NAD - 3210 (3rd Time's a Charm?)

[fitz]

Picked up this 3210 today from a local CL listing as "not working".
It was listed with a 1965A cab as a half stack deal for a decent price.
Told the seller I kinda just want the amp, and someone else told him they kinda just want the cab.
He had a moment of brilliance - I got the amp for $100.



Good shape cosmetically.
V serial #, so 1987.
Looks all original, reverb tank seems intact, and it has the back grill.



Initial look inside revealed a blown fuse.
Pack of T3A ordered, should be here tomorrow.
Begs the question of why the fuse blew...



Here's a full gut shot.
I can post details if anything looks odd.
Didn't see any scorch marks or exploded components.
A few strange things seemed to check out against the schematic I have.



Hopefully the new fuse does the trick.

 

[Neptical]

You probably know I enjoy seeing this post. Lol

Happy NAD @fitz - what a score!
Hopefully just a fuse type thang!

 

[fitz]

While I'm waiting on a fuse (should be here today), I got started on getting the 3210 to match the 2556A cab.
Scrounged some gold piping from the scrap bin and swapped the script logo for the block logo.
Tolex will probably go green at some point.



Moved the 5100 to the old home-made C5 style cabs (inverted).



Put the G215RCD chassis in the little green shell a few days ago and sold it on Reverb.
Netted $95 after shipping and fees, so I'm kinda at a trade of sorts for about $5 to get the 3210.

 

[BlueX]

so I'm kinda at a trade of sorts for about $5

says the accountant

 

[KraftyBob]

A check of the output transistors and the bridge rectifier before the fuse gets there wouldn’t hurt. Do you have a variac or lightbulb limiter to power up with?

Nice score btw!

 

[fitz]

A check of the output transistors and the bridge rectifier before the fuse gets there wouldn’t hurt. Do you have a variac or lightbulb limiter to power up with?

Nice score btw!

Thanks!
I have a workbench thread going for the blown fuse and some mods I've uncovered.

3210 mods help?

Comparing a new-to-me 3210 that I picked up today to one I had a few years ago. Had a blown mains fuse, so I'm waiting on some fuses before I can power it up. Not sure if these are good or bad things or cause for a blown fuse - any input appreciated. Pics are all new one with something added...

www.marshallforum.com

 

[fitz]

OK, I'm updating this thread 'cause it's not really workbench stuff.
Got some help getting the 3210 rockin' again.
Thanks again to @PelliX & @BlueX for not giving up on my ineptitude.

Here's some new pics of the functional rig.







If you notice, I turned the headshell green to match the 2556A cab.
Shamefully admit I didn't change the tolex - I rattle can spray painted it....
Tolex texture doesn't match, but I think I almost nailed the color match with Behr Black Evergreen satin.

So now I have a pair of 100w MOSFETs with the 5100 in the downstairs workshop.


And do you think I might have hooked them up in stereo?

 

[FleshOnGear]

What would you say is the difference in tone between the 3210 and the 5100? The circuits are not the same, AFAIK.

 

[fitz]

What would you say is the difference in tone between the 3210 and the 5100? The circuits are not the same, AFAIK.

Hard to say that they are drastically different from just playing for a short while.
I didn't try any kind of A-B switching back and forth with similar settings.
Quick shoot from the hip answer would be that I think I like the 5100 drive tone a little better. (might be why this is 3210 #3...)
But I'm also running them through different cab and speaker sets, so not sure how objective a comparison would be.
I'll probably get the stereo rig set to run clean with a shared front end, so I don't mind that they sound a little different.

 

[fitz]

I didn't try any kind of A-B switching back and forth with similar settings.

Ok, I did try A/B ing them with no effects in front or loop.
Wondering if there's something wrong with the 3210 boost channel tone pot.
Kinda mid scooped honk, while the 5100 sounds more normal (?).

