TFM-45 Problems???

I recently received a TFM-45 via UPS Ground and found the amp
to have, what I believe, are several problems. I'm very confident
the amplifier was in excellent shape when sent as the previous
owner only sold it as he accquired a Lightstar Reference 2.0 amp.

First, the VU meter lights do not illuminate. I removed the cover
and examined the lamps to find one of the blubs has a broken
filament. Okay..no big deal....simple lamp replacements.

I then connected the amp to my C-4000t preamp, TX-12 tuner
and Polk SDA-2B speakers. The amp sounds great, but
demonstrates a few odd characteristics. When powered-on there
is a buzzing sound for about 2 seconds. The left channel seems to
be 5db +/- lower than the right channel. I had to adjust the preamp
balance control at 10:30 - 11 to achieve volume balance.
When powered-down the amp produces a shuttering sound
(Shssss-Thut-tut-tut-tut-tut....tut....tut) starting in the right
channel and migrating to the left channel. Also, when powered-off,
the VU meters jump to a 5-8 watt reading and then slowly (10-15
seconds) dissapate to zero with the right channel meter returning
to zero faster than the left channel.

Are these symptoms normal for a TFM-45?
Can anyone give me a general diagnosis?
I'm concerend that the package had impact during shipping and
the amp needs to vist Rita's repair shop. If so, I would need to
file a damage claim with UPS.

What do you think?????

Well, a couple of things. First the amp probably needs alignment, both the power supply idle voltage and the bias current. That should take care of the balance problem unless the caps are going bad, which could cause the noise problem you describe on shutdown as the caps collapse assymetrically, rather than gracefully lose their charge.

I'd get a service manual and do the tuneup first and see how it sounds. There might be some service bulletins about your shutdown problems, I don't know as I've never had a TFM-45. Just my 2¢ worth.

Absolutely agree with Billd: the L-R channel imbalance is almost certainly due to need for a bias/damping adjustment (ESPECIALLY if your unit has not had the service bulletin (SB) "fix" done for the damping adjustment sensitivity). When I got my 45 it had the same channel imbalance of several db (balance controls were just enough to correct!). I did the damping adjustment (and the others) several times before doing the damping SB "fix". That was almost a year ago and I have not had this issue since (the way i knew it needed damping adjustment was when one channel was louder or softer then the other AND the sound quality had "degraded" to the point where it had to addressed!). My 45 has been 100% "even keeled " since this damping SB "fix" (which involves "downgrading" the pot to a lower value and adding a "constant" resistor in the loop to make up the difference = lower sensitivity to pot - and "other" changes).
Ed

I recently received a TFM-45 via UPS Ground and found the amp
to have, what I believe, are several problems. I'm very confident
the amplifier was in excellent shape when sent as the previous
owner only sold it as he accquired a Lightstar Reference 2.0 amp.

First, the VU meter lights do not illuminate. I removed the cover
and examined the lamps to find one of the blubs has a broken
filament. Okay..no big deal....simple lamp replacements.

I then connected the amp to my C-4000t preamp, TX-12 tuner
and Polk SDA-2B speakers. The amp sounds great, but
demonstrates a few odd characteristics. When powered-on there
is a buzzing sound for about 2 seconds. The left channel seems to
be 5db +/- lower than the right channel. I had to adjust the preamp
balance control at 10:30 - 11 to achieve volume balance.
When powered-down the amp produces a shuttering sound
(Shssss-Thut-tut-tut-tut-tut....tut....tut) starting in the right
channel and migrating to the left channel. Also, when powered-off,
the VU meters jump to a 5-8 watt reading and then slowly (10-15
seconds) dissapate to zero with the right channel meter returning
to zero faster than the left channel.

Are these symptoms normal for a TFM-45?
Can anyone give me a general diagnosis?
I'm concerend that the package had impact during shipping and
the amp needs to vist Rita's repair shop. If so, I would need to
file a damage claim with UPS.

What do you think?????

I am dismayed this happened. Dennis told me the packaging showed slight damage to several places on the boxing but you wouldn't think it was enough to break a lamp. More and more it seems the carriers are getting lax in their attention to caring for thier packages. I take really good care of my gear and want the next owner to be able to enjoy it also. Damn shame UPS has to fuck it up.

ray

Does the 45 have dual knobs on the gain pot? If so, are they both in sync? If they're not both hitting the stop when turned all the way to the left,the channels will be at diff. levels. Might be as simple as that....or not. My ailing 55 makes some racket on startup for a few seconds but doesn't do it on shutdown. It's destined for a trip to Rita, soon I hope. Good luck !

No gain pots on the 45, gdb

Thanks to BillD and elgrau for the info.

Can anyone tell me if it is normal for a TFM-45 to have
a prolonged reverberating buzz after power-on?
One of my M-1.5t, which needs an opamp replaced, has
a muted power-on buzz, but nothing like what I'm hearing
from this TFM-45.

Thanks again...
Dennis

....wonder if this is why there have been so many 42's and 45's
on ebay lately?

Might be. New owners might not realize it's normal. My 55s went to Rita to be repaired 2 years ago, did it whren they left, did it when they returned. The 45 was no different than my 55s, they ALL DO IT. Lights dim, amp clicks then a 1-2 second buzz. Amp comes on, everything is cool. Nature of the beast. The 45 isn't as loud as the 55 though.

M 500 t doesn't make a sound. hmmm.

Someone wanna ask Bob about this....James?

ray

Neither my 45 nor 42 has any (audible that I can hear) "buzzing" @ turn on. The 45 perhaps the faintest of buzz/hum that lasts at most one second when it's COLD*. Nothing when turned on if warmed up even a little. Nothing from the "Rollandized" 42 at any time. This buzz/hum could indicate an out of adjustment damping pot (Rolland replaced this pot with "fixed" resistance on the 42; I did the service bulletin "fix" for this issue on my 45). I did notice once (before SB "fix") when I turned this pot the wrong direction when adjusting it (and the adjustment hence went "way" out of range) that I did hear a loud "buzzing" from the circut/transformer/something. If your 42/45 does buzz, might want to check this damping adjustment (the one that requires a 1V RMS output with an 8 ohm load across the speaker terminals for a 35 mv (I believe) 2000 Hz input signal).

*whch "fits" because they require the damping adjustment be made AFTER the unit has warmed up. So when cold, it could be very slightly "off" and thus "buzz" a bit before it warms up and thus gets "back in range" for this adjustment?

There is a slight hum in some of my amps as the come up. The ones with relays more so than ones without. For instance my M-500 hums a little when it comes up before the relay kicks in, as does my A-500x. Nothing on the M-400s or the C-500 or the Sunfire though.