Hello Fleetie,
Do you have pictures of your work to modifie the TEAC's?
And how do you use the amplifiers?? As mono? How are the cabled??
Greetings,
Marcel
Holland
One of them drives the woofers, and the other the tweeters. I wanted to be able to change the levels sent to the woofers and the tweeters separately.
(To do this, I had to go right inside my very-nice-sounding Dynaudio Audience 52SE speakers, which annoyingly were not supplied bi-wirable. I had to cut tracks on the crossover PCBs and add another pair of binding posts to each speaker. Scary, since they were quite expensive. But it went ok.)
I could have used one to drive left and one to drive right, BUT then I would have had to engage the balance controls (both of them, for L and R speakers) to change tweeter level relative to woofer levels. To do that, I'd've had to turn off the "CD direct" button. Now, to change the tweeter level, I just aim the remote and turn the volume up or down. The woofer amp has its remote sensor covered by a square of black electrical insulation tape to stop it reacting.
Basically I am just using them as power amps via the CD input with "CD Direct" enabled, because to change the overall volume level, I use the volume buttons on the remote for the Audiolab M-DAC that drives them.
I am very pleased with the results.
I also changed the speaker binding posts on both units to high-quality gold-plated ones. In doing that, I ended up removing the rather-elaborate-looking Zobel-network-type circuits fitted to the very small PCBs that the existing binding posts were soldered into. That could have meant the amp might start oscillating at high frequencies and blown my tweeters, but I took the gamble and it's been fine.
I found it difficult to install the new speaker binding posts, because the holes punched into the chassis for the original ones were SO large. I had to do a lot of faffing and experimenting with various washers and various types of binding posts, to get a result that was sufficiently strong mechanically.
Oh, and I installed new 3-core mains cables in both, so I could earth the chassis. I did find the amps had alarmingly bad hum issues if the source connected to the phono sockets was not grounded at the 0V connections. Even then, I needed to use another single crocodile clip patching wire from the earth connector on the rear panel, to one of the unused phono sockets' 0V connecter to completely silence the hum. Presumably, since these amps were sold to be parts of complete systems, the earthing then works because of the way the earth/chassis and audio 0v connections were all connected together. Taken on its own, without managing the earth and 0V connections carefully, it does hum badly. In fact sometimes I heard no music at all, just nasty noisy hum.
Now I've got that sorted, the amps are very quiet through the speakers when the input signal is zero, even when the volume is turned right up.
The amps were a bargain at £159 each from the same seller on eBay.
They are really well-built inside.
Oh, and yesterday I bought some matt black spray paint and I'm going to spray the greenish grey metal covers of the amplifiers. Obviously I'm not going to pain the front panels.
