Author Topic: Need advice for a tube pre-amp  (Read 45782 times)

Offline JLM

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Need advice for a tube pre-amp
« on: July 13, 2011, 06:09:15 PM »
I've been a fan of the purist approach.  Currently I spin CD's, send the signal via coax to a Behringer DEQ2496 for EQ, then via AES/EBU to an Eastern Electric DAC, then via RCA's to Channel Island Audio D-100 (modded 100 watt Hypex class D) monoblocks that are hardwired into Fostex F200A drivers (Bob Brines FTA-2000 speakers).  All signal cabling was custom ordered from Scott Endler.

These speakers use mass loaded transmission line loading, the drivers are not typical Fostex, and have been EnABL'd by Bud Purvine.  These single driver speakers are rated 30 - 20,000 Hz, 8 ohms, 91 dB/w/m.  (The DEQ also replaces the speaker's baffle step/zobel circuit as recommended by Brines.)  They play in a dedicated 8ft x 13ft x 22ft listening room ala Cardas (Golden Cuboid) and Cardas prescribed nearfield setup.  I'm a speaker guy.

I like what I hear (AlNiCo richness, great imaging), but have had issues trying to use a passive pre-amp (muted treble).  Out here in the audio hinderlands I don't get out much.  I've only found two places that even sell tubed equipment within a 2 hour drive but neither had anything close to a decent listening room.  I'm looking for more palpability, bigger/deeper soundstage, and increased dynamics.

My goal is to spend less than $1,000 USD for a tubed solution (buffer or pre-amp).  A single input is fine.  I've been looking at all sorts of solutions from Burson buffer, Decware buffer, Decware "Z-Stage", Kingrex pre-amp (but am canceling the order due to failure to deliver), Music Hall headphone amp, Nightshade Beacon 1, and Mapletree 2A SE.  I prefer zero interaction/maintenance (having been a solid state guy forever).

Another option would be to sell the EE DAC as the Behringer has had the DAC modded by Scott Endler and really sounds very good.  This might induce me to spend a bit more on the pre-amp (or go with the Decware/Music Hall options that use "forever on" designs).

I'm confused, please help.
« Last Edit: July 13, 2011, 06:11:32 PM by JLM »

Offline richidoo

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Re: Need advice for a tube pre-amp
« Reply #1 on: July 13, 2011, 07:45:54 PM »
Spaciousness and microdynamics are the purview of tubes. How bout Manley Stingray?

The Cardas setup didn't work well for me in a similarly sized room. Try other placements according to what sounds good. Remove absorptive treatments and furnishings from the front wall and anywhere behind the front baffles. Treat the front corner seams for more beautiful tone ala 8th nerve if desired. Put the big bass treatments in front of the speakers to maximize soundstage size.

I think the stock EE DAC has LM4562 opamps. These kill the spaciousness in my DAC using same DAchip. I am building another with transformer output, no opamps. You could try the opamp mod for the EE, or sell it if DEQ is already nice. Upgrade the power supply on the DEQ too. It is a switcher and kills the focus. Behringer stuff is basically good for the software and everything but the processor and memory need to be upgraded, PS, clock, in/outs.

If you are willing to use a PC for EQ with Audiolense you might do better with a nice audio card like Shanes Lynx2, or the Juli@ into the tubes.

Offline Rob S.

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Re: Need advice for a tube pre-amp
« Reply #2 on: July 13, 2011, 08:24:54 PM »
If mapletree 2a Se makes your "very short" list of preamps, you can borrow mine.  It's just collecting dust in my spare bedroom.  let me know if you want to hear it.

Rob S.
No new money spent on audio!!  but starting in 2012!!

Offline tmazz

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Re: Need advice for a tube pre-amp
« Reply #3 on: July 13, 2011, 09:03:52 PM »
I'm confused, please help.

If you want help getting confused you've come to the right place. :rofl:

So many preamps, so little time........ :drool:
Remember, it's all about the music........

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Offline topround

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Re: Need advice for a tube pre-amp
« Reply #4 on: July 14, 2011, 02:56:34 AM »
If you do decide on a Mapletree, I have a list of mods(to the preamp section and power supply), that I personally know take it to the next level. About $300 in parts.
Used Mapletrees go for about $500, plus $300.....I could not think of a single pre that can come close at this price point.

