Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on August 29, 2012, 06:03:20 am
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From a friend I received an old military modem to be dismounted
I recovered a few 6ak5 tubes with sockets and some nice shielded caps
on the unit there were also a good number of audio transformers, lowpass and band pass filters
I think this stuff (because of the restricted bandwidth) haven't a practical use in amp or effect building
however before to carry all this "beauties" to the dump I've think it will be better to ask to the member of the forum
What I have to do ? Must I carry all this stuff to the dump without regret ?
Thanks
Kagliostro
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Are this transformers usable in some way ?
short answer. for an amp, no.
you could use the band pass & low pass xfrmrs in effects box or active tone stack?
--DL
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Measure them. The usable response is probably MUCH wider than what it says on the can.
These are from telephone systems which might have dozens of transformers in a line. The "300-3.5KC" may be at only -1dB so that a bunch of them in the line will still pass speech.
The -3dB points are at least an octave more, 150-7K, which is nearly guitar. They could be much more. Telephone engineers were pretty conservative.
You get even better bass response when you can drive with a LOW impedance. Such as an op-amp.
The Low-pass begs to be used. It probably is a sharp cut-off, but 3.5KC covers nearly all guitar sound.
The other problem is that guitar amps are mostly high-impedance points and transformers are low impedance.
The15K:600 is a natural for tapping a speaker output to a balanced line-level feed to the sound board.
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Thanks PRR
There are a couple of transformers (I've more than one of this for any type)
that are labeled Z = 2000:1275 and Z = 2000:600
0.3 - 20KC 0DBM
the 0.3KC gives me discomfort
but I was wondering if those will be usable for a line output connected to a cathode follower tube output
K