Re: Plate blocking caps YC156
Nope,? you? got it? ass backwards.? Measure? the plate? block? cap? current if u don't? believe me.? W8JI, W8ZR, and John? Lyles? also? concur.?
At? 29? mhz,? the anode? to? chassis? capacitance? becomes? most? of the resonant? tank? capacitance.? ?How? do u? ?think? the main? tank? coil? gets? connected? to the tube? C.....? via? the? plate? block? cap of? course.
If the plate? block? cap is? installed at the 50? ohm? end? of the? PI /? PI-L? network,? then? u? end? up? B+? on? both? the? tune +? load? caps, tank? coil(s),? bandswitch,? roller? coil? (if? used).? It? would? work, but? u just? added a ton? of? stress to? all? those? aforementioned? tank components.?
Those? 4-5" (100-120mm)? diam? 'puck'? style? caps? won't? handle 142A? like? 4 x? 250? pf? HT-59's? will.? ? Even? the? ?140-150-200-205-250 mm? 'puck'? style? caps? won't work.? ?Trying to parallel 'puck'? style?caps? is an? exercise? in? futility.? 2 x 200mm? pucks eats? up? ?8" x 16.5" !?
As? Carl? noted,? the? Centralab? 859? /? HEC? HT-59? is only? 2.25" diam? x 3" long.? ?I mounted? 4 x HT-59's? on a 3" x 3"? x 1/4"? thick? piece? of? copper..? (used on a single 3CX-20,000A7, 27 mhz amp).
4 x HT-59's? are? good? for 25 kv, 142A? CCS,? and? 200? KVA....? and? 1000? pf? total? C.? ? Good? luck? trying? to? find a? puck style cap that? remotely comes? close? to? those? specs... they? don't? exist.?
The? 'kva'? rating is? typ a non? issue.? ?Knowing? the capacitance? of? each? block? cap, the? XC? of? each? block? cap? is? easily? calculated.? ?We already calculated? the? current through? each? block? cap.
Current? x? XC? =? AC? Vdrop? across? each? cap...which? is? typ? a?very low? value.? ?The? AC? V? drop? +? any? bias (B+)? can't? exceed the block? cap's? stamped? V? rating.? ??
The? AC? current? through? the? block? cap....? x? the AC? Vdrop? across? the? cap = va power.?
Using the? 2 x 3x15 tubes on? 27? mhz? for the? following? example.?
250? pf? = 23.59? ohms.?
100.93 A? /? 4? =? 25.23A? PER? each? of? the? 250? pf? caps ( 4 x caps used? in parallel.)?
?23.59 ohms? ?x 25.23 A =? ?595 Vac? across? each? ?of? the? 4 x caps.?
595 vac? x 25.23 A? = 15,012? VA? ?( 15 kva)? Per? cap.
Each? cap? rated? for 50? kva...so? within? spec.?
On low? bands,? like? 160 ,? ?XC? per? cap is a lot? higher, but cap? current? is? very? low....so? it's? still a non? issue? as? far? as KVA? ratings.?
Download? the? HEC catalog.? ?It? depicts kva/current / voltage vs freq? in? graph? form? ?I? will? post? the? HEC Catalog on? this site since I? have it already? in PDF? form.? ??
Jim? VE7RF??
|
Re: Plate blocking caps YC156
?
Not even close at?2.25" wide by 3"
tall..? Ive vever used them above?160 anyway and that was in?an
Omega match of a shunt fed?big 4 el 10/15/20 yagis top loaded
100'?tower in the mid 80's.?Resonant frequency was around 1500
kHz.?The RF HV was arcing a 7KV variable in a plywood box at only 1200W.
Moisture loaded air didnt help.
?
Modified another cheap hamfest variable for about
11 KV spacing for fine tuning and all was fine for a few years before moving
here.
?
Carl
?
