My weekend project, a Sunn 2000S

[johnk_10]

Well, my old (1971) Sunn 2000S was getting due for a bit of service so I thought that I'd take advantage of the holiday weekend to bring it back to spec.

Since I already had them, I replaced all of the filter caps with the equivalent values and retubed it. They consisted of two new Sprague 20uf 600V caps, a new 20-20-20-30 /525V multicap (made on the Cornell-Dubilier tooling) and two 47uf/250V bias caps. While I was in there, i cleaned and retensioned the tube sockets, cleaned the jacks, pots and switches and retubed it with a matched quad of NOS GE 6550A's, a NOS RCA 6AN8 and a NOS Amperex 12AX7 and set the bias. Man, this amp is really awesome now. Dead quiet, even at high volumes (when I'm not playing of course) and has that distinctive Sunn midrange growl when you push it (volume past 5).

Since it sounds so good now, it deserved to have its cabinet cleaned up as well. I was surprised that underneath all of the dirt and dust, the tolex didn't have any rips or tears. This is the best one that I've had since it doesn't have the dual tube rectifiers as some of my other ones did. Looking at it now reminds me of when I got my first one (a 1970) that I bought used in 1973. I'm kind of going thru a nostalgia thing with it now (i'll probably never grow up ).

anyways, here's some pics of it. I'll test its actual output power tomorrow and see just how many watts she's putting out now.

Here's a pic that shows all of the new caps (they're the blue ones):

 

[Stumbo]

My favorite amp. Yours looks very good.
It weighs about twice as much as some of the current combos.

How does the front grill cloth cover come off?
I have one and need to replace the grill cloth.
Thanks

 

[johnk_10]

My favorite amp. Yours looks very good.
It weighs about twice as much as some of the current combos.

How does the front grill cloth cover come off?
I have one and need to replace the grill cloth.
Thanks

Thanks. Yes, its heavy but its still alot lighter than my SVT's. re: the grill board:
there are four philips head screws that hold it on from the inside. If you use a drill/driver, you can remove it in under a minute.

 

[Stumbo]

Thanks for the tip.

 

[denton57]

Very, very, cool. I have always wanted one of those. Say, you gonna sell any of that stash of GE 6550's? (i remember a previous thread where you said you had a few!)

 

[RHFusillo]

I love those amplifiers. I had a Sunn 350B, a similar, later (1973) model, and regret getting rid of it. That was my amplifier of choice back then -- SVT's sounded like mud to me compared to my Sunn.

 

[rumblethump]

I had to sell mine a few years ago. Let's see, house payment or amp?. Regretted it ever since. All the amp I ever needed. Weight was 58 lbs, not bad compared to the SVT.
What a beauty you have there. I'm using a MM HD 130 now that is close but no cigar.

 

[johnk_10]

Very, very, cool. I have always wanted one of those. Say, you gonna sell any of that stash of GE 6550's? (i remember a previous thread where you said you had a few!)

thanks! i still haven't decided on selling the GE 6550's yet. i'll let you know if i do.

regards,

 

[denton57]

OK! I only need 6 total for my SVT!

 

[ryco]

Man!! That is a thing of beauty!! You cleaned her up really nice!

I have the little baby bro 200s I bought in '72. I retubed and cleaned the chassis a couple of years ago, but I do need to take it to the shop to have the caps replaced and get her cleaned up. I hardly use it anymore, though I did take it to a bar gig last year just for fun. Sounded sweet!

Rock on!!

 

[JimmyM]

Man, you must be good with equipment. Almost 40 years old and looks like it doesn't have a scratch on it. I've already torn the tolex on my 77 B-15N and I've barely had it a month.

 

[johnk_10]

Man, you must be good with equipment. Almost 40 years old and looks like it doesn't have a scratch on it. I've already torn the tolex on my 77 B-15N and I've barely had it a month.

i have found that a good padded cover is a great (spelled cheap) investment that keeps them looking new for years. when i take them to gigs, i almost always transport them in an ATA case (with the cover on it inside the flight case).

 

[JimmyM]

i have found that a good padded cover is a great (spelled cheap) investment that keeps them looking new for years. when i take them to gigs, i almost always transport them in an ATA case (with the cover on it inside the flight case).

An ATA case, huh? Our guitarist carries his JCM 900 combo in a flight case and doesn't have a scratch on it after about 16 years. I've always been too lazy to want to deal with them. But maybe I should reconsider. I guess I'll look into one.

 

[johnk_10]

yeah, i'm lazy too, but once its packed up in the case you don't have to worry about being all that careful with it. About 6 years ago i saw a guy's 1969 SVT head that looked brand new and i asked him if it had been restored or if it was NOS and he said, "No, i just bought an anvil case for it when I bought it new and I always use it whenever I gig." That made me see the light, since his Ampeg head was probably worth a small fortune. you can get a inexpensive one on ebay for about $100 shipped. while they're not as beefy as a heavy duty Anvil, but it'll do the job.

 

[GregC]

Nice! I'd love to try one of those one day. But they're going for a pretty penny on eBay these days, about $1k.

 

[Psycho Bass Guy]

How did you get its tolex so clean? I've found my 2000S to be impervious to most anything I throw at it. No matter what I use or how I scrub it, it still stays dusty.

 

[johnk_10]

How did you get its tolex so clean? I've found my 2000S to be impervious to most anything I throw at it. No matter what I use or how I scrub it, it still stays dusty.

PBG,
I sprayed simple green all over it and let it soak a bit to emulsify the dust and dirt, then used a soft scrub brush to loosen it all up. Then i took a new terry towel so absorb all of the dirt. Then I used vinylex (made by lexol) and let that soak on it to condition the tolex. wiped that off with another new terry towel and that's it. The vinylex doesn't leave it shiny like most other sprays do, and it even smells just like new tolex.
i did the same thing to my 190B and 2-15 JBL cab about a month ago:

 

[Stumbo]

Could be in a ad for Sunn.
Looks brand new.

Mr. Sunn emailed me with some info on matching speaker ohms with amp ohms.
Based on your experience, does it match his observation:

-----Original Message-----
From: Conrad Sundholm [mailto:[email protected]]
Sent: Friday, May 23, 2008 5:52 PM
To: [email protected]
Subject: Re: amp/speakers - ohms

Tube amps are very forgiving when it comes to impedance mismatches. Since the speaker jacks are wired in parallel each jack sees the impedance selected on the switch. Therefore with two 8 ohm cabinets the selector would normally be set to 4 ohms. In your case, cabinets with different system impedances resulting in an impedance somewhere between the two I would try the 2 and 4 ohm settings to see which sounded best to you.

On the Conrad Blues Jammer amp I recommend if the player wants more of a compressed sound to plug into the 4 ohm jack. The speaker in the amp is rated at 8 ohms.
Conrad Sundholm

 

[johnk_10]

yep. while i was testing it last night, my 2000s actually has more power and headroom when i plug it's single 4 ohm 18" vega cab into its 8 ohm output than an 8 ohm cab. I have tried putting a dummy jack in the extension speaker jack to switch it to 4 ohms but it sounds better running a 4 ohm load on its 8 ohm output.

And yes, tube amps are very forgiving and versatile. this is really nothing new as all of the old fender amps that i grew up with (i.e. bassmans, bandmasters, dual showmans and showmans) would all run fine on 8 and 4 ohms.

 

[Stumbo]

http://www.talkbass.com/forum/showthread.php?t=430228&highlight=sunn+club&page=2

You should consider joining the Sunn club.