There is a misunderstanding.
The trafo's came from 100V distribution amps.
At least 2 of them have 100V, 70V and 50V secondary windings.
So these could be used for a PP tube amp, if I'm not mistaken. Maybe even ultra linear...
The other 2 only have 100V, but I'm not sure. I'll get back here on monday with the correct info.
The trafo's came from 100V distribution amps.
At least 2 of them have 100V, 70V and 50V secondary windings.
So these could be used for a PP tube amp, if I'm not mistaken. Maybe even ultra linear...
The other 2 only have 100V, but I'm not sure. I'll get back here on monday with the correct info.
You said previously that the windings don't feature taps. Now, on a sudden, they do? Well, we have spring on the northern hemisphere. Maybe your transformers have grown branches??
Anyway, the transformed impedances, measured between the 100 V taps, are those that I've wrote above. Not really useful for a PP tube amplifier
.
Best regards!
Anyway, the transformed impedances, measured between the 100 V taps, are those that I've wrote above. Not really useful for a PP tube amplifier
.Best regards!
Sorry for the misleading info I provided.
Better and more detailed info:
The 2 bigger trafo's are rated 100V at 33Ohm and have 1 primary winding connected to the output of the amp. The 100V windings are dual, so these can be used as a PP output trafo (I think). The amp is a Siemens XV600, can't find any info on that, but it's beautiful designed amp with a high quality symmetric circuitboard layout. A lover of amps designed this thing.
Other than this, there are no numbers on the trafo's or any other part of the amp.
The other 2 trafo's come from a QSC CX6T. These trafo's have 5 cables coming out. 2 of them are connected to the amp output, the other are the 0V, 70V and 100V outputs. Info here: Amplifiers - Discontinued Products - QSC
I have already removed the 45Hz 3 pole highpass input filter from this amp.
Edit: Trafo part number QSC p/n: XF-000024-00 Magnetic Core Corporation MCC p/n: 32002 revision D
So what can I do with these trafo's?
Right now I'm thinking a PP amp from the big trafo's and maybe a small SE amp from the smaler trafo's, but I'm basically clueless. For instance what is the impedance from these trafo's, how do I measure this, etc etc...
Better and more detailed info:
The 2 bigger trafo's are rated 100V at 33Ohm and have 1 primary winding connected to the output of the amp. The 100V windings are dual, so these can be used as a PP output trafo (I think). The amp is a Siemens XV600, can't find any info on that, but it's beautiful designed amp with a high quality symmetric circuitboard layout. A lover of amps designed this thing.
Other than this, there are no numbers on the trafo's or any other part of the amp.
The other 2 trafo's come from a QSC CX6T. These trafo's have 5 cables coming out. 2 of them are connected to the amp output, the other are the 0V, 70V and 100V outputs. Info here: Amplifiers - Discontinued Products - QSC
I have already removed the 45Hz 3 pole highpass input filter from this amp.
Edit: Trafo part number QSC p/n: XF-000024-00 Magnetic Core Corporation MCC p/n: 32002 revision D
So what can I do with these trafo's?
Right now I'm thinking a PP amp from the big trafo's and maybe a small SE amp from the smaler trafo's, but I'm basically clueless. For instance what is the impedance from these trafo's, how do I measure this, etc etc...
Last edited:
The website does not identify anything about the line output transformer except speaker side voltage and power ratings. If the amp side of the OT was connected internally, and presented an 8 ohm loading at 250W, then an estimate of the OPT turns ratio is primary voltage of sqrt(8 x 250) = 45V, to 100V, or 1:2.2 where the speaker side impedance is 40 ohm. You could do a simple turns ratio voltage test to confirm what the actual turns ratio is.
You probably can't tell if the two windings are connected in series or parallel for a 100V output ?
These transformers are effectively what is seen inside any solid-state PA amplifier from the last few decades - they have been designed for very low impedance matching. As such, they are pretty impractical to use for 'typical' valve amplifier applications. You would need to be fairly experienced to utilise them in a valve amp, such as in an output stage that uses multiple parallel tv line output valves that would be happy with driving a low impedance, and even then the speaker would likely need to be an effective 16, 32, or 48 ohm combination of series connected speakers.
I've had a go at designing up some solid-state pa amps for valves (as the amps are cheap as chips and have a chassis, front panel, power transformer, and output transformer all ready in place), but not yet made a practical conversion, as there are a lot of design and construction issues to work through.
Last edited:
100 volt line transformer, if rated down to 30 or 40 Hz, could in theory be used as a power transformer. The caveat is that you don’t know how well it’s insulated.
Many of the tube amp designs that use line transformers are just a few watts. The little 5 to 15 watters you find on the back of ceiling speakers work pretty well for that, given the cost (usually free) - and the fact that you drive it with something dirt cheap on relatively low B+ (ie, 50C5). Unfortunately, higher power doesn’t help here unless you use exotic tubes which are “impractical”.
Many of the tube amp designs that use line transformers are just a few watts. The little 5 to 15 watters you find on the back of ceiling speakers work pretty well for that, given the cost (usually free) - and the fact that you drive it with something dirt cheap on relatively low B+ (ie, 50C5). Unfortunately, higher power doesn’t help here unless you use exotic tubes which are “impractical”.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.