2- Sunn 2000's compared

[pbman1953]

I have 2 - Sunn 2000s amps and I have not had them at home for a while. They are kept a studios where I play.


They are very similar as far as internal parts but have some differences. I looked at both and I figure , why not A/B them before they leave again.


Before I list parts I'll list sound differences. I can't say they are night and day but they are different.


Keeping mind the following:


The speaker is the same during the flipping back and forth
The bass boost is on for both and tone controls are set the same.
I set volume by ear. Both amps are wired for 4 or 8 ohm


Amp A- Deeper and a bit more transient that Amp B. Deeper in the sense of having more density in the mid to lower bass.


Amp B- Cleaner and brighter, less transient. Plus turning up the bass control still doesn't equal Amp A, deep bass wise.






Parts difference-


Amp A- 2- bias pots , one per pair
2- New Sensor- Tung Sol 6550
2- Winged C- 6550
2- Weber Copper caps in the rectifier sockets
1- Sylvania 12ax7




Amp B-
4- New Sensor Tung Sol 6550
Diode rectifiers - under the tube socket
1- Amperex Bugle Boy 12ax7

It's not like I'm looking to fix anything , but I'd love Amp B to dig ( bass wise) like Amp A does. Plus I'd like Amp A to have the clarity like Amp B.

Thanks

[drgonzonm]

It might be the rectifier modifications.  It is my understanding from other forums the webber cooper will sound different than SS rectifiers. 

[Ritchie200]

Does amp A have old Winged C or are they the new ones made by EH?

Try swapping OP tubes to see if the characteristics follow the tubes.

Also, these are not new amps.  Things inside may have drifted over the years - I know I have!  Or just get a Y cord and enjoy both!

Jim

[pbman1953]

Winged C were from SED, not New Sensor (EH  all others ).


I could try both amps with 1 pair of Tung Sols and see if that changes anything.

[Ritchie200]

Oh gosh, I was thinking Svetlana!  Sorry about that!  I know a couple of Major buddys who love the old 6550 Winged C tubes.  I keep telling them to use KT88s and they insist the Winged C have enought omph.  It would be interesting to see if those charactoristics follow the tubes.  I think the old Winged C KT88 tubes were the best since the Gold Lions.  I dont doubt that quality crossed all production.


Jim

[pbman1953]

Any other comments out there?

[pbman1953]

Jim,


I've always loved SED Winged C 6550's. I don't see many KT88 listed anywhere. I'd still use them but I refuse to pay the current price. SED went down and some are asking up to triple of what they originally sold for.


My other favorites are GE's but again I can't justify to pay. I've had decent success with the Newer Tung Sol reissues. But one company makes so many brands, I question how different they really are.


Think of GM back in the day- The Olds Cutlass, Buick Skylark, Chevy Malibu & Pontiac Lemans all had the same motors and I think transmissions. the different was the body and interior. So I question New Sensor on how different these tubes are :


Too many brands-


EH
Sovtek
Svetlana
Tung Sol- actually I using both the 6550 & KT120 ( which are excellent)
Mullard
Gold Lion- even though these may be their best

[drgonzonm]

Think of GM back in the day- The Olds Cutlass, Buick Skylark, Chevy Malibu & Pontiac Lemans all had the same motors and I think transmissions. the different was the body and interior. So I question New Sensor on how different these tubes are :

It wasn't until the mid 70's GM used common motors and transmissions, I remember Skylarks with 326 c.i. motors.  Use this link http://442.com/oldsfaq/ofeng.htm

[pbman1953]

Did some testing last night.


Both amps with 1 set of Tung Sol's- No sound changes




Then, One amp with 1 pair of Tung Sol's, the other with the SED winged C- no real differences - Still Amp A was beefier , bass wise, while Amp be had more clarity.


The one thing that stood out is that Amp A, with 2 bias pots, did not like 1 pair removed. Had a farting type sound . I had the amp on a very low level for any of these tests.. I put the second pair back and it was fine.

[Ritchie200]

SED quit making receiving tubes about....5 years ago?  That was a dark day....  EH/New Sensor makes all the "old" branded stuff as you probably know.  If you look at the internal parts the KT88's look like 6550's in a different envelope.  I've heard they both sound pretty sterile.  Maybe Ed can jump in here about the newer KT88's.  I've got 8 old Winged C KT88's stockpiled and have not bought any other brands since the early 90's and they were all crap - except for the Winged C.  I've got a bunch of OLD good ones that have been Major'd and unfortunately are no good...  I think you would like KT88's as they are very musical, big and bold.

Jim

[pbman1953]

That's why I'm liking the Kt120's and I know Ed has experience with them and gave me the thumbs up.


I have them in the Traynor YBA 3 Custom. Running well and the transformers are as cool as with the El34 stock tubes.

[Ed_Chambley]

Jumping' in.  You see, I am old dammit.  I really remember the GEC's and these tubes set the bar high, so high I am not sure we are going to see anything like them anymore.