----- Original Message -----
Sent: Friday, December 27, 2019 12:47
AM
Subject: Re: [ham-amplifiers] Plate
blocking caps YC156
Those style? caps? are? way? too? big
in diam,? like? 4-5" !? ? They? end? up?
adding too? much? stray? C.? ?Been? there,?
done? that.?
HT-57? in 200? pf is rated at?
?15A? CCS...and? 35KVA.? ? ?4 in?
parallel? make? for a compact? plate block? assy.?
?Good? for 60A? +? ?140 KVA..on? 10M?
band.??
To calculate? current through a plate?
block? cap? assy? is? as? follows.?
1)
calculate? XC? of? tube(s)? ?anode to? grid
C...? ( which? will? increase? with? tube?
in? socket...or? grid flange bolted? to? chassis.?
Caused? by? proximity of lower anode? fins? to?
chassis.)??
2)? calculate RF? RMS voltage at
anode.? ?( .6 X LOADED B+)
3)? ?RMS? voltage
/? Tube XC? ?=? ?RF? current through?
plate? block? cap assy.? ?
Example.?
?YC-156 on? 29? mhz.? ?52? pf? from?
anode? to? chassis.....? measured? with LCR
meter.?
1,000,000? /? (2 x pi x F x C
)?
=? 1,000,000? /? (6.28 x 29? x
52)
=? 105.6? ohms? ? of? XC? on?
?29? mhz.
Assume? ?a loaded? B+? of?
6? kv.?
RF? voltage is? ?.6? x 6000?
?=? ? 3600 vrms.
3600 / 105.6? ?=?
?34.1? Amps flowing through? plate? block? cap?
assy.....? on? 29? mhz.?
? Above?
is? the? worse? case...(6M? is? even?
worse).? ? ? Do? a similar? calc? for?
lower? bands.? ?On 14.5 mhz,? ?xc? is now
211? ohms.? Plate? block? cap? current? is?
down? to 17.05? amps. (8.5 amps? on? 40M....?
4.26? amps on 80M...... and 2.13 amps on? 160M.?
??
HT-59 in? a? 250pf version? is?
good? for 35A? +? 50? kva.? ?On buddy's? 2
x 3CX-15,000A7? amp? on? 27? mhz,? things?
go? crazy.? EACH? tube? is? 62 pf? from?
anode? to? chassis.?
XC? =? 47.56 ohms?
? ? Loaded? B+? is? 8 kv.? ?RF?
voltage = 8000? x? .6? = 4.8 kv
Current? through
plate? block? cap assy =? ?4800 / 47.56? = 100.93
Amps.?
4 x HT-59's in? 250 pf version? used.? (1000
pf? total).? ?Good? for?
140A?
Later....? Jim? VE7RF?
??
|
Re: Plate blocking caps YC156
Jim,
?
Why should the circulating RF current you
calculated, depending on Xc of the YC-156, flow through the plate blocking cap?
In the 29MHz case most anode capacity will
be within the tube and therefore only a small percentage of that RF current is
flowing through the blocking and tuning caps.
?
And imagine the plate blocking cap being
at the 50 ohm side of the pi coil which I frequently prefer...
?
Tell me why the size of 4-5¡°
diameter for a blocking capacitor matters when a pair of 3CX15000A7 is used?
You will need at least a 8-10¡° width
of copper sheet to mount 4x HT59 in a square on it.
?
73
Peter
?
?
Those style? caps? are? way? too? big in
diam,? like? 4-5" !? ? They? end? up?
adding too? much? stray? C.? ?Been? there,?
done? that.?
HT-57? in 200? pf is rated at? ?15A? CCS...and?
35KVA.? ? ?4 in? parallel? make? for a compact?
plate block? assy.? ?Good? for 60A? +? ?140
KVA..on? 10M? band.??
To calculate? current through a plate? block? cap?
assy? is? as? follows.?
1) calculate? XC? of? tube(s)? ?anode to? grid
C...? ( which? will? increase? with? tube?
in? socket...or? grid flange bolted? to? chassis.?
