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Your thoughts please

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I would like suggestions from tube guys.

I won't be able to get started till I finish my house renovation that is in progress, but want to work out my game plan and possibly start collecting parts, etc.

I want to tri-amp using SS for around 100 hz down and use four tube amps for mid and tweeter - speakers would most likely be a Linkwitz Phoenix or Orion - www.linkwitzlab.com

I like designs that use chokes, interstage transformers - and almost revived the Ralph Power thread for this - but didn't want to lock into any one design - Plus the Ralph Power design has a pretty high tube count when you're running 4 monoblocks

I also thought I would probably use Lundahl iron mostly - they seem to be pretty good value for the money and the US rep isn't that far from where I live - but I'm open to any concepts on iron.

What circuits and tubes do you suggest ?

What about it, Frank, Brett, Mohan, Planet 10 ? and anybody else who will get in?

Thanks

Ken L



:)
 
Ken L said:
I won't be able to get started till I finish my house renovation that is in progress, but want to work out my game plan and possibly start collecting parts, etc.
I think this is one of the best ways to do it. I've been collecting tubes and iron for a while now, and grab anything I think might be useful (that I can afford at the time) because I <i>always</i> find a use for it, and it often costs very little. Plus, I'm very much a beleiver in design it in your head 50 times, make it once, and for letting designs have time to stew for a while. Usually, all the obvious errors you can easily miss, really become obvious before you build it.
I want to tri-amp using SS for around 100 hz down and use four tube amps for mid and tweeter - speakers would most likely be a Linkwitz Phoenix or Orion - www.linkwitzlab.com
I really don't like these speakers simply for the complexity of the crossover. There is no way I'd bother with good tube amps after pumping the signal through a ton of opamps. Blech.
However, if you keep the crossover at a low enough frequency, SS can blend in really well.
A problem you might run into though, is the RP will only put out about 6-8W, and the P and O are quite heavily EQ'd, and not that sensitive, so I think you might run into dynamic compression. 20W is about all you can get out of a class A PP DHT amp, with the exceptions being things like 813 and 845 as outputs, but then you're into 1000V B+ supplies and a more complex topology. IHTs will give you more, but aren't quite as linear.
I like designs that use chokes, interstage transformers - and almost revived the Ralph Power thread for this - but didn't want to lock into any one design - Plus the Ralph Power design has a pretty high tube count when you're running 4 monoblocks
I like tubes, chokes (PSU and anode load) and ITs too.
The RP design is about as simple an amp as you can get, a very elegant design, although I'd prefer to see a diff driver stage like the Amity. Even a 6B4G SET will only have one less tube per channel.
I also thought I would probably use Lundahl iron mostly - they seem to be pretty good value for the money and the US rep isn't that far from where I live - but I'm open to any concepts on iron.
You won't beat the Lundahls for performance/$. There is a Lundahl forum just starting on audioasylum too, run by Kevin of K&K.
What circuits and tubes do you suggest ?
if you want a tube driven open baffle, there might be better ways to go about it
I reckon a larger baffle (without active EQ, to get you to 100Hz or lower, say with a PHL mid and a good tweeter, passively crossed, driven by tubes like the RP, with a correctly EQ'd dipole sub (Linkwitz even) driven by a sand amp might actually give you the performance package that exceeds the Linkwitz.

JMO
 
diyAudio Senior Member
Joined 2002
CAVEAT EMPTOR

Hi Ken,

Did you ever had the chance to listen to these speakers?

Can't help but notice the rather high power requirements:
50 to 200W.



I really don't like these speakers simply for the complexity of the crossover. There is no way I'd bother with good tube amps after pumping the signal through a ton of opamps. Blech.

I agree with Brett here.
Think there must be easier ways to achieve audio heaven.
Does the Fertin thread in the LS section appeal to you?
It certainly does away with a lot of compromises IMHO.

Later,;)

Frank.
 
Well, uhhh - Yeah?

I'm really not married to any speaker setup -

And like any other addict, idiot - although I've got the Linkwitz boards - I ordered some slick fiberglass horns out of Australia as part of a group purchase with a bunch of other guys from the Dixie Bottleheads -

Never heard the Linkwitz setup and I think few have, but the ones that have built em, love em - none of this is a big issue to me - I figure I can sell the boards and horns and get most or all of my money back - :xeye:

I'm not afraid of high voltage - I'm careful and would rarely do anything while powered up - and the best sound I've ever heard was an 845 through horns.

The horns that are coming are just the horns without the drivers.

