I have a pair of Acoustat 2's with the 121 a supply. Is there a thread here about powering them up after 12 years of sitting. I think I read a post about a fire issue on this model? I will also need a thread to all recommended mods for the 121 a if parts are still available. I have a variac and a inline bulb extension. How much do they draw? Thank you for your response.
I think you can plug them in without any issues, so long as they have not seen any extensive water intrusion from storage in a leaky garage or unconditioned space.
Roy Esposito in Florida services Acoustat interfaces.
Roy A. Esposito <acoustat.service.usa@gmail.com>
Good luck.
Roy Esposito in Florida services Acoustat interfaces.
Roy A. Esposito <acoustat.service.usa@gmail.com>
Good luck.
The MK121 series of interface has been used for many years on many Acoustat models, and I have never heard of a 'fire issue'. Yes, they could catch on fire if you drive them with a bazillion watts, but so will any speaker.
The bias power supply draws only a few watts, and I don't think you need to use a Variac or bulb for current limiting. If there's a real problem, the internal 1/4-amp slow-blow fuses should blow. You might want to check the fuses for correct value before power-up. Allow several hours of charging before making any evaluation of the sonic performance of the speaker.
Acoustat USA has been out of business since the very early 90's, and except for generic items, parts are not readily available. As mentioned in the previous post, Roy Esposito, a former Acoustat employee, is a good source for upgrades and repairs if you reside in the USA.
what may be an issue is the caps that form part of the multiplier string on the HV supply. They tend to short and the diodes tend to blow.
Older supplies may or may not actually run up to the full voltage. That depends on the condition of the multiplier string parts: HV diodes + caps.
But there is no danger in firing it up. Worst case you get less than full voltage, which means a channel imbalance, unless they both happen to have the same voltage deficit.
I'd order some appropriate high voltage diodes and caps, and "shotgun" desolder and replace all the parts.
Another issue with older panels is that sometimes the styrene glue that holds the wire stators to the plastic lattice, usually at the ends of the cells, breaks off. In this situation the wires may cause an audible buzz at low bass freqs... repair is possible, but requires some skill and time.
_-_-
Older supplies may or may not actually run up to the full voltage. That depends on the condition of the multiplier string parts: HV diodes + caps.
But there is no danger in firing it up. Worst case you get less than full voltage, which means a channel imbalance, unless they both happen to have the same voltage deficit.
I'd order some appropriate high voltage diodes and caps, and "shotgun" desolder and replace all the parts.
Another issue with older panels is that sometimes the styrene glue that holds the wire stators to the plastic lattice, usually at the ends of the cells, breaks off. In this situation the wires may cause an audible buzz at low bass freqs... repair is possible, but requires some skill and time.
_-_-
- Status
- Not open for further replies.