Caused? by? proximity of lower anode? fins? to?
chassis.)??
2)? calculate RF? RMS voltage at anode.? ?( .6 X LOADED B+)
3)? ?RMS? voltage /? Tube XC? ?=?
?RF? current through? plate? block? cap assy.?
?
Example.? ?YC-156 on? 29? mhz.? ?52?
pf? from? anode? to? chassis.....? measured? with
LCR meter.?
1,000,000? /? (2 x pi x F x C )?
=? 1,000,000? /? (6.28 x 29? x 52)
=? 105.6? ohms? ? of? XC? on? ?29?
mhz.
Assume? ?a loaded? B+? of? 6? kv.?
RF? voltage is? ?.6? x 6000? ?=? ? 3600
vrms.
3600 / 105.6? ?=? ?34.1? Amps flowing through?
plate? block? cap? assy.....? on? 29? mhz.?
? Above? is? the? worse? case...(6M? is?
even? worse).? ? ? Do? a similar? calc?
for? lower? bands.? ?On 14.5 mhz,? ?xc? is
now 211? ohms.? Plate? block? cap? current?
is? down? to 17.05? amps. (8.5 amps? on? 40M....?
4.26? amps on 80M...... and 2.13 amps on? 160M.? ??
HT-59 in? a? 250pf version? is? good? for 35A?
+? 50? kva.? ?On buddy's? 2 x 3CX-15,000A7?
amp? on? 27? mhz,? things? go? crazy.?
EACH? tube? is? 62 pf? from? anode? to?
chassis.?
XC? =? 47.56 ohms? ? ? Loaded? B+? is?
8 kv.? ?RF? voltage = 8000? x? .6? = 4.8 kv
Current? through plate? block? cap assy =? ?4800 /
47.56? = 100.93 Amps.?
4 x HT-59's in? 250 pf version? used.? (1000 pf?
total).? ?Good? for? 140A?
Later....? Jim? VE7RF?
??
|
Re: Plate blocking caps YC156
Those style? caps? are? way? too? big in diam,? like? 4-5" !? ? They? end? up? adding too? much? stray? C.? ?Been? there,? done? that.?
HT-57? in 200? pf is rated at? ?15A? CCS...and? 35KVA.? ? ?4 in? parallel? make? for a compact? plate block? assy.? ?Good? for 60A? +? ?140 KVA..on? 10M? band.??
To calculate? current through a plate? block? cap? assy? is? as? follows.?
1) calculate? XC? of? tube(s)? ?anode to? grid C...? ( which? will? increase? with? tube? in? socket...or? grid flange bolted? to? chassis.? Caused? by? proximity of lower anode? fins? to? chassis.)??
2)? calculate RF? RMS voltage at anode.? ?( .6 X LOADED B+)
3)? ?RMS? voltage /? Tube XC? ?=? ?RF? current through? plate? block? cap assy.? ?
Example.? ?YC-156 on? 29? mhz.? ?52? pf? from? anode? to? chassis.....? measured? with LCR meter.?
1,000,000? /? (2 x pi x F x C )?
=? 1,000,000? /? (6.28 x 29? x 52)
=? 105.6? ohms? ? of? XC? on? ?29? mhz.
Assume? ?a loaded? B+? of? 6? kv.?
RF? voltage is? ?.6? x 6000? ?=? ? 3600 vrms.
3600 / 105.6? ?=? ?34.1? Amps flowing through? plate? block? cap? assy.....? on? 29? mhz.?
? Above? is? the? worse? case...(6M? is? even? worse).? ? ? Do? a similar? calc? for? lower? bands.? ?On 14.5 mhz,? ?xc? is now 211? ohms.? Plate? block? cap? current? is? down? to 17.05? amps. (8.5 amps? on? 40M....? 4.26? amps on 80M...... and 2.13 amps on? 160M.? ??
