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Hi Shannon,

I have noticed that you have referenced in a few post here that you have been experimenting with a 6B4G version of the eiclone.

I would love to have more details or progress of this variant, will it become a reality offered to the public in the near future?

Thanks

Norris Wilson

Anonymous wrote:Hi Shannon,

I have noticed that you have referenced in a few post here that you have been experimenting with a 6B4G version of the eiclone.

I would love to have more details or progress of this variant, will it become a reality offered to the public in the near future?

Thanks

Norris Wilson

Hi Norris,

Earlier this year I built a couple prototypes on the Ike board. One was a cathode biased version using a Hammond 270HX and Z565 (sound familiar?). I was using the open bracket 4H Hammond as input choke, with a small tuning input cap to give me a B+ around 320V. The neat thing with this arrangement, is that with a different 'tuning cap' we can use a tube rectifier like the 5AR4. The rest of the unit was basically like the Ike, except tweaks everywhere for the negative feedback and DHT filaments.

The neat thing now is that I've put a spot for the National Semi LM334 on the board, which makes a fixed bias version feasible. The grid resistors on the 2A3/6B4 are supposed to be 50K in fixed bias arrangements (though I think you can get away with 100K per some of the old schematics I've seen). The CCS allows us to get adequate drive in fixed bias, which is difficult otherwise, at least with the Ike topology.

I have a couple chassis in the shop right now (err, I'll get those drawings to you asap, Bottlehead). I'm hoping to have these be my official pair to use for releasing the finalized cathode biased design. Realistically, my goal is by the end of '04. I've got a couple projects almost done around here I must finish first. But anyone dying to tackle this project now, just drop me a line. I'll give some pointers.

Shannon

Thank you Shannon for the update on the DHT 6B4G using the eiclone boards.

I am very interested in the outcome of your experimentation using the 6B4G.

I also appreciate all that you do to make this a fun and successful hobby by offering variety and new amplifier posibilities using your circuit boards.

I unfortunetly do not have a great deal of experience in building audio amplifier or electronics in general, so I will need your completed circuit information to insure that I narrow the possibilities of making costly mistakes.

I am patient and will be waiting for you to complete your experimentation, no hurray at all.

I wonder if the use of 2A3's with your circuit would give more choices of output tube brands and quality? I have seen a few newer versions of the single plate 2A3 hit the maket recently, the EH single plate gold grid 2A3 and the Chinese Audio Art single plate.

If you have any feedback on these or other quality 2A3 tubes that do not cost a mint, I would love to learn about them.

Thanks

Norris Wilson

[quote]I have a couple chassis in the shop right now (err, I'll get those drawings to you asap, Bottlehead). I'm hoping to have these be my official pair to use for releasing the finalized cathode biased design. Realistically, my goal is by the end of '04. I've got a couple projects almost done around here I must finish first. But anyone dying to tackle this project now, just drop me a line. I'll give some pointers.

Shannon[/quote]

Eh, Shannon,

It's the end of '04. What's up with the 6B4G eiclone? ;-)

Francois

Francois_G wrote:Eh, Shannon,

It's the end of '04. What's up with the 6B4G eiclone? ;-)

Francois

You rascal, Dr G! 8^)

You think I've done nothing, but I actually have it on my test bench right now. Sure, I'm a slow poke - but toobin' is a lot like wine making. I'll post some data and maybe a schematic in a bit.

Shannon

Here's some 6B4 Ike data. I'll throw up a schematic ASAP. I'm also going to retest with a Z565. BTW, the A490 looks to be a deluxe ST35 output.

http://www.diytube.com/6B4IKE.pdf

One more thing. I just started to edit the schematic to post it, and realized that with either the cathode biased or the fixed biased versions that the LM334Z current sink mod needs to be in place (due to the lower B+ for the LTP). Indeed, I was using it during the above testing.

Shannon

6B4 Ike Schematic

95% accurate, anyway. I see I left R41 and R42 in there by accident.

Shannon

I am amazed at the simplicity of the phase splitter, considering what you read @ http://www.aikenamps.com/ Designing long-tail pairs - the load line approach , almost too simple!

Comments?

Don[/quote]

I wonder how well some 300Bs would work with this? The cathode resistors would have to be changed, probably about 410 ohms from the 333 for the 6B4Gs and 2A3s. 5V for teh filaments (a good use for some of those 5V, 3A linear power supplies I have laying around, perhaps).

I'm not talking about WE 300Bs here, (only wishing for them...) just some Svvtex/EH, JJs, or ValveFarts, perhaps

/ed B in NH

EWBrown wrote:I wonder how well some 300Bs would work with this? The cathode resistors would have to be changed, probably about 410 ohms from the 333 for the 6B4Gs and 2A3s. 5V for teh filaments (a good use for some of those 5V, 3A linear power supplies I have laying around, perhaps).

I'm not talking about WE 300Bs here, (only wishing for them...) just some Svvtex/EH, JJs, or ValveFarts, perhaps

/ed B in NH

Actually, Ed, I think I'd like to make an Ike board with the power tube half cut off - like Pete Millett's - but for a stereo SE amp. I'd be tempted with the 211s and 845s before the 300B. Too much moolah! Even the Shuguangs.

Shannon

Looks like the 6A5G might also work here, looks to be a 6B4G with an indirectly heated cathode, which is connected to pin 8 - along with the heater CT. Same pins for grid, plate, heater as 6B4G, so it should be plug'n'play compatible with Ike.

/ed B in NH

http://hereford.ampr.org/cgi-bin/tube?tube=6A5G

EWBrown wrote:Looks like the 6A5G might also work here, looks to be a 6B4G with an indirectly heated cathode, which is connected to pin 8 - along with the heater CT. Same pins for grid, plate, heater as 6B4G, so it should be plug'n'play compatible with Ike.

/ed B in NH

http://hereford.ampr.org/cgi-bin/tube?tube=6A5G

Hi Ed,

Do you have a cheap source for these? Sounds interesting!

Shannon

So far I haven't located any 6A5Gs yet. I'll be busily searching during the upcoming flea markets and swapmeets. THis one doesn't seem all that well known, so hopefully the available prices reflect this anonymity...

/ed

Anyone seen the 6B4G (6C4C) old stock Svetlana "C" brand? NOS domestic brands are getting expensive, so I was wondering if these would be a good sub.