Rolling with 6as7 tubes

Rolling with 6as7 tubes

In the past couple of weeks, I rolled a lot of tubes from the 6as7 family. That was quite a lot of fun, although I have to admit that rolling power tubes is not as much fun as rolling preamp tubes – the darn things are hot as hell (at least some of them).

All the reviews of the tubes have been posted on this site and here is the summary (since the number of choices is limited, I can actually do the summary – try doing the same with 12ax7 🙂 )

  • Tung-Sol 5998 – very relaxed, very deeeeeep. very smooth. The reference tube – great for instrumental and vocals.
  • Cetron 7236 – very close to 5998 at a fraction of the cost (~$20). It’s not as relaxed, but at the same time more dynamic – the bass is very tight – great for rock.
    Sylvania Gold Brand 6080 – very liquid tube, you just want to continue listening. The price is unbelievable – $9 a tube!
  • Bendix 6080 – very dynamic, very detailed – superb performance during complex passages, separates instruments like no other. The best overall tube and would work everywhere.
  • Svetlana 6H13C – great mid-bass and very dynamic and detailed. Bass extension is OK. Would work great for pop.
  • Raytheon 6080 – very dry, very tight. Good overall balance, but doesn’t shine in any one area.

So here you go, based on the music you listen to the most, you can choose the best tube, but you can also get all of them and switch 🙂

Sylvania 5751 – Quest for a gem

Sylvania 5751 - Quest for a gem

As quite a few of you know, Sylvania 5751 JHS or GB with 3 micas is considered to be “the holy grail” of audio tubes. However, everybody is trying to purchase the JHS version with black plates or GB version with gray plates. They totally look cool with all these gold pins or gold letters and if you collecting them, definitely go for gold, but if you want to buy them to listen to them… I will try to help to save you some major bucks and get the same famous sound. There will be no compromises, just a way to get the same gold brand but for $20-25 a tube – I got them as low as $15!!! I will focus on gray plates – I actually prefer the sound of gray plates to black plates – it’s much creamier.

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GE 6829 Long Gray Plates

GE 6829 Long Gray Plates

1 Star2 Stars3 Stars4 Stars5 Stars (5 votes, average: 4.00 out of 5)
GE 6829 Long Gray PlatesLoading...

” Sound was again in the top group for overall detail and tone quality. Low level detail was probably the most apparent of all the tubes tested, and it had a particularly subtle tonal presentation, distinguishing between some hues and colours missed by the others.” Read

“rich, detailed, warm, and thanks to the lower mu, very quiet and low in microphonics.” Read

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Bellari HA540 Headphone Amplifier

Bellari HA540 Headphone Amplifier

1 Star2 Stars3 Stars4 Stars5 Stars (11 votes, average: 3.27 out of 5)
Bellari HA540 Headphone AmplifierLoading...

And now another headphone amp review. I got Bellari because it’s the only headphone amp out there that uses 12ax7 and thus 5751 tubes. So I was excited that I would be able to use my favorite Telefunken, Mazda or Sylvania GB with it. I got the amp really quickly from Amazon ($3 next day shipping with Prime rules!)

This review is going to be very short… I got the amp, yanked out the Shuguang tube – garbage. The first thing I’ve noticed that power supply was puny – 150ma I believe. I was wondering how that little thing could provide enough power to drive filament and the amp at the same time – but it did. I inserted Mazda 12ax7 with Silver Plates – plug my Sennhisers HD650 – lighted a cigar and turned on an album by Diana Panton. The first thing that I’ve noticed, the sound was quite flat and not much airiness to it. I tried both inputs, but with the same results. But what the hell, I had a good cigar. I continued listening for about 30 more minutes and when the cigar was done, I went to try a different tube – I thought that maybe the amp just doesn’t like Mazda. I plugged in Amperex and discovered that only one channel was working. I plugged back Mazda and then Shuguang, but the amp was dead. 🙁

So a very short review – broken amp (awesome return policy with Amazon) – and a sound that didn’t excite senses even with a fantastic tube.