ceramic fuses
Rick,
it is interesting that you mention the ceramic fuses. I have found the same, both with my 2A3 tube amp with tube rectification on the B+, and with my maxed-out mini-Aleph build. Apparently the ceramic body slow-blow fuses (at least the ones from Schurter) are more sensitive than the glass body fuses, also Schurter, with the same ratings. Incidentally, it was also 2.5A fuses on the tube amp. On the Aleph, it's 2.0A that showed the same difference between ceramic body and glass body - the ceramic body ones were blowing at switch-on, but the glass body ones were fine.
A CL-60 on the Aleph as a slow-start cured that ... I just checked, I am using a 1.6A ceramic body fuse on that one. It is built with a 500W transformer, 2 x 100,000 µF with chokes in the middle in CCLC configuration, and approx. 42W dissipation on the Mosfets, so about 170W by them on the 2 channels together ... 🙂
Best regards,
Claas
Rick,
it is interesting that you mention the ceramic fuses. I have found the same, both with my 2A3 tube amp with tube rectification on the B+, and with my maxed-out mini-Aleph build. Apparently the ceramic body slow-blow fuses (at least the ones from Schurter) are more sensitive than the glass body fuses, also Schurter, with the same ratings. Incidentally, it was also 2.5A fuses on the tube amp. On the Aleph, it's 2.0A that showed the same difference between ceramic body and glass body - the ceramic body ones were blowing at switch-on, but the glass body ones were fine.
A CL-60 on the Aleph as a slow-start cured that ... I just checked, I am using a 1.6A ceramic body fuse on that one. It is built with a 500W transformer, 2 x 100,000 µF with chokes in the middle in CCLC configuration, and approx. 42W dissipation on the Mosfets, so about 170W by them on the 2 channels together ... 🙂
Best regards,
Claas
Claas,
Thanks for that.
Funny thing is, I am using a 300VA transformer with three CL60s in series and the things blew. I went through two and then figured I had done something wrong - could not imagine what.
Walked away for about an half hour and then thought, "why not try the one that was in there" to be delighted when the meter started moving up.
Needless to say I am not going to try any $25.00 dollars fuses in this amp!!!
With another night's listening I am more convinced this was worth the trouble. The amp with the choke input supply just sounds better. AS good as the SIT1 is it can still be better with a good old fashioned brute force power supply - just like about any other music amplifier in my unhumble opinion!
Take care,
Thanks for that.
Funny thing is, I am using a 300VA transformer with three CL60s in series and the things blew. I went through two and then figured I had done something wrong - could not imagine what.
Walked away for about an half hour and then thought, "why not try the one that was in there" to be delighted when the meter started moving up.
Needless to say I am not going to try any $25.00 dollars fuses in this amp!!!
With another night's listening I am more convinced this was worth the trouble. The amp with the choke input supply just sounds better. AS good as the SIT1 is it can still be better with a good old fashioned brute force power supply - just like about any other music amplifier in my unhumble opinion!
Take care,
Hello,
Toroidal transformers, especially bigger ones often make fuses go dead. Even with choke input which should slow down the charging proces of the caps. One more reason to start using R core transformers!
Still no new about my Vietnamese friend about his Lundahl chokes.
It seems that are not a lot of people willing to try true choke input.
I honestly think that a smaller R core with the right choke will sound better than a massive toroidal with no choke at all.
Greetings, Eduard
Toroidal transformers, especially bigger ones often make fuses go dead. Even with choke input which should slow down the charging proces of the caps. One more reason to start using R core transformers!
Still no new about my Vietnamese friend about his Lundahl chokes.
It seems that are not a lot of people willing to try true choke input.
I honestly think that a smaller R core with the right choke will sound better than a massive toroidal with no choke at all.
Greetings, Eduard
Hello,
I find nothing wrong with moderate R core and a massive choke. The late Allen Wright told us that the choke should be bigger than the transformer. Of course he was building tube gear where the power transformers and chokes are more same seize.
Once i did ask Lundahl if they were willing to use a bigger core to make a high current choke but they were not interested. Higher inductance and lower dcr than the present ones would be nice.
Greetings, Eduard
I find nothing wrong with moderate R core and a massive choke. The late Allen Wright told us that the choke should be bigger than the transformer. Of course he was building tube gear where the power transformers and chokes are more same seize.
Once i did ask Lundahl if they were willing to use a bigger core to make a high current choke but they were not interested. Higher inductance and lower dcr than the present ones would be nice.
Greetings, Eduard
So as to not start another thread for a simple question I will post here.
Is there any reason not to have a high impedance load, in my case at the moment, of 27 Ohms to the amplifier? A JBL 2441 and an Lpad composed of 50R parallel and 15R series.
My intuition is that the amp would like it but I know better than to trust my intuition.
Thanks,
Is there any reason not to have a high impedance load, in my case at the moment, of 27 Ohms to the amplifier? A JBL 2441 and an Lpad composed of 50R parallel and 15R series.
My intuition is that the amp would like it but I know better than to trust my intuition.
Thanks,
I like using ceramic fuses for ability to withstand vibrations. Never had a problem with Littel fuses. Used in several FW amps and F5T v2. Don't know if I ever used Schruter. Have used their fuse bodies. Using CL-60 for slow turn on.
Don't use slow turn on with both L'amps. No problems there.
Vince
role of properly sized factory made adjustable Lpad is to maintain loading impedance ..... meaning that impedance is still defined by driver itself
thus these Lpads are different/declared for/as 4 Ohms , 8 Ohms , 16 Ohms
if you are calculating your own fixed L Pad attenuating cell , you're always inputing driver's impedance value,besides wanted amount of attenuation
on the other hand , I see no reason that amplifier isn't happy having easier load
max power is declining , but THD is declining too
thus these Lpads are different/declared for/as 4 Ohms , 8 Ohms , 16 Ohms
if you are calculating your own fixed L Pad attenuating cell , you're always inputing driver's impedance value,besides wanted amount of attenuation
on the other hand , I see no reason that amplifier isn't happy having easier load
max power is declining , but THD is declining too
It is not a question so much as "like" but rather that the amplifier will
respond a little differently in terms of gain (limited df) and the 2nd harmonic
will display a different amplitude and maybe phase.
AS ALWAYS, thanks for you answers to my myriad questions.
I am not going stratospheric - about 24 ohms peak at 1kHz.
I am not going stratospheric - about 24 ohms peak at 1kHz.
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