"Black Flag" Power Supply Question

[Danhalen]

I have been reading up on early '67 Super Leads for a while now and I want to build one in the near future. The one thing I cannot seem to find any consensus on is what exactly the difference is between the single and dual rectifier setup. Most posts and articles I have read suggest that the dual rectifiers make the attack stiffer but I have seen a couple of people say the opposite. Anyone with specific experience with both in this type of circuit?

[neikeel]

I have both set ups and I think that you notice more difference with the filtering and the power valves than the rectifier set up.

On my original '67 it is the two rectifier version and on my black flag build there are two sets of rectifiers but only one secondary so I have the two blocks in parallel with each other

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[shakti]

I can't precisely answer your question, as I have not tried the exact same amp with both single and dual rectifier. However, I did build an early '67 style JTM100 black flag with dual rectifier, and my main impression is that it's a funny kind of "hybrid"...both very fast and quite sluggish at the same time. I *assume* that the sluggishness comes from the extremely low filtering (only 32uF mains, 16uF screens and 16uF PI), but the dual rectifier "saves" it and makes it very bold. The bass is particularly powerful. I love the sound of mine, but it's quite different from my other Marshalls.

To make a fair comparison, I've toyed with the idea of building a later '67 style (i.e. single rectifier, 50uF mains, 1202-132 OT), but you can only have so many Marshalls...(notice I didn't say exactly how many that means... )

[neikeel]

but you can only have so many Marshalls... )

Oh really, since when (well actually my wife has not counted the contents of my store cupboard recently )

[Danhalen]

Thanks for the info guys very helpful stuff!

Once I heard that the second Free album and Hendrix's Catfish Blues were black flags I became very interested in building one. I originally thought I wanted to build a JTM45/100 and would still consider it, but I like the midrange character and slightly more aggresive tone of EL34's. Also, through experimentation with my amps I have realized that I love the sound of low filtering. I really like a cleaner rhythm tone and then when I dime my guitar volume I like when it gets fat like early Clapton/Kossoff for my lead tone. I really like he looser more bouncy compressed on the edge sounds you can get with lower filtering also. But then I also don't want the amp to sound saggy. So this amp really sound intriguing to me.

So Neikeel you are saying that your two amps with the different rectifier setups sound very similar?

[neikeel]

Yes they do.
My 45/100 with El34s has a -119 OT -114 choke and -80 PT with 32uFcans (32/32/16/16/32, pre-amp>mains)
My clone has EL34s, -132 OT, -114 choke, -80PT with 32/32 preamp, 22 PI, 22 screens, 47mains

The original has a bit more bloom about it but the clone is pretty good. I still hover between taking the KT66 45/100 or my 68 with me as a 'go to' when I need a 100watter with the 45/100 needing a dirt pedal to get any high gain sounds but it is sweetest for cleans.

The EL34 45/100 and the clone are pretty much classic Marshall crunch rhythm/riffing amps IMO and I find the KT66 amp a bit more controllable for my gigging which has to cover pop, funk, indie and rock.

[Danhalen]

Thanks so much that's exactly the info I was looking for! "classic Marshall crunch rhythm/riffing amp..." sounds like what I'm after. How does the EL34 amp compare gainwise to the KT66 amp?

Also Shakti, the thing you said about the amp being sluggish and bold at the same time I think I can hear that on the second Free album. Especially on "Broad Daylight" where he is playing with a cleaner sound and from the sounds of it a single coil pickup strat possibly, it has a nice "bounce" to the sound and yet it doesn't sound saggy. I love that and want to be able to get that sound. My 50watt frankenstein amp, which is probably closest to a solid-state rectified JTM50 or a 1986 with lower filtering, can get pretty close but not quite there.