Hello 🙂
I'm thinking about building a Class A integrated, or an A/B strongly biased towards Class A.
I currently own a Nad C326 BEE (with upgraded caps) and would like some more transparency, without losing warmth...
- It will feed a pair of Seas A26 (home built, I opened a thread on this forum), which are speakers very easy to drive
- I don't need too much power, my 50W Nad rarely goes over 10 o'clock and I can't remember I went above 11 o'clock... So I guess 30W or even less would be suitable.
- Budget is not unlimited, I'd say under 500€/$.
I'm interested in the Sugden A21 so far....
Are there any kit for this particular design?
Or would you recommend another design?
Maybe should I start with the amp section in the first place (together with the preamp section from the Nad which is maybe not its weakest point) ?
Or should I go for the preamp as well?
Anyway, any advice would be welcome!
I'm thinking about building a Class A integrated, or an A/B strongly biased towards Class A.
I currently own a Nad C326 BEE (with upgraded caps) and would like some more transparency, without losing warmth...
- It will feed a pair of Seas A26 (home built, I opened a thread on this forum), which are speakers very easy to drive
- I don't need too much power, my 50W Nad rarely goes over 10 o'clock and I can't remember I went above 11 o'clock... So I guess 30W or even less would be suitable.
- Budget is not unlimited, I'd say under 500€/$.
I'm interested in the Sugden A21 so far....
Are there any kit for this particular design?
Or would you recommend another design?
Maybe should I start with the amp section in the first place (together with the preamp section from the Nad which is maybe not its weakest point) ?
Or should I go for the preamp as well?
Anyway, any advice would be welcome!
In my experience even lightly biased class AB sounds fine.
I run mosfet amp output pairs on 10mA and it sounds good.
I run mosfet amp output pairs on 10mA and it sounds good.
EaZy prefers a class A/AB, so a Krell clone of 50W or the like can be possible, and pinching the bias current renders it in a A/AB thing.
EaZy.
What does the impedance of your SEAS build look like? The sim Lozek posted is not flat. (your picture links are broken)
If that is the case, you want an amp with lowish output impedance.
This forum is rich with Class A amplifiers that can easily be made into an integrated, many as simple as adding a potentiometer to the front.
Many Nelson Pass amps (the ACA is an inexpensive killer, but you might need to run a paralleled pair to get the Rout out lower. JHL, Hiraga, Fx, Alpha Nirvana, SEWA, more Pass designs and inspirations, and more.
An AB amplifier almost universally has GM droop when the bias moves out of Class A. My dual mono bass amp is biased heavily into Class A, but if you do not need the power then i’d go Class A.
dave
What does the impedance of your SEAS build look like? The sim Lozek posted is not flat. (your picture links are broken)
If that is the case, you want an amp with lowish output impedance.
This forum is rich with Class A amplifiers that can easily be made into an integrated, many as simple as adding a potentiometer to the front.
Many Nelson Pass amps (the ACA is an inexpensive killer, but you might need to run a paralleled pair to get the Rout out lower. JHL, Hiraga, Fx, Alpha Nirvana, SEWA, more Pass designs and inspirations, and more.
An AB amplifier almost universally has GM droop when the bias moves out of Class A. My dual mono bass amp is biased heavily into Class A, but if you do not need the power then i’d go Class A.
dave
My Nad has an idle current between 300 and 350mA (nominal values, I should check them). Is that too much?
Simulation results were on a previous windows laptop whose I lost datas. So far I can remember, the impedance curve was around 8 Ohms with a drop at 4 Ohms around the fc (2 kHz).
However is it reasonable to implement a hot Class A amp section in my actual chassis ?
What about Sugden A21a / A21se design then? The concept of avoiding symmetricizing-desymmetricizing (sorry for my english!) signals appeals to me !
That concerns me much less than the bif rise often seen near the XO caused by the XO. With a high output impedance that will boost the FR just where your ear is most sensitive.
I am not the one to answer that. All i wil say, is that you probably don’t need as much power as you think, many good Class A amps clip very gracefully, and the power output directly impacts the size of the PS and heatsinks required.
They have always been on my radar, but i have never heard one. There are some thread son cloning them, and if well done should be another good choice.
dave