Krell KSA50 clone simpler alternatives.

[beppe61]

Dear Sirs,

First of all please excuse my english very poor.
I have come to the conclusion that in a normal listening room with speakers of normal efficiency a low power high current amp is preferable.
I say this on the basis of the following considerations:
1) some speakers are a demanding load and so require high current from the amp expecially to give a solid bass response
2) at low voltage supplies the SOA of the output stages is maintained also at higher currents
3) power transformers with low voltages on the secondary windings are able to source a great amount of amperes.
4) in a normal listening room 40-50W /8 ohm that increase with lower impedances should be more than enough.

The most famous amp of this kind can be the Krell KSA50 so well cloned by DIY members.
I looked at all the threads about it but in the end I find it too demanding for my limited skills.
So my question is: are there any other "simpler" DIY projects that can give with a suitable power supply a very good peak current ?
I am thinking to a project even with just a pair of powerful output devices/channel.
Of course I do not pretend to drive a pair of Apogee Scintillas (1 ohm impedance !) with it (eh, eh) like I understand the Krell is able to do adequately.

I stress that Watts are not important to me: Amperes are.
Thank you so much for your extremely kind and valuable reply.

Kind regards,

beppe

P.S. Another similar Kind of amp was the ML2 for instance.

[MikeB]

You really should try the symasym, it always did a great job driving speakers, especially woofers. Don't be tempted by large amperes or watts, these tell nothing...

Mike

[beppe61]

Originally posted by MikeB
You really should try the symasym, it always did a great job driving speakers, especially woofers.
Don't be tempted by large amperes or watts, these tell nothing...
Mike

Dear Mr. Mike,
thank you very much for your kind and valuable reply.
I was thinking to something even more simpler for topology.
Very few components and just one pair of output devices/channel.

Thank you so much indeed.
Kind regards,

beppe

[Elso Kwak]

Originally posted by beppe61

I stress that Watts are not important to me: Amperes are.
Thank you so much for your extremely kind and valuable reply.

Kind regards,

beppe

Amperes involves Volts; Ohm's law?
Power = (V x V)/R or I x I x R
V= I x R (Ohm's law)

R= your speaker load

[beppe61]

Originally posted by Elso Kwak

Amperes involves Volts; Ohm's law?
Power = (V x V)/R or I x I x R
V= I x R (Ohm's law)
R= your speaker load

Dear Mr. Kwak,

thank you for your kind and valuable reply.
My question is: why and amp like the Krell KSA50 is so worldwide famous and the thread here about its clone had so many replies?
For me this means a huge interest in this kind of product.
Why no clone of the Adcom GFA 545 (mine of course and I say this crying)?
Maybe because the need to have a low wattage but very powerful amp with exceptional driving power is real and common among audiophiles.
I understand that most of the real speakers out there are very far from acting like a 8 ohm resistor.
You are completely right: V=RxI but what is R in the real condition?
In the old days I understand Krell became famous as the only amp able to drive properly the Apogee Scintillas, a real speaker that reaches the 1 ohm impedance.
I do not want to say that all the speakers are demanding as the Scintillas but from what I read "any" speaker benefit from being driven by a power amp with ample power (current) reserves.
I have two amps in my house that fail miserably in this regard.
I tried an old Krell KSA50 with my current speakers: what a gloriuos and monumental sound ! I want it.
Now my question is: do I have to spend 1500 euro at minimum for a used old Krell or there is a DIY solution out there that can give me a little of that prodigious driving power at a lower price and of course not very difficult to build because my skills are quite limited?
Another old interesting amp was the Mark Levinson ML2.
A mono monster of 25W/8 ohm that doubles with every halving of the impedance.
To end I am sure that "every" speaker can benefit to be driven by amps like this.
On the other hand I think it is the only way to get that solid bass response I am looking for.
Any your further suggestion would be very precious and much appreciated.
Even a change of speakers if this way is simpler and less expensive.

Kind regards,

beppe

[beppe61]

Looking at the numer of replies and of the readings of this thread
Krell KSA 50 pcb
I would call the thread interesting.
This is very interesting in general because could mean:
1) a lot of people have problem with their speakers
2) a loto fo people like a very solid sound from tehir speakers
3) a very interesting DIY alternative is possible.

Kind regards,

beppe

[pinkmouse]

Beppe, I have a couple of the prototype KrellClone boards here that are tested and working, (well, saying that, I need to solder a few components back on ), and I would be quite willing to sell them to you for my costs if you want. You will need to build the output stage, PSU, and enclosure, but the main and driver boards will be fully built and tested. Drop me a line if you're interested.

[Elso Kwak]

Hi Beppe, the GAS Son of Ampzilla can also drive low-Ohm loads.
But GAS is long dead as company....The Son is class AB though. Saves on your electricity bill.
Occasionally you can buy them for 300 Euro on Ebay.
The schematic is very similar to the Krell.
http://www.audio-circuit.dk/Schemati...f_Ampzilla.pdf

[MikeB]

Originally posted by beppe61


Dear Mr. Mike,
thank you very much for your kind and valuable reply.
I was thinking to something even more simpler for topology.
Very few components and just one pair of output devices/channel.

Thank you so much indeed.
Kind regards,

beppe

Beppe, if you want something that has good driving abilities you shouldn't go too simple... The "complexity" of Krell or symasym is quite the minimum here. Symasym has quite few components and one single pair of output devices... You get more infos with my "www" button.

Mike

[still4given]

Hi beppe,

I have built both the KSA50 clone and Mike's Symasym. I have limited skills as well, though they are better now since I've tackled some of these amps. Both designs sound wonderful. If you are willing to ask questions, there is plent of help here on the forum to build either.

The Symasym will need a lot less in the way of heatsinking than the Krell.

I've been told that the DoZ is a very simple amp to build and it is low voltage high current. Maybe that will get you to where you want to be.

Blessings, Terry