HT-59 in? a? 250pf version? is? good? for 35A? +? 50? kva.? ?On buddy's? 2 x 3CX-15,000A7? amp? on? 27? mhz,? things? go? crazy.? EACH? tube? is? 62 pf? from? anode? to? chassis.?
XC? =? 47.56 ohms? ? ? Loaded? B+? is? 8 kv.? ?RF? voltage = 8000? x? .6? = 4.8 kv
Current? through plate? block? cap assy =? ?4800 / 47.56? = 100.93 Amps.?
4 x HT-59's in? 250 pf version? used.? (1000 pf? total).? ?Good? for? 140A?
Later....? Jim? VE7RF?
??
|
Re: Plate blocking caps YC156
?
The 57/857 are toy sizes, the 859's are for the big
boys
?
Carl
?
?
?
----- Original Message -----
Sent: Monday, December 23, 2019 3:02
AM
Subject: Re: [ham-amplifiers] Plate
blocking caps YC156
Email Dr Alex.
Log into his page at
He will look after you and get you the correct capacitor, at the most
reasonable price.
73, Alek. VK6APK
Anyone suggest a plate blocking cap brand?
The only
capacitors that i can? get RF current data on is the HT57's. I was
thinking of using a couple of? HT57 1000pf in parallel. Its really hard
getting getting RF current data. Anything without RF current data I pressume
is just ordinary? non RF rated capacitors. RFPARTS publishes very
little RF current data so you dont know what you buying. What are people
using on YC156 type amps for 160 through to 10. The Pancake Dralorics are
massive? and the current seems limited on the higher frequencies that
is for the big 6 or 8 inch pancake types.
Henry
|
Re: Plate blocking caps YC156
I would prefer a single capacitor any
time.
?
73
Peter
?
?
?
HEC? (high energy? corp) has? detailed?
current? vs? freq? info).
For? 10-10? YC-156? amps,? use? 4 x?
HT-57's.? ?200 pf? are? the? go? to?
standard.? ?The? 200? pf? HT-57? will?
easily? handle 15A? @ 32 mhz.?
800? pf? is? ample,? even? for? 160m.??
The? YC-156? ends? up? being? aprx? 52 pf?
from? anode? to? chassis,? once? bolted? to?
chassis.? ?The? tube? provides most? of the?
tune? C...with the? tune? cap? being? a small
adjustable? padder? in? parallel.? Problem? is, the
plate? block? cap? is between? the? anode and
the? tune? cap.? Since? the? tube? C has?
most? of the? RF? current? flowing? through?
it...vs? the? tune? cap,? all? that anode to?
grid? Current? now? has? to? also? pass through
the? plate? block? cap? assy.? ?That's?
where? the plate block? caps? are? stressed...?
on? 10m ...and? upper? bands.?
Install a strap? coil? between? plate? block? cap
assy? and the tune cap..to? reduce? plate? load?
Z.? Then a PI? net? with a normal? loaded? Q can?
be? used.? You? can? see? that? effect? asap?
when? playing? with the? GM3SEK? PI spreadsheet.
I? posted a pix? of buddy's? 80-10? YC-156? amp?
under the? photo? page.? ?The? 160m?
monoband? YC-156? also? uses 4 x? HT-57's...also?
200? pf? each,? 800 pf? total.??
Jim? VE7RF
|
Re: Plate blocking caps YC156
I used this trick on my two x 3-1000z amplifier. I cut and wound
a flat coil and placed it as you suggested. Higher frequencies
gained a ton of power. Before my C1 cap was always min.
C
On 12/25/2019 7:48 AM, Jim VE7RF wrote:
HEC? (high energy? corp) has? detailed? current? vs? freq? info).
For? 10-10? YC-156? amps,? use? 4 x? HT-57's.? ?200 pf? are? the?
go? to? standard.? ?The? 200? pf? HT-57? will? easily? handle 15A?
@ 32 mhz.?
800? pf? is? ample,? even? for? 160m.??
