Hi,
I'm building a Differential DAC around a pair (potentially two pairs) of TDA1541 chips. A common choice is to use a Sowter 1465 in the I/V conversion, which can stand some offset DC.
I might try the Sowter regardless, but I was wondering if anyone know whether Tamura input transformers can stand some DC? The datasheets don't specifically mention this, at least not in English 🙂
I'm eyeing a pair of TD-1 or TK-10, but I'm open to advice on that front as well. I'm planning to put an Valve stage behind the transformers so I'm not looking for gain per se.
Thanks!
Matthew
I'm building a Differential DAC around a pair (potentially two pairs) of TDA1541 chips. A common choice is to use a Sowter 1465 in the I/V conversion, which can stand some offset DC.
I might try the Sowter regardless, but I was wondering if anyone know whether Tamura input transformers can stand some DC? The datasheets don't specifically mention this, at least not in English 🙂
I'm eyeing a pair of TD-1 or TK-10, but I'm open to advice on that front as well. I'm planning to put an Valve stage behind the transformers so I'm not looking for gain per se.
Thanks!
Matthew
TD-1 is rated for 13dBm according to: https://www.tamura-ss.co.jp/en/electronics/trance03/pdf/audio.pdf
13dBm into 600 ohms is about 9.8Vpp (for a sine wave) according to: https://coretechgroup.com/dbm-calculator/ However, the RMS value of 3.45Vrms is what relates to power (dBm is a measure of power -- 1mW into 600R)
If you run some DC current through the primary, it will offset the nominal operating point for an AC audio signal to some point offset from the origin in the B-H curve. So, the point where it would saturate/clip the audio would occur at a lower AC signal level. How much DC current would flow depends on the DC resistance of the coil and the DC bias voltage applied.
You might have to test to see how much DC current can be applied before distortion of audio becomes excessive. You might also want to take a look at heating caused the DC bias power dissipation.
Maybe somebody else could chime in if there is more you might want to consider.
13dBm into 600 ohms is about 9.8Vpp (for a sine wave) according to: https://coretechgroup.com/dbm-calculator/ However, the RMS value of 3.45Vrms is what relates to power (dBm is a measure of power -- 1mW into 600R)
If you run some DC current through the primary, it will offset the nominal operating point for an AC audio signal to some point offset from the origin in the B-H curve. So, the point where it would saturate/clip the audio would occur at a lower AC signal level. How much DC current would flow depends on the DC resistance of the coil and the DC bias voltage applied.
You might have to test to see how much DC current can be applied before distortion of audio becomes excessive. You might also want to take a look at heating caused the DC bias power dissipation.
Maybe somebody else could chime in if there is more you might want to consider.
