latest "bargain"

latest "bargain"

I'm just a sucker -- sometimes I buy cheap iron on eBay just to see what it
is. I'll probably sell this one. I didn't pay enough to get hurt -- $16
with shipping. Before I spend time testing it or list it on eBay, I thought
I'd ask if anyone here thinks this PT might be used with a doubler.

Numbers on the tranny are 300261-1MOD; 93-011-031-97; 606125, making this a
Woodard-Schumacher, and that was the big draw along with it being NIB, never
soldered. It weighs in at about 8.5#, and the laminations are 2 3/8" thick.
There is a copper band around it. So, this is really quite a hefty PT, not
a wimp.

There are 4 windings, unloaded: 34-0-34 (blue); 127-0-127 (brown); 214
(red); 6.7 (green). Does this combination ring a bell for anyone? I know
it's a longshot.

The 34-0-34 winding strikes me a rather pecuiliar, in that it is center
tapped. LOL, I could run a pair of 35L6's on that winding and use the
127-0-127 to power the plates. The 107-107 could power the pre-amp along
with the 6.3v winding. It this nuts or what?

If I thought I could double the HT winding, I'm guessing I could wring out
215-215 through a FW bridge. I could probably run a pair of 6AQ5 at a low
wattage.

C'mon fellas. There isn't much on topic stuff here lately. Go ahead and
speculate. Have some fun with this.

Regards,
Phil

Re: latest "bargain"

Phil S. wrote:
> I'm just a sucker -- sometimes I buy cheap iron on eBay just to see what it
> is. I'll probably sell this one. I didn't pay enough to get hurt -- $16
> with shipping. Before I spend time testing it or list it on eBay, I thought
> I'd ask if anyone here thinks this PT might be used with a doubler.
>
> Numbers on the tranny are 300261-1MOD; 93-011-031-97; 606125, making this a
> Woodard-Schumacher, and that was the big draw along with it being NIB, never
> soldered. It weighs in at about 8.5#, and the laminations are 2 3/8" thick.
> There is a copper band around it. So, this is really quite a hefty PT, not
> a wimp.
>
> There are 4 windings, unloaded: 34-0-34 (blue); 127-0-127 (brown); 214
> (red); 6.7 (green). Does this combination ring a bell for anyone? I know
> it's a longshot.
>
> The 34-0-34 winding strikes me a rather pecuiliar, in that it is center
> tapped. LOL, I could run a pair of 35L6's on that winding and use the
> 127-0-127 to power the plates. The 107-107 could power the pre-amp along
> with the 6.3v winding. It this nuts or what?
>
> If I thought I could double the HT winding, I'm guessing I could wring out
> 215-215 through a FW bridge. I could probably run a pair of 6AQ5 at a low
> wattage.
>
> C'mon fellas. There isn't much on topic stuff here lately. Go ahead and
> speculate. Have some fun with this.
>
> Regards,
> Phil
>
>

Phil,

How do you dare not include political, social,
or <reader's pet peeve here> content in your post? ;)

There are color code specs for power transformers, but
they are not always followed.

Red should be the B+
Green should be the filament.
Brown should an additional filament.
Blue ...

Remember your thread a while back re: "Transformer
mA Rating"? Time to go through it...

The red winding is 214. I assume that's not a center-tapped
winding. If that is correct, use a full wave bridge rectifier
for about 300VDC. You need to determine the ampacity of the winding.

You could, if you wanted to get creative, use the blue and
brown windings for different screen voltages. The brown,
using a full wave rectifier, will give you about 170VDC.
The blue, no connection to the center tap, full wave bridge
rectifier, will give around 90VDC. You *could* switch between
these screen grid supplies to net an amp with three different
power ranges. The lower the screen grid voltage, the lower the
output power. You will probably need to address the bias voltage
for each of the three different power ranges, as well.

Of course, you need to determine each winding's ampacity.
Once you've established these numbers, you can peruse tube data
sheets, interpolate certain values, and come up with a truly
unique design.

Phil, you can have a lot of fun with this one; and learn
a great deal, as well. But it will take some effort.
You can certainly do it.

