Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

Return to Tube DIY Asylum

Message Sort: Post Order or Asylum Reverse Threaded

LOL, Didn't last long, under two months

71.50.25.141
Posted on January 16, 2017 at 12:01:10
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
 Well, my new dual-mono JJ 2A3-40 amp, which I debuted up here on December 2 2016, has already been taken out of service.

I liked it so much, I decided to re-do it, as two monoblocks. People such as Tube Wrangler, and Used Hi Fi, encouraged me. Dennis tells me, I can optimize lay out FAR easier with monoblocks, and I totally agree.

I LOVE hearing a non-shared ( left to right ) power supply now a days BTW, ...for me - the ONLY way to fly.

Stay tuned, photos of the monoblocks will be posted, in the future. Lay-out will be COOL to do !!!

Jeff Medwin

 

Hide full thread outline!
    ...
RE: LOL, Didn't last long, under two months, posted on January 16, 2017 at 14:57:18
deathtube 667
 Since you are in DF's inner circle and know what he is doing, why not copy his amplifiers as close as possible with the 7B4 driver?

 

RE: LOL, Didn't last long, under two months, posted on January 16, 2017 at 17:18:14
xaudiomanx
Audiophile

Posts: 3647
Joined: August 16, 2004
 Jeff,

I personally always liked the dual mono power supplies(one power tranny). But the power tranny has to be a beast. Probably unlikely to find one of your tastes being that you like very low DC resistance parts with your L.S.E.S. power supplies. I always felt with my hearing tests using two totally independent power supplies was a bit less coherent than using a single massive power tranny with almost 10 times the current output needed to supply an amp or preamp.

 

RE: LOL, Didn't last long, under two months, posted on January 16, 2017 at 17:32:40
sony6060
Audiophile

Posts: 1465
Location: USA
Joined: August 8, 2014
 Tried both single and dual power supplies. I agree, I like just one power supply.

 

RE: LOL, Didn't last long, under two months, posted on January 16, 2017 at 17:41:13
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005



DF helps me a lot!!!

re: a 7B4, a very nice, transparent tube, but I am using a different driver, experimentally to me, but precisely sounding as DF suggested it would, and it is doing just fine.

Recall the experimental " Hockey Puck " caps in my 12-2016 amp ? The experimental use will continue in the 2017 build, and DF has not yet gotten the time to evaluate that quite yet. I use them experimentally in my 800 HZ VOTT A7-800 12 dB DIY speaker crossovers also.

Jeff

 

RE: LOL, Didn't last long, under two months, posted on January 16, 2017 at 18:44:10
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
 LOL, Hiah !! You are "Preaching to the Choir" !!!

I have, over a decade ago, custom designed, and had Heyboer in Michigan build for me power transformers such as you discuss. Typically weighed 18 pounds and 18 Ohms end to end, maybe 840 VCT, or whatever was needed.

In 2016 - 2017, I am satisfied with 90 Ohms end to end, and rated at four times the current capability being used. The "effective" DCR is quite good enough. Such a power transformer can follow initial transients, and musical decays, more accurately, better sounding to my ear, that my old always - loafing, "ten-times HOGs".

When you use a shared supply, it adds a romantic artifact to the music, that is NOT there originally, and it may give you a " warm and fuzzy " feeling. Some VERY good designer friends of mine have heard it this way, and gotten suckered- in. IMHO, as of 2016, the " shared " power transformer is a incorrect design choice.

A single power transformer for each channel is the ONLY thing " I" can now live with. Its more honest.

If the system is not SOTA overall ( electronics, wiring, efficient speakers ), separate power transformers WILL and can sound thinner, because the added artifacts of a shared power transformer are missing. Overall, I gain more listening enjoyment, feel it is a far more honest listening experience, especially as the music program material gets complex, with a GOOD separate supply for each channel.

Unlike most listeners, ALL my filters to the Finals are L1/C1/L2/C2, and chokes are under ten Ohms in DCR. Just today, I was on the line with Hammond Manufacturing Company Engineers, and discussing a 6 Ohm at 1 A. rated choke of theirs, which they will be measuring additionally for me, this week. ( 159ZA )

Chokes are the driven passive elements, and as such, are more important ( than active power transformers ) to be low in DCR. Lead in and lead out wiring on chokes, actually, all magnetics, are critical, needs to be carefully executed, NOT like you see it today.

So, today, I consider a shared supply to be euphonic, but dishonest. That is clearly expressed, isn't it.

By the way, the reason I am going from Dual Mono, to Two Monoblocks, is simple. A monoblock is FAR easier to lay-out properly, parts, fields and space wise, for optimal audio performance.

Have fun, I am !!

Jeff

 

RE: LOL, Didn't last long, under two months, posted on January 17, 2017 at 08:01:31
rage
Audiophile

Posts: 793
Joined: December 17, 2010
 Jeff -

you helped design a great power transformer with heyboer. they were able to add 2.5V center tapped filament to the secondary for me... they're actually nicely priced for such a robust massive transformer.