The? YC-156? ends? up? being? aprx? 52 pf? from? anode? to?
chassis,? once? bolted? to? chassis.? ?The? tube? provides most?
of the? tune? C...with the? tune? cap? being? a small adjustable?
padder? in? parallel.? Problem? is, the plate? block? cap? is
between? the? anode and the? tune? cap.? Since? the? tube? C has?
most? of the? RF? current? flowing? through? it...vs? the? tune?
cap,? all? that anode to? grid? Current? now? has? to? also? pass
through the? plate? block? cap? assy.? ?That's? where? the plate
block? caps? are? stressed...? on? 10m ...and? upper? bands.?
Install a strap? coil? between? plate? block? cap assy? and the
tune cap..to? reduce? plate? load? Z.? Then a PI? net? with a
normal? loaded? Q can? be? used.? You? can? see? that? effect?
asap? when? playing? with the? GM3SEK? PI spreadsheet.
I? posted a pix? of buddy's? 80-10? YC-156? amp? under the? photo?
page.? ?The? 160m? monoband? YC-156? also? uses 4 x?
HT-57's...also? 200? pf? each,? 800 pf? total.??
Jim? VE7RF
--
Please let me quote you for your parts needs!
I offer a discount on Protunes with parts order!
Clark Turner
480-695-2898
|
Email? Econco.? Only? difference is? the? high? mu-grid.? ?They also? may? well? take? your F1's in? trade for? some F7's.
Jim? VE7RF
|
Re: Plate blocking caps YC156
HEC? (high energy? corp) has? detailed? current? vs? freq? info).
For? 10-10? YC-156? amps,? use? 4 x? HT-57's.? ?200 pf? are? the? go? to? standard.? ?The? 200? pf? HT-57? will? easily? handle 15A? @ 32 mhz.?
800? pf? is? ample,? even? for? 160m.??
The? YC-156? ends? up? being? aprx? 52 pf? from? anode? to? chassis,? once? bolted? to? chassis.? ?The? tube? provides most? of the? tune? C...with the? tune? cap? being? a small adjustable? padder? in? parallel.? Problem? is, the plate? block? cap? is between? the? anode and the? tune? cap.? Since? the? tube? C has? most? of the? RF? current? flowing? through? it...vs? the? tune? cap,? all? that anode to? grid? Current? now? has? to? also? pass through the? plate? block? cap? assy.? ?That's? where? the plate block? caps? are? stressed...? on? 10m ...and? upper? bands.?
Install a strap? coil? between? plate? block? cap assy? and the tune cap..to? reduce? plate? load? Z.? Then a PI? net? with a normal? loaded? Q can? be? used.? You? can? see? that? effect? asap? when? playing? with the? GM3SEK? PI spreadsheet.
I? posted a pix? of buddy's? 80-10? YC-156? amp? under the? photo? page.? ?The? 160m? monoband? YC-156? also? uses 4 x? HT-57's...also? 200? pf? each,? 800 pf? total.??
Jim? VE7RF
|
Re: Plate blocking caps YC156
Email Dr Alex.
Log into his page at
He will look after you and get you the correct capacitor, at the
most reasonable price.
73, Alek. VK6APK
toggle quoted message
Show quoted text
Anyone suggest a plate blocking cap brand?
The only capacitors that i can? get RF current data on is the
HT57's. I was thinking of using a couple of? HT57 1000pf in
parallel. Its really hard getting getting RF current data.
Anything without RF current data I pressume is just ordinary? non
RF rated capacitors. RFPARTS publishes very little RF current data
so you dont know what you buying. What are people using on YC156
type amps for 160 through to 10. The Pancake Dralorics are
massive? and the current seems limited on the higher frequencies
that is for the big 6 or 8 inch pancake types.
Henry
|
RFpARTS used to sell a heavy duty Pi Style choke that was rated to at least 3 amps. It had 10 pie sections on it with gaps and it no resonances in the ham bands. I wonder why they stopped selling them.
