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Fidelity Fan · 14th Jan 2013, 5:50 pm

Hi,

Was there an exact equivalent to the ECC83, but with a higher voltage heater in the 'U' series?

I have read elsewhere that the EL84 had a slightly higher supply voltage, (the UL84 is rated at 250v absolute max). However, comparing the amplifier circuit used in the Dansette Tempo for example, in comparison to a Fidelity HF35 there is not much difference. The main one is that the Tempo has no supply dropper resistor on the metal rectifier anode (it would need one if replaced with a diode due to the lower voltage drop). The HF35 had a 130 or 150 ohm connected to the UY85 anode. The resistor between the HT smoothing electrolytics is 12k in the Tempo and 10K on the HF35.

The PCB in the Tempo was used on other Dansette models. It also has holes for another valve holder. This leads me to believe that the same PCB was also used in models using UY85 and UL84 valves.

14th Jan 2013, 5:50 pm	#11
Fidelity Fan Hexode Join Date: Jan 2013 Location: Wigan, Lancashire, UK. Posts: 372	Re: UY85 UL84 Amplifier Hi, Was there an exact equivalent to the ECC83, but with a higher voltage heater in the 'U' series? I have read elsewhere that the EL84 had a slightly higher supply voltage, (the UL84 is rated at 250v absolute max). However, comparing the amplifier circuit used in the Dansette Tempo for example, in comparison to a Fidelity HF35 there is not much difference. The main one is that the Tempo has no supply dropper resistor on the metal rectifier anode (it would need one if replaced with a diode due to the lower voltage drop). The HF35 had a 130 or 150 ohm connected to the UY85 anode. The resistor between the HT smoothing electrolytics is 12k in the Tempo and 10K on the HF35. The PCB in the Tempo was used on other Dansette models. It also has holes for another valve holder. This leads me to believe that the same PCB was also used in models using UY85 and UL84 valves.