I think the design could be revisited with sony6060s idea of using M6 and shrinking the monster down.

in my opinion you got some of these things right "the first time", the heyboer power transformer being one of them.

those hammond 159ZA are great chokes BTW - I've had them as the first element after the rectifiers with over 80mA and no buzzing.


 

RE: 159ZA chokes ... , posted on January 17, 2017 at 08:19:58
deathtube 667
 "those hammond 159ZA are great chokes BTW - I've had them as the first element after the rectifiers with over 80mA and no buzzing."

Rage,

How did you use that 159ZA choke?

Can I assume it was a flywheel filter and not LSES (L1=L2)?

dt 667


 

RE: 159ZA chokes ... , posted on January 17, 2017 at 08:42:09
rage
Audiophile

Posts: 793
Joined: December 17, 2010
 no it wasn't flywheel, although I experimented with that then also.

seems like I Was using the 159 as input choke, followed by 50uf, then a triad c40x, then 50uf, then another triad c40x...

it worked well... around that time jeff started telling us that 3 LCs was bad so I started reducing.

my recollection is that with 80mA and a KT120 in an SE amp that "LSES" wasn't clean enough.


my current main rig is l-critical choke input class A push pull... with ~ 700uF of film caps... big heavy choke, too much capacitance, wrong wire in single runs, constant current sinks, cree diodes, the jeff anti-thesis... ;)

have to build both sides to compare after all!

 

RE: 3 LC section filters ..., posted on January 17, 2017 at 09:19:52
deathtube 667
 I added a C40X LC section to the end of a flywheel filter and it seemed to buck down the ripple at C2 lower than C3 for some reasons.

Jeff told me that 2 LC section to finals were best as per DF, but we use other finals than JJ 2A3-40's.

Always a challenge to get a good balance of operating parameters.

 

RE: 159ZA chokes ... , posted on January 17, 2017 at 09:21:18
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
 The NICE thing is, Rage and I do different things, but we remain trusted friends. We respect each other. One huge advantage I have is I get to spend about three days every year in Denver, RMAF, listening to, sometimes even exhibiting, Dennis Fraker's set up.

This year Dennis got a rave review from Herb Reichert / Stereophile, as one of Herb's two most favorite rooms to visit and hear, among 100s of rooms at the Show.

Guess what guys, in Denver - 2016, we were all listening to LSES, ( L1 = L2) chokes measuring LESS THAN the Hammond 159ZA is speced, both in HY and DCR / Ohms, and no caps over 50 uF. Sorta cool for me to know ( below the deck ) what I am hearing, experience the combo on differing program material, and HEAR how it can perform.

Since the show, DF tells me he has gone BEYOND that pair of amps he demoed, from his recent telephone descriptions to me. Much Fun !

Have a great day. My upcoming JJ 2A3-40 monoblocks will be using custom Partridge output transformers, tiny things, with a primary DCR of only 35 Ohms !!! versus the Magnequest DS-050's 360 Ohms of primary DCR. THAT change, with the LSES supply, should truly be nice to listen to.

'Next up, need to source Midnight Blue Wrinkle Powder Coat. EZ.


Jeff

 

RE: 3 LC section filters ..., posted on January 17, 2017 at 09:24:06
rage
Audiophile

Posts: 793
Joined: December 17, 2010
 look at jeffs original documents where he quotes jlh and pasternik (spelling) - triad c56u and two triad c40x is great budget low dcr supply. I thought the flywheel c56u worked better with more current across it as well.

 

RE: 159ZA chokes ... , posted on January 17, 2017 at 09:29:30
rage
Audiophile

Posts: 793
Joined: December 17, 2010
 I've thought about your new driver tube Jeff and I like it quite a bit.

Still laugh that Douglas suggested it ~ 4 years ago? Kind of funny how these things come full circle sometimes.

I'm going mono blocks with you... looking forward to having my DC2a3 up and running again..

There is something to be said for the ultra simplicity of the circuit. I came to appreciate it more after building a handful of push pull amps.

I really enjoy both PP and SE, particularly the direct coupled SE stuff.

 

RE: LOL, Didn't last long, under two months, posted on January 17, 2017 at 14:26:46
xaudiomanx
Audiophile

Posts: 3647
Joined: August 16, 2004
 Jeff,

I happen to like warm, fuzzy, tubey, colored, or whatever else it can be called. I do use a 26 tube preamp and as you know they are a colored sound as well so with that in mind you know my taste. But I have to say a single power transformer sounded much more coherent that two separates but again maybe your implementation of monoblocks might change ones mind. But the power tranny must be a beast.

 

RE: 3 LC section filters ..., posted on January 18, 2017 at 19:12:38
drlowmu
Manufacturer

Posts: 9730
Location: East of Kansas City
Joined: January 10, 2005
 What final tubes do you use, and at what current, and what is the filter's total current / and accurate supply schematic of your amp??

JM

 

Page processed in 0.020 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]