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In Reply to: RE: EML vs. Sophia Meshplate 2A3 posted by tube wrangler on July 18, 2012 at 19:39:10
You said: "All the solid plates except the JJ 2A3-40 sit there-- waiting for something...."
Huh, so the EML solid plates are not so great. Interesting.
So, the superior cathode construction of the EML does not exert its advnatages with their solid plates? Or are EML's solid plates just unsuitable for the job? Or is the JJ cathode construction superior to the EML? JJ's dynamic prowess makes the most of the solid paltes' strengths; EML does not?
Of course, some folks prefer EML's solid plates over the mesh: 2A3-S vs M versions; 45 globe vs mesh...
Surprise! No one's opinion is absolute in these matters of subjectivity. Ah, the joy of concepts. Dogs, tails and tales.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
Follow Ups:
EML's Mesh is a very excellent tube. It combines most Solid-Plate strengths with some of the introspection, timing accuracy and depth of image that is found in the old AVVT Mesh.
EML's superior filament setup shines through the Solid-Plates as well as the Mesh. The Mesh is now a Solid-Plate frame with a welded-in frame which houses the woven Mesh section.
Is this tube the ULTIMATE in perfect music? TODAY it is- but the old AVVT Mesh beats it musically overall. ONLY certain LATER AVVT batches could do that-- some batches didn't.
Next, you might consider musical POWER and DRIVE. Here, the Solid-Plate EML is better, and it is surprisingly good at the details staying intact also-- as in the old AVVT Mesh.
The JJ 2A3-40 is not superior to the EML Solid-Plate, but it's a great bargain, and is powerful and rugged, with extended highs, and very potent lows. Midrange clarity is good, but some of the midrange-- full-midrange linearity-- cannot compete with either EML type, or the old AVVT Mesh..
Get out your wallet and buy EML-- either type, if you've got good enough amps, speakers, sources and wiring to tell the difference. Otherwise, bask in the delights of the JJ's super cheap price, and its terrific ruggedness, longevity, potent drive and build quality.
You'll never notice the lesser midrange potency unless you insert an EML. Then, it's no contest! I said "get out your Wallet".
---Dennis---
I will certainly be looking into the EML tubes. I'd actually like to try running an AVVT AV8 as an output, but not unless EML is going to take on production of this tube.
My first amp will be a pancake for the dog, but for subsequent builds I will be taking your advice and running my outputs at low dissipation and using a more 'modern' PSU design. I am also having a pair of ~10ft^3 MLTLs built for running the GPA 604 driver. Hell, I might even use a simple, well-made stainless steel chassis, directly couple a wimpy driver (a pentode in my case) and tune my cathode caps...
Seems like some of your suggestions are not lost on folks. I will at least give myself an opportunity to challenge and learn. I might even end up with a system that I enjoy.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
You're on the right track, assuming you stay on it and spend the bucks necessary until you get it.In the long run it's less costly because you'll not be needing something better later on.
The GPA 604-- even with their included passive crossover, is still the best thing out there if you really enjoy all kinds of music presented right. That crossover can be used-- and you can get good results-- if you'll unsolder the input and output wires and install something good like Siltech LS-38 or its modern equivalents.
Also, take a good look at the traces on any circuit board, and bypass them or short-cut them with better pieces of wire where runs get more than an inch or so away from a use-point. Make the whole thing more efficient.
The extra wires can be soldered directly onto the existing traces (parallelling them), and the original trace wiring can be left intact. Be sure to consider what you're doing-- for instance, a tweeter should "see" its capacitor first-- not find it further up the trace-line behind something else..... If this mistake is made on the board, bypass it with a wire, leaving the trace hooked up also-- use an equal-length high-quality, 12ga., multistrand audio-quality wire. Of course, Multistrand silver.On a budget? Use Tinned Copper just like what came with it, but double-run each input and woofer wire with an equal length of the same-- simply ask GPA to send you some extra wire when you buy the drivers.. NOT untinned, and NOT solid strand-- use Multistrand of high quality.
For the tweeter? I'd splurge here even if broke and install single run of 12 ga. Siltech multistrand to the driver.. When you hear Cymbals, Triangles and Harpsichords, you'll thank Siltech.
Capacitors need not be replaced, just bypass then with small Dynamicaps. That bathtub resistor you're looking at isn't going to bite you-- you can keep it in, or you can slip-in a MILLS (12 watt sizes, please) to upgrade a bit. You can double the value and parallel two of them to get back to the original value, but match those to about 1/4% if you do that.
Why? Parallel resistors allow two paths for electrons to take-- so acceptance of a pulsed transient is faster, cleaner and is much more complete as the pulse passes thru the system.
Downside? Parallel resistors must have absolutely equal lead-lengths, and must measure within 1/4% of each other.
What about the stock inductors? Leave them alone!
---Dennis---
Edits: 07/21/12 07/21/12 07/21/12 07/21/12
Dennis, thank you for sharing those details. I have saved them and might just experiment with this in the future.
At this point I'd also like to thank you and Jeff for suggesting this driver. Your posts are in part what got me looking seriously into the GPA 604. After much investigation and procrastination I finally thought it the most suitable option for me. We will see.
The drivers and Rick Craig crossover have been received; the custom cabinet has been designed and the build is under way. I posted some details at the link below. There is not much expense being spared (within reason), though capacitors and wire are two areas I look forward to experimenting with. I will certainly try your suggestions.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
Can you make it to the October 2012 Denver RMAF show, and listen with us to all of this stuff, including MLTL GPA 15s??? Its fun to do. Plane fares have dropped.
Jeff Medwin
Hi Jeff,I'd really, really like to hear Dennis' stuff and more importantly meet you guys! Living in Australia makes it a challenge. I am helping someone based in New Jersey with a project... so perhaps I could make an excuse to visit then kick on from there? Unlikely, but let's see if I can get comfortable with the idea.
If not this year, then next.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
Edits: 07/22/12
How did the 2A3 amp with the modified 91A circuit sound to you?
{2.8 microfarad oil cap in the input stage)
The Mind has No Firewall~ U.S. Army War College.
Thanks for asking!
Unfortunately I could not get the supplied layout to work to my liking, so I ended up pulling it down before completion. Since then work and domestic stuff have taken the majority of my time so have not rebuilt it yet. Hopefully I will have it done in the next month or so.
Will keep you updated!
Keep well.
Cheers.
“As long as we have any intention to be right… we should be wary. So long as words have the slightest ego attachment, they are dishonest.” Charlotte Joko Beck
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