Again, different speakers and cab configurations that may be skewing results a bit..
5100 is on a pair of 112 cabs with G12 Heritage 8 ohms that can be switched from series to parallel so I can have 100w @ 4 ohm, or about 50w @ 16 ohm.
3210 is on a 212 with Haze Marquee T-66 16 ohm parallel to an 8 ohm load on the amp.
They do sound good in stereo, and the clean channels seem to work great.

 

[FleshOnGear]

Wondering if there's something wrong with the 3210 boost channel tone pot.
Kinda mid scooped honk, while the 5100 sounds more normal (?).

Are you using the boost channel with the 3-band tone stack engaged?

 

[fitz]

Are you using the boost channel with the 3-band tone stack engaged?

I've tried it.
Seems to be a volume drop and to EQ a tone I like, it messes up the tone settings I like for the normal channel.
IIRC, the other two 3210's I've had were similar.
We'll see if a new set of pots changes anything on the 3210.

If I can find a good drive tone on that Zoom gizmo, I could use it as a splitter and front end both amps on the normal channel and be happy.
Still gotta say the boost channel on the 5100 is way better - closer to my 800 tone.

Keep in mind, these are my basement workshop amps and can't hold a piss bucket compared to the rigs upstairs.
Planning on eventually putting the op amp sockets in both and trying different chips in the IC slots.

 

[DirtySteve]

So glad to hear you got it fixed! I was following the workbench thread and holding my breath. Congrats!!!

 

[fitz]

So glad to hear you got it fixed! I was following the workbench thread and holding my breath. Congrats!!!

Thanks!
Not sure if "fixed" is entirely accurate, but at least it's functioning.
Resurrected from the dead, so to speak.

Glad I was able to learn a few things about tracing circuit problems and I may have a better understanding of some of this stuff from the process.

Fortunately, or unfortunately, these amps are going to be living in Dr. Frankenstein's lab, and he has a few plans...

 

[Mitchell Pearrow]

Congratulations @fitz
HNAD
Glad you were able to bring it back to life.

 

[fitz]

Wacky side story: I got the G215 back.

It was damaged in shipment and the kid that bought it was clueless about why it didn't work.
I packed that thing so well that I couldn't even imagine what would have happened to it.
Hard to file a damage claim with Reverb when the problem is unidentified, so I sent him a return shipping label that cost me $22.

Got it back and found the problem.
The amp somehow took a blow hard enough to rip all 4 legs out of both of the output transistors.
The board on the little amp is supported by the pots on the front and the heat sink for the transistors on the back.
It must have dropped straight down from a good height and landed flat on the box bottom - there was no sign of any kind of impact on the box.

Well, I filed a claim with reverb with pics of the damage and they refunded the buyer in full.
I got to keep the initial net of fees transaction money, but ate the return shipping.
Everything was covered by their "safe shipping" guarantee that I ALWAYS get for an additional fee.

Might be fixable, but not sure it's even worth trying.
The head shell parts (and logo) are worth more to me than $22, so I'm not upset at all with the eventual outcome.
Seller would have probably just binned it after getting his refund if I didn't ship it back.

 

[fitz]

I found the overdrive tone I was looking for going into the front end of the 3210 on clean normal channel - it's the 5100 preamp.
Loop send split the 5100 with an A/B/Y over to the 3210 Zoom board input.
Separate loop effects and EQ, and I can still run the 3210 solo with a quick cable change.

I ordered all new pots for the 3210, except for the push/pull gain and the DI level pots.
If it makes a difference, ok, otherwise I think I have a good working solution for the workshop stereo setup.

 

[BlueX]

So now I have a pair of 100w MOSFETs with the 5100 in the downstairs workshop.

And do you think I might have hooked them up in stereo?

Might get loud

 

[fitz]

Might get loud

What?

 

[FleshOnGear]

Yeah, those old Mosfets are loud, for sure. They kinda put the theory of solid state watts being quieter than tube watts to the test.

AFAIK, Marshall’s Mosfet power amp design is kinda hard on those transistors, maybe capable of being driven too hard by the corresponding preamp. I’m not an electronics expert, but I imagine most modern SS amps are driven conservatively, so maybe that’s part of why everyone says SS watts are quieter.