Session 400 and LTD page

Brad Sarno · Post by **Brad Sarno** » 26 May 2003 7:59 pm

I threw together a webpage on the old Session 400 for those interested.
http://home.earthlink.net/~bradsarno/session_400page.html

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

Bob Lawrence · Post by **Bob Lawrence** » 26 May 2003 8:23 pm

Brad,

You did a terrific job. Lots of pictures. Very informative.

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jim milewski · Post by **jim milewski** » 27 May 2003 4:39 am

well you know I loved it! You may be starting a revival!

Mike Brown · Post by **Mike Brown** » 27 May 2003 5:18 am

Brad, your knowledge of electronics impresses me each time that you post on the Forum. The informative message here is great and I'm sure that all other Forumites appreciate it as well.

Thanks,
Mike Brown
Peavey Electronics Corporation

Jeff Agnew · Post by **Jeff Agnew** » 27 May 2003 10:26 am

The Session 400 was my first true steel amp and it has remained in my inventory since purchasing it new in '74. The only one I've ever seen that might be older is Reece's. And his doesn't have the original grill cloth

Mine was the dreaded EV 212 model. Heavier even than my JBL-equipped Twin, I swapped the big honkers out for a single 15 as soon after the hernia operations as was feasible.

I've also owned every subsequent Peavey steel amp up through and including the 2000. No matter the bells and whistles, the original still sounds competitive with any of them. Arguably, it sounds better.

Fortunately, I've never sold it, despite being tempted on several occasions when I was swayed by the NextGreatThing. It remains my favorite to this day. I've done similar upgrades to those Brad describes on his page (nice job, BTW) and doing so really brought the old girl back to life without changing the basic sweet character of the amp.

On a side note, it has also been virtually bullet-proof for almost thirty years. Once during its second decade I had it begin developing distortion during a road gig. I was fortunately within a day's drive of Meridian and arranged to send it ahead to the factory on a bus. Also fortunately, I was scheduled to play a show in Meridian within 48 hours. The fine folks at Peavey had it repaired and delivered to me at the show in plenty of time to make the curtain call.

They charged me a grand total of $19 and change. Parts only, obviously. This was for an amp almost two decades out of warranty. Oh, and while they had the amp apart, they said they found a few other odds and ends that needed tweaking and went ahead and fixed them at no charge because, according to them , "they shouldn't have gone bad in the first place." That treatment, to me, defines what customer service should be.

I've made some poor decisions and purchased a number of bad products in my time, but my Session 400 may just rank as the smartest purchase ever.

Brad Sarno · Post by **Brad Sarno** » 28 May 2003 7:40 am

Gino Iorfida · Post by **Gino Iorfida** » 28 May 2003 8:00 am

Very cool page! Generally, speaking, larger coupling caps WILL affect the tone, howev ef, in the case where you are replacing 2uf with 8uf in the reverb return, I agree that it is o verkill (simply put, the extended low end you could effectively reproduce is simply NOT there)... but in terms of economics, you had them laying around. You wouldnt have an electronic copy of the schematics laying around, would you? I know I can get a print copy from Peavey, and I probably will do so, however, I like working off of an electronic copy for archival purposes etc (that and I do my best thinking late nite on the PC when I cant have lights on, lest I wake up the rest of the family)

I agree, though on the tone of these amps. It's a nice 'compromise' between the tone of an old Fender (heavy, low power, etc), and the modern Nashville series etc (very hi-fi sounding, etc).... it's like this amp is a good balance of the tube warmth, and the solid state reliability etc....

mark my word on this, i see the prices on these old Session 400's going up FAST. I'm seeing more an dmore just on here with a renewed interest in these old amps.

Brad Sarno · Post by **Brad Sarno** » 28 May 2003 9:35 am

Gino, I've noticed that the bigger cap's do help to extend and improve low freq response because the phase shift gets shifted even lower. So yea they do change the tone. On the reverb return cap I kept the .047uF value the same but just improved the cap quality. I agree with you that there's not much down there in the reverb tank except potential LF feedback.

If you've got any cool photos or tech notes on the Session, I'd love to add them to my page. Thanks for the feedback.

I dont have an electronic copy of the 400 schematic, yet.

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

Bill Terry · Post by **Bill Terry** » 28 May 2003 1:07 pm

This is a PDF of the manual and schematic. Sort of small, but readable.

http://www.peavey.com/media/pdf/manuals/80344000.pdf

Actually, not bad. I just zoomed the viewer in to 400% and it's very readable. It's a scan, but a good one.[This message was edited by Bill Terry on 28 May 2003 at 02:12 PM.]

Brad Sarno · Post by **Brad Sarno** » 28 May 2003 4:56 pm

webpage has new corrections
http://home.earthlink.net/~bradsarno/session_400page.html

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

Brad Sarno · Post by **Brad Sarno** » 29 May 2003 5:56 am

page has new link to Session 400 preamp schematic w/cap upgrades.

http://home.earthlink.net/~bradsarno/session_400page.html

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

RickRichtmyer · Post by **RickRichtmyer** » 29 May 2003 6:39 am

Great stuff! Thanks!

In my collection of Peaveys I have a Session 400 (2/12 model, I bought it at a pawn shop 20 or more years ago). The reverb long since quit working but I don't care since I prefer digital reverb anyway. At this point it's the best working amp I have. I also have a non-functioning LTD 400 and two semi-functioning Vegas 400's as well. One of these days I plan to yank out the amplifier sections and ship them all to Mike Brown. I just haven't gotten one of those "round tuits" yet.

