One of the pair of Audio Innovations 1st Audio monoblocks I bought makes quite a whoosh on power up through the speakers. This is.a new development. I’ve swapped the valves between the pair and it makes no change. I’ve opened it up and it’s all very clean and tidy. No obvious signs of bulging or leaking caps no brown resistors. The 220uf 400v. caps look to be the same brand I swapped out from my Audio Innovations 500 that I’ve owned from new. Any ideas where I should start looking? I’m not competent enough to poke around with them plugged in but more than capable of swapping out a few parts a day or so after any caps have discharged. Couple of valves are a bit wobbly but it looks like the contacts moving inside the base not bad connections.
Whoosh from Audio Innovations amp on startup
- Thread starter SteveLuck
- Start date
Locheeboy
pfm Member
More info Steve,
Are the monoblocks new? Valve type and model. Have ye narrowed down the valves to which one(s) are causing the problem? Normally, ah’d say … 1. ye need new valves. 2. Ye need new valves. 3. ye need new valves. but I have no experience of these monoblocks. It could be a recurring fault with these amps.
Do you have a valve tester? Know someone who has one ? If not go to (or send valves to ) a local dealer and have the valves tested. Get the valves eliminated before anything else..
Are the monoblocks new? Valve type and model. Have ye narrowed down the valves to which one(s) are causing the problem? Normally, ah’d say … 1. ye need new valves. 2. Ye need new valves. 3. ye need new valves. but I have no experience of these monoblocks. It could be a recurring fault with these amps.
Do you have a valve tester? Know someone who has one ? If not go to (or send valves to ) a local dealer and have the valves tested. Get the valves eliminated before anything else..
Hi Guys not the valves as I’ve swapped them between the pair of monoblocks and the same block is still noisy. Power supply diagram I have shows only one rectifier and caps for the Audio circuit the rest are just heater/filament supplies. My guess is this inrush current coming from the two big 220uf 400v caps that feed the audio circuit? Would a rectifier make noise?
That’s the one turn on quiet for a second or two then the noise and pretty quiet after that. I’m going to order some replacement main caps. I’ve found some direct replacements with screw terminals like the originals. I think what’s in there is very likely to be 30yrs old plus. Easy swap with a screwdriver.
I’ve ordered some Kemet/RIFA caps which are long life low ESR. Amp is clean as a whistle inside with some work done in the not to distant past to make them hybrids of the original early amps with original power tubes 6C4C and newer different driver/phase splitter tubes all ECC802S. Safety and convenience in mind new main caps could be a very easy win. Only a total of four caps in the power supply of each monoblock. If it gets more complicated than swapping those out I’ll find a technician.