Please welcome MAPLETREE AUDIO

[kjohnsonhp]

I've had two manufactureres at different price points recommended to me by TNT-Audio, and I've invited them to introduce themselves to us in case others are interested. I'm hoping some of the senior contributors to this community can engage MapleTree in a discussion to explore the fit w/Klipsch and value of their products vs some of the more popular options discussed on this board.

NOSValves seemed interested, and I'm certainly interested in finding phono stage and preamp for my Conrwalls. When I buy something I hope to bring the DFW Klipsch fans over for a listen. I also have a loaner Scott 299c for comparison.

I guess the first question would be this:

What do you recommend for amp, pre-amp and phono for our Klipsch Heritage speakers, and how would that solution compare to some that are popular here:

* Scott 299c or EICO HF-81 restored

* Dyanco ST-70

* pre-amps like AES-3, Cary, Wright Sound

* 2A3 SET amps like Welborne Labs Moondogs

There seems to be two general kinds of buyers on this forum:

1. Tube newbies owning their first Klipsch speakers (often Cornwalls, LaScalas, Belles, RFIII, & RF7) and tube setup and they often are shopping for an amp/pre/phono totalling around $1k. Vintage restored integrated amps are often recommended.

2. Veteran Klipsch fans looking to upgrade a component and willing to spend more. The SET owners seem to be in this group.

Again, I hope the more senior members will be more engaging than I have attempted in this initial post.

Please welcome Mapletree Audio Design http://hollowstate.netfirms.com/.

[hollowstate]

Thank you for the welcome to the Klipsch forums. I hope that I can learn something about the special needs of owners of Klipsch speakers and at the same time let you know what is available from Mapletree Audio Design (MAD) that is of interest. As an introduction, and to answer kjohnsonhp's questions, I will provide a short description of the MAD products of interest to members of this forum.

In many ways, my design philosophy is rooted in the era that produced the classsic components and kits. I think that the main improvements over these designs lie in the availablility of higher quality passive components (resistors, capacitors, controls, etc.), and perhaps the deletion of excessive tone controls and other filter/equalization circuitry. Also, since tube audio is not a mass market business these days, the financial bottom line is not the only factor governing engineering design decisions. Lastly, I favor new old stock octal-based tubes over NOS and currently manufactured miniatures in terms of overall sonic performance, probably influenced by their inherent low distortion.

Power Amplifiers: The newest addition to the MAD lineup is the Stealth 5 monobloc. It is a class A push-pull design using 12A6 output tubes producing 5 Watts. In terms of power output, it is well suited for use with efficient speaker systems. It also has a very high damping factor, which is an advantage in driving single-speaker systems which often present a widely varying load impedance across the audio spectrum. The high sensitivity and inclusion of a volume control in the Stealth 5 makes operation without a line preamp possible if desired.

Preamps: The MAD "flagship" component is the Octal 6 line preamp which includes three switchable circuit topologies--passive, classic common-cathode/cathode-follower, and shunt regulated push-pull(SRPP). The two active topologies offer slightly different sonic characteristics which gives the user increased flexibility in matching to different source material, powoer amps, and of course, speakers. It is available in kit or assembled form. The latest MAD preamps come in a modular package which includes a phono stage, line stage, combination phono/line unit, plus the choice of two separate power supplies. The phono preamp circuitry employs a combination of passive and active equalization and with the separate power supply, offers very low noise performance.

Specialty components: The MAD Eye 2 is a stereo signal monitor/power indicator using magic eye cathode ray tubes that can be used with any system components. The very popular Ear+ headphone amplifiers are designed to drive a wide range of headphone types and impedances with very wide frequency response and low noise.

I invite you to view more details of all the MAD components on the MAD web site hollowstate.netfirms.com. You can download the user and kit assembly manuals plus read what owners have said about the MAD units. There are also links to reviews of MAD products. Lastly, I am glad to answer all questions (there is no such thing as a dumb question!) wether on this forum or by private email. I look forward to hearing from you.