Now if you want to spend $3k , I can recommend something great


Mike
System consists of an amp a preamp, 2 speakers a turntable and a phono preamp, Also some cables and power cords and a really cheap cd player.

Offline Hugh

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Re: Need advice for a tube pre-amp
« Reply #5 on: July 14, 2011, 07:57:57 AM »
I recommend our own PB101.

You can search for a review recently done as well as another upcoming one to be published soon.
Hugh Nguyen
Angel City Audio
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Offline JLM

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Re: Need advice for a tube pre-amp
« Reply #6 on: July 14, 2011, 06:21:50 PM »
Wow, thanks guys...

Rich,

But I like the Cardas setup.   :o

I have six GIK 244 panels at front/side wall first reflection points and in front corners.  Frankly they did made very little difference (maybe due to beaming of 8 inch whizzerless drivers, maybe due to having EQ, maybe due to Cardas room dimensions/nearfield).  Moving them all over did do much either.   :?

My Behringer DEQ2496 has been modded by Scott Endler (AK4395 direct out with only 4uf stacks of foil coupling caps).  I've bought modded pieces with mixed success, and don't want to invest more in mods than the original unit cost.   :?

After the warrantee expires on the EE DAC, I might swap op-amps, but I'm not electrically handy (a vast understatement).   :rofl:

Music server is not currently on the radar screen.   :)


Rob,

Thanks for the kind offer, I'll let you know.   :thumb:


tmazz,

You're not helping.   :-P


topround,

Do you know someone who would do the mods on the Mapletree?   :drool:


Hugh,

My budget is under $1,000 USD, the PB101 cost as much as I've spent on the rest of the system (without the EE DAC), so I'll pass.   :roll:


Please keep the advice coming. 

Offline Response Audio

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Re: Need advice for a tube pre-amp
« Reply #7 on: July 14, 2011, 08:35:47 PM »
Just to add another option to the mix, take a look at the Ming Da MC7. This is an exceptional piece for under a grand. They run about $650 new and obviously a bit less on the used market. It's presentation is is seductive and has great detail, resolution, speed and dynamics.

http://www.pacificvalve.us/MingDAMC7R.html

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Offline tmazz

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Re: Need advice for a tube pre-amp
« Reply #8 on: July 15, 2011, 03:49:41 AM »
Quote from: JLM link=topic=3246.msg40032#msg40032 date=1310692910
tmazz,

You're not helping.   :-P

[/quote

Hey what are friends for?  :rofl:

All kidding aside, I do not have much personal experience in this arena since I bought an ARC SP-9 in 1988 and have never looked back since. Great synergistic match with the rest of my system and the thing is built like a tank. In 23 years it has never so much as hiccuped once. You can get one on the used market for under a grand.  If you are ever thinking of dabbling in the vinyl world this is a great buy since it also has an excellent phone stage.

Wasn't there a thread here not too long ago about a Niteshade pre in that got a lot of good reviews from our members?
Remember, it's all about the music........

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• VPI HW-19 Mk IV/SDS/SME IV/Soundsmith Carmen Mk II ES
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Offline richidoo

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Re: Need advice for a tube pre-amp
« Reply #9 on: July 15, 2011, 04:13:52 AM »
But I like the Cardas setup.   :o

You can always put it back!  :-P  

When I had my best sounding feastrex speakers they sounded best with no acoustic treatments in the room at all. I think your idea that they beam treble instead of wide dispersion and subsequent reflections could be the explanation. But even on traditional speakers getting the soft stuff off the front wall has always helped open up the stage. The best place I have found to use the GIK 2x4' absorbers is leaning against the side wall lengthwise along the floor on 45 angle, with the edge starting at the front baffle and projecting out in to the room. Then if you have wide dispersion tweeters place another 2x4 vertically on top of the leaning panel to cover the reflection point. This works really well in several rooms I've tried it. Getting the bass absorption very close to the woofers is important for efficiency, its the highest velocity location near a wall. The bass is treated before it starts bouncing around and dispersing energy. If you don't have a problem with side reflections of mid/highs, then lay more panels horizontally along the floor corner, or vertically in the rear corners. But closer to the speaker makes stronger effect. You can also put them anywhere you want, even on the front wall if you put a thin membrane over the front to reflect the higher freqs that provide location information. Thickest poly sheet is good, or kraft paper, but the paper has a sound of it's own, thin cardboard, etc.  

