EL83 / 6CK6 valves in place of EL84

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Seppola
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Re: EL83 / 6CK6 valves in place of EL84

Post by Seppola »

DaveW wrote:Since reading this thread ref. Rory Gallaghers modified AC30 using EL83s in place of EL84s I have been tempted to try these. I have finally done so and am really impressed. I think they give a slightly emphasised mid range and break up very well. They are also very cheap: picked up NOS Teslas off eBay for a couple of pounds each. I have had these running for a few weeks now with no problems.

Original link to Rory's AC30

http://vintageamps.com/plexiboard/viewt" onclick="window.open(this.href);return false; ... 30#p795629

Just a bit of a wiring change, didn't need to change any component values. I have now fitted a small toggle switch in between the bases to allow me to fit either. Having the switch set to the wrong position doesn't seem to do any harm either, they just don't work.

If anybody else wants to try I have listed what I did here.

http://s59.photobucket.com/albums/g293/" onclick="window.open(this.href);return false; ... cture6.png

I ignored the screen connection on the EL83, would welcome any opinions on whether this is correct.
Hello!
I have both 6P15P-er and EL83 tubes, and I want to try this. Sadly, that photobucket picture does not open. The figure would understand better how the connection is made. EL83 datasheet says that the maximum screen grid voltage would be 150 volts, while EL84 withstand 300 volts. Have had durability problems?

Seppo
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davidw
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Re: EL83 / 6CK6 valves in place of EL84

Post by davidw »

Old Image

Image

Haven't got that amp anymore but ran it with EL83s for quite a while and had no problems and sounded great. You could always hardwire for EL83s and try them before adding the switching.

Hope this helps, Dave
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Seppola
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Re: EL83 / 6CK6 valves in place of EL84

Post by Seppola »

Thanks, it helps a lot!

[/quote]Haven't got that amp anymore but ran it with EL83s for quite a while and had no problems and sounded great. You could always hardwire for EL83s and try them before adding the switching.

Hope this helps, Dave[/quote]
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niCko
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Re: EL83 / 6CK6 valves in place of EL84

Post by niCko »

I'm thinking of trying El83 as well. Seppola please report how it goes. I guess the only way to really find out the sound difference from EL84 is to try them out. If they sound good I will probably try to make adapters.
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niCko
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Re: EL83 / 6CK6 valves in place of EL84

Post by niCko »

I was looking at datasheets and 6p15p is not directly equivalent with EL83, they have different pinout and characteristic data is measured at different voltages. Also I found the Tesla EL83 datasheet and they claim that "Tesla EL83 replaces foreign type 6CK6, CV2726, Soviet equivalent 6p14p."
So if this isn't a misprint this tesla el83 valve is closer to 6p14p than 6p15p.

I wonder how is the headroom of the EL83? Does it distort earlier?
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niCko
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Re: EL83 / 6CK6 valves in place of EL84

Post by niCko »

I ordered som El83 tubes cheap yesterday, I think mostly were made by siemens but a couple telefunken and mullard as well. I found a datasheet with curves at 250V g2 and to me it looks like they will work just fine with 8k load. They will bias at a lower voltage however. I'm expecting lower current and around 7Volts at the cathode for typical "18watt amp" set up .
If this turns out to be true they should distort earlier than El84 tubes. Who ever put them in the "Rory gallagher AC30 amp" and used them they must have done so for a reason. I know some AC30 users don't like the sound when they start to distort(cold PI distortion?). They like the sound just prior to distortion and on full throttle when the EL84 is working hard. However then it might be just too loud. I know on a arena loudness is good but I remember Brian May saying that the loudness of the AC30 was not helpful in recording situations and as you know they often used the Deacy transistor practice amp. Perhaps the use of El83 was to get earlier PA distortion and somewhat mask the PI distortion. I'm just speculating here and unfortunately I do not own a ac30.
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Seppola
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Re: EL83 / 6CK6 valves in place of EL84

Post by Seppola »

niCko wrote:I'm thinking of trying El83 as well. Seppola please report how it goes. I guess the only way to really find out the sound difference from EL84 is to try them out. If they sound good I will probably try to make adapters.
I put EL83 tubes to Fame 15 Studio Tube Head. Before i used old Philips EL84 and EL83:s are too Philips (nos).
I think they both sound very good and they sounds very similar.

Note! Philips EL84 cant use in this Fame amp withoud little modding. Pin 1 is used on pcb and Philips tubes pin 1 is used something inside. Example JJ EL84 works right.

I modded it first to Philips EL84, then i modded amp to use EL83.
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rayandkerry
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Re: EL83 / 6CK6 valves in place of EL84

Post by rayandkerry »

Hi, all.

Anyone know where to find the switch wiring diagram that used to be in this topic?

Ray
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rayandkerry
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Re: EL83 / 6CK6 valves in place of EL84

Post by rayandkerry »

How about this. Is this what we're talking about?
DPDT switch for EL83-EL84 tubes.png
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