Lloyd

[Deang]

Hi Lloyd -- thanks for popping in.

Considering the low power of the Stealth I'm surprised you didn't opt for a DHT in a SET configuration -- seems this is the rave these days. I know George Wright also likes the octals -- but does use the 2A3 in his power amps. If you wouldn't mind, would you elaborate on why you chose a low powered push-pull over SET?

I noticed the very high damping factor and low distortion specs -- I would imagine there is considerable local feedback. I know Mike Sanders of Quicksilver used almost 25db of negative feedback in his Horn Monos. Many feel that a liberal use of negative feedback kills the transparancy or "see through" imaging of an amp. The most popular amps are zero feedback. Any thoughts you would like to share on this?

Most here are fairly open-minded. I have used high powered SET (18wpc using the KRB300XLS), a zero feedback Class A push-pull using KT-88's, a straight up pentode push-pull, and have settled in nicely with a pair of monoblocks running in Ultra-linear with EL-34's. Of the three amps -- the latter are my favorite.

Nice stuff Lloyd -- but you need to change that "Mother's Against Drunks" logo. Why not a nice silk-screening with cursive/script?

[LonestarBlues]

Hello & welcome Dr. Lloyd. I am tube newbie with no technical background. I have followed the MAD threads at the manufacturers section at Audiocircle.com. I remember the thread Mad Ear+

headphone amp No 25 Special Edition with Russian paper in oil

caps & Black Gate coupling capacitors. I am interested in your Octal 6A preamp and I have several questions for you. Could you use paper in oil caps in the Octal 6A preamp & would there be any sonic benefits? Would there be any higher peformance in sonics by upgrading any of the parts used in the circuit of the Octal 6A preamp? If so, would you build a Special Edition of the Octal 6A preamp if I were to pay for the increased costs involved in using high peformance parts? We used to have a Tube Guru here at the 2 channel forum-Kelly aka Mobilehomeless. Kelly always extolled the virtues of upgraded high peformance parts raising the

sonic level of performance in gear

i.e. amps & preamps. I own a factory assembled Welborne Labs SET 2A3 Moondog monoblock amps with the Ultimate parts upgrade. The Ultimate parts upgrade in the Moondogs consists of using Caddock

resistors in place of Allen Bradley resistors, using Black Gate electrolytic capacitors in place of Elna Cerafine capacitors,

using Jensen paper in oil capacitors in place of Aura MusiCaps polypropylene capacitors, & using teflon tube sockets in place of ceramic tube sockets. I have another question, where is a good source for 12SN7 tubes. I just recently bought a used 2 month old Llano Phoenix CAS 300 mosfet/tube hybrid amp. The Phoenix is a 2 gain stage amp, Class A, uses no negative feedback, mosfet output with separate enclosures for the voltage & current sections of the amp. The VA2 voltage amp uses 6SN7,6SL7 & 12SN7 tubes. I got 4 pair of tubes with the amp-

Raytheon 6SN7 GTB, Sylvania 6SN7 GT, JAN Sylvania 6SL7 WGT & G.E.

12SN7 GTA. I am currently running the G.E. 12SN7 GTA tubes in the VA2 voltage amp. I am using the Llano amp with a solid state Mcintosh C38 preamp. I am possibly interested in matching the Llano amp with your Octal 6A preamp. I am in the research mode right now

looking at and reading about preamps. I pulled a Mcintosh MC 7150 amp out of my second system

last week when Fedex delivered the Llano amp. I have enough spare gear collecting dust that if I buy a 3rd preamp I will use the Mcintosh gear in a bedroom system.

Thanks for your reply.

