Sweet Cary EL84 amp

[Tom Bombadil]

Listening to my Cary Audio SLA-30 amp. This is a fairly rare little power amp, manufactured by Cary in the mid-90s. Said to be a Dennis Had design, but I don't know for sure. He was still there when it was designed. It uses 8 EL84 tubes, 4 per channel, to produce 30 wpc, pure Class A. I'm using EI brand EL84 tubes, picked up in the late 90s when they were fairly inexpensive and not highly sought after. Got a couple of RCA 12AX7s in the pre-driver stage.

I picked it up in the late 90s for $450. Wouldn't part with it for that now.

I'm using a Pioneer Elite DV-59AVi as a transport into a Parasound D/AC-2000HD. Output from the DAC is 2.75V @ 600 ohms. Then into a dual mono passive volume control and into the Cary. The Cary's input impedance is 150K ohms, so that's a 250:1 ratio, and needs only 0.625V for full output, perfect for a passive.

This is such a sweet sounding combo. Wonderful vocals and midrange, with good definition on highs, and rich bass. Maybe not quite as defined and deep as with a big SS rig, but nice.

I rarely run across a reference to this amp, but I am very pleased with it. Only downside is retubing with good quality EL84s can be expensive.

 

[TubeHiFiNut]

VERY nice!

That is most outstanding.

 

[ictwoody]

I had a SLA-30 for a couple years, I really miss it other than the "hot enough to fry eggs" part. I also ran mine with a passive, had Luminous Audio build me one for it. Sweet sounding amp and a good amount of power gives plenty of speaker options.

- Woody

 

[Tom Bombadil]

I had a SLA-30 for a couple years, I really miss it other than the "hot enough to fry eggs" part.

It does get hot! Not surprising with eight EL84s cooking under the hood. I need to get mine up on the top shelf and run it without the cage.

I'm driving 89db speakers with it, in a large'ish room, with no problems.

 

[gadget73]

PPP amplifiers at this power level really make me scratch my head. It would be small effort to get the same thing out of a pair of output tubes. Its probably more difficult to do it with parallel output tubes just because you run into possible stability issues.

Then again I don't really get into the non-scientific reasons for aspects of amplifier design. I just think in terms of component count efficiency. If I can get something done with half the parts, I'll do it. For 30 watts a channel, a 6L6 family tube would do the job.

 

[tube-a-lou]

Great looking amp and I'm sure sounding as well and with those EL-84's there's
something about their sound.

Tube

 

[analog addict]

Listening to my Cary Audio SLA-30 amp. This is a fairly rare little power amp, manufactured by Cary in the mid-90s. Said to be a Dennis Had design, but I don't know for sure. He was still there when it was designed.

Yeah it's one of his. What you don't hear are the stories behind the gear. For instance one line of CARY preamps has several models, but the entry model was actually a prototype Dennis never intended releasing commercially. However, other forces in play wound up having it produced anyway. I was looking at buying one of the entry models, and he said it sounded like crap. The next model up, was a full fledged polished design, and would be fine (Of course if one was available) Bottom line, essentially anything tube designed while he was there was his, but not everything was created equal...

PPP amplifiers at this power level really make me scratch my head. It would be small effort to get the same thing out of a pair of output tubes. Its probably more difficult to do it with parallel output tubes just because you run into possible stability issues.

Then again I don't really get into the non-scientific reasons for aspects of amplifier design. I just think in terms of component count efficiency. If I can get something done with half the parts, I'll do it. For 30 watts a channel, a 6L6 family tube would do the job.

I haven't asked him specifically about this amp, but I've seen him build several parallel SEP amps in the past several years. Knowing him, it could be anything from what tubes and transformers were available at a good price point, to wanting to see what it would sound like, to which way the wind was blowing. Remember, commercial builders have different concerns than us DIY'ers. He might have had a surplus of iron from another project that was phased out, or there may have been a supplier shortage of something else.

Also, he's never thought like a tube collector. I have one of his EL84 SEP prototypes that typically makes the 6BQ5s plates glow just a tiny little bit orange. His comment..."It's good for them!" Many times he's trying to squeeze the last little bit of performance out of the tubes. So what if they only last 2000 hours instead of 10,000 hours? He just builds 'em. It's your job to keep tubes in them....

 

[volcano_pioneer]

Bill Beard (England, I believe) also built PPP EL84 amps. I had a mono bloc pair (M70?) with 8 tubes per channel. They were rated at 70 watts per channel but offered a "half power" switch for 35 per channel. We used to kid about them doing double duty as a room heater in addition to music amplification. They are very nice looking and of course sounded wonderful.

 

[MX117.MC7150]

Nice. The Manley Stingray is similar in using a quad of EL84s per channel and has been quite popular over the years and still in production, with many upgrades. Feel sure your SLA-30 is a Dennis Had design, as he only left Cary 2-3 years ago.

 

[primosounds]

EICO came out with HF 30 and HF 32 in the late 50s

Yes, in the late 1950s EICO was selling kits of a PPP el84 amp filled with Mullard 12AX7, EZ81, 12AU7, AND EL84 for less than 60.00!!!! Of course that was more than a week's worth of wages back then. But you can still find these on the bay for quite a reasonable price. I rebuilt a couple of them and they are great sounding amps. The transformers are quite large and the HF 32 was a mono integrated amp so you even had a preamp with a phono stage cheers, Dak

 

[Tom Bombadil]

When I was shopping, I was looking for an EL34 amp which produced 35-40 wpc. But I kept coming back to the EL84, as I had two Dynaco SCA-35s and an Eico with EL84s and I just loved that sound. So when I found this one, at a very reasonable price, from a very respectable company & designer, I popped for it. At that time the amp was only about 5 years old.

For a while I had it in my bedroom system, driving less efficient Spica TC-60 speakers, which measure at about 85dB. It did a great job, that combination produces a very pleasing sound. I never drove it to high volume levels.

It is more difficult to purchase a matched set of eight EL84s, and even more difficult for them to stay matched over the long haul. However I just decided to not worry about that unless I noticed sonic deficiencies, and I never have.

 

[Tom Bombadil]

Nice. The Manley Stingray is similar in using a quad of EL84s per channel and has been quite popular over the years and still in production, with many upgrades.

Yes, they push the EL84s even harder, I believe he gets close to 50 wpc. Stereophile reviewed that amp several years ago and measured the output as 45-46 wpc across a full 20-20K bandwidth. Getting 30 wpc out of the Cary SLA-30 is pretty easy.

 

[gadget73]

30 out of PPP EL84 is pretty much what I'd expect. A pair runs about 15 watts, so it wouldn't be unreasonable to get 30 out of a quad. Getting 45 a channel out of a quad would be running those things for all they are worth. Heck, most EL34 amps don't do that much. My Pilot is good for 30 a side, and the ST-70 only claimed 35 a side.

I guess I can appreciate liking a certain sonic signature out of a tube. I have something of a variety of amps myself. I have 4 now that run EL84 tubes. I have a 7355 amp, a 7868 amp, an EL34 amp, and a pair of mono amps that run 6L6's. They all have something of a different sound, but considering they are all made by different people and with completely different components there isn't much surprise there.