EL-84/ SV-83 Interchangeablility

[Deang]

It has been a very rough two weeks for me. At some point I will write it all out, for now -- I just need some quick resolution.

Several weeks ago I received some NOS RCA EL-84's. I put these in my Super Amp expecting further improvement. I thought they sounded a little lean, and figured tube break-in. So -- I wait.

Complicating matters further has been my exposure to the DQ's, which provide a dark, deep growl. I go back upstairs to listen to the RF7's and think -- "Man, that sounds thin -- is this the sound I have been swearing by for over a year?!"

So, I think maybe I got some bad tubes from Brent Jesse -- I throw the next set in. Same thing. I spend a week going back and forth between the systems. Every session with the Klipsch is agony. I think that maybe my ears just got used to them sounding that way, and hell -- it is clean as can be. But lean. No bite. No grip. Just midrange, and a lot of it. I figure the DQ's have just screwed with my frame of reference. I wait. I grow impatient.

In the end, I actually decide I like the DQ-10's better -- because that's where I'm doing all of my listening.

So, how to fix this? Well, obviously it's time to sell the Super Amp. I mean, my ears became used to a sound that was clearly not right. How could it be? It was giving me headaches now.

Sold it in 3 hours.

I'm packing it up and boxing tubes. The RCA's are going back to Brent -- and I'm sending the "stock" tubes. You know, the EL-84's that came with the amp from AES/Cary.

As I'm putting the tubes in the boxes, I see on the flap...SV-83.

SV-83?

I pull a tube out and look see this:

Svetlana

SV-83

huh?

I start searching. I end up at Triode Electronics and read the following:

"Svetlana SV83 Note that this tube does not directly interchange with 6BQ5/EL84/7189. Instructions for converting amps to use SV83 can be found on the Svetlana company site."

O.K., off to the Svetlana site. There, I finally dig up the following page:

http://www.svetlana.com/docs/TechBulletins/appnoteNo.29.html

At this point I am not getting warm tube fuzzies. I go back through all my emails, and find the original correspondance between me and the previous seller. He says, "Just retubed a year ago with tubes purchased from Cary Audio."

I just sent Dennis Had an email asking what the deal is. "Hey Dennis, you guys ever mod any of these things to accept the SV-83? No, then why does my AE-25 use them?"

Here is the awful part. I mean truly awful.

The amp is boxed up, and the check is in the mail.

I fear I have just made a terrible mistake

If I back out of the deal I'll get negative feedback, but what I really want to do unpack the amp (Oh how I DON'T really want to do this -- it's wrapped in 50 yards of bubble wrap and tape) -- and stick those SV-83's back in there and see what happens.

Lord help me!!

[arco]

**** happens!

[mobile homeless]

To show how late it is, I still dont know what you are actually saying here... Unless the owner did something on his own, that Superamp really isnt meant to use the SV-83. It's true, the two are not interchangable, even though they look like it. The more common amp that uses the SV-83 is Steve Deckart's ZEN SET amp, but it uses the SV-83 as the output. Which is also what that Eric Barbour article it talking about, converting a EL-84 amp to run SV-83 in the output spot.

Still, I dont get whether you are saying it sounded BETTER with the SV-83 or you think it was modded to use the SV-83, or.....

Personally, if you read on the forums, many users do not like the Superamp wired in TRIODE mode. I think I wrote this to you a few times. Since you have gotten much better at soldering, I am surprised you didnt convert the amp to Ultralinear to test. Also, it really DOES TAKE MANY HOURS for those EL-84 to break in and even out, especially in that position. I dont know. I wouldnt have jumpled to conclusions so fast about the amp. Still, I dont think the Superamp is one of my favorites either in some ways. IT does not have the low end heft of other amps but the sound that you are describing tells me something is not up to snuff. IT shouldnt sound THIN and be hard to listen to... Yet, I never did understand how you were listening to heavy metal via the Superamp in any guise as the stock model I had here for those months wired in triode did NOT like that spectrum at all. Also, did that amp have the oil caps or the film and foil?

I dont know. I hesitate to say this... But there are a lot of great speakers out there... And in some ways, I dont think Klipsch is always in that list. Not the best thing to say on a Klipsch Forum. But there are a hell of a lot of options in audio. System matching is all important and doenst get anough air time here. WE have talked about it in the past, but it needs repeating often.

Something is definitely amuck over there, somewhere in the chain. I really dont think the Superamp is your best choice for your music while wired in triode mode. What did you think of the RF-7 when run with the AE-3 DJH pre and the Aragon 4004 mk II? You havent mentioned this.

Also, I noticed you sold the AE-3 from downstairs. Did you ever try something like Sylvania 6SN7 in place of the 5692? The 5692 is a more atmospheric, lush type tube that does not always work in some applications; you might have preferred the more sharp, focused sound of a good 6SN7. There are so many variable going on and drawing the wrong conclusions as to which is doing the negative is a common faux pas.

Seems you are running into a lot of problems at once, many making you question what you are really hearing. You need to stop and get some bearings before making a lot of rash decisions.

kh

[No Disc]

Well, if it were me, I'd take the negative feedback. If you refund the money and explain I doubt any reasonable person would give you negative feedback after the explanation.

It's your amp isn't it?

Hell, keep the amp, put the stock tubes back in and see if indeed your theory is true. Easier now than after its gone!!!!!!!!!!!!! Just pat yourself on the back for catching it before you let it go!

That's my $.02

- tb

[NOSValves]

Deang,

I bet something really goofy is causing your thin sound. I once thought I had something amiss with my Scott 299 because of real thin sound (lots of high end and almost no low end). It eneded up being a set of RCA cables in the wrong position from the tape out to my Tape deck LOL !! You will find it be methodical.

