Lafayette LA-90 vintage integrated tube amplifier

[bsco]

good afternoon....I am searching for believe it or not, a power transformer for this unit...the original Lafayette part # is PT-164-3....and help would be greatly appreciated...

 

[TLS Guy]

good afternoon....I am searching for believe it or not, a power transformer for this unit...the original Lafayette part # is PT-164-3....and help would be greatly appreciated...

I did a search and see there are some others looking for that power transformer. Those units were not top end units even back in the day. Lafayette was a bottom feeder brand and sold bottom of the market reel to reel tapes also, which you avoided if you valued your tape heads and guides. It was close to sandpaper.

 

[bsco]

I did a search and see there are some others looking for that power transformer. Those units were not top end units even back in the day. Lafayette was a bottom feeder brand and sold bottom of the market reel to reel tapes also, which you avoided if you valued your tape heads and guides. It was close to sandpaper.

I realize that they were not top of the line by any means but would be a good candidate for a restoration.and this is a hobby for me now and this unit belongs to a friend of mine.....so I am trying to fix it up for him......

 

[TLS Guy]

I realize that they were not top of the line by any means but would be a good candidate for a restoration.and this is a hobby for me now and this unit belongs to a friend of mine.....so I am trying to fix it up for him......

I could not find a circuit for that unit, at least not one I could get for free. Do you know the LT and HT voltages and whether the secondary is center tapped or not?
You might have to modify the unit to take a different transformer with the same voltages and configuration. More likely that is what you will have to do, if it is possible. I suspect those transformers were substandard to start with, as others are looking for them and power transformer failures are unusual even on older gear.
All I can say is good luck.

 

[bsco]

the secondaries are 600VAC CT at .016 A.....6.3 AC..CT at 2.8A and 6.3VAC CT at 2.7 A..so all secondaries are center tapped....would a 5V center tapped @ say 5 or 6 amps work....that way the 5V CT could supply heater current to all the tubes with one winding instead of needing two for this application........just curious....

 

[TLS Guy]

the secondaries are 600VAC CT at .016 A.....6.3 AC..CT at 2.8A and 6.3VAC CT at 2.7 A..so all secondaries are center tapped....would a 5V center tapped @ say 5 or 6 amps work....that way the 5V CT could supply heater current to all the tubes with one winding instead of needing two for this application........just curious....

That is really unusual to have two heater circuits. Is one rectified and smoothed and not the other? If one is rectified, and or smoothed, then you still could use a 6 amp or more rated transformer. It is always an upgrade to rectify and smooth the heater supplies. It causes less noise and makes the tubes last longer.

That high tension winding is very low current draw. That would leave virtually no margin and is probably the reason for the failure. I guess junk products have always been with us and I guess always will be.

 

[bsco]

That is really unusual to have two heater circuits. Is one rectified and smoothed and not the other? If one is rectified, and or smoothed, then you still could use a 6 amp or more rated transformer. It is always an upgrade to rectify and smooth the heater supplies. It causes less noise and makes the tubes last longer.

That high tension winding is very low current draw. That would leave virtually no margin and is probably the reason for the failure. I guess junk products have always been with us and I guess always will be.

all the heaters are AC powered.....I will see if I can upload the schematic later...getting ready for a musical performance for later this evening...

 

[bsco]

I couldn't get the schematic uploaded for some reason.....and it has been awhile since I took another crack at this as I have been busy.....anyway, I dis-connected the transformer secondaries from the circuit and tried to measure the secondary voltages.....when I increased the AC supply voltage from the Variac to 120V, the transformer started to smoke....so I shut off the Variac right away.....the transformer that is currently in there is a Hammond...model is 273BZ......Type Z......CL A........(I guess that must be a specific class), VA is 133..... Pri V is 115V @60 Hz....this is not the proper transformer for this unit.....any suggestions of other repair forums that I can check?? I would rather get the original if I could......anyway, thanking everybody in advance for the help...in the meantime, I will see if I can find something that will work but to be quite honest I have never had to do that sort of thing before....

 

[TLS Guy]

I couldn't get the schematic uploaded for some reason.....and it has been awhile since I took another crack at this as I have been busy.....anyway, I dis-connected the transformer secondaries from the circuit and tried to measure the secondary voltages.....when I increased the AC supply voltage from the Variac to 120V, the transformer started to smoke....so I shut off the Variac right away.....the transformer that is currently in there is a Hammond...model is 273BZ......Type Z......CL A........(I guess that must be a specific class), VA is 133..... Pri V is 115V @60 Hz....this is not the proper transformer for this unit.....any suggestions of other repair forums that I can check?? I would rather get the original if I could......anyway, thanking everybody in advance for the help...in the meantime, I will see if I can find something that will work but to be quite honest I have never had to do that sort of thing before....

Honestly, I think you are wasting your time. If that is not the correct transformer it could have done all kinds of damage.

This unit was junk when it wa new, and if you could restore it, it will still be junk, just antique junk. I think the unit needs a decent burial. It is not a sort after vintage piece of kit. One of the first and most important things you must learn is what is worth the restorers hand and what is not. As far as I'm concerned, this is well in the not category. So I restrict my restoration time, to truly iconic pieces.

 

[bsco]

you are probably right...I am trying to do this for a friend....He already knows that it might not be repairable.....but I told him I would see what I can do.....Cheers...