When I looked at the Fertin's they seemed out of my price range, if I remember correctly -

right now the speakers I'm using are Scanspeak solist kits by Madisound - with outboard crossovers and 9500 tweeters

I have never tri-amped - and thought that if I built say a pair of 300 B's to stick in my current system for the tweeters - I could use my VAC 30/30 push-pull for the mids - build something better than the plate amps for my two subs - and I might be doing surprisingly good just with that - the system with two subs is no slouch right now

Anyhow, if I started with a pair of monoblocks that I could use for the tweeters now - I'm trying to make sure that I choose something that will work reasonably well with the horns or maybe Fertins if I there is a group purchase or I could afford them.

I really am trying to phase this in in a flexible manner - it's too time consuming and expensive to do otherwise.

Please keep pointing me in the right direction.

:D

Thanks

Ken L
 
PS

The Linkwitz speakers should work well with low power tube amps on the mids and tweeters - they would need to have identical gain, though. Not married to them - but I do think he's on the right track -

from Linkwitz site - Quote

Tube....Usually their power output is below 20 W and insufficient to drive most speakers. A speaker with active crossovers, though, eliminates the waste of power that usually results from circuit losses and matching of driver sensitivities through passive R, L, C, crossover networks. The PHOENIX main panel should work really well with low power tube amplifiers, because of its high sensitivity over the midrange and the generally low power requirements on most program material for the tweeter (see FAQ20). The drivers represent an easy, low reactance load to the amplifier output transformer due to the restricted frequency range used. The output impedance should be low (<0.4 ohm) to maintain tight control over the voice coil motion.

End quote

Via e-mail he indicated the output impedance is the major consideration if I rmember correctly

One of the major things I have to take into consideration is the sheer size and space taken up by four tube monoblocks and two SS monoblocks - Which is why I'm selling out the parts I had been pulling together for a 304TL amp - Just too big - might be a reason to stay away from the 845's also

My home theater setup has two 19" square shelving/rack towers 5 foot high with one on each side - one side is full right now and the tube preamp isn't even in the system -

Just trying to keep narrowing it down -

Ken L

:Popworm:
 
diyAudio Senior Member
Joined 2002
AUDIO PUZZLE.

Hi Ken,

All this is pretty complex matter.
Your choice of speakers being one thing,amplification being another.
Since I'm by no means a speaker expert I suggest we split the matter in two parts.

In this thread we could address the amplification once the speakers are more or less known.
There is no need for an active filter IMO and if active I would prefer to take the tube (being British helps to understand the pun here).

For the little I know about horns,aren't they usually calculated for a particular driver?
The Fertin are not that expensive compared to horns + driver+ woofers and xover etc.
Moreover they're pretty much fullrange making amplification straightforward.
Must it be a triamped system?
Personally I would opt for a biamped one.
Much more coherent and easier to match.

Keep us posted,

:)
 
Actually, you're right

It truly is a puzzle -

Which is why I'm hoping you guys will save me from myself:xeye:

I've been on a idea track that tri-amping active was the way to go.

I also am an overkill kind of guy on physical solutions -However, I really like elegant, simple and direct solutions - there is an elegance and beauty in the simplicity.

Bi-amping may well be the way to go -

I think it's a good idea to focus on the amp here, but I do want to keep speakers possiblities in mind - they are so interdependent

I almost built an Amity and had seen the Ralph Power design before and liked it -

I think Brett may have an excellent suggestion here - in terms of Ralph Power ala amity

Are there any other circuits/designs I ought to consider??

I read the thread on Fertin's and I could handle 1500 per pair - I thought it was 1500 each - Duhh

I noticed bcherry liked a 45 push pull design with the Fertins-

Bi-amping Fertins with a woofer is looking more and more like a simple and elegant solution -

What tubes - circuits should I be looking at?

I think I'll stay away from the 845's as a friend has recommended.

Thanks

Ken L

:Popworm:
 
Ken,

I'd stay away from the 845 or any other expensive tube, just out of principle.

You should definitely START with the speakers, then pick an amp design to drive them. Since you seem to be thinking relatively low power triodes, just get some efficient speakers. I started my system by acquiring Altec Falmenco's, at 98dB sens. With them in place, I could pick almost any amp style, and wattage. They are so efficient, I could drive them with a #31 triode in each channel no problem. [Average listening wattage for me is 40mW RMS]

Why not have a class AB push-pull for the bass (ultralinear maybe?), and a small triode for the mid & highs? (45?)
I just built an ultralinear 6SL7/6V6GT monoblock that sounds GORGEOUS. I used a 12 henry choke in the ps, and only 6dB of neg feedback. It's a roaring 12W, and fit in a 6"x10"x2" chassis.
 
Joel,

You say
<b>I'd stay away from the 845 or any other expensive tube, just out of principle.</b> and then go on to recommend <b>a small triode for the mid & highs? (45?)</b> Huh?

