Electron Blue Pearl

This is unusual for me. A parallel single ended amplifier. I don't get a lot of single ended type output transformers and I build based on what I have. This nice pair of good sized single ended outputs fell into my hands so I thought I'd give it a go.

Firstly, if you're comparison shopping for price or looking at commercial units straight off the rack from Audio Boutiques, please read no further. Those units are made to meet a price point or to fill what is perceived to be a niche in someones analysis of customer buying trends. That's not what I do. If you're looking for a good deal on a commercial amplifier at a specific price point, please do buy one. There are many out there and some are very good. None of them are my amplifiers.

This unit, like all my amplifiers, is built completely from scratch using only hand tools and a small electric drill. There are no circuit boards. Everything is hard wired and tuned by ear. My ear. I've noted to some that over the years my stamina has declined. I can't build with anywhere near the speed of my labors of the past. My ear though has only gotten better.

It has been noted online that my amplifiers rarely show on the used market. If you've been waiting for one you may be in for a long period of inactivity. Everything shows up on the used market eventually. Audiogon readers see lots of fancy equipment all the time. If that equipment is so good, why is someone selling it? Most that buy my units keep them and sell their other equipment. They sell that other equipment on Audiogon.

I trust I need say no more on that subject.

Single ended amplifiers have something of a well deserved reputation for being wimpy. With the exception of crazy units that use 845 or 211 output tubes at 1000v+ for the plate voltage, most single ended units have modest power output.

This unit uses parallel 6L6 outputs to achieve something like 20 watts a side. Like all my units I built it, tuned it, tuned it again, and then tuned it several more times. All custom units are different and it's a matter of making changes, listening, and refining that gets a unit where it should be.
The unit is set for tetrode. There is no triode provision. I've always found that triode makes for a boring presentation while cutting power dramatically. Some people like it. I'm not one of them. Single ended triode is particularly uninspiring. A good glass of sherry will produce the same torpor in a more pleasant fashion at considerably lower expense.

I do prefer something of a laid back state of affairs. Detail coming from a black backdrop instead of constantly hitting you in the face. That's what we have here. I wanted it to sound at least as good as one of my push-pull amplifiers.

That's not easy. I'm picky about how these things sound. It did follow a progression as I tuned it. My bench speakers are ADS-L200C. Those are small speakers that easily fit on the workbench. Easy to drive and with those marvelous ADS tweeters, you can tell a lot with them. After I was satisfied there I moved on to the bane of single ended units, a pair of acoustic suspension speakers. Single ended units are mostly paired with horns or electrostatics, not acoustic suspension.

Horns have the efficiency that mates well with low or flea powered single ended amplifiers. Larger Single ended units are frequently used with electrostatics as the speed of the electrostatics coupled with the revealing nature of the single ended output yields a level of clarity hard to achieve otherwise. Due to the limited power of most single ended units that coupling is generally of the Quad ESL57 and so forth.

I digress. This unit handled the acoustic suspension KLH 26 I paired it with quite well. Still, most KLH and speakers of that ilk are better served with push pull units that can deliver lots of power. What was a revelation was when I fed this unit into some Sansui 2500's.

The Sansui are vintage 65 pounders. Something like six way with 105dbw efficiency and fifteen inch woofers, they were a perfect match. Even so, I'm picky, I usually tune to the local radio station and stop there. In this case I hooked up a DVD player and slipped in a CD that I knew particularly well.
The Modern Lovers as a source was exquisite. Pablo Picasso of course is a classic and was rendered beautifully but later, on other cuts when Curly played a stand up acoustic bass it sounded like a stand up acoustic bass, not that one note bass you so often hear. It was the real thing. I'm a little Dinosaur, a live cut, sounded live. No, not just the clapping and hoots from the audience, the ambience from the hall, the lights flickering behind the bar, it was all there.

Those Sansui are great speakers for testing.  Not that they're particularly wonderful speakers, it's not that. Audiophiles sneer at the stuff that GI's brought back from Vietnam but honestly that stuff was designed to work with the lovely Sansui and Pioneer and Trio tube amplificatiion of the day. The Sansui 2000 are particularly good by the way. They sound very nice with just about any amplification.

The 2500 is not that way. Driven by transistor units the 2500 can sound awful. Really, they've gotten a well deserved reputation for mediocrity from people hooking them up to cheap receivers and the results are, uh, poor.

Driven by good tubes however, the speakers can be glorious. The difference is more than one would expect by large measure. For fairly low power tubes those speakers tell the story better than most. I picked these up on Craigslist for $50. Sure, they needed some work but for situations like this they are invaluable. When a unit can have the Sansui sound so wonderful that they can transfix one, the job is complete.

At first I finished the unit in a high gloss. It looked great but every time a dust particle or whatever landed on the finish it was obvious and bothersome. Too blasted fussy for me.I redid it in matte. Perhaps you have a maid with a feather duster that can keep all your units dust free. I don't. I'd rather listen to music than be bothered with things like that. Matte it is.

All the pictured tubes are included. There are a pair of 12AU7 and four 5881. The unit is amenable to tube rolling for those that are so inclined. The 12AU7 have a gain of 20. 12AX7 have a gain of 100. There are several steps in between, 12AT7, 12AV7, 12AZ7, 12BH7, those and all the industrial equivalents such as 6201 and 5814 will work perfectly. Plug in what you like and compare.

Here's how it works in terms of gain, the 12AU7, with the lowest gain, draws the most current. Because it draws the most current it will therefore have thje lowest plate voltage and be the most laid back of the options. As one plugs in tubes of higher gain, those tubes will necessarily have higher plate voltage and therefore will be less laid back with the 12AX7 being the most forward of the lot. At a gain of 100 one can expect the plate voltage to be 100vdc higher than the lower gain 12AU7 with a commensurate increase in the forward nature of the realized sound.

Nothing is absolute. No taste of predilection final. Should your speakers or room acoustics or personal preference dictate an adjustment in tonal balance, you can easily achieve what you desire. Play around a bit. I don't know what speakers you have or how high your living room ceiling may be. You can trim such to fit your needs as you like.

For output tubes we have some Ukranian 5881. Nice tubes. They will last you many years. Should you prefer KT66 or KT77 or EL34 just plug them in. All will work as before. There's no risk or any adjustments to fiddle with. The sound will change though not as much as changing the small tubes but feel free to substitute as you like.

Sorry for going on overlong. Unlike a typical listing which tends to the terse, I thought a little detail was in order. Really when you buy a commercial unit you know what you're getting. Perhaps that's not true. You think you know what you're getting because you've read a review. Then you listen to the unit and reality sets in.

My units are like that in a way. The difference is that the reality is positive as opposed to that other scenario.

The best buy in HiFI.

Get it or regret it.

Lance Cochrane