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Rick Richtmyer
Sugarloaf Recording
Good News

Darvin Willhoite · Post by **Darvin Willhoite** » 29 May 2003 6:55 am

I have an LTD 400 that I bought new in early 1980. It still looks and sounds just like it did the day I brought it home. I even still have the original cover, owners manual, and sales receipt. Besides a great steel amp, this is a great jazz amp. I think the reverb sounds much better than most of the later Peavey amps.

BTW Brad, all the steel on the project you just mastered for me was recorded with the LTD, and my Fessenden steel. I used just a slight bit of reverb on the amp, the rest of the effects were from a Kurzweil effects unit in the studio.

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Darvin Willhoite
Riva Ridge Recording

Brad Sarno · Post by **Brad Sarno** » 29 May 2003 8:20 am

Does anyone have any decent LTD photos that I can add to my webpage? Anyone have any photos of the circuit guts with no modifications? I'd like to take that photo and use it to point to certain cap's. It'll help for people to locate certain components because I dont think there's a circuit diagram anywhere, only a schematic.

Thanks in advance,

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

Gino Iorfida · Post by **Gino Iorfida** » 29 May 2003 8:32 am

My Session is in my bandds practice room (left it go home with the PA after last job... didnt want to lug it when I was leaving for vacation anyways)... I'll either be bringing it home tonight, or Sat after the gig, and I'll post pics of the inside then, I need to update the caps in mine anyways, so I'll kill 2 birds w/ one stone.

RickRichtmyer · Post by **RickRichtmyer** » 29 May 2003 9:00 am

If you don't get any other LTD pictures first I'll open up mine and shoot a picture and E-mail it to you. It doesn't work, but that won't matter for the picture and it's never been modified.

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Rick Richtmyer
Sugarloaf Recording
Good News

Tom Mortensen · Post by **Tom Mortensen** » 29 May 2003 1:54 pm

I'm trying to figure what year my Session 400 is. Pretty sure that I bought it in late 1975.
The face plate is painted/screened flat as described on the web page that Brad has, but the knobs are smooth, not grooved as shown in the picture.
Also the amp came with a JBL M31-4.

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tombleu.com

Bill Terry · Post by **Bill Terry** » 29 May 2003 5:54 pm

Not sure what year Tom's Session would be, but generally speaking the flat faced knobs like on his Peavey were the predecessor to the ones with the recessed face like in Brad's pics. I had an early Musician amp that had the flat ones too. Seems it was a '74 model maybe?

Didn't the serial number on the early Peaveys indicate year of manufacture? 5A-xxxxxx being a '75, etc? Mike B?

John Macy · Post by **John Macy** » 29 May 2003 8:29 pm

Hey Darvin--which Kurzweil unit? I just ordered a KSP8. They sound amazing...

Dennis Detweiler · Post by **Dennis Detweiler** » 29 May 2003 9:19 pm

I still have my 1974 session 400. I bought it new. I still have the lifetime warranty card and the original cover (with much duct tape on it). The 74's had smooth knobs and metal faceplate. It came with a 15" JBL. I've replaced it 3 times. Currently has a BW 1501. My 74 was bench tested against a 76. The 74 tested with an honest 200w rms, the 76 with 160w rms. The electronics "wizard" that tested them said the sessions after 74 had protective circuitry added because the early models tended to blow up or blow speakers.
I also have a 1975 session. The 74 has a much mellower tone compared to the 75.
Dennis[This message was edited by Dennis Detweiler on 30 May 2003 at 05:56 PM.]

Darvin Willhoite · Post by **Darvin Willhoite** » 30 May 2003 11:29 am

John, it is the Kurzweil KSP-8. This a great unit, it was a bit pricey, but Travis loves it. I don't think the old Quadraverb II, or the old Lexicons will get much use now. We've added a set of Adam monitors also in the last year. Amazing sound from a small package.

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Darvin Willhoite
Riva Ridge Recording

Brad Sarno · Post by **Brad Sarno** » 30 May 2003 3:48 pm

Thanks for the info Dennis. Does anyone know more about this "protective" circuitry in the post'74 Session 400? I'll poke around and see what I can find.

Thanks,

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Brad Sarno
Blue Jade Audio Mastering
St. Louis

Brad Sarno · Post by **Brad Sarno** » 31 May 2003 12:23 pm

site updated - bump

brad sarno

Ken Fox · Post by **Ken Fox** » 31 May 2003 2:19 pm

There are some back to back Zener diodes across the output stage. Maybe that is what is referred to above. I see the same setup in the Nashville 400 and the old 400BH power module(Session 500) as well.[This message was edited by Ken Fox on 31 May 2003 at 05:55 PM.]

Ken Fox · Post by **Ken Fox** » 5 Jun 2003 6:06 pm

Brad, the page looks great! I just ordered a Session 400, sight unseen today. It is supposed to be cosmetically OK, a JBL K-130(checks good) but not sounding very good! I was told it was missing a power transistor off the back of the amp! Also missing the logo. Looks like I am am headed into another amp restoration soon! I am anxious to incorporate your mods in the amp. Do you feel the Orange Drop by Sprague would be a good choice for the amps preamp section (and even the filter bypass caps)?[This message was edited by Ken Fox on 05 June 2003 at 07:09 PM.]