You've been using the EE's volume control, right? A preamp will give you that flexibility to use a source without a VC. I'm in the same boat, all my sources have volume controls, except for my Vista Phono 1 preamp, so I'll need another one too.

An EE minimax is better built and designed than mapletree, but uses 9pin tubes so generally not as meaty tubular sound as octals, but it is more transparent. It makes incredible space and imaging and is a great value. My friend Sol who worked QC at Cary for many years said it was one of the best tube preamps he ever tested. It made 22V>1Mohm!, and drove 600ohms@1%, low noise, low distortion. Mine had tutay mods. dangerbird was just selling it on AC a couple weeks ago, maybe it's still for sale. Uses 12au7 tubes of which there are many choices to roll.

Offline topround

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Re: Need advice for a tube pre-amp
« Reply #10 on: July 15, 2011, 04:08:22 PM »
I had the CIA 200's with the Mapletree for a short time and it had great synergy.
The fatter sounding 6sn7'd really compimented the digital amps in a very musical way.
The 6sn7 is just a wonderrful sounding preamp tube IMO.
System consists of an amp a preamp, 2 speakers a turntable and a phono preamp, Also some cables and power cords and a really cheap cd player.

Offline JLM

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Re: Need advice for a tube pre-amp
« Reply #11 on: July 15, 2011, 04:34:04 PM »
topround,

Thanks much for sharing nearly direct experience.  You're not making this easy.   :thumb:

Bill,

Thanks for the heads up.  Nice to know that there is an upgrade path available.


tmazz,

Yes, the Beacon 2 is also of interest to me.


Rollo,

I have book cases on either side of "the" chair and an office setting in the back of the room, but otherwise I've tried lots of different locations for the 244's including angled along the side walls.  Just didn't make much difference.  

Yes, I'm using the EE DAC volume control.  I do have stepped attenuators, perhaps I'll try plugging them into the back of the amp (the usual/recommended location) and try them with the EE DAC.

I've read that the EE house sound is "tube thin" and that 9 pins are less palpable than their bigger cousins.  As I understand it's largely a matter of personal taste and system synergy.  With my hefty AlNiCo drivers I'd say the system already have lots of "body/warmth".

What's the tutay mods?  (I saw the piece for sale and tried searching for tom tukay, but came up empty.)


Wish I knew how various tubes, circuits, etc. affect the sound.   :roll:

Offline richidoo

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Re: Need advice for a tube pre-amp
« Reply #12 on: July 15, 2011, 05:05:36 PM »
You can read about how different tubes sound, but you won't really know until you hear it. You have the right idea about matching alnicos with fatter tubes, but there are less fat 6sn7s and the octals add a nice sexy something. I wouldn't worry about too much meatiness in a single driver system.

If you have the endler attenuators, I'm curious how it sounds  with just DEQ analog out >  D100, compared to EEDAC>D100. Thanks!

Tom Tutay is in FL, he mods tube gear, repairs gear, etc. From the web, fwiw:

"Tom Tutay
Transition Audio Design
24 Elm Avenue SE
Fort Walton Beach, Florida 32548-5622
Phone-850-244-3041

Tutay does the Altec 1570 Modification. He also repairs, custom designs and builds tube preamplifiers, crossovers and power amplifiers. He is even now making his own audio cables. He is also the repair center for Air Tight components."

Rich
« Last Edit: July 15, 2011, 05:07:17 PM by richidoo »

Offline JLM

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Re: Need advice for a tube pre-amp
« Reply #13 on: July 16, 2011, 04:56:19 PM »
Rich,

Like many others, I just don't hear much difference in the EE DAC going between solid state and tube.  So I'd like to try a bit more "tubiness".

