New project; Musical Machine

[boywonder]

The reason I'm considering the two box solution is that the Silk OPT's that I got are nicely potted and look very nice; the choke and Toroid don't look quite as nice. I'm trying to get creative on how I can make this thing look the part. A two box solution seemed like a slick solution and I wouldn't mind running two umbilicals but would for sure be open to other ideas.

Bigjp: If you don't mind stretching your wallet a little (actually a lot...) you could consider the James 9611 transformer (280-0-280 @.3a) or the 9615 (260-0-260 @ .45a). They are very sexy and are available in champagne or black. There is also a US supplier TC Tubes - specializing in vintage vacuum tubes. I have been emailing them and they will have the 9611 in stock shortly for $239 (ouch!) The value of the fist cap will have to come down a little to reach the target B+.

As far as umbilicals go, I've built a 9 pin AMP circular plastic (CPC) connector cable with some 9 conductor Belden cable that looks pretty good. The back shell is missing on the plastic connector in the pic. The CPC series is available from Digikey, etc in many pin and shell arragements. The metal Amphenols are very "industrial" looking and a lot pricier. If you end up going this route, I can crimp the contacts for you if you don't have a crimper.

 

[Kyle K]

Can't help with the choke, but Antek sells covers for the toroidal transformer.

http://www.antekinc.com/pdf/CA-xxx.pdf

They are pretty nice; made of very thick steel with the center post made slightly longer than the height of the "pot" so it there's a small gap between the cover and the mounting surface. (necessary to prevent a shorted turn condition if you use a conductive mounting surface)

Price is reasonable enough that combined with the toroid, this option would probably still be cheaper than other alternatives.

Kyle

 

[Flappytango]

Nothing is nailed down, ever. I'm sure there's a stupid mistake in here somewhere; my original point was just that the odds of finding it now by taking a WAG are pretty low.

Heres the power supply:
...

Im real new at this stuff... but I was trying to understand how you get 12.6Vac and 6.3Vac out of this tansformer as shown in your power supply drawing? can you put the two 6.3 outs in series (orgn-brwn+green-blu) and still pull 6.3 off of one set (grn-blu)?
thanks

 

[bigjppop]

Bigjp: If you don't mind stretching your wallet a little (actually a lot...) you could consider the James 9611 transformer (280-0-280 @.3a) or the 9615 (260-0-260 @ .45a). They are very sexy and are available in champagne or black. There is also a US supplier TC Tubes - specializing in vintage vacuum tubes. I have been emailing them and they will have the 9611 in stock shortly for $239 (ouch!) The value of the fist cap will have to come down a little to reach the target B+.

As far as umbilicals go, I've built a 9 pin AMP circular plastic (CPC) connector cable with some 9 conductor Belden cable that looks pretty good. The back shell is missing on the plastic connector in the pic. The CPC series is available from Digikey, etc in many pin and shell arragements. The metal Amphenols are very "industrial" looking and a lot pricier. If you end up going this route, I can crimp the contacts for you if you don't have a crimper.

Thanks for following up on this. I've thought about a different PT, but at 239... that's almost what I paid for all my other parts combined! I thought about doing the Antek and the choke under the chassis and the OPT's on top but that would kind of defeat the work Poinz did in keeping the power and audio circuits separate.

I've seen several commercial products with a single umbilical but I've never seen one with multiples; do people feel pretty strongly that the various voltages need to be kept separate? I'm a newb here so I'm guessing.

Boywonder, I definitely don't have a crimper (not really sure what it does) but if I need one, I will most definitely take you up on your offer.

 

[boywonder]

I've seen several commercial products with a single umbilical but I've never seen one with multiples; do people feel pretty strongly that the various voltages need to be kept separate? I'm a newb here so I'm guessing.

Boywonder, I definitely don't have a crimper (not really sure what it does) but if I need one, I will most definitely take you up on your offer.

I think running the filtered DC in one umbilical and the AC heaters in another would be fine. That keeps the high current AC heaters away from the filtered B+ voltages. You could also rectify the filament voltages into DC in the PS chassis, and then everything could be run in one umbilical, but that would be a lot of aggravation for very little gain. Most folks here think that DC heaters on a power amp are not needed.

I would consider breadboarding the two chassis and try one umbilical between them to see if hum is a problem. You don't even need umbilical connectors for that, just hardwire both ends.

I've been tweaking my 6GK5/EL34 MM's for a few hours.....they are both dead quiet on my 90db speakers...I'm measuring about 2 mv rms of noise on the scope.

You need a crimper to crimp the pins on the circular connectors. they are crimp instead of solder. We have several at work for different series/brands of connectors. Crimpers for these connectors can get very expensive ($300-$400+ each)

 

[bigjppop]

I think running the filtered DC in one umbilical and the AC heaters in another would be fine. That keeps the high current AC heaters away from the filtered B+ voltages. You could also rectify the filament voltages into DC in the PS chassis, and then everything could be run in one umbilical, but that would be a lot of aggravation for very little gain. Most folks here think that DC heaters on a power amp are not needed.

