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LD91 Mono Max with P:USH Power

218.188.205.67

Posted on September 4, 2009 at 02:07:50
bcherry
Manufacturer

Posts: 2216
Joined: March 11, 2001
Contributor
  Since:
June 1, 2001

Our universe became a little disordered last year when we introduced the single chassis LD dual mono. Due to escalating costs the 8 year old LD monoblock was not sustainable as a product on two counts: 1. cost of materials and manufacturing had almost tripled since the original Billie was offered for $700 (including all the upgrades we progressively built into the kit) and 2. shipping overseas by Fedex had doubled from <$200USD originally to >$400USD by 2009 (also due to the extra weight of all the upgrades and enhancements).

The LD dual mono chassis gave us an opportunity to keep a sane selling price and also to forever dump the poison of electrolytics in the power supply and thus offer the one and only all film cap SET amplifier. This is where our universe became disarranged - the single chassis LD sounded better than the monoblocks. I guess not a surprise since the single chassis LD has everything the monoblocks had except minus one power transformer but plus 200uf of film caps. Raise the bar and that's what happens.

In the meantime we've developed our own filament supplies and FCUPS (film cap universal power supply) which raises the bar again.

I still had in mind to show some respect to the establishment.

Here's a preview of what is coming: LD in Projekt chassis with FCUPS and filament supply standard. The extra cost of the FCUPS will be covered in part by the lower shipping cost due to the weight saved by not having huge chokes and caps. Also the added performance of the FCUPS is not subtle and is too good to not have.

The discerning eye will notice this is our 91 circuit with Level 3 parts. This will be our standard for this LD monoblock. I will also do a version without the tantalums/teflon caps and some other expensive bits, but it will still be a 91. I fact, to maintain current naming convention and avoid confusion with previous circuits I'll probably name that one the Level 3 and this one the LD Mono Max.
I'll also sell an 'open kit' version which will include all the basic infrastructure, chassis, transformers etc, for those that want to build their own way.

So what's this P:USH Power business?
Power for Ultimate Signal Headroom! Because the FCUPS with it's huge store of inductive energy and in virtual battery mode is in a totally different league than banks of caps, resistors and even big chokes in their little puddle of inductance. You really need to hear it - inductive energy store is totally better than capacitive energy. Like Iron Man beats Chickenman.

So that the LD91 Mono Max with P:USH Power.

More to come.
DIY - Done Right!

More 91 Max with P:USH, posted on September 9, 2009 at 22:55:20
bcherry
Manufacturer

Posts: 2216
Joined: March 11, 2001
Contributor
  Since:
June 1, 2001



You saw the bottom.
The top side:
The tubes are mounted on an iso- suspended mounting plate, 3mm aluminum.
Chassis is the 240mm wide x 360mm x 70mm Projekt style. Very rigid.
Sockets are teflon, except for the 310a.

The RCA input is at the back where you like it. Although the output transformer comes with 4/8/16 secondary, there are only 3 speaker binding post: 0/4/8 or 0/8/16 - whatever suits.

Horn guys: These are quiet! 0.2mv.

Running in now and I'm mighty pleased with how this has turned out.

Next I'll get out the adding machine to determine where this lands cost-wize.
DIY - Done Right!

RE: LD91 Mono Max with P:USH Power, posted on September 8, 2009 at 04:47:23
Clive
Reviewer

Posts: 286
Joined: June 2, 2004
Hi Brian,

That's a very neat layout, it's the most straight forward 91 build I've seen. It has me wondering in what way it sounds different and better than my 91 - your original version with steel chassis and BG PS caps. Maybe I shouldn't think about it!

the pair, posted on September 9, 2009 at 22:58:21
bcherry
Manufacturer

Posts: 2216
Joined: March 11, 2001
Contributor
  Since:
June 1, 2001



Here more or less in final form. One last change is to put a film cap in the 310a cathode bypass.
DIY - Done Right!

RE: LD91 Mono Max with P:USH Power, posted on September 8, 2009 at 17:00:24
bcherry
Manufacturer

Posts: 2216
Joined: March 11, 2001
Contributor
  Since:
June 1, 2001
Hi Clive

The difference should come down to the FCUPS power supply. As we've dropped the FCUPS into the Ella and CCS/6SL7 LD, that difference has been quite significant. We will begin listening this week so I should soon have more to report. I'm also interested in which direction this will take the LD91 since the 91 circuit has a rather strong personality of its own.
IIRC the FCUPS won't fit into the steel chassis you have though.

regards
DIY - Done Right!

RE: LD91 Mono Max with P:USH Power, posted on October 29, 2009 at 07:10:49
Gary B.
Audiophile

Posts: 56
Location: No. Cal.
Joined: January 9, 2000
Brian,
Are there any updates on this project. It looks quite interesting and I'm curious to know if you're going to offer this as a product.
Thanks,
---Gary

RE: LD91 Mono Max with P:USH Power, posted on November 1, 2009 at 05:00:57
bcherry
Manufacturer

Posts: 2216
Joined: March 11, 2001
Contributor
  Since:
June 1, 2001
yes, just waiting for the power transformers. Everything else is ready to go.
DIY - Done Right!

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