Krell KSA5

[spritzer]

We did have a unit to analyze for this project plus we got lots of documents that an owner sourced from Krell.

I'll be ordering some prototype amplifier boards soon so a fun holiday project.

 

[blackdod]

I join!

I want a new headphone amp.

 

[albertNL]

This sounds a lot better than the O2 I built earlier this year!

 

[blackdod]

No news?

Cheers

 

[Congo5]

No news?

Cheers

I asked Spritzer and
He is busy with many many projects......
I would hate to guess when.

 

[blackdod]

 

[trident900fi]

I've just order everything to build one. I let you know, as far as he run !

 

[fordgtlover]

I am excited about this project. A very big thank you to those involved.

Is there a preferred variant of the LSK389 for this amp?

 

[kevin gilmore]

working klone boards
http://gilmore.chem.northwestern.edu/ksa5klone.jpg

 

[blackdod]

OOOH!!! Nice

I´m waiting a group for buy the PCB!!!

Regards

 

[ExStaxy]

OOOH!!! Nice

I´m waiting a group for buy the PCB!!!

Regards

+1 on that .

I NEED it

 

[Grindingthud]

Same here.

 

[bogdan_borko]

I haven`t heard it but I don`t understand that you wish to clone it just for the brand name... Maybe ZM have something to say about the sound of this mediocre discrete opamp (imo the schematic looks something like that...)??

 

[kamis]

I built new version of the KSA-5 power supply with 13v zener reference as shown in BOM, and output is regulated to 23,5V , perhaps too high for OP27 servo op-amp.With schematic value of12V reg. voltage is 21.5V as in the manufactured Krell amp. Why zener voltage was changed? Why zener current is set to about 19ma with CCS? I made all the PCB-s myself( 680 holes!) and I am matching current mirror transistors at the moment.

 

[kamis]

I have not yet decided which transistors to use- MPSA 06/56 or BC 546B/556B.
There are versions with both. KSA5 power supply is very usable for other projects. The same PS was delivered with Krell KPE reference phono stage.

 

[Luke]

Kamis, use MPSW 06/56 if you can, they can dissipate 1 watt, it is a class A amp after all

 

[kamis]

Kamis, use MPSW 06/56 if you can, they can dissipate 1 watt, it is a class A amp after all[/QUOTE
There are MJE15030/31 TO-220 transistors for class A output stage.

 

[Luke]

I must have the wrong amp

 

[kamis]

I have finished building KSA-5 clone today. It works perfectly well-no noise, no hum , just neutral and dynamic sound. I have to put it in a enclosure now.

 

[kamis]

After prolonged listening I think that it is better headphone amp than my Borbely all-fet single ended headamp. It has the perfect grip on the headphone driver which result in explosive dynamic.
Bogdan Borko, could you elaborate more why do you think it is a mediocre discrete- op-amp? Have you designed a better one? J-Fet input, current mirrors,high current driver stage, and classA output stage of 5W in 8 Ohm.What more to expect ?