Session 400 (not Limited nor LTD) Question

[Jeffrey Shu]

I’ve had a Limited, but am wondering about the original 400s: is there any difference in a 1974 model versus a late-run model (1980?). I think Peavey switched from JBL to a sturdier BW, and notice from pics the knob style changed. But is there any significant design difference otherwise? Cab size or density? Any reason a late model wouldn’t be the same?

[Dennis Detweiler]

I bought a Session 400 new in 1974 and still have it. Great amp. It has the smooth knobs, metal face and Peavey logo mounted in the upper left corner. I've played through 400's after 1974 and couldn't hear the fatness of the later years. I asked Buddy Emmons about it and he agreed and wished that he still had his 1974. The first speakers were a choice between 2-12 ElectroVoice or a single JBL D-130F. I blew two of the JBL's until Peavey introduced the BW. I had my 74 bench tested against a 76. The 74 put out an honest 200 RMS. The 76 put out 160 RMS. I'm told that Peavey added protective circuitry which lowered the output? Maybe this is why the 74 sounded a little better? Of course, the speakers make a difference also. I tried 4 different 1501 BW speakers in it through the years. They all sounded slightly different. However, the early flat magnet 1501 sounded best to me. That is what is currently in my 74.

Session 400.JPG

[Jeffrey Shu]

Interesting. Thanks for sharing your experience - much appreciated.

[Jeffrey Shu]

Not to belabor the point, but is it a hard cutoff between 1974 and 1975 - a 4A would be the first design and all 5As would have the protective circuit?

Fender seems notorious for using what’s on hand until it’s gone. Would Peavey do the same?

[Dennis Detweiler]

I'm assuming the first issue 4A would be the full 200 RMS? I think the very early 5A still resembled the 4A in outward looks? When they added protective circuitry, I don't know. I only know the 74 vs 76 bench test. I have the 1974 schematic. There may have been an updated schematic sometime thereafter? Likely, only someone that worked in the production of the amp at that time would know for sure? I'm going by recollection from those years and the bench test that compared my 74 from our band's lead guitar player's 76. However, any of the Session 400's from the 70's would be worth having. I'm still waiting and anxious to receive the Session 400 pedal.