SAE 2300 quiescent current
- Thread starter drumbum
- Start date
I don't think SAE ever used the voltage across the emitter resistor method of setting output stage idle current. The preferred method was to use a distortion analyzer, .03-.04 % THD @ 20KHz, 1W into 8 Ohms. The alternate method was to measure the voltage across the collectors of Q7 and Q8, 2.1VDC is what most of the other SAE amps are adjusted to. I'm not sure if you can get those collectors in the 2300 but the base of the drivers, Q11 and Q12 will get you the same results.
Craig
Craig
FootFungus
Super Member
I'd leave it at 12.5mv. I've never been happy with the sound when doing it by distortion levels.
Thank you for the reply.
Thanks FF. I discovered your earlier post on the subject also.
Prior to adjusting, I was intrigued by the temp difference between chs. at idle w/ 10mv and 18mv.
Are you able to do the alignment by the distortion method? If so I'd be curious to see what the emitter voltage is after that alignment, I guessing it will be lower than the 12.5mv. I don't think I've worked on a 2300 before, with the larger SAEs it is so difficult to get to the emitter resistors I've never tried. James B. never cared for the emitter voltage method.
Craig
Craig
FootFungus
Super Member
After rebuild I can get it to sub .05% at 20khz with around 4.5-5mv. With 0.2ohms emitters it works out to 22-25ma of bias per device. 50-60ma sounds a lot better after warm-up.
SAE 2300 is sounding pretty good driving some Advent Legacy II's.
Now to decide if I will paint the top and side covers. Hate to do so, but the anodized finish has seen better days. Cheese and crackers, the lengths I've gone with this amp that I picked up with a blown channel.
Now to decide if I will paint the top and side covers. Hate to do so, but the anodized finish has seen better days. Cheese and crackers, the lengths I've gone with this amp that I picked up with a blown channel.
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