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Super Amp DJH is Gone


Deang

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Craig,

The Thetas may not be able to tolerate the higher temperatures found in a tube design. I'm also wondering if this cap might end up making the amp sound to "syrupy", or thick.

RelCap RTX would be outstanding, but again running into the heat thing. Values may dictate some RTX being used though.

I think the best RelCap for the Scott is the PPFXS polypro. film and tin foils. It's a multicap design (internally bypassed), and able to tolerate temperatures up to 105 degrees Celsius. I couldn't find any other cap willing to take the heat:)

Only problem here is that Mike doesn't carry the PPFXS, only the PPFX (polypro. and aluminum foil). The PPFXS have to come from http://www.partsconnexion.com

Good resistors you're getting ready to try. Jeepers, 30 of them! About $30 to $50 depending on wattages used. Kewl.

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No !! Kiwame Resistors are a about $45 for the entire amp and I sure hope there worth it !! I'm taking a gamble on Kelly word !! I'm buying 225 of them LOL ! What I use now is about $20 a amp and sound pretty darn good to me after they break in !!

Craig

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I also don't see why the RTX wouldn't work ? What operating temp are they rated at ?? I just checked the Capacitor.com sight and they are rated to +85 deg. Celcuis that is fine. The factory Caps are also 85 degrees. The only thing I could find was RT series is this the RTX from Percy Audio ??

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Yea, I think I can do the RTX's, which would be sweet.

RTX caps are in the second block on Mike's RelCap page in the Cat. All the values are there.

RT's are at the bottom. We will need to use RT's for the .0012 value. Everything else can be RTX. That's cool, I can give Mike all of my money again (I still don't like thinking about how much I spent on those DQ crossovers!). I think Kelly's Cary pre uses the RTX caps, and my AE-3 DJH has a few in there too. I think he would approve of that cap.

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ahh...that's because they are discontinued!

The RTX caps utilized POLYSTYRENE film, which has been deemed unsafe for the environment by the EPA, so Richard Marsh quit making them. What's out there is all there is. The PPFXS has similiar characteristics as the RTX, and is considered the cap superceding the RTX. The PPFXS also has the better heat characteristics (105c as compared to 85c). However, the polystyrene and tin foil RTX is considered to be the best sounding Multicap.

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Pat says the cans are good. Worst case -- how much are those things?

I've got the tubes covered. Brent owes me four NOS EL-84's, so I only have to come up with the rest. Can the EL84/6BQ5 be used in place of the 7189? Same tube isn't it?

What the hell is that tube compliment again? What, about 20 tubes in that thing, or something like that?

O.K. -- 11 tubes

4) 7189/6BQ5/EL84

4)12AX7

2) 6BL8...or does this one use the 6GH8?

1) 5AR5

Guess this amp is going to cost me about a grand. O.K. Kelly, you can have it16.gif

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EL84's will work but the Amp will be over driving them. The Scotts take 7189s which are Higher voltage rated EL84's. Alot of people run regular EL84's the only problem is that they burn out faster. I've been told there really is no difference between the tubes the manufacturers just oicked the cream of the production crop and named them 7189s and charged more for them.

The amp takes

4- 7189

2- 6U8A

4- 12AX7

1- 5AR4

What brand tubes are in the amp now ?? You never know they all may be still good !!

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Hi Guys,

This amp is dead quiet,so no can problems.The outputs are excellent Raytheon 7189,all test over 110% on my Eico 667.The rest of the tubes are fine,so save your money.I'll send a quad of TFK smoothplate 12ax7's for evaluation,but I can tell you that a set of Ei elites are shockers(meaning great),and they're about 7.00 from Ned at triode.You be the judge.

Sounds like you guys are going over the top on parts.Ought to be interesting.

Best,

Pat

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Hey Craig,

I built a pair of Billie's for a friend and we listened to them with and without the Kiwame resistor upgrade.I'd put them in the signal path,but maybe just use what you've been using elsewhere.They sound like super clean carbon comp resistors:I love them.

Pat

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How about those phase splitters Pat, which ones are they?

Craig, here is the deal on the EL84/7189. One can use a 7189 to replace an EL-84 -- but a 7189 MUST be replaced with another 7189. Only three current production tubes provide the necessary output to support a circuit designed to run off the 7189.

Sovtek EL84

Ei-Yugo EL84

Tesla-JJ El84

These tubes match up spec wise with a 7189, and the Ei-Yugo, is an exact copy of the old Amperex 7189. I wouldn't mind hearing this particular tube.

At any rate, this explains why NOS EL-84's burn up fast in the Scott.

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Hi Craig,

It's got NOS 6BL8(you're thinking 299C for 6U8) as phase splitters marked"made in Great Britain",so probably Mullard or Brimar.The 5AR4 is a NOS Admiral(a Mullard with the hole in the locating pin).It doesn't get any better.

I've had Ei 12ax7's that were horrible(and microphonic),but I think these are carefully culled examples.They really are good.

Best,

Pat

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Pland,

The 6BL8 - 6U8A and 6GH8 are all interchangable tubes any of them will work in almost any Scott Intergrated amps unless it was specced with a 7199 which a few were. The Amps that use a 7199 can easily be changed to use a 6U8 just by swamping around 4 pins.

Deang,

I know why the 6BQ5's burn out I believe I told you why didn't I LOL !! The 7189 and the 6bQ5 are the same tube with slightly different plate voltage ratings. This is why a HF-81 puts out 14 watts and the 299 puts out a conservative 17 watts more like 23 or so actually. I already have 3 sets of telefunken 7189's and 2 sets of Amperexs also have RCA and GE's and then of coarse what I run Russian Military 7189s from the 70's there really isn't that big of a difference between any of them. The sound on my Opinion is in the 12AX7's and 6U8's of which I have every NOS brand you can imagine. The joy of scoring one here and there on Ebay !!

Craig

Oh Kelly is out of town for his Mothers 75th birthday party !!

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