6sl7 front end

[funkmeblue]

TJ full music makes a 6sl7 based on the old rca in a huge bottle but it's a bit pricey and I haven't tried it. The chinese 6n9p and the sovtek 6h9c sound the same to me and not real good. The new tung sol sound good in my HI FI but not so good in my express.....not bad, just not as awesome as the old RCA's and my recently aquired and new favorite the sylvania vt-229.

[passfan]

Passfan,

That sounds encouraging. I've got a buddy who tries to build every amp using Octals so 6SL7's are usually part of the line up. He just loves those tubes! They are a famous for great tone but also some hum, and microphonics. If you found a quiet set then you've scored big. There is somebody that has those in production again, right?

Do you think the difference of the gain plays a role in your results? I think it's 70 on a 6SL7 vs. 100 on a 12AX7.

Congrats on putting together something that works really well. It really looks like something in the true spirit of Ken Fischer.

rj

The ones I am using are Phillips JAN 6188's for V1 and V2. V3 is a saratov made 6sn7 which sounded better and A pair of Russian 6L6GC's in the output. Yes I think you are right , they are lower in gain but my PT is a 350 - 0 350 and my B+ is just over 400. I am also using you setup for the filter section. I'm almost scared to pull it apart.

[passfan]

TJ full music makes a 6sl7 based on the old rca in a huge bottle but it's a bit pricey and I haven't tried it. The chinese 6n9p and the sovtek 6h9c sound the same to me and not real good. The new tung sol sound good in my HI FI but not so good in my express.....not bad, just not as awesome as the old RCA's and my recently aquired and new favorite the sylvania vt-229.

The two 6h9c's that I had sounded like dirt as well. I had a different pair that had no markings that were okay but I swapped the one out for a 6sn7 in the PI and it was an improvement.

[FYL]

TJ full music makes a 6sl7 based on the old rca in a huge bottle but it's a bit pricey and I haven't tried it.

Modified 6N9P in an ST bulb with a brass base and gold plated pins. Very silly marketing ploy targeting gullible audiofools with more money than neurons.

The chinese 6n9p and the sovtek 6h9c sound the same to me and not real good.

Vintage 6H9C and 1579 are some of the best 6SL7GT's ever, grade J 6N9P's are nearly as good.

[passfan]

Here is the chassis and cabinet I built for the permanent home. The cabinet I put together the past weekend. I had a rain day today and some gibson gold flake so the chassis got a coat or two of lacquer, the expanded metal is going in the black cabinet which houses my rocket. The one for this amp will be black.

[passfan]

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[passfan]

One more

[andrew]

Hi all, This suggestion was posted by david g : I would like to know about using the 4th triode as a cathode follower on an Express with a 6sl7 in V2? Is there a schematic or layout anywhere?



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An alternative to paralleling triodes would be to use the 4th triode as a cathode follower after the 3rd stage

[tweedeluxe]

I too just built a Rocket-ish amp with 6SL7s in an old Bogen PA head. 6L6 outputs, 5U4 rectifier, 47ohm "sag" resistor. Around 470V on the plates and 390 on the screens, if I remember correctly. I used a voltage divider in the power supply between the OT primary and the screen node, just like the original PA circuit.

First two triodes are wired in parallel with a shared 47k Rp/820 Rk. The rest of the amp is pretty much the stock rocket circuit but with 68K plate loads and a 820ohm cathode R / 33k tail resistor in the PI.

here's a clip: http://www.youtube.com/watch?v=h65mFjybi4o

[FUCHSAUDIO]

You could always adapt.....

[passfan]

Wow, I barely finished the new head and played it for around two weeks. The first guy that heard it snatched it right up and now it's gone. He ab'd it against my express and my rocket and picked it as soon as he heard it. Now I have to build another one. By the way it took a rat pedal with ease and didn't even burp. I have found with a 6SL7 in the PI it stays somewhat dirty down to lower volumes. If you swap out to a 6SN7 you get the clean chime from 12:00 down. This is great for people who want some dirt late at night to practice.