Gary Gerhart
Gerhart Amplification

Re: latest "bargain"


"Gary Gerhart" <Gary@GerhartAmps . com > wrote in message
news:sqsSj.630$J16.107@newssvr23.news.prodigy . net ...
> Phil S. wrote:
>> I'm just a sucker -- sometimes I buy cheap iron on eBay just to see what
>> it is. I'll probably sell this one. I didn't pay enough to get hurt --
>> $16 with shipping. Before I spend time testing it or list it on eBay, I
>> thought I'd ask if anyone here thinks this PT might be used with a
>> doubler.
>>
>> Numbers on the tranny are 300261-1MOD; 93-011-031-97; 606125, making this
>> a Woodard-Schumacher, and that was the big draw along with it being NIB,
>> never soldered. It weighs in at about 8.5#, and the laminations are 2
>> 3/8" thick. There is a copper band around it. So, this is really quite a
>> hefty PT, not a wimp.
>>
>> There are 4 windings, unloaded: 34-0-34 (blue); 127-0-127 (brown); 214
>> (red); 6.7 (green). Does this combination ring a bell for anyone? I
>> know it's a longshot.
>>
>> The 34-0-34 winding strikes me a rather pecuiliar, in that it is center
>> tapped. LOL, I could run a pair of 35L6's on that winding and use the
>> 127-0-127 to power the plates. The 107-107 could power the pre-amp along
>> with the 6.3v winding. It this nuts or what?
>>
>> If I thought I could double the HT winding, I'm guessing I could wring
>> out 215-215 through a FW bridge. I could probably run a pair of 6AQ5 at
>> a low wattage.
>>
>> C'mon fellas. There isn't much on topic stuff here lately. Go ahead and
>> speculate. Have some fun with this.
>>
>> Regards,
>> Phil
>
> Phil,
>
> How do you dare not include political, social,
> or <reader's pet peeve here> content in your post? ;)
>
> There are color code specs for power transformers, but
> they are not always followed.
>
> Red should be the B+
> Green should be the filament.
> Brown should an additional filament.
> Blue ...
>
> Remember your thread a while back re: "Transformer
> mA Rating"? Time to go through it...
>
> The red winding is 214. I assume that's not a center-tapped
> winding. If that is correct, use a full wave bridge rectifier
> for about 300VDC. You need to determine the ampacity of the winding.
>
> You could, if you wanted to get creative, use the blue and
> brown windings for different screen voltages. The brown,
> using a full wave rectifier, will give you about 170VDC.
> The blue, no connection to the center tap, full wave bridge
> rectifier, will give around 90VDC. You *could* switch between
> these screen grid supplies to net an amp with three different
> power ranges. The lower the screen grid voltage, the lower the
> output power. You will probably need to address the bias voltage
> for each of the three different power ranges, as well.
>
> Of course, you need to determine each winding's ampacity.
> Once you've established these numbers, you can peruse tube data
> sheets, interpolate certain values, and come up with a truly
> unique design.
>
> Phil, you can have a lot of fun with this one; and learn
> a great deal, as well. But it will take some effort.
> You can certainly do it.
>
> Gary Gerhart
> Gerhart Amplification
>

Hi Gary,
I wasn't looking for a short cut here, as I know there isn't one. I
thought, however, it was an unusual collection of windings that might ring a
bell with someone.

So, I've started a bit of research, as that's something I can't seem to
resist.

The primary winding measures 1.5z on my Tripplett meter. Sorry, now I'm
wishing I had a Fluke! According to a table published here many moons ago
by Phil Allison, that ohm rating suggests VA is between 225 and 300, so
let's call it 260 for the sake of having a discussion. That would be a nice
number to start with.

Then, I came across this power transformer calculator.
: * w w w .angelfire . com /electronic/funwithtubes/Programs/Power_Transformer-98.exe

Who know if it's any good, but I gave it a try. Plugging in the unloaded
voltages and the ohms of the windings S1 (Blue-Black/White-Blue) 5.5z, S2
(Brown-Brown/white-Brown) 1.6z, S3 (Red-Red) 16.3z, and S4 (Green-Green)
0.4z, the physical dimensions of the transformer and its intended
orientation, it supposedly corrects for loading and solves for current.
Here's what I got in results:

S1 239v @ 1.2A
S2 67v @ 1.1A
S3 207V @ 340mA
S4 6.3V @ 800mA

I was "good" with these results up until the last one. Although, by some
miracle, it gave the filament winding a loaded voltage that's correct, I'm
finding the low mA rating either disappointing or simply out of sync with
the S1 amd S2 ratings. Yikes, if the amps are correct on S1, running it
through a quadrupler will still leave about 300mA on the B+ supply. So, I
ran some data from a known PT into the calculator, and it proves to be
unreliable. Either I don't know how to use it, I've got the wrong data, or
its a POS. Anyhow, it was a "nice try". Maybe I'll try it again. I've got
two PT's on the shelf with known spec, but I've got to fire them up to get
unloaded voltages and that's too much of a PITA right now.

