Yes, and I can't think of any other examples of such low filter capacitance in the post-1932 era. There are a total of 2 mfd filtering for an entire channel. Normal is 10 mfd or more per stage, this is a design theory from an earlier time, still used as tried-and-true, and more bulletproof for lack of electrolytics. The 50 mfd bypass cap on the 6c4, earliest version, is the only thing you ever find bad or previously replaced in one of these. 1 mfd is low enough to not pass bottom frequencies to B-, thus boosting the lows a bit.
Note the extra large interstage coupling cap. The output stage coupling cap is standard here.
All the caps here are hermetically sealed, metal cased, paper in oil 'bathtub' types.
Note the extremely low plate resistances; matching condition or less, rather than 2x or more. Lassoharp pointed this out recently, and my initial thoughts were:
6Q headroom is same for each stage, based on field observation. Rare; usually the front end is much lower, here the front end is higher and the output is lower than normal. PRR pointed out somewhere that this is an old trick to cancel distortion.
6AQ6 stage at 47K about 1/5 what you normally see. Less than matching condition.
Not going for gain, so much as current to drive mixing bus? 70 dB in the 6N program amp. Output headroom is relatively low in 6Q.
Early 30's power tube POV is that matching condition is lowest distortion, and double plate resistance load is best balance of voltage gain versus distortion. PRR disagrees below, and I can't argue other than to reference some articles from the era.
6Q already weird using a high mu 7 pin small bottle front end in 1947. I go on about hating 12AX7's, and here we have half of one. And 6AQ6 sounds good here. But, not as usually implemented.
On THD, whatever it is, if you want it, it's gorgeous here. These are the quintessential tube overdrive pieces, IMO. You need to replicate early Little Richard records, this is your easiest ticket. I hesitate to use words like creamy, but some electric guitars through one of these get 200% better than they actually are, immediately. Distortion content has a clearly audible 20 dB curve when you put an interstage volume control in place. I have never found that in any other circuit.
Note the extra large interstage coupling cap. The output stage coupling cap is standard here.
All the caps here are hermetically sealed, metal cased, paper in oil 'bathtub' types.
Note the extremely low plate resistances; matching condition or less, rather than 2x or more. Lassoharp pointed this out recently, and my initial thoughts were:
6Q headroom is same for each stage, based on field observation. Rare; usually the front end is much lower, here the front end is higher and the output is lower than normal. PRR pointed out somewhere that this is an old trick to cancel distortion.
6AQ6 stage at 47K about 1/5 what you normally see. Less than matching condition.
Not going for gain, so much as current to drive mixing bus? 70 dB in the 6N program amp. Output headroom is relatively low in 6Q.
Early 30's power tube POV is that matching condition is lowest distortion, and double plate resistance load is best balance of voltage gain versus distortion. PRR disagrees below, and I can't argue other than to reference some articles from the era.
6Q already weird using a high mu 7 pin small bottle front end in 1947. I go on about hating 12AX7's, and here we have half of one. And 6AQ6 sounds good here. But, not as usually implemented.
On THD, whatever it is, if you want it, it's gorgeous here. These are the quintessential tube overdrive pieces, IMO. You need to replicate early Little Richard records, this is your easiest ticket. I hesitate to use words like creamy, but some electric guitars through one of these get 200% better than they actually are, immediately. Distortion content has a clearly audible 20 dB curve when you put an interstage volume control in place. I have never found that in any other circuit.
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