57 pm, edited 1 time in total.
There's nowhere you can be that isn't where you're meant to be
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#3

Post by Nick »

I guess you mean 250mv across the R47 resistor? That would be 530ma. So that would be 3.2A from each rail, so 300va should be well within its limits. I think the piltron Ian used was 300va. Mind you, there will be some hefty spiked into the first cap.
Last edited by Nick on Mon Jan 14, 2008 7:59 pm, edited 1 time in total.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#4

Post by ed »

sorry posts overlapped..I was editing as you posted.....
There's nowhere you can be that isn't where you're meant to be
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#5

Post by ed »

yes thats exactly what I remember coming up with...which means 75watts per channel at idle....which gives 150 watts both channels....So I doubled that for the trannie spec(cos I'm accurate with things like this....DTB style) and came up with a safe 300va......

and what do you know......300 gets terrible hot...go figure
There's nowhere you can be that isn't where you're meant to be
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#6

Post by pre65 »

Hi-you cant have a transformer thats too big ! :lol:

Within reason of course in case Darrens got one the size of a dustbin !!!! :wink:
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#7

Post by ed »

Nick wrote: Mind you, there will be some hefty spiked into the first cap.
If you mean at switch on then I think the thermistor should cope. Its the same CL60 that is used in the big aleph psus and IIRC some of those milk bottle caps are way bigger than my puny 15000ufs(120000 in total).
There's nowhere you can be that isn't where you're meant to be
Darren
Old Hand
Posts: 659
Joined: Mon May 21, 2007 10:58 pm
Location: N/Wales
Contact:

#8

Post by Darren »

pre65 wrote:Hi-you cant have a transformer thats too big ! :lol:

Within reason of course in case Darrens got one the size of a dustbin !!!! :wink:

Nah, the largest one I have is only 75Kg, nowhere near the size of a dustbin.
Andrew
Eternally single
Posts: 4206
Joined: Thu May 24, 2007 2:18 pm

#9

Post by Andrew »

Darren wrote:
pre65 wrote:Hi-you cant have a transformer thats too big ! :lol:

Within reason of course in case Darrens got one the size of a dustbin !!!! :wink:

Nah, the largest one I have is only 75Kg, nowhere near the size of a dustbin.

Chuffin 'eck is that a two 'man' lift?

The iron-ware for my current power amp was about 35kg, came in 3 separate boxes, and I thought that was more than enough....in fact I'm trying to ween myself off, so I don't have to strengthen the floor....
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#10

Post by ed »

hey you ironmongery megolomaniacs clear off, this is the lightweights section
There's nowhere you can be that isn't where you're meant to be
Darren
Old Hand
Posts: 659
Joined: Mon May 21, 2007 10:58 pm
Location: N/Wales
Contact:

#11

Post by Darren »

Andrew wrote:
Darren wrote:
pre65 wrote:Hi-you cant have a transformer thats too big ! :lol:

Within reason of course in case Darrens got one the size of a dustbin !!!! :wink:

Nah, the largest one I have is only 75Kg, nowhere near the size of a dustbin.

Chuffin 'eck is that a two 'man' lift?

The iron-ware for my current power amp was about 35kg, came in 3 separate boxes, and I thought that was more than enough....in fact I'm trying to ween myself off, so I don't have to strengthen the floor....
It's on wheels, flippin needs to be..... :D

Well you need some weight around here Ed..!!! 8)
User avatar
Nick
Site Admin
Posts: 15711
Joined: Sun May 06, 2007 10:20 am
Location: West Yorkshire

#12

Post by Nick »

No I meant the charging current for the first cap. What I found was everything in the amp got hot, mainly becase it was surrounded by two heatsinks dissapating several hundred watts of heat.

One thing I did change, was replace the four parallel resistors between the caps, with TO220 resistors mounted on the case, that removed a small but extra source of heat. What I found was the heat was conducting into the caps and gatting them hotter than the needed to be.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
User avatar
Paul Barker
Social Sevices have been notified
Posts: 8881
Joined: Mon May 21, 2007 9:42 pm

#13

Post by Paul Barker »

Darren wrote:
The iron-ware for my current power amp was about 35kg, came in 3 separate boxes, and I thought that was more than enough....in fact I'm trying to ween myself off, so I don't have to strengthen the floor....
It's on wheels, flippin needs to be..... :D
[/quote]

Well mine isn't as big as Darren's but it's for sale if anyone is thinking of building one of these F4's.

http://cgi.ebay.co.uk/Large-Valve-Trans ... dZViewItem
iansr
Old Hand
Posts: 401
Joined: Thu Nov 08, 2007 10:44 pm
Location: West Riding

#14 Re: Pass Labs F4

Post by iansr »

Nick wrote:Continuing from all over the place :-)
btw did you source Ian's Plitrons and if so can you tell me where
Nope, Ian did, but I am sure he will tell you.

I think I should create a solid state area, to give this a place to live.
[/quote]

I got the Plitrons through a group buy on diyaudio, and yes they are 300va. Because it was mainly americans who were participating in the group buy they were rated for 115v or 230v. I'm sure that 240v is within their tolerance range (my mate Nelson who always uses them says it is :wink: ) but I discovered later that they do another variant which is rated for 240v. I'm pretty sure you can buy direct from Plitron in Canada if you want.
User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#15

Post by pre65 »

Hi-what are the transformer specs ?

ie secondary voltage (s)
The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
Post Reply