Cool-running Krell - Oxymoron?
- Thread starter Soun!
- Start date
FootFungus
Super Member
The KSA-50S sort of will. It uses the plateau bias system.
Soun!
New Member
Thank you very kindly, dear experts!
@bhunter - Would you consider the Threshold SA 3 a cool-running one? It does about 50 W/ch in class-A, if I am correct. And it has no fans: completely silent!
@Kev_rat - It is very interesting your monster runs so cool! How noisy is it under normal working conditions? What's her name?
@FootFungus - Can you confirm the KSA-50S is a forced convection-cooled design (same as the original KSA-50)?
Are there any (relatively) cool-running fan-less solid-state power amplifiers providing up to 50 W/ch in class-A you would recommend me to consider, please?
Please chime in!
@bhunter - Would you consider the Threshold SA 3 a cool-running one? It does about 50 W/ch in class-A, if I am correct. And it has no fans: completely silent!
@Kev_rat - It is very interesting your monster runs so cool! How noisy is it under normal working conditions? What's her name?
@FootFungus - Can you confirm the KSA-50S is a forced convection-cooled design (same as the original KSA-50)?
Are there any (relatively) cool-running fan-less solid-state power amplifiers providing up to 50 W/ch in class-A you would recommend me to consider, please?
Please chime in!
I have a Bedini 45/45 that runs fairly cool. I like it more than the Krells I have had in the past except for the old KSA 250. That 250 was one of the best amps I have ever heard but puts out a lot of heat, so not for you.
FootFungus
Super Member
The KSA-50S is not forced air cooled like the original. It raises and lowers the bias based on signal input to 1 of 4 levels. Only the original KSA series and their most recent designs are force air cooled.
The SA-3 would be cool-running by your definition. The earlier units (I and II) were biased to 42 degrees and the later optical versions were biased to 49 degrees which you could lower if you wanted.
The SA-3 would be cool-running by your definition. The earlier units (I and II) were biased to 42 degrees and the later optical versions were biased to 49 degrees which you could lower if you wanted.
Soun!
New Member
I must confess I have never heard of Bedini... Could you please elaborate a bit on the SOUND they deliver? Better than Krell: it says a lot...
Now the problem is to get one, which is a nontrivial task in my neck of the woods...
Kev_rat
Active Member
N
totally quiet
no fans involved at all
Good idea - I must think up a name
Must not be running it hard - plus the plateau biasingThank you very kindly, dear experts!
@bhunter - Would you consider the Threshold SA 3 a cool-running one? It does about 50 W/ch in class-A, if I am correct. And it has no fans: completely silent!
@Kev_rat - It is very interesting your monster runs so cool! How noisy is it under normal working conditions? What's her name?
@FootFungus - Can you confirm the KSA-50S is a forced convection-cooled design (same as the original KSA-50)?
Are there any (relatively) cool-running fan-less solid-state power amplifiers providing up to 50 W/ch in class-A you would recommend me to consider, please?
Please chime in!
totally quiet
no fans involved at all
Good idea - I must think up a name
Similar to Nelson Pass's sound, which I'm a very big fan of. Smooth like most well designed class A amps.
You might find out more info on these if you Google Bedini 25/25. A lot more of them were made than the 45/45. They made some more powerful ones and have read good reviews of them but have not heard any of 'them'. The 25 and 45 are his pure class A designs...less power but the sweet spot in their line up, IMO.
Re Krell... I first owned their 300s, didn't care for it's sound, sold it a few months later. Then had a FPB600 on loan for a month or so, better but still not to my taste. A good friend (in the know) offered me a KSA250 for a good price. I told him I just wasn't a "Krell" guy. He knew me well and said he would pay shipping back if I didn't like it. I tried it and kept it for 7 yrs and always enjoyed listening to it.
FWIW, I currently own two of Pass's XA.5 amps and love them...and I'm a tube guy.
Good luck in your search.
Soun!
New Member
Thank you, dear experts!
@onemug - Could you please recommend me the best outfit to get Bedini amp from? Is there anything similar to Reno Hi-Fi for PASS Labs gear, but for Bedini?
Wow! If Bedini 45/45 is anything like XA.5, I am definitely in!
@onemug - Could you please recommend me the best outfit to get Bedini amp from? Is there anything similar to Reno Hi-Fi for PASS Labs gear, but for Bedini?
KentTeffeteller
Gimpus Stereophilus!
Krell is a hot running amplifier. Many run Class A and they're biased high enough to run hot.
Bedini stopped making amps some time ago so there won't be any places selling them. Your hope is to find one used. I don't see them that often but they do pop up every once in a while.