A pair of matched Chinese 845's (quite good tubes) are all of $US80 from <a href="http://store.yahoo.com/triodeel/triodpowtub2.html">Triode (bottom of this page)</a>. NOS or good second hand 45s are expensive, and not neccessarily reliable or quiet, and VV45s are a couple of hundred dollars each. Doesn't make sense.
 
Joel,

My comment about "a couple of hundred dollars" referred to the Vaic Valve new production 45's.

I watch ebay too, and have several tube dealers I do business with, and I still feel buying a 45 unless it's tested NOS from a reputable seller/dealer is a lottery.

Cheers
 
diyAudio Senior Member
Joined 2002
Tubes.

Fellows,

Think we're way ahead of the project as such by pinning down any tube types.
Luckily there's still some tubes left so while there is a choice....

However,personally I wouldn't even consider buying used tubes.
Doesn't mean you can't find any good ones but I rather buy some good NOS from someone I know.
If I can visually expect them before forking out the money I will always prefer that too.

BTW,have any of you ever seen a 211W or 845W made by United?
To me these are in the same league as the Bendix Red Bank stuff.
Marvelous stuff,once you had a listen to a set of those it was pretty hard to go back to Chinese glass.

Just my 2 Eurocents,;)
 
Administrator
Joined 2001
Paid Member
Ken,

looks like you are slowly getting pointed in "the mostly full-range" route. This is a term i use for a multi-way system that is centred around a full-range speaker as an extended midrange -- in some cases the midrange extends high enuff that a supertweeter is not needed (ie Fertin). At the Frugal-phile(tm) level that i am playing in, the FR usually needs a little help at the top -- above 10k in the case of the RS 40-1197s i'm using at the moment, and probably more like 13-15k when i get around to getting the FE103As into a box. If a ST is needed a simple cap XO is all that is required. And then you fill in the bottom with a pr of active woofers, using a nice SS amp. The FR/extMid can be run FR or have a PLLXO built into the amp... i am currently not running my woofers because of the veil that the op-amp 4th order LR was adding ...

I have been using a dumpster diver EL84 single-ended pentode amp, but it is just a bit lacking in dynamics when i want to turn things up. An Allen Wright inspired PP EL84 amp is in the queue (monoblocs based on Dyna SCA35 or a stereo amp based on a Scott LK48). Those and the more efficient FE103As should hopefully get the dynamics up (and since i'm running bipoles i can always add a 2nd amp for the rear firing drivers for another 3 dB if needed).

The basic concepts apply to almost any level of spending... i'm trying to get my whole system down to less than a kilo$ -- maybe less. The hardest part is a good TT that costs nothing...

dave
 
Dave, I think you're pointing me in the right direction-

General direction- Full range-extended range mid-falls right in with Frank suggesting bi-amping

A safe assumption that could go with a Fertin or other full-range.

Now what circuits and tubes? Brett's suggestions of Ralph Power/Amity is definitely on the short list -

Joel - thanks for your thoughts - I don't think I want to go ultralinear -

Frank - what ideas do you have? Any adaptation of the circuit you posted several weeks ago?

I'm not necessarily locked in to a 6B4G design -

What else should I consider?

Mohan - you out there now?? I hoped for a comment from Mohan -I guess he might not be around.

Later

Ken L
 
diyAudio Senior Member
Joined 2002
DECISIONS...

Hi Ken,

Am I wrong or do you have a PP 300B amp already?
Do you want to integrate it in the new system?
If so,it could be used to drive the FR.
Which one you have BTW?

In case you decide to add a tweeter, a SE would be great using a small DHT.
Keep in mind tube availability since we don't want you (nor anyone else for that matter) to pay through the nose for spare tubes.

For the lower registers I think you already have a set of subwoofers with active Xover and SS amps so my only concern there is sonic integration.
If this filter allows for different orders of filtering then you're fine since it allows for some experimentation as to integrating the sound of the woofers with the rest of the system.
In general I prefer 1st order series filtering if the units can take it,here you should not have such problem.
If you decide not to keep the active crossovers then we will need to calculate a 2nd or 1st order filter for the subs.(Lowpass)

The signal for the FR and tweeter I would take from the preamp if
it's a tube design with low Zout.
The FR I would leave as such but if deemed necessary integrating a first order highpass filter is a piece of cake.
The eventual tweeter I would also filter with a series cap 1st order at the amps input.

Best regards,:)
 
Yep

I've got a VAC 30/30.

Actually, I am thinking to build 4 monoblocks and then sell the VAC.

It's the current production model - depending on various prices if I could get what the recent ones have sold for on Audiogon, I might even have change left over - If I don't build something that sounds better I'll keep it.

What do you think I ought to build to replace it??

The subs don't integrate as well as I would like at this time -

Later

Ken L
 
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