Looking at the item, its physical size and weight, and the apparent VA
rating, I think maybe this one is worth testing. I don't think I've got the
right sandblock resistors for load testing. I have one 1k5 25W, two 15K
10W, and one 10K 10W. I'd gladly accept some suggestions here.

I'll have to build out a power supply and rectifier, and put a cap on it.
Then, I can see what the three non-filament winding produce in VDC. I
assume it is OK to do this on a wood board (breadboarding)?

So, what's an appropriate load for the filament winding. I'm lost here. I
know, for example 6.3vac running two EL84 and three 12AX7 requires 2.41A.
That's 15.2W. So, how do I solve for the number of ohms that should drop
from 6.66 to 6.3? I have a mental block on this stuff. Well, OK, maybe I
don't. I get 2.6 ohms is needed to tell me it supports those five tubes.
Is that right? I jusst seems so small. So, I need a 2.6 ohm 15W resistor.
LOL!

I'll sleep on this.

Thanks.

Phil

Re: latest "bargain"


"Phil S." <psymonds_no_spam@comcast . net > wrote
...

> Here's what I got in results:
>
> S1 239v @ 1.2A
> S2 67v @ 1.1A
> S3 207V @ 340mA
> S4 6.3V @ 800mA
>
> I was "good" with these results up until the last one.

I'm choking on the *first* one... almost 300watts, for HV?
How big *is* this thing?
__
Steve
.

Re: latest "bargain"

On Fri, 02 May 2008 03:32:09 GMT, "Stephen Cowell"
<scowell@sbcglobal . net > wrote:

>
>"Phil S." <psymonds_no_spam@comcast . net > wrote
>...
>
>> Here's what I got in results:
>>
>> S1 239v @ 1.2A
>> S2 67v @ 1.1A
>> S3 207V @ 340mA
>> S4 6.3V @ 800mA
>>
>> I was "good" with these results up until the last one.
>
>I'm choking on the *first* one... almost 300watts, for HV?
>How big *is* this thing?
>__
>Steve

Yeah, that sounded unlikely to me too. Better rezero the meter or
calibrate with some low-value resistors. If it comes out the same,
then I bet the website's math is off.

Re: latest "bargain"


"Stephen Cowell" <scowell@sbcglobal . net > wrote in message
news:ZWvSj.2164$506.1219@newssvr27.news.prodigy . net ...
>
> "Phil S." <psymonds_no_spam@comcast . net > wrote
> ...
>
>> Here's what I got in results:
>>
>> S1 239v @ 1.2A
>> S2 67v @ 1.1A
>> S3 207V @ 340mA
>> S4 6.3V @ 800mA
>>
>> I was "good" with these results up until the last one.
>
> I'm choking on the *first* one... almost 300watts, for HV?
> How big *is* this thing?
> __
> Steve
> .
>
Hi Steve.

Notice that "good" is in quotes. It was all humor as far as I was
concerned. I don't think that calculator is correct or I don't know how to
use it.

This one is large, but not obscene like the one I've got with a 6.3v
winding rated at 9A. That one is meant for an organ.

This particular PT, the lams is 2 3/8" across the stack, and 3.75" h x
3.25" w. It is about 4 3/8" across the outer side of the end bells. Mounts
are 2.5" OC and 3.25" the other way.

There is no question in my mind that the wiring color scheme is a bit "off".
The primary is black-black and the 6.3v is green-green. From there, it gets
weird. The HT secondary is blue-black/white-blue, and the other main
secondary is brown-brown/white-brown. The red-red (no CT) is clearly
odd-ball, and I suspect is a low current winding.

Thoush no one seems to want to weigh in on my Ohms Law calc for the filament
winding, I stopped by the electronics store. The had a 25W 2.7 ohm 5%
sandblock that meters at 3.0 ohms.

Here is some easy preliminary data. I am rather unsure about these
calculations. Please tell me, did I get this right?

Filament winding, 6.6vac drops to 6.35vac across 3 ohms::
I=V/R; I= 6.35/3 = 2.12A. Not that robust, but enough to run two 6AQ5's (or
6V6) and three 12AX7, a total of 1.8A. Barely enough to run a pair of
EL84's and two 12AX7.

HT (blue) secondary, 1k5 drops 254.0vac to 251.5vac
I=VR, I = 251.5/1500 = 168mA. Seemed cool enough. Try this with a 1K
resistor? That would get me into the 250mA range, probably enough to use a
doubler for a low power amp. This would also be reasonably consistent with
the VA chart that is based on the ohms of the primary winding.

Red secontary, 1k5 drops 213.4vac to 210.4vac:
210.4/1500 = 140mA, but there was a bit of smoke here, and I think it may
have been the insulation on the red wires. I was quick to shut it off, as I
was watching very closely. I'm guessing I was over the limit on this one.

