Since so many people have been bugging me about this,
I thought I'd mention it just to get the word out.

Unless I get run over by a bus or something before tomorrow,
we'll have new replacement PA135 power transformers
for the Dynaco Mark 4 as of St Patrick's Day (17 March). Sloncha!
(I know that's not spelled right, but my command of
Gaelic is a wee bit weak)

See: http://www.dynaclone.com

Next, (to say it Irish-style) we'll be after making a
downsized knockoff of the Dynaco A441, you know, the one with
the tertiary screen winding. That'd open up a whole realm
of possibilities for cheap, good quality NOS output tubes
that are currently mostly ignored because of low screen
voltage ratings, like 12E1, EL509, 6CD6, 6146, etc.

--
Ned Carlson Triode Electronics Chicago,IL USA
www.triodeelectronics.com

On 17 Mar 2005 02:20:02 -0600, "Ned Carlson"
wrote:

Next, (to say it Irish-style) we'll be after making a
downsized knockoff of the Dynaco A441, you know, the one with
the tertiary screen winding.

Thank you, Uncie Ned. I can't wait. By downsized, do you
mean a smaller core, etc? What primary impedance? Will
the tertiary winding be sized for cathode current too?

Much thanks,

Chris Hornbeck
"That's where my forebears came from. Three of them
anyway. Who's been sleeping in my porridge?" -F&S

On Thu, 17 Mar 2005 23:55:12 +0000, Chris Hornbeck wrote:

On 17 Mar 2005 02:20:02 -0600, "Ned Carlson"
wrote:

Next, (to say it Irish-style) we'll be after making a downsized knockoff
of the Dynaco A441, you know, the one with the tertiary screen winding.

Thank you, Uncie Ned. I can't wait. By downsized, do you mean a smaller
core, etc? What primary impedance? Will the tertiary winding be sized for
cathode current too?

Downsized as in being made on the same core as the Mk3's A431 (which is a
pretty substantial transformer as is). The original A441 was a freakin'
25 lb. monster made on the same core size as the 120W A451. If we
tried knocking off an exact copy of an original A441, you'd be
looking at $200+ price tag, well above the "credit card statement
wife complaint threshold" for the average Joe Sixpack hobbyist.
IOW, we wouldn't sell many at $200 a pop. If we downsize to the
60W core I can probably retail at $110.

If you think the prices are nuts, take a look at retail prices
for magnet wire, $20 per pound or more!

The primary would be 4300 ohms just like the A431 and A441.

Yes, you could use the tertiary winding in the cathode.


--
Ned Carlson Triode Electronics Chicago,IL USA
www.triodeelectronics.com

On 17 Mar 2005 22:58:05 -0600, "Ned Carlson"
wrote:

Downsized as in being made on the same core as the Mk3's A431 (which is a
pretty substantial transformer as is). The original A441 was a freakin'
25 lb. monster made on the same core size as the 120W A451. If we
tried knocking off an exact copy of an original A441, you'd be
looking at $200+ price tag, well above the "credit card statement
wife complaint threshold" for the average Joe Sixpack hobbyist.
IOW, we wouldn't sell many at $200 a pop. If we downsize to the
60W core I can probably retail at $110.

Sounds just right. There are serious downsides to an oversized core
for a particular task, especially push-pull, including greater
core losses and parasitic reactances, but especially the bigger
B-H flat spot. I'd say you've got it just right for modern
builders, more interested in fidelity than in squeezing 100
watts out of a pair of 6550's; that's been done already.


If you think the prices are nuts, take a look at retail prices
for magnet wire, $20 per pound or more!

On the contrary, I'd say that the proposed prices, and your
other Dyna(clones) are very reasonable. Fair, enough to stay
in biz, and enough to bother doing it, hopefully.


The primary would be 4300 ohms just like the A431 and A441.
Yes, you could use the tertiary winding in the cathode.

Quick quiz: without using your calculators, class, what is the
primary impedance of this transformer using the tertiary
winding in the cathodes? Tick, tick, tick...

Chris Hornbeck
Father Lonergan:
"Well, then. Now. I'll begin at the beginnin'. A fine soft day in the spring,
it was, when the train pulled into Castletown, three hours late as usual, and
himself got off. He didn't have the look of an American tourist at all about him.
Not a camera on him; what was worse, not even a fishin' rod."

On Fri, 18 Mar 2005 02:12:17 +0100, François Yves Le Gal wrote:

On 17 Mar 2005 02:20:02 -0600, "Ned Carlson"
wrote:

we'll have new replacement PA135 power transformers

Ned, have you considered extending your offer of models with 120 -120 V
primaries beyond the announced PA522?

I have thought about it, hovever, note that the additional cost of
adding that feature increases with the size of the transformer,
since with the 240V split primary, there's twice the length
of smaller diameter wire.

On a PA522, the difference in price is negligible. On a PA060,
we're talking about roughly a 25% increase in cost.

Also, the shipment costs for larger transformers via air mail
are considerable, and I'd rather avoid people asking for
surface shipping, which nearly always has had complications
every time we've tried it in the past. Delivery times for surface
(boat) are unpredictable and letting the post office have posession
of the goods for 4 to 8 weeks just gives them more time to find
ways to damage the package.

OTOH, Sowter is charging almost US$240 plus VAT (17-27%
depending on where you live) & shipping (much higher in the EU
than the USA for similar distances) for an ST70 power transformer,
which is more than what our transformer would cost with
airmail, VAT & duty.

We've had several Japanese customers order PA060's and pay for
Fedex or Express Mail shipping..note Japanese line voltage is
100 volts, so they'd still need an adapter transformer!..so
there's definitely people out there who are willing to pay.


Even if Sowter as well others produce some really nice equivalents, using
hecho in Norte America components

You mean "hecho en Estados Unidos". While Mexican made components
*ought* to be fully equivalent to US made...it's not like the people
aren't capable, probably half the people working in US transformer
factories are Mexican or Mexican-American, and even back in the
"vintage" days, a lot of the people who made those old Strats
& Fender amplifiers were, too.. bad management & QC is a problem,
ask Schumacher & Magnetek-Triad. The folks we deal with are
running at 100%+ capacity, mostly to accomodate ex-Schumacher
and ex-Triad customers.

And the USD is so weak those days that the difference
in shipping costs is more than offset.

Yeah, but it needed some deflating.

--
Ned Carlson Triode Electronics Chicago,IL USA
www.triodeelectronics.com

Hi Ned:

It's Slainté



"Ned Carlson" wrote in message
news
Since so many people have been bugging me about this,
I thought I'd mention it just to get the word out.

Unless I get run over by a bus or something before tomorrow,
we'll have new replacement PA135 power transformers
for the Dynaco Mark 4 as of St Patrick's Day (17 March). Sloncha!
(I know that's not spelled right, but my command of
Gaelic is a wee bit weak)

See: http://www.dynaclone.com

Next, (to say it Irish-style) we'll be after making a
downsized knockoff of the Dynaco A441, you know, the one with
the tertiary screen winding. That'd open up a whole realm
of possibilities for cheap, good quality NOS output tubes
that are currently mostly ignored because of low screen
voltage ratings, like 12E1, EL509, 6CD6, 6146, etc.

--
Ned Carlson Triode Electronics Chicago,IL USA
www.triodeelectronics.com