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Old 3rd January 2011, 03:27 AM   #21
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nope. If you need big output under 40hz, you are building the wrong amp.

In fact, probably you are in the wrong forum!

E&OE and IMHO as usual
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Old 3rd January 2011, 03:36 AM   #22
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Originally Posted by platplaas View Post
Would the GXSE 15w model offer any advantages over the 10w model? I'm thinking not, but if the frequency performance is based on 40hz at 15w then there is more cushion for performance at 3.5w?
It really depends on where your 'sweet spot' is with budget/performance.
Like 6L6, if given a choice, I'll generally go with the 'bigger is better' (or 'better is better').
I think you will be happy with the 10W, if you'd rather put the $20 upcharge for the 2x15w someplace else.

The RH84 is an excellent project, but not-at-all an 'ultimate amp', so just get reasonable parts and put it together. (I wouldn't bother with expensive 'audiophile' caps and the like either. I used a couple of Russian PIOs and the rest ordinary stuff from justradios and was happy.)

John
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Old 3rd January 2011, 03:59 AM   #23
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Now you have me curious! What would be an ultimate amp build?

Regarding bass: I don't need anything crazy - just trying to confirm whether there might be a tangible difference between the two options.
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Old 3rd January 2011, 04:29 AM   #24
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Originally Posted by platplaas View Post
Now you have me curious! What would be an ultimate amp build?
Ask 10 different people on this forum, you will get 10 different answers!!!

My question to you is why you decided on a single ended, pentode-wired EL84.

(I have typed that out 3 different ways and I can't make it not read somewhat condescending... Please do not take it as such!)

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Old 3rd January 2011, 04:45 AM   #25
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Yeah - that's one of the frustrating things about being a newby in audio DIY - so many choices and no consensus! (Understandably in some cases.)

Reason for building a Single Ended EL84 is that it will be replacing my single ended Miniwatt EL84, which has really impressed thus far. The miniwatt has a switching power supply and I can't find details on the output transformers, but I'm hoping to improve on it by using a similarly simple design, but with better components. If all goes to plan, then I'll sell the miniwatt and ponder what to build next.

I like the EL84 sound, though would consider maybe trying a direct heated single ended triode next. I will admit that I've been tempted to go straight to a DH SET and then just keep the miniwatt, but given that this is my first build I should probably start with something simple and relatively low cost...
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Old 3rd January 2011, 04:49 AM   #26
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\My question to you is why you decided on a single ended, pentode-wired EL84.
I'm not the one building the amp, but I can take a couple guesses:

It's a relatively easy, straightforward build.
Many people have reported building it with good success.
The required tubes are common, readily available, and reasonably priced.

Perhaps if he wanted the "ultimate" (?) amplifier, he could be looking at Koren's TENA?
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Old 3rd January 2011, 04:57 AM   #27
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Originally Posted by platplaas View Post
Now you have me curious! What would be an ultimate amp build?
What 6L6 said....

My point was:
Just get going on this project- once you have it completed you will have a better idea of your 'next project', and then on-and-on.....

The RH84 is a good amp if you have reasonably efficient speakers. I liked mine and gifted it to one of my nephews. Built a Pointz (Audiotropic) Music Machine to fill its spot...

I see a lot of projects online that never get completed while the builder is accumulating a pile of expensive components. (paralyzed in preparation/planning)

I try to put myself a bit more in the 1950s diy style (improvise and get 'er done) and find it rewarding.

As they say , YMMV......

John
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Old 3rd January 2011, 05:04 AM   #28
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you're on the right project. Will it ultimately satisfy? Who knows. But its cheap and easy (and hence cheap and easy to upgrade or play with) and easy to get stuff for.

I doubt its your ultimate end point.

In my experience, nothing is...
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Old 4th January 2011, 12:12 AM   #29
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Rh84is highly recommended as a first build. No actual need for boutique parts except maybe for the coupling cap and bypass cap. Good sound but limited power. A perfect match for the 206e. I know, I have exactly the same setup.
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Old 4th January 2011, 02:55 AM   #30
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Now that I have the choke and output transformers settled....

I'm a little puzzled about the power transformer. The schematic calls for 600v (300-0-300) plus 6.3v x 2 for the filaments plus 5v for the rectifier circuit.

I can't seem to find transformers with the double 6.3v. I did find one at Edcor but it also has a 25v and goes for a fairly steep price: EDCOR Electronics Corporation. XPWR167-120

Hammond has the 372jx but the Hammond site seems to indicate that it only has a single 6.3v (vs Parts Connexion which seems to be worded such that it might be a double 6.3v)

If anyone can shed light on this it would be appreciated. I am a bit puzzled by the transformers because a lot of people talk about using old iron...but if it is so hard to find the right specs in even new iron then I'm not sure how they make old iron work?
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