I prefer the KT120's simply because they are strong, feel and sound.  No denying a noticeable bass extension in HiFi, Bass and Guitar.  Next, I hate to write this, but the Chinese Valve Art have outlasted the new Gold Lions, which do look a lot like the new production 6550 which look nothing like NOS Tung Sol or GE.


I was lucky with 2 tube types, really 3.  Since I have had Leslie speakers around most all my life I have had big tubes and all of us have our tube stories.  Well, I fell into a case of real Winged =C=, all paired matched along with some kt88's and I am holding them.


What I do not speak of often is the Xf2 Mullard, purple boxed matched pairs that the man who owned the TV and Radio shop gave me when he closed his store.  I will say I have some, but it would be bragging to say how many.


My preference for big tubes are Real GEC and I do like the New Gold Lions, but I still hear better mid definition using NOS Tung Sol 6550.  I have to give it up for the new Chinese tubes I have installed for me and others.  I have a pair of Valve Art that I have beat the hell out of running them wide open with 569 Plate Voltage (remember I have a little soundproof closet for cabinets) and they sound really good.


Pete, Dummyload tipped me off to use a 12At7 in the PI position of my Push Pull 2 tube monster and the preamp is EF86.  I have to admit the Chinese tubes sound so good I refuse to put any of my real RCA, GE or Tung sol 6550's in anything.


I am still keeping them.


Jim, yes Rich and I communicate often.  We are a lot alike.  Always happy with our sound and never happy with our sound.

[pbman1953]

Nice write up Ed, real solid info on old & new. Thanks!

[pbman1953]

One more factor,




The brighter amp has a Mercury Magnetic OT and the other has  Schumacher

[Ed_Chambley]

Oh you have quite a few more factors.  As i I mentioned to you in an email, just the differences in Pot values in the tone stack could make very noticeable changes.  Fender made a video when they released the RI Bandmaster Tweed showing 4 different amps and how they used all of them to create the reissue.


I wrote to the associate at Fender asking how they determined which way to go with component drift.  He told me out of the 4 amps the played, 2 of them were preferred by everyone for the same reason.  Early breakup and dirty tones.


Upon part selection the averaged the components.  I thought that to be sort of cool, but when the first one I saw arrived in a friends store, I opened it up and it was exactly the same as the schematic of the original.  No components differed.  Also the thing shipped way cold bias.


They almost fooled me, but it is still a great sounding amp.

[Willabe]

Next, I hate to write this, but the Chinese Valve Art have outlasted the new Gold Lions, which do look a lot like the new production 6550 which look nothing like NOS Tung Sol or GE.

Ed are you talking about KT88's here or 6550's? (I'm asking because you started the paragraph talking about KT120's.)

[Ed_Chambley]

Next, I hate to write this, but the Chinese Valve Art have outlasted the new Gold Lions, which do look a lot like the new production 6550 which look nothing like NOS Tung Sol or GE.

Ed are you talking about KT88's here or 6550's? (I'm asking because you started the paragraph talking about KT120's.)

Sorry, I see the confusion. I am speaking of Kt88 Chinese. Whenever I mention 6550 I am referring to NOS compared to new kt88 because a lot of folks tend to say new production kt88 are l the same as 6550. The new Tungsol for instance.


Let me wrap this up better. Tha kt120 is the best new tube and up until recently the New Glod Lions were lasting well and had a good balanced tone, but still not as good as NOS 6550 in mid clarity, but close. Better or firm bass from gold lions new.


In the last year I have used A lot of Valve art and they are holding better and seem to be lasting longer. Chinese Kt88. When I speak do lasting longer, there is a crispness in the bass with kt88 that goes first. Usually around 1000 hours, but the Chinese tubes I has installed are lasting over twice this time and the tone is there.


AES ran a special and I bought 12 and have been using them. A lot of the guys I know still use tube bass and prefer since usually we Have a nice sound system and stage volume is lower.

[Willabe]

I thought you were talking about new KT88's, I just wanted to make sure.

Thanks Ed, very good sonic info.     

I forgot now but have you tried the KT150's yet? And if so what do you think of them?

A pair of those in PP AB1 might be great for 150w+ for a bass rig?

[sluckey]

The Sunn 2000 was designed for a bass instrument and the tone circuit is voiced accordingly. The speaker cab was also designed for bass. The power amp is the same as a 'guitar' designed amp. How are you using them?

[pbman1953]

Bass guitar strictly

[Ed_Chambley]

I thought you were talking about new KT88's, I just wanted to make sure.

Thanks Ed, very good sonic info.     

I forgot now but have you tried the KT150's yet? And if so what do you think of them?

A pair of those in PP AB1 might be great for 150w+ for a bass rig?

No kt150. From the hifi guys they are dull.

[Willabe]

Hmmm, ok, thanks Ed.