Soun!
New Member
I use tube preamps... a Conrad Johnson ART 3 with my 100.5's and an Audio Research LS7 with some 'special' caps in it for the 30.5.
In a big surprise to me...I have a vintage Marantz tube set up in the same room. I ran interconnects from the Marantz 7 into the 30.5 once 'just wondering'. Turned out to be a very special pairing. So I do that every once in awhile.
Live and learn...2 very important words, especially the first one.
I'll take an excellent sounding single ended design over a good sounding balanced one every day.
Soun!
New Member
Thank you, @onemug !
While I am looking for the beautiful Bedini 45/45, I need to clarify if this amp is compatible with my Primare PRE30 pre-amplifier and Monitor Audio Silver RS6 speakers.
In my understanding, this depends on the output impedance of the pre-amplifier and the speaker’s impedance. I was unable to find any data on my pre-amplifier, but for Primare PRE32,
the closest “relative”, the Output Impedance is 110 Ohms. Speaker’s impedance swings between about 4 and 14 Ohms.
Could you please help me understand if 45/45 is indeed compatible with my components, and, most importantly, if PRE30 is a good pair for the 45/45 or I should be looking for some other pre-amplifier instead?
While I am looking for the beautiful Bedini 45/45, I need to clarify if this amp is compatible with my Primare PRE30 pre-amplifier and Monitor Audio Silver RS6 speakers.
In my understanding, this depends on the output impedance of the pre-amplifier and the speaker’s impedance. I was unable to find any data on my pre-amplifier, but for Primare PRE32,
the closest “relative”, the Output Impedance is 110 Ohms. Speaker’s impedance swings between about 4 and 14 Ohms.
Could you please help me understand if 45/45 is indeed compatible with my components, and, most importantly, if PRE30 is a good pair for the 45/45 or I should be looking for some other pre-amplifier instead?
Not really. Follow the signal flow, or 'chain of command'
...the preamp drives the amp, the amp drives the speaker. The preamp does not 'see' the speaker, only the amp, and the spec you would want to look at is the 'input impedance' of the amp to be compatible with your pre's output impedance. General thought is you want a minimum ratio of 10 to 1 with the amp being the 10x more. So the PRE32 having 110 ohms, you would want the amps input to be at least 1100 and I've never ever heard of an amp with that low of an impedance. Your PRE30 should be compatible with just about any amp. For the record, the Bedini's is around 50,000 ohms.I would highly second the recommendation of the Threshold SA3. I've heard it and think it sounds wonderful and would probably be easier to find.
Just to share...After replying to your post, I got to thinking about my Bedini. I haven't listened to it for over 3 yrs, it's just been sitting around as a spare in case something goes bump in the night. Curiosity got to me and hooked it up. It brought a big smile to my face, still love it. Turns out we have been experiencing an extra strong/long heat wave here in So Cal. Our house as excellent A/C and I can listen to my tube amps or Pass's without a problem but let's just say the Bedini has been playing every day for the last 8 days. So this was serendipitous to say the least.
btw, you haven't stated a budget. It may help with some recommendations.
Soun!
New Member
Thank you very kindly, @onemug !
Now I understand the power amp - pre-amp compatibility requirements: a minimum 10:1 impedance ratio. Very simple indeed. I wonder if there is a recommended maximum ratio?
And another question regarding tubed pre-amps: what is the average lifespan of the tubes employed (what are the factors in play here: work hours, amount of On/Off cycles…), and what is the required maintenance (bias current adjustment, e.g.)?
My budget for a power amp is limited: up to about 1.5K only, I am afraid…
Now I understand the power amp - pre-amp compatibility requirements: a minimum 10:1 impedance ratio. Very simple indeed. I wonder if there is a recommended maximum ratio?
I see you prefer tubed pre-amps, and am wondering what their “characteristic” output impedance is? What if it is much higher than the solid-state designs have, like in the kOhms area? What is the input impedance of your EXCELLENT (!!!) XA30.5 power amp? About the same as Bedini’s, i.e. 50 kOhm, I would guess?
And another question regarding tubed pre-amps: what is the average lifespan of the tubes employed (what are the factors in play here: work hours, amount of On/Off cycles…), and what is the required maintenance (bias current adjustment, e.g.)?
Yes, thank you, I will expand my search accordingly. So far I have got no responses on my request for 45/45, unfortunately enough... Hopefully, I will have some luck with SA3...
What?! I cannot believe you!
That is more like it! I see you really enjoy the SOUND of your 45/45!
My budget for a power amp is limited: up to about 1.5K only, I am afraid…