New Little Amp—Edward 14 watter
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how about this little amp??? http://www.hi-fi.com/edward/ The ED – guitar amplifier
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> how about this little amp??? > http://www.hi-fi.com/edward/ > The ED – guitar amplifier
Interesting. I wonder what the "mystery" power tubes are? srd
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What tubes? How much? Hey Moik, it’s got a 110/230V switch!! ..Giri — e-mail: giyengar "at" ford "dot" com
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: > : > how about this little amp??? : > : > http://www.hi-fi.com/edward/ : > : > The ED – guitar amplifier : Interesting. I wonder what the "mystery" power tubes are? ECL82 tubes. See post 19494 from marko on the HC Guitar forum for more details on these tubes from the maker of Ed amps. gerry
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> : Interesting. I wonder what the "mystery" power tubes are? > ECL82 tubes. See post 19494 from marko on the HC Guitar forum for > more details on these tubes from the maker of Ed amps. > gerry
Cool. Thanks Gerry. I’ll go and check it ou. (If I’m not back in 2 hours, please send a search party and a deprogramming specialist.) srd
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> how about this little amp??? > http://www.hi-fi.com/edward/ > The ED – guitar amplifier
Others in the thread have asked about the ECL82’s. Svetlana manufactures an ECL82 in the form of the American system named "6BM8". (See www.svetlana.com for details.) The 6BM8/ECL82 is a triode/pentode package. The triode characterisics are a little like one section of a 12AY7 (popular in 50’s Fenders and others) with a gain of about 70 under normal operation. The pentode has a DC plate dissipation rating of 7 watts. Given 80% transformer efficiency and maybe 70% (stretching it more than a bit) efficiency in converting DC to AC (audio) power, the output of a pair of the pentode sections in push-pull should be about 8 watts at the speaker jack. Svetlana offers a design using two 6BM8/ECL82’s that they rate at about 10 watts, using a Hammond model 1620 transformer (off-the-shelf). Very nice for small packages! The power ratings of guitar amps are at best a murky subject. If one will accept more than 5% distortion (output section), then the power output claim is higher. For example, a fixed bias EL84/6BQ5 push-pull output (Class AB1), can deliver 18 watts at 4-5% total harmonic distortion and 10 watts at less that 1% THD. The classic Mullard 5-10 stereo power amp behaves this way. The EL84 type has a 12W DC plate dissipation rating. One might claim 24 W from a pair of EL84’s. This would be like a claim of 14 watts from a pair of 6BM8/ECL82’s. Whatever the number, it still is as loud as it is.
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I’m thinking of DIY project for myself. I don’t play loud by most standards, but I’ve recently begun playing traditional jazz where warmth and clean headroom would be a benefit. I’ve known of some cases where Deluxe Reverb players have swapped in 6L6’s and SS rectifier plug-ins for increased headroom. I’ve also heard that Zener diodes can be utilized to drop some PT voltage (anyone try this?). And if I select a multi-tap OT I should be able to more closely match the primary needs of different power tubes. So I’m wondering just how far I can take this idea: One amp – driving a pair of tubes – designed to go from ‘brown’ to ‘jazz’ with just a switch and a tube swap. ??? Might there be better choices for a warm/clean power tube than the 6L6 (KT??). For example, If the Zener can be switched in/out and a 5Y3 (or other high-sag type?) interchanged with SS I would expect a 660ct to yield maybe 375v and maybe 525v or so. If this makes sense so far, what would be some good choices for a warm/clean power tube to use and what are its current requirements and primary needs (push-pull class AB)? Anyone try to accomplish this sort of experiment? If you liked your results let me know what tubes and trannys you used. Thanks!
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> I’m thinking of DIY project for myself. I don’t play loud by most standards, > but I’ve recently begun playing traditional jazz where warmth and clean > headroom would be a benefit. snip… > So I’m wondering just how far I can take this idea: One amp – driving a pair > of tubes – designed to go from ‘brown’ to ‘jazz’ with just a switch and a tube > swap. ???
