Solved the problem with my amp, there were two resistors out of tolerance. Instead of 470K, they were putting out 500K. Replaced them checked everything else and done. Just in case adjusted the pin sockets, and cleaned the amp, though it was very clean.

While repairing the amp, we decided to hear the recently installed EL84-STR's in another equipment. We plugged them to a Magnavox 15WPC amp with Paraphase circuitry (excellent sounding unit), Conrad Johnson PR-2 Pre, for CD's we used an Acurus ACD-11, and for LP's we used a 1950's Rek-O-Kut with rim drive, 70's S Tonearm (mfg unknown), and Moving Coil cartridge (forgot mfg). Speakers were a pair of Klipsch KG-4.

We played various tracks from Bob Marley, Eric Clapton, Jarabe de Palo, but I especially enjoyed Moonlight Serenade (Ray Brown & Almeida) on CD.

First we played using EH EL84's, nothing espectacular, actually pretty bad. After that we used EL84-M's, a huge improvement, very open soundstage, airy, good mids, nice controlled bass. Then changed to TAD EL84-STR, what a difference, soundstage expanded to the sides and deep. The STR is extremely musical, detailed, with an extended and controled bass. The bass is something you have to hear, such an improvement without being muddy or boomy. And what about details, you hear the musicians efforts while playing their instruments, the singers "gasping" for air, the pianist taping the piano pedals. I noticed things that I have never noticed. For example, the soundstage was so good that in some of Sergio Mendez batucadas when they whistled the sound from the whistle was coming straight from the side of us, almost 90 deg. from our seating position, and we were some 5 ft. away from the speakers. The speakers totally dissapeared. We also tested the Heathkit SA-2 integrate amp with similar results; I found the CJ PR-2 and Magnavox combo to be a better performer, but not by much. The Heathkit was more laid back.

You have to hear it, and come to your own conclussions, but personally and my cousin's opinion is that the STR's are excellent. Great for the price, and very well built.

Cool review. I am looking for some new EL84's to replace some EH's I have now, maybe I will give these a try!

Forgot to mention that we did a head to head comparison using a modified Conrad Johnson MV-45 that uses EL34 (NOS Siemens) tubes, which is considered by many more "musical" than the EL84, and the EL84-STR sounded much better than the EL34's.

Here is the list of equipment used to do comparisons:

Tubes:

EH EL84
Russian EL84-M (From The Tube Store)
TAD EL84-STR

Pre-Amp:

Conrad Johnson PR-2

Amp:

Magnavox 15WPC (Paraphase circuitry)
Conrad Johnson MV-45 (Siemens NOS EL34)
Hethkit SA-2 Integrated Amp

Digital Player:

Acurus ACD-11

Analogue (Turntable):

1950's Rek-O-Kut with Rim Drive
Denon DL-103 Cartridge
Aftermarket S-Tonearm (unknown mfg)

Speakers:

Klipsch KG-4

Cables:

Vampire Speaker Wire 10 AWG (2100C) with Vampire Bar-8 Connectors on the amp end, and Monster Banana Plugs on speakers end.
DIY Interconnects: Belden 1505 with Vampire 800 RCA Male Plugs.

Music:

Cocaine - Eric Clapton: Slowhand (Vinyl)
Redemption Song - Bob Marley: Legend (Vinyl)
Complete Disc - Ray Brown & Almeida: Moonlight Serenade (Redbook CD)
Bonito - Jarabe de Palo: Bonito (Redbook CD)

Jarabe de Palo is a very popular Rock/Pop group from Spain, their recordings are very well made and mastered.

Has anyone else used the EL84-STR's, or am I alone here? Would like to know what others thought about it. Now that they got full break-in they sound even better.

Solved the problem with my amp, there were two resistors out of tolerance. Instead of 470K, they were putting out 500K.-----------------------------------


470 K Ohm reads 500 K Ohm, thats about 6 % high, what is the tolerance on the original resistors?

I'm using a matched quad of STR's (from Doug's) in my Fisher Electra console. So far, I like them very much even though I doubt they are fully broken in yet. I've likely only got about 15 hours on them and I still need to recap the speakers. They've really help to fill in the bottom end and the mids seem a bit smoother. The highs are still a bit lacking, but I suspect that's due to the crossover caps. Of course anything may have been an improvement. I had a mis-matched quad of 7189's (1 Fisher/Tele and 2 Lorenz) in there before that included 1 7189A (Rat Shack gold).

Dave

470 K Ohm reads 500 K Ohm, thats about 6 % high, what is the tolerance on the original resistors?

Not sure, but understand it is close to 10%, so it was within tolerance. I feel ashamed to admit that after all the trouble the problem was the Sony DVD/CD Player that was being used as source, changed the source and problem solved.

I'm using a matched quad of STR's (from Doug's) in my Fisher Electra console. So far, I like them very much even though I doubt they are fully broken in yet. I've likely only got about 15 hours on them and I still need to recap the speakers. They've really help to fill in the bottom end and the mids seem a bit smoother. The highs are still a bit lacking, but I suspect that's due to the crossover caps. Of course anything may have been an improvement. I had a mis-matched quad of 7189's (1 Fisher/Tele and 2 Lorenz) in there before that included 1 7189A (Rat Shack gold).

Dave

Good...Even though any matched EL84 would have been an improvement, those sound characteristics are the same I found; though the highs were detailed and not harsh, so in your case it might definitely be the X-over caps. Once you finish your mod's and the STR's are fully "broken" let us know if the highs improved.

... Once you finish your mod's and the STR's are fully "broken" let us know if the highs improved.
PR:

Oh, ya know I will! :thmbsp:

Dave

Not sure, but understand it is close to 10%, so it was within tolerance. I feel ashamed to admit that after all the trouble the problem was the Sony DVD/CD Player that was being used as source, changed the source and problem solved.

No shame,

Just that any equipment that only function properly with components spot on is not designed very well.

I know, have designed prototype stuff like that myself! Changed design after though!