Regards, Mike

[hollowstate]

Thanks for the good input Dean. My experience in designing/building DHT/SET amplifiers was not as positive as many of you, probably due to the lack of appropriate speaker systems. I was also plagued by low level hum that persisted as long as I stuck to ac filament excitation. I cannot tolerate audible hum, especially in a component offered for sale. But as there are quite a few popular SET designs out there, I felt that I couldn't do any better given the general simplicity of the circuitry and limited options for doing something a bit different. Hence the 12A6-based class A push pull. It is based on the Mullard/Leak topology using a pentode for the input stage. You are correct in surmising that there is considerable global feedback as you can actually see from the frequency response/loop gain plots--amd it is responsible for the low output impedance and low noise. I know many of you prefer the sonics of zero feedback amplifiers. So the Stealth 5 is not everyone's amp but those who have tried it have been positive in their response.

Thanks again for your input.

Cheers,

Lloyd

[hollowstate]

Hi Mike,

Glad to get some questions about the Octal 6A preamp. I have purposely taylored the sonic presentation of each of the two active circuit topologies of the Octal 6 by using carbon films in the classic common-cathode/cathode-follower (CCCF) circuit and metal films in the SRPP circuit. Both use a single Solen polypropylene capacitor coupling the output signal in each channel. Since my aim was to offer two (three, including the passive option) different sonic choices, depending on the listener's choice of program material, the associated componenets, especially speakers, and mood, it might be interesting to go further in that direction, using carbon composition (e.g. Allen Bradley) resistors and paper/oil caps in the CCCF circuit and high-definition film resistors/capacitors in the SRPP circuit (you all have your experiences/opinions on what these might be). The only upgrade I normally offer with the Octal 6 is the Alps volume control as it offers a long-term reliability advantage in addition to any subjective sonic improvement. The new channel gain controls are plastic element types and are not in series with the signal at normal full operating position--same situation as with the Alps Black Beauty balance control I had been using.

So if you would like to specify what passive components you want in each circuit, I will be glad to oblige with the increased cost equal only to the diffence in component costs. This can add up of course (e.g. the Beyschlag-Centralab metal film resistors I use are $0.12 each in quantity).

I have obtained stocks of 12SN7GTs from a number of sources. AES always has a supply--they are increasing in cost but still a bargain compared to 6SN7GTs.

Regards,

Lloyd

[mike stehr]

WTF is a tube guru?

[LonestarBlues]

Hello Mike. My reference to Kelly as a Tube Guru was a complement to old Mobilehomeless. Kelly was very

knowledgeable about tube equipment

while others like myself did not know didley squat. Kelly spread the gospel of tube gear-both push pull & SET amps & tube preamps like a tube evangelist. Kelly got me and many others interested in and buying tube equipment on the 2 channel forum. I have 2 individuals that have been my tube mentors so to speak. Andrew Weiss of San Antonio who sold me my first pair of 1977 Cornwalls. Andy

had 2 tube systems. A EAR 859 integrated SET amp hooked up to the Cornwalls & a EAD transport & dac. The first tube amp I have had the pleasure to listen to. I liked tubes upon my first listen. Andy's main system at the time was an Audio Research VT 100 mkII amp

with a Wadia cd player with digital volume control hooked up direct to the amp & Proac Response 5 tower speakers. Andy had high dollar speaker wire,interconnects, & after market power cords. I was in hog heaven asking questions & getting to listen to his tube systems. I had only read about this type of equipment before. I had never gotten to sit down & listen to high end tube equipment. Corpus Christi(population-275,000) where I live in south Texas has

one shop Marco's Electronics that carries Adcom, Sunfire, Sony ES, B&W speakers & Energy speakers. They are pretty much a hometheater dealer. The rest of the stereo shops are all hometheater reciever-ville, no separates what so ever. Kelly is my other tube mentor. Without him posting about how good tube equipment was, I probably never would have purchased my Welborne Labs Moondog amps & Revellie tube preamp. I did not always agree with everything Kelly said, but I respected his opinion. I miss both his knowledge & humor & wish that he would come back to the 2 channel forum.

Regards, Mike

[LonestarBlues]

Excellent post Mark. I am definitely an untrained amatuer. I

follow what you are saying. I

guess an example would be George

Wright's-Wright Sound 2A3 SET amp.

