Though at first glance it might seem counter-intuitive, but, for a load like the Thiels you might be better off with a bigger Classe' than two bridged smaller ones. |
Thank you Chadnliz. I have removed my Furman power conditioner from the amplifier. My system still gets hot but no blown fuses yet. I will keep testing. Thanks. |
I have 2 Classe CA 150 amps, I bridged them when I had issues with the one amp going into protection (my speakers require biamp but I only had 1 Classe for some time) so I added a second and bridged them with same result. So the advice you have gotten would probably be correct.
I run a Aragon 400 amp on that area of speaker now with no issue at all.
Speakers are VMPS and the ribbon mids and tweets are where my issue is, they do drop to around 2ohms I believe. |
Thank you Gbart, I think I am down to the biasing issue and the power conditioer. I will chek out both. Thank you for the comments! |
*You can get a technician to check the bias for you. Its not difficult to do but if you're not careful, a slip of a test probe can cause expensive damage. If you need the service manual, send me a PM and I will reply with a copy.
*IMO, the AC supply should not be causing the issues you're experiencing.
*"DC coupled" means having no capacitors in the signal path. A DC coupled preamp or amp will pass/amplify DC. This can be a problem if for example a source component or preamp has high DC offset. The amp will amplify that DC and pass it to your speakers, which can damage them if the DC level is high enough. Many/most modern amps have DC protection circuitry that will open an output relay in the event of severe DC offset. IMO, high DC offset should not be blowing your mosfet fuses. The CA-200 has protection circuitry for that purpose. |
Thank you for all the great comments. Sounds like a second CA-200 is probably not the answer. In response to some of the questions,I have the following information:
* I'm not that technical so I don't know how to check the bias.
* AC may be a problem, I will try to plug the amp into a seperate circuit from the other equipment.
* Not sure what it means for the amp and preamp to be DC coupled, sorry.
* The CA-200 is a side heat sink version.
* The amp is well ventilated.
* I do have a Furman power conditioner which is a relatively new addition. I will bipass that and see if it helps.
Thanks for all the ideas! Sounds like a call to Classe is in order as well. Thanks! |
Since I service my own amps, I've had quite a bit of back and forth with Classé tech support. I am reminded in an old e-mail message from them I have archived, that "in response to reports by some owners that amps were running too hot", they lowered the recommended bias setting for the CA-series amps. It is probably best to contact the factory to discuss the amp issues. |
Is their good airflow around the amp?
The 1 person I know that had Classe swears by its capabilities....and stability. |
As stated above, for many years I have been running Classé with speakers that drop below 3 ohms, also have quite severe phase angle, and never had a failure. |
Hi,
I agree with Ngjockey that bridging will mostly double your voltage whereas you may (MAY) need higher current.
However,from your description it seems that its the raise in temperature trigger the fuse failure.
I would check your power conditioner first - if its regenerator then by removing it you will, most probably will solve the problem.
Next, I would call manufactuurer as no one here knows strenghts and weaknesses of your amps as they are. Prepare SPL/Frequency and Ohm/Frequency data of your speakers. If you can obtain the Phase/Frequency data it would be more informative for Classe people.
I owned Classe a few years ago and it also failed (they save on rail fuses 30 cents or 40 cents) and I had to sent it to them for very expensive repair - I sold it upon return and never touched Classe since and never recommend it to anyone but you have what you have.
Good Luck ! |
I agree with the above. It is probably a good idea to get the amp checked out. It should not be blowing mosfet fuses repeatedly like that. Is the amp adequately ventilated ? Is your CA-200 a rear or side heatsink version ? I have a CA-300 (biased to factory recommended setting by yours truly) and it never gets hot driving my PSB Stratus Gold i's, which drop to around 2.7 ohms in the midbass.
A CA-300 would give you a little more headroom at about 50% of the cost of a second CA-200. Similarly, you could sell the CA-200 and get a CA-400 for roughly the same as a pair of CA-200s. |
Finding it hard to fathom the ruggedly built CA-200's not being able to handle the Thiels. Granted, the Thiels are a fairly tough load but gotta think that something is wrong with the amp. Perhaps, the bias has drifted and needs to be adjusted. Is there an AC issue? Are both amp and preamp DC-coupled?
Anyway, bridging not advisable as that doesn't increase current into low impedance loads and just as likely to make problem worse. The increase in power from bridging is mostly voltage which only helps you keep the volume knob a bit further back. |
