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Old 23rd October 2002, 01:35 AM   #1
Ken L is offline Ken L  United States
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Wink Your thoughts please

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



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Old 23rd October 2002, 07:54 AM   #2
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Default Re: Your thoughts please

Quote:
Originally posted by Ken L
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.
Quote:
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.
Quote:
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.
[QUOTE]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.[QUOTE]
You won't beat the Lundahls for performance/$. There is a Lundahl forum just starting on audioasylum too, run by Kevin of K&K.
Quote:
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
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Old 23rd October 2002, 11:44 AM   #3
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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.



Quote:
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.
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Old 23rd October 2002, 08:49 PM   #4
Ken L is offline Ken L  United States
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Lightbulb 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 -

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.



Thanks

Ken L
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Old 23rd October 2002, 09:10 PM   #5
Ken L is offline Ken L  United States
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Default 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

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Old 23rd October 2002, 09:19 PM   #6
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Default 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,

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Old 23rd October 2002, 11:02 PM   #7
Ken L is offline Ken L  United States
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Talking Actually, you're right

It truly is a puzzle -

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

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

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Old 24th October 2002, 02:26 PM   #8
Joel is offline Joel  United States
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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.
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Old 24th October 2002, 02:51 PM   #9
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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.
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Old 24th October 2002, 02:57 PM   #10
Joel is offline Joel  United States
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Default a "couple hundred dollars"?!?!?!

Brett,

I regularly see used #45's on eBay in the $10-$15 range. I do not buy tubes retail. I own a dozen UX based antique triodes, none of which cost me more then $10.
You have to know where to look.
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