I’ve built an amp based on the 5E7 late tweed Bandmaster circuit, but with a power supply setup similar to a ’60s Marshall (a pair of dual-50uF LCR cans for filter caps, plate supply moved to the rectifier end of filter choke….). I used an off-the-shelf Hammond transformer (600VCT, 150mA–yields a solid 425VDC with a 5AR4, around 395 with a 5Y3, has 6A of 6.3V filament and 4A of 5V filament, both centertapped…), a Mojo "6L6-Fender" replacement choke, and a Korg Vox reissue AC30 output transformer. This puts out at least 40W, probably more like 50W (never measured it) with EL34s or 6L6GCs, and probably around 20W with 6V6GTs. I set up the bias with a regular pot and knob, so that it’s easy to adjust for the different tube types, and I’ve marked right on the chassis where EL34, 6V6, and 6L6 like to be biased, so that I can safely "ball-park" it with no meter. If I had it to build again, I’d build the same circuit in a larger chassis, so that I’d have room for a quartet of output tube sockets. That way, I could use a quad of 6V6GTs in the thing. It sounds amazing with 6V6GTs, but isn’t quite loud enough to play a clean lead in a rock band, so I usually end up with EL34s in there (which also sound quite good). BTW, it turns out that at 425VDC plate voltage, EL34s and 6V6GTs bias up at the same voltage, so it’s an easy swap….. Anyway, I hope all this verbage helps you out! Dutch
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> I’m thinking of DIY project for myself. I don’t play loud by most standards, > but I’ve recently begun playing traditional jazz where warmth and clean > headroom would be a benefit. > snip… > So I’m wondering just how far I can take this idea: One amp – driving a pair > of tubes – designed to go from ‘brown’ to ‘jazz’ with just a switch and a tube > swap. ???
I just finished the chassis work on a "Double deluxe". Essentially it’s a tweed twin with a low voltage B+ transformer, oil caps, Telefunken tubes for preamp, 4 RCA’s (6V6) for power, and a Mullard GZ34. Because I have top quality parts in it makes it expensive, but what I now have is one of the most expressive amps ever made. My only regret is that it doesn’t have reverb. Oh well….next project Pete
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: I just finished the chassis work on a "Double deluxe". : Essentially it’s a tweed twin with a low voltage B+ transformer, : oil caps, Telefunken tubes for preamp, 4 RCA’s (6V6) for power, and : a Mullard GZ34. Because I have top quality parts in it makes it : expensive, but what I now have is one of the most expressive amps ever made. Hello Pete; I’m interested in working on a project similar to yours; if you could provide some details, tips and a rough estimate of what you spent, I’d certainly appreciate it. -Bill
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>> I’m thinking of DIY project for myself. I don’t play loud by most standards, > but I’ve recently begun playing traditional jazz where warmth and clean > headroom would be a benefit. >snip… > So I’m wondering just how far I can take this idea: One amp – driving a pair > of tubes – designed to go from ‘brown’ to ‘jazz’ with just a switch and a tube > swap. ??? >I’ve built an amp based on the 5E7 late tweed Bandmaster circuit, but >with a power supply setup similar to a ’60s Marshall (a pair of >dual-50uF LCR cans for filter caps, plate supply moved to the rectifier >end of filter choke….).
There’s not enough postive posts on this NG. (Like I don’t piss enough bandwidth making fun of Dr Stereo, huh?) Bravo. Sounds like you did a great job. Congrats. Now, do what Bulls fans do, turn over & torch a taxicab to celebrate. 
Ned Carlson Triode Electronics,2225 W Roscoe Chicago, IL, 60618 USA ph 773-871-7459 fax 773-871-7938 12:30 to 8 PM CT, (1830-0200 UTC) 12:30-5 Sat, Closed Wed & Sun http://www.triodeel.com
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