Craig

[Deang]

Although you might never be able to tell from my posts -- but I'm pretty anal when it comes to my systems. .

I traced all my connections out several times, and even unscrewed all of the rca jacks and checked the solder connections themselves.

No, Kelly -- you understood the post correctly. The amp had been sent to me with SV-83's, which I had been running all along. I mean, they look identical to EL-84's in physical appearance, so I just never gave it a thought. I plugged them in a was a happy person until recently. I ordered RCA EL-84's from Brent, and just swapped the tubes out, naturally thinking I was swapping apples to apples. After I got the amp packed up, I was gathering tubes together when I noticed the label on one of the boxes from the tubes originally sent with the amp. Egads!

So, one or the other is correct, but which? My ears tell me the SV-83's belong in there. The only way to be sure is to pull the amp out of the box, pull the bottom plate off, and see if I can detect evidence of the mod as per the instructions I found at the Svetlana site.

I have sent the buyer an email asking to call me. I decided it would be a dis-service to not tell him what I've discovered. I'm still waiting to hear from Dennis Had as well. What Dennis tells me will determine my next step. It is apparent however, that I am going to HAVE to pull the amp out and make a physical inspection, after which I wire it up again and give it another listen. I avoided the DQ's last night, and will tonight as well. This will make it much easier to make an objective analysis of what I'm hearing.

I have never read anywhere where someone said they did not like this amp in triode. In fact, I have read the complete opposite. Of course, I am not as well read as you. I didn't need the power of ultralinear -- so why do it? I will say that with the RF7's -- it is(was) simply magic. In spite of the fact there being a multitude of other choices on the market as far as speakers go -- It will be cold day in hell before I get rid of my RF7's.

As far as the compatibility between my listening taste and the Super Amp, I can't agree with you here either. Whether I used the base version of the amp, or the DJH -- both sounded fabulous. The RF7's responded very well to these amps. Trust me, I know what Rock-n-Roll is supposed to sound like.

I also don't agree I did this in haste. I worked the problem pretty good for over a week. I pulled out what I thought to be Russian EL-84's, and replaced them with NOS EL-84's, not just once -- but twice. I really thought the problem was related to break-in of the new tubes. What right minded person would ever have thought to put the 3 year old Russian tubes back in? Uh, well, evidently not me. I also really felt that the exposure to the DQ's had somehow changed my baseline, or reference point in my hearing. It is a very different presentation. I believed it more than possible that I had simply gotten used to the sound of the RF7's with an amp that wasn't really wringing the best out of them. I know from experience, that the ears and brain can get used to just about anything as long as it's clean and balanced.

This also explains my bump, and additional post in the "Impendance Curves" thread. -- I was really searching for an explanation.

The Aragon 4004 MKII and AE-3 (stock version) on the RF7's was a very "balls to the walls" kind of sound. It sounded very good, but it was not the sound I was aiming for on the upstairs system. I wanted the RF7 based system to give me detail, clarity, and rich texture - at low to medium volume levels. There wasn't much to write about regarding the combo. I had already said I really liked the amp (it is a very good amp), and lighting up that monster on the RF7's was indeed frightening. However, it was for the DQ's that amp had been slated.

When I finished the DQ's -- there was a surprise waiting for me.

The tweeter mod took most of the "bite" out of the upper treble. The upper treble on the DQ's is now very much like one would expect to hear from your run-of-the-mill high-end "audiophile" speaker. It's nice. There is nothing "wrong" with it. However, it is very "soft" sounding. I considered changing out one of the resistors on the crossover board in the tweeter circuit, to raise the output to the tweeter. The first problem I had is I don't really have the necessary skill-set to make proper judgements in this area. I also had the problem of already having a resistor in place between the tweeter leads to regulate the impedance. I had real concerns that I was going to open a can of worms here. While in the midst of this dilemma and listening to music one night -- my eyes fell on the Thalia. I thought..."why not".

In goes the Thalia, and out comes perfection. I spent two days going back and forth between the Thalia and the AE-3 (I did try the Sylvania 6SN7 Chrometops as well) -- and each time, though losing some 3 dimensionality in the image -- the Thalia sounded much cleaner, had more grip, and put a very nice shimmer on the upper treble. I recieved a double benefit from this revelation. Since the Thalia is a full function preamp, I have the flexibility to add another satellite receiver and my wife's nice Yahmaha cassette deck (which she uses to play karaoke type cassettes to sing with -- to work out songs she sings in church when she solos). Based on sound comparisons alone -- I had no reservations selling the AE-3.

Now, I wait for Dennis.

I pull the amp out when I get home.

Let the games begin.

[Deang]

Well, it didn't take long to resolve this issue.

I just talked to Dennis, and as usual - it was very enlightening.

Dennis said that he is not using the EL-84's in the Super Amp as a power source, but as a current source. He says the Svetlana SV-83 "sounds wonderful", and says it is perfectly acceptable to use it in place of the EL-84 in that application (current source). Dennis does not doubt he sent the SV-83 to the original owner, as he is "fond" of it.

Dennis then began asking me a lot of questions about the RCA EL-84's I bought. He indicated that all NOS EL-84's are not created equal, and related that he himself had come across a bad batch as of late. I asked him if he thought it was possible that the RCA's were not supplying enough current, and that my speakers in turn started tracking the impedance curve. He said this was very possible.

I had contacted the buyer earlier and made him aware of the situation, and just emailed him again telling him what I found out. I gave him a choice of buying it, or not buying it. Since I put it up for sale, and he bought it -- this is the fair and right thing to do. I can always buy another AE-25 -- but I can't reverse the damage from negative feedback.

Wonder what those new Brystons sound like