These Fostex drivers (F200A) are NOT your typical thin mid-bass/shouty midrange Fostex drivers.  So while I'm trying to gain "tubiness" I'm wary of getting too much of a good thing.

I have tried the Behringer modded DAC with stepped attenuators (plugged in at the monoblocks) but these D-100's don't fit quite as tight as my previous Channel Island Audio VMB-1 monoblocks.  So I had a hard time not getting a nasty short, I'll have to try it again (maybe get out the pilers and carefully (with protective pad) squeeze the attenuators a wee bit.  But from what I could tell with limited success it did sound good.

Thanks for the contact information.  Know how to get in touch with Don Allen in Phoenix (supposed to build a really good sub-$1,000 tubed pre-amp too)?

Offline richidoo

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Re: Need advice for a tube pre-amp
« Reply #14 on: July 16, 2011, 05:46:33 PM »
doninphx@aol.com might be it, if the website I found it on is not outdated.  From another page on that site (http://www.high-endaudio.com/RC-Amplifiers.html)

"DON ALLEN AMPLIFIERS
I've never heard of these amps, but the same reader who liked the Wavelength Cardinals (in October above), went "crazy" over them. So have a number of other audiophiles who post at Audio Asylum (SET). Here's the letter with some slight editing:

"...the absolute finest amps I've heard recently are being made by Don Allen of Phoenix, Arizona. He makes them all: 45, 1626 Darlings, 2A3, PX25, 300b's, EL 84 all for very reasonable prices ($1700-2000 for a stereo, $2200-2600 for monoblocks!!!). His $1700 2A3 amps blew Gordon's Wavelength Cardinals out of the water!!! Better resolution, better dynamics (yup, that's right!), better frequency extension.

Go to the Audio Asylum's SET page and type in "Don Allen"......see what people are saying. The guy is a genius! His trade mark is a lightening bolt on the front of his amps that is backlit at night! (you can get the amps plain as well....) He uses good stuff (James, Tango, Tamura iron; NOS caps and tubes)...This guy amkes amps that high end manufactureers can only dream about. They're that good."

Personal Notes- I read some of the enthusiastic experiences posted on the SET Asylum, and can verify the reader's observations. The prices appear to be very reasonable to me, with little risk involved. There is no contact information or website URL. To contact Allen, you must make a request to a SET member, such as Todd Kreiger, and he will send you the information directly by e-mail.

I later asked this same reader for more clarification on the Don Allen amplifiers, especially how they compared to the best from Wavelength, and here is his reply to me:

"Are they better than Gordon's? Well.......that's saying a lot if its true. What I will say is that Don Allen amps are sonically just as good, including a comparison to Gordon's Jupiter 50s and 45s which most people feel are Gordon's best amps. BUT remember, Gordon's amps cost 4-10 times the cost of Don Allen's amps! So if considering a cost/performance ratio in any comparison, its not even close!

This isn't my opinion, its the opinion of a growing number of people as you can see on the Audio Asylum. I suggest you contact Todd Krieger, a highly respected Audio Asylum member and audiophile, who has several of Don's amps and knows Don quite well. You can find Todd's moniker (his name) on the Audio Asylum in the SET section.

The nice thing about Don Allen is that he doesn't simply go out and buy super expensive parts and throw them together, claiming to make a world class amp. Instead, he very carefully researches the synergy between a wide variety of components and transformers, usually with the help of 6-8 local audionuts in the Phoenix area. In the process, Don may select less expensive or more esoteric iron and other components, NOT based on price but on performance and design criteria.

Once Don and his band of merrymakers agree that a prototype amp (or preamp or phonostage) has "spoken to God", Don offers the amps to the public. The end products speak for themselves. I'm not 100% sold on his signature "lightening bolts" (he offers amps without them) but I'm willing to look past the bolts and enjoy the music."

Personal Note- I endorse the method Allen uses to design his electronics, particularly his reaching out to the local Phoenix audiophiles for help and confirmation. This is a proven method to get outstanding results and avoid mistakes. The more I hear about Don Allen's amplifiers, the more I am intrigued about them."

from http://www.high-endaudio.com/RC-Amplifiers.html