May 26, 2018 · HI Friends , i finished one d3a-300b amplifier. 300b would work with 420v 80ma aprox. D3a with 185-190v 16-19ma. When i turn on the amp, i can measure 520v high tension , an then in five minutes go down to 420v..

Jan 10, 2010 · I was wondering if anybody knew of a great 300B design that uses the D3a as the driver. I have searched this forum and eleswhere but I continue to only come up with a DRD topology. I recently sourced all the parts to build the JEL 300B and bought an extra set of OPTs from James (6123HS).

300B栅偏压按一般值取60V，对应有效值为60V/√2=42.5Vrms，即要求电压放大级输出至少42.5Vrms才能推满300B。 这就要求：①第一级电压放大管的栅偏压的绝对值不能小于1.5V；②电压放大管的在路放大倍数最小值是Av=42.5。 所以，第一级放大管必须采用高跨导S、高放大倍数μ、低内阻ra的。 备选的适合管子有：6C45п-E、SQ级5842、D3a、EF184、E180F。 （2）只有电压放大管的阳极负载满足高交流阻抗、低直流电阻、高传输效率的条件时，才有可能使在路 …

Feb 16, 2011 · This amplifier is superior to any other 300B design because it have a very low distortion, an extended frequency response and an incredible high damping factor. These characteristics are obtain by the use of an ultra linear driver stage and a high output transformer impedance (5600 ohm instead of normal 2500-3500ohm).

May 2, 2024 · 300B是玩胆机绕不过去的关。 但一台好的300B，却又是凤毛麟角。目前充斥市面的300Bse，一般都是这种指标： 1，功率8W，根本谈不上什么动态。 2，频响很差，基本没高没低， 3，大部分机器失真很大，1W输出时经常高达1%失真。 4，噪声很大，隔着几

Nov 4, 2021 · 300b和2a3 不能放在一块讨论。 假设人为认定300b的推动难度是“1”，那么2a3只有0.6左右。 能切实推好300b的管子很少，包括神乎其神的所谓“绝配”310a

Aug 2, 2005 · To make a long story short and after a few small “experiments” I decided to build my first serious amp. It was going to be a 300B. Never heard one before but there would have to be something about it after all the buzz that there is around.

May 1, 2008 · 5.9v加个小电阻到300b灯丝，可以减小开机时的冲击电流，还是有好处的。 胆坛吸收新鲜血液，招版主，欢迎您的加入！ 并将清理不合格版主

May 10, 2013 · 两级三极管电压放大去推300b，得到一个好指标而已---那是一种类似于石机的、呆板的声音，虽然高低频都很通透，但是这种声音确实无情的、死的、欠缺灵气。

Given you already have a D3a (about the best driver tube for a 300B Amp I can think of) in your amp, why not use it? Wire it as triode with 100R from both screen grid and suppressor grid to the Anode.