I would consider breadboarding the two chassis and try one umbilical between them to see if hum is a problem. You don't even need umbilical connectors for that, just hardwire both ends.

I've been tweaking my 6GK5/EL34 MM's for a few hours.....they are both dead quiet on my 90db speakers...I'm measuring about 2 mv rms of noise on the scope.

You need a crimper to crimp the pins on the circular connectors. they are crimp instead of solder. We have several at work for different series/brands of connectors. Crimpers for these connectors can get very expensive ($300-$400+ each)

I think 2 umbilicals would work okay and I'll for sure get in touch with you for some crimping assistance; anything to avoid buying yet another tool that I'll probably only use once!

Also, your monoblocks sound pretty awesome; any pics?

 

[Poindexter]

Flap, the Antek transformer has four secondaries:

Two 250V that can be connected in series (for fullwave rectification) or parallel (for bridge etc.)

One 6.3v

One 12.6V

It's a very usefully designed transformer.

Poinz

 

[Eli Duttman]

Flap, the Antek transformer has four secondaries:

Two 250V that can be connected in series (for fullwave rectification) or parallel (for bridge etc.)

One 6.3v

One 12.6V

It's a very usefully designed transformer.

Poinz

Poinz,

Be carefull about some AnTek Models, as they have been revised. A model I was interested in switched from a 12.6 and a 6.3 VAC winding to 2X 6.3 VAC windings. Double check the latest spec's for a model of interest by linking from AnTek's grid.

 

[Flappytango]

Poinz,

Be carefull about some AnTek Models, as they have been revised. A model I was interested in switched from a 12.6 and a 6.3 VAC winding to 2X 6.3 VAC windings. Double check the latest spec's for a model of interest by linking from AnTek's grid.

I guess that why i was confused because currently that is what antek shows for the AN-1T250, no 12.3

 

[Poindexter]

Sh!t.

P

 

[Pano]

Just when you get something good....

Say, you're up early!

 

[boywonder]

one blue sock and one black sock

Also, your monoblocks sound pretty awesome; any pics?

Here are some pics. They are not completed yet, but close. The one on the left needs it's Edcor blacked out and the top deck needs bead blasting, not to mention some housekeeping underneath. As of late last nite I'm running the EL34's at 400V/60 ma and they sound great.

 

[Golana]

Those monos look great!

So whats the game plan on the Antek? Run the 6.3 as a doubler? wouldnt that be a simple solution? I never even thought to check or for that matter question ordering, ratz.

 

[Poindexter]

I was already rectifying the 12. 6V winding with a doubler, for the bias supply. I may try a quadrupler, to see if it works okay; I had not wanted to do this, because the doubler is full-wave, and only will take half the value of filter components to get the ripple down to the same value as the half-wave quadrupler. We'll see.

Aloha,

Poinz
AudioTropic

 

[Eli Duttman]

I was already rectifying the 12. 6V winding with a doubler, for the bias supply. I may try a quadrupler, to see if it works okay; I had not wanted to do this, because the doubler is full-wave, and only will take half the value of filter components to get the ripple down to the same value as the half-wave quadrupler. We'll see.

Aloha,

Poinz
AudioTropic

Poinz,

I think you will do fine using the 2nd schematic in the graphic, "ripped" from Voltage Multiplier Inc., I've uploaded. A bias rail has to provide only a few clean mA. The half-wave parallel topology puts equal strain on the diodes, but the voltage rating of the caps. has to increase with each successive stage.

 

[Poindexter]

Eli, those are the same schematic electrically, just rearranged graphically. Yes, that's what I'm looking at, but smoothing 60Hz ripple is twice the PITA as 120Hz ripple. I hate it, but what's to be done?

Mahalo,

P

 

[Eli Duttman]

Poinz,

The 2 circuits are different. The 1st places equal stress on both caps. and diodes, but it's good only in very low current situations, like CRT 2nd anode.

Check the VMI site out. It's too bad that VMI has updated things. IIRC, they used to show a full wave quadrupler.

 

[bigjppop]

Poinz:

Just wondering if you, or anyone else, has found a new solution for the PT on this amp. I seem to recal a couple months back that Antek changed the PT you normally recommend.

 

[Poindexter]

I don't think a new solution is necessary. Since I don't know a fullwave quadrupler circuit, I think I'll just pull off the existing -66v supply for the tail. The current draw (about 2mA max) won't affect that supply at all, and the net power supply will be simplified.

BTW, you're right, Eli; those quadrupler circuits are not the same. Mea culpa.

Aloha,

Poinz
AT

 

[Eli Duttman]

Poinz,

A nice circuit for multi-stage full wave voltage multiplying is available and I've uploaded it. Unfortunately, it's costly to execute, as AC film caps. are necessary in the "arm" positions. 'Lytics are OK in the central "spine".