Some questions about Audio Transformers and IC"s??

[Minion]

Hi Folks, I just aquired some electronics parts for pretty cheap but I don"t know much about them or if they are even usefull....

I just got 6 new Mini audio Transformers for $4 that are used in Telecomunications...Thjey seem to be 1:1 Ratio as they have a 30ohm primary and a 30ohm secondary....

These were the specs I could get from them...

amorphous alloy laminations
Core size 15 mm x 12 mm x 4 mm
Center leg cross sectional area: 16 sq. mm

Each winding has about 700 turns of 36 AWG wire, and has an inductance of 1.6 H (Henries)

Frequency response is from 20Hz to 1MHz.

There is a resonance peak at 644 KHz, as observed on an oscilloscope. Response starts to fall above 900 KHz at about 40dB/decade, as core losses take over.

Would these Transformers be usefull for any audio type stuff?? Like as Input or output transformers in Mic preamps?? It seems that the frequency responce seems pretty good (20hz to 1Khz) which covers the audible audio range.....

Any suggestions on these would be great.....

Next I got a couple LM3886 Power opamps that I was thinking of useing to build a Guitar amp out of....Would these be good for that purpose?? I have a 100vA Torroidal transformer (18v,0v,18v @2.38Amps) would that be enough power for a 50w amp useing this transformer.....

Do you folks happen to know of a schematic for a simple Guitar or Bass amp that uses this Chip???

My last set of questions are about these Opamps that I picked up and I know very little about them but they seemed interesting so I grabbed them....

They are called "TC913" opamps and they are "Dual Auto Zero Opamps" they claim to have "Zero Offset Voltage"Zero Drift" and over 100db PSRR..

Here is the DataSheet:
http://ww1.microchip.com/downloads/en/DeviceDoc/21482C.pdf


Can I use these Opamps the same way I would use any Dual Opamp like a NE5532?? Or are these only used in certain circuits??

Any infor on these Chips would be very usefull....

ThanX a Lot Guys.....

 

[Kit]

Would these Transformers be usefull for any audio type stuff??

Yes, telecomunication.
:razz:

But seriously, i think the core is to small. It might saturate when the drummer goes nuts.

Thats my guess.

But im not a transformer expert, far from it.

Ask ironman.

Wheres ironman?

 

[Boswell]

The opamps are chopper-stabilised for very low dc drift in instrumentation applications. They are not suitable for high-quality audio use.

 

[Minion]

The opamps are chopper-stabilised for very low dc drift in instrumentation applications. They are not suitable for high-quality audio use

Could they be used in audio circuits like for DC Offset or as a Buffer??

But seriously, i think the core is to small. It might saturate when the drummer goes nuts

The Audio transformers in Microphones are about this size so they might be usefull for this...There was some information talking about saturation with these Transformers at frequencies under 100hz with a 1v square wave......

I guess I"ll just play arround with them and see if I can do something with them....

Cheers

 

[mikka]

I guess I"ll just play arround with them and see if I can do something with them....

I like that idea. Sometimes it's more educational to just try it..... mmh .... maybe I should listen to my own advice......

 

[gyraf]

1.6H inductance means that you need very low drive source impedance in order to get low frequency through these..

Most telecom transformers are spec'd 300Hz and up

Jakob E.

 

[mikka]

I've got a Tamura from a Tascam board out of it's can at the mo....Just stuck a ruler on it ..... approx 19mm by 15mm by 6mm. Don't know how much use 1:1 would be though.....

 

[mobyd]

[quote author="gyraf"]1.6H inductance means that you need very low drive source impedance in order to get low frequency through these..

Most telecom transformers are spec'd 300Hz and up

Jakob E.[/quote]

Actually, whilst many telecom trannies are fairly foul, there are a some that are not too bad. I recently had need for hundreds of transformers for press/media audio distribution amps. The budget did not run to Jensens so began an investigation of tiny trannies, fair and foul. What I ended up with were Midcom 671-8056 which look like this...

and the distortion figures are entirely adequate for the application.
........ +6dBU 0dBU -10dBU
31Hz 29% 0.51% 0.12%
50Hz 0.43% 0.14% 0.04%
100Hz 0.09% 0.04% 0.02%
1KHz 0.02% 0.02% 0.01%
Measured with a Neutrik Minilyser and Minirator
Primary inductance 12H
Cost (on the Asian market) <$2
M

 

[Michael Krusch]

 

[TedF]

Those transformers you have are telecoms transformers designed to operate probably with 150 ohm impedance circuits as isolation transformers. They will not be very exciting in proaudio if ued conventionally, but as line in isolation transformers operating in current mode they would be spectacular.
The power amps are my personal favourites for general audio up to 50 watts. They are very forgiving and are hard to blow up!
Follow the data sheet and they will work fine. :guinness:

 

[rafafredd]

Each winding has about 700 turns of 36 AWG wire, and has an inductance of 1.6 H (Henries)

Frequency response is from 20Hz to 1MHz.

Really, it seems it would work great as 1:1 mic input transformers, like you need in a spectrasonics type of thing... But you will need to shield it.