From what I have read here, at the AudioAsylum and an old Positive Feedback magazine review on several brands of SET amps. George Wright uses a circuit with solid design & does not use botique designer parts. His amps are well reviewed & the guys here on the 2 channel forum & the Asylum that own them like them very much. Ron Welborne-Welborne Labs makes a standard product & then one with upgraded parts like my Moondogs. I remember reading Erik Mandaville's post about fixing Edster's Moondog 2A3 SET amps. Erik built his own Moondogs & is constantly tweaking them with changes to the circuit to hear the different sonic results. Edster's Moondogs have

the ultimate parts upgrade in them. After repairing Edster's Moondogs he hooked them up to his system with Lascallas and liked Edster's Moondogs sonics much better. If I remember correctly Erik attributed the major difference in sonics to the

Jensen paper in oil caps which his did not have.

Hey Mark, I unboxed my Advents & gave the wanut veneer several coats of lemon oil. I hooked them up in the old venerable double stacked configuration with the top Advent inverted. Them old dogs(Advents) will still hunt. They sound good to my ears. Not as dynamic as the Cornwalls. It's funny but I am the only guy of 4 friends that owned Advents that never fried his tweeters. Thanks for your informative post.

Regards, Mike

[NOSValves]

Mark,

You are braver then me But he speaks the absolute truth !

Craig

[hollowstate]

As a manufacturer and engineer, I have to agree with Mark's analysis. The circuit design is the most important element in making good music. If the design isn't right, you will know about it right away or perhaps after a long listening session ("my ears are killing me!"). If you are enjoying what you hear and hate to turn it off, it is a successful design, regardless of how little it costs. Now if you change components, tubes, etc. it may sound different, usually in subtle ways. However, it isn't really accurate to say it sounds "better", just different. You may like it better in the short or even long term but, again, it isn't related to what you spent on the new parts. I think the term "upgrade" is probably the wrong description of these modifications. If you design something that you plan to manufacture and sell, even on a small scale, the engineering challenge is to produce the best product you can at the cost target you have decided is reasonable. The MAD componenets all have parts selected to work reliably within the circuit design requirements. Reliability includes long life so meaningful parts quality is not a waste of money--hence the Alps pot substitution available on most preamps. Lastly, if customers wish to susbstitute stock items with specialty parts, and it brings them excitement and satisfaction (and they can afford it), I would say go ahead. Just remember though that it is no longer really a Mapletree Audio design, but your own creation; something different.

Regards,

Lloyd

[kjohnsonhp]

I'm not clear on your recommendation for pre-amp and phono capabilities.

There seems to be the flagship Octal 6 preamp and then a modular set of boxes for power supply, line, and phono. If I want a pre-amp for SACD/CD and phono stage do I buy the three modular boxes or the Octal 6 plus the phono module?

Any suggestions on sharing the same front speakers for HT? I have a DVD player and Outlaw 1050 AVR for HT. For music I would have the ST-70, pre-amp w/phono, TT and CD/SACD player. I assume without a HT passthrough switch I will have to swap cables.

[sansui80]

dear sir,

I live in the tulsa oklahoma area and have a scot299c that need a rebuild and retubing. Is there anyone in the dfw area that you could reccommed.

thanks,

Ben

By the way I aggree with your previous posting.

[ben.]

This thread is over 2 years old. I'd suggest starting a new one with a little more specific info as to the trouble you're experiencing.

[Coytee]

!!!!!!!!!!!

Dangit...

I gotta start looking at the dates. I read through this whole thing then whammo... 2 years old!!

Oh well, was interesting none the less

[Parrot]

So did Lloyd give up on the Forum in just the one day?

[Colin]

2 years old or not I still recommned NOSvalves, who has a web site and frequents this forum for refurbishing vintage tube amps.

[Guy Landau]

I read Mark's posts and find it difficult to understand why he acts against his belief and use all these hyped, fancy and expensive Auricaps and Hovland capacitors instead of the good old Orange drops......

If the circuit is good who needs these expensive parts?

[Speedball]

I second Colins post about "NOSvalves" and I havent even purchased from him yet.....