Krell KSA 100mkII Clone

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F

Flodstroem

Member
Joined 2004
Fix said:
@Mark A. Gulbrandsen
Wherer did you find/buy this heatsink shown in this post ?
http://www.diyaudio.com/forums/showthread.php?postid=1036763#post1036763
Or if anyone else knows. [/B]
Click to expand...


Those heat sinks in the pictures are from a test setup for the first pair of the KSA-100 mk-II prototype test boards

They came from a stripped old Cerwin Vega power amp that Mark used for the final tests before ordering whole batch of printed circuits boards. Those heat sinks was not a recommendation for optimal heat sinks etc.. they where only used for the test at that particular of time.

In this set up amp was running at a reduced idle current (not full bias) but that didnt matter due to the final evaluation of the boards quality. ;)

I have received your e-mail FIX but I dont know what to answer.

There have been a to low/no interests for Avel Lindberg´s Krell original transformers due to pricing. AndrewT is right about a lot of things he tel you about Krells specifications of the original transformer which Avel has in a way verified.

Those transformers are specified to approx. 900VA but the cores are far bigger than for a conventional 900VA mains transformer (and quality too) . It could deliver power to 2 ohms speaker which is about 450W++ and that could indicate some 20-25 Amps secondary windings which in turn could indicate the use of a 1.5kVA core. :bigeyes:

If interests could rise for at least an order of 10 "Krell"-transformers, then I would be happy to start a GB for those transformers (or a member in the UK as well?).

Regards :cool:
 
F

Flodstroem

Member
Joined 2004
Ok, new 2008-prices for the original Krell transformer as follows:

1-4 units: £ 200 ($ 400)
5-29 units: £ 155 ($ 310)

Regarding shipping to the US Avel says this:

With regards to shipment costs, if you require some units manufactured I will contact our US office to obtain whether we can use their carrier system when we ship to them.
However, please be aware, we only ship to the USA four times a year and so, unlkess your order is received at a convenient time, it may not coincide with a shipment.
Click to expand...

Regards :cool:
 
H

Harry3

Member
Joined 2005
Hi
you will need a heat sink section that is only 2mm thick to mount the transistors on. If it's thicker, the legs of the transistors will not be long enough to go right through the PCB. I had to beg some to mill my heatsink down.

Jozua might be able to tell us what switch was used on the original. Is the switch metalic or plastic?
If it's plastic, they look similar to the Eaton 1600-11E (single pole) or the 2600-11E (double pole) 16A 250V switch ?? Another option could be the 92PM40411E.
Hope this helps.

regards
Harry
 
B

bobgroger

Member
Joined 2005
PWatts said:
If anybody want to take up the job of having another GB for KSA boards I can supply the gerbers, and make a few SMALL adaptions to the layout if there's demand for it.

Pierre
Click to expand...

I would continue on distributing boards if there is enough interest to get a decent price, and if I didn't have a big out-of-pocket expense. I have seen what work a GB is through my limited experience with this one. I can maybe suck it up once more....

Bob G.
 
J

Jozua

Member
Joined 2003
ribbonspeakers.com
Ksa 100.2 vs KSA 150

Gentlemen

I have been comparing a KSA150 with a KSA100.2 for some time now and my subjective impressions is the following;


The 150 is better in terms of;

The bass control is exceptional.
Speed
Dynamics
Overall listening impresion= Sometimes a bit clinical and 2 dimensional


The 100.2 is better in terms of

Soundstage much more solid
Better sweeter tops
Overall listening impresion = much warmer sound and very 3 dimensional


This just shows what an exceptional amp the 100.2 is and it will be interesting to see how a 100.2 clone compares to the original.

Just for the record: I thought that the 100.2 runs hot but the 150 run's even hotter.

Regards

Jozua
 
S

stolbovoy

Member
Joined 2004
Flodstroem said:



Interesting to see if you get a quote and what it will be? :rolleyes:

Regards :cool:
Click to expand...
I just got quote from Avel US:
Viktor:

We are pleased to quote:

Description : Toroidal Transformer.
Primary : 115v + 115v 50/60Hz
Secondary 1 : 38v @ 12.0A rms.
Secondary 2 : 38v @ 12.0A rms.
Secondary 3 : 60v @ 0.8A rms.
Secondary 4 : 60v @ 0.8A rms.
Secondary 5 : 18v @ 0.1A rms.
Secondary 6 : 18v @ 0.1A rms.
Total Rating : 1012va approx.
Int Shielding : Interwound Pri-Sec Screen.
Ext Shielding : External Silicone Steel Band fitted.
Fixing : Fixing Kit Supplied.
Finish : Polyester Tape
Leadouts : 150mm Stranded Style.
Size : 168mm O.D x 68mm Ht approx.

2 units: $533.00 each
4 units: $505.00 each
10 units: $395.00 each

Delivery: 6-12 wks
FOB: CT
Validity: 30 days
Click to expand...
:bigeyes: :xeye:

Looks like I'm going to order from Antek
 
F

Fix

Member
Joined 2008
Price Quote from Fischer Elektronik

This model is 108mm long Heatsink + fan.
Special model for better cooling.


LA 1A 03 8 X TO 3 230V - With 8 x TO 3
H 108mm (Heatsink)

1 € 116,50 ea.
10 € 97,20 ea.
25 € 86,35 ea.
50 € 77,70 ea.

+ drawing costs / once € 40,00

Leadtime: about 6 – 7 weeks after receipt of order


Interested, please sign up at GB thread at:

Heatsink tunnel GB Thread
 
jacco vermeulen

jacco vermeulen

Member
Joined 2004
Bare in mind that the Fischer heatsink tunnels are fitted with a 94cuft/s fan that does 47dBA. (aka 4656/8N)
Getting the noise figure under 20dBA requires dropping the rotational speed from the nominal 2650RPM to roughly half the number, on top of the mechanical silencing works.

For a high power stereo setup (1 duct for 2 channels) it would be better to assemble a one-off ducted heatsink with the largest axial fan that's still acceptable.
e.g. a 7" diameter one like a Papst 6000 series.
As with propellors/screws for ships, submarines and airplanes, most of the noise is generated at the tip of the blades.
 
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