I didn't bother with the brown winding. I have no idea what I'd use it for
except maybe bias voltage, and for that I'd guess 10mA would be 2x what's
needed.

Re: latest "bargain"

Gary Gerhart wrote:

>
> How do you dare not include political, social,
> or content in your post? ;)
>
Phil consistently takes the high road and let's
the shit roll down into the gutter. We should
all be that considerate. The ankle biters and
baiters are easily recognized, yet it never ends.
AGA reminds me of a room of 5th graders rioting
when a substitute teacher shows on a Friday.

Re: latest "bargain"

WB wrote:
> Gary Gerhart wrote:
>
>>
>> How do you dare not include political, social,
>> or content in your post? ;)
>>
> Phil consistently takes the high road and let's
> the shit roll down into the gutter. We should
> all be that considerate. The ankle biters and
> baiters are easily recognized, yet it never ends.
> AGA reminds me of a room of 5th graders rioting
> when a substitute teacher shows on a Friday.
>
>
>
>
Nah, more like 8th graders. 5th graders have their shit way more
together than that!

Re: latest "bargain"

Thank you for your technically enlightening On Topic post.

"WB" <warbaby@ppp . com > wrote in message
news:481a7ac4$0$4038$bbae4d71@news.suddenlink . net ...
> Gary Gerhart wrote:
>
>>
>> How do you dare not include political, social,
>> or content in your post? ;)
>>
> Phil consistently takes the high road and let's
> the shit roll down into the gutter. We should
> all be that considerate. The ankle biters and
> baiters are easily recognized, yet it never ends.
> AGA reminds me of a room of 5th graders rioting
> when a substitute teacher shows on a Friday.
>
>
>
>

Re: latest "bargain"

Elvis Kabong wrote:
> Thank you for your technically enlightening On Topic post.
>
My pleasure ! I always like to particular in activities
that move a concept towards a successful win-win solution
for everyone. Special kudo's to Gary too.

Re: latest "bargain"


"Elvis Kabong" <ampscience@tuneland . com > wrote in message
news:KBxSj.25664$DY1.21540@bignews5.bellsouth . net ...
> Thank you for your technically enlightening On Topic post.
>
> "WB" <warbaby@ppp . com > wrote in message
> news:481a7ac4$0$4038$bbae4d71@news.suddenlink . net ...
>> Gary Gerhart wrote:
>>
>>>
>>> How do you dare not include political, social,
>>> or content in your post? ;)
>>>
>> Phil consistently takes the high road and let's
>> the shit roll down into the gutter. We should
>> all be that considerate. The ankle biters and
>> baiters are easily recognized, yet it never ends.
>> AGA reminds me of a room of 5th graders rioting
>> when a substitute teacher shows on a Friday.
>>

OK, girls, take it outside. I'm trying real hard for on-topic.

Re: latest "bargain"

Phil S. wrote:
> I'm trying real hard for on-topic.
>
>
ack. Watch out for your ankles.

Re: latest "bargain"


"WB" <warbaby@ppp . com > wrote in message
news:481b8f3a$0$4071$bbae4d71@news.suddenlink . net ...
> Phil S. wrote:
>> I'm trying real hard for on-topic.
> ack. Watch out for your ankles.

I've got a Dachshund to watch out for those. Her name is Frankie! Oops.

Re: latest "bargain"

Phil S. wrote:
> Phil
>
>


The thing about black box transformers is you have no idea
what the ratings are. Red is typically B+, yellow/green heaters.
Blue ... bias tap ? .. black(s) primary ... With a 254v on the
secondart .. it is feasible for a amp ..

---> how about 12ax7 preamp only ?

Re: latest "bargain"


"WB" <warbaby@ppp . com > wrote in message
news:481a7be7$0$4038$bbae4d71@news.suddenlink . net ...
> Phil S. wrote:
>> Phil
>
>
> The thing about black box transformers is you have no idea
> what the ratings are. Red is typically B+, yellow/green heaters.
> Blue ... bias tap ? .. black(s) primary ... With a 254v on the secondart
> .. it is feasible for a amp ..
>
> ---> how about 12ax7 preamp only ?
>

Blue is clearly the HT. I"m hoping I can run it through a doubler to a pair
of 6AQ5. I'm thinking that I'll build one and see how it works with cap
input. I could do this with a choke input, too. I've got a 20H 100mA meant
for a Vox AC30. I'm a bit concerned that 100mA rating is on the low side.

The preliminary test suggests that the red winding is probably no more than
100mA.