Henry
|
Will Econco? rebuild a 3cx3000F1 into a 3cx3000F7. I have a few genuine F1's which I wish were F7's
Anyone know if this is possible?
Henry
|
Plate blocking caps YC156
Anyone suggest a plate blocking cap brand?
The only capacitors that i can? get RF current data on is the HT57's. I was thinking of using a couple of? HT57 1000pf in parallel. Its really hard getting getting RF current data. Anything without RF current data I pressume is just ordinary? non RF rated capacitors. RFPARTS publishes very little RF current data so you dont know what you buying. What are people using on YC156 type amps for 160 through to 10. The Pancake Dralorics are massive? and the current seems limited on the higher frequencies that is for the big 6 or 8 inch pancake types.
Henry
|
A? 50 ohm? glitch? resistor...and a fast,? correctly? sized / rated HV? fuse? will? save? just? about? any fault.?
Note the? part? about correctly? sized? HV? fuse.? 1A? for? a 8877,? not? 3A.
For? 3CX-3000A7? and? bigger? tubes, 50? ohms? is as low as? you? want for? the? glitch? resistor.?
HV fuse? 1st.? Glitch resistor on? outboard side? of? fuse.?
50? ohm? glitch R......? ?LIMITS? fault? current? to a safe? value.
? HV fuse INTERRUPTS? ?fault? current.....? and? typ? <2msecs.? ?
Don't? do? silly? stuff,? like a 10-15 ohm? glitch R...and? NO? ?HV? fuse......? you? will? do? severe? damage.
Jim? ?VE7RF
|
Above? is? the? zip? file.? ? Note, SS? ?has? been? removed? from? the? master? list.
Shoulda left it on.? SS? is? so? bad,? it was? at the? bottom? of? the? previous? list.?
Jim? ?VE7RF?
|
Latest? version? is? available...called coil 3.77? ?
3.77? has? replaced 3.72
Jim? VE7RF
|
Elevate the? choke? above the? chassis,? and u? can? increase? the? B+? through? the? roof.? The? 4.5 kv rating is? cuz the bottom? transverse screw? is? extremely? close to chassis.?
2 x HT-57 bypass? caps a few? inches apart? on? chassis.? Flat? AL strap,? like? 1" x 3" x 1/8"? thick? ,? between? tops? of? caps.? Choke dead center, on? top? side? of al? bar.
Bottom? lug? of? choke? bonded to? bar.? B+? fed? to? bar.? ?Problem? solved,? run? all the B+? u? want.? 8 kv,? no? problem.? ? u? can? also? use? 2 x? identical? assy's in parallel,? spaced well? apart.....and? run? 3A? CCS? ?
It? appears? the? ameritron? choke in? the? pix? is? way? too? close? to the? rear? wall.? that? can? really? screw? things? up...and? fast.? ?
Jim? ?VE7RF
|
?
Im still laughing Dave.
?
Some get a litle anal when it comes to hams pushing
things a bit but we are not in the commercial or military world. Blowing a choke
with that tube only hurts the choke.
?
BTW the big B$W choke mentioned earlier was ferrite
loaded and hams blew them left and right without pushing the
ratings.
?
I still have a bad one returned from a customer and
quit selling them ages ago.
?
Carl
?
Carl
----- Original Message -----
Sent: Tuesday, December 03, 2019 4:35
AM
Subject: Re: [ham-amplifiers] 3CX3000F7
10-80m
Some joke, Peter. ?One failure in nearly 20 years.?
The HRC fuse has blown twice during that time - once when the top band
antenna broke and once when a gamma matched beam flashed over.
It¡¯s not perfect, I¡¯ll concede that.?
73
Dave?
On Monday, December 2, 2019, 8:08 pm, Peter Voelpel
<dj7ww@...> wrote:
It?s an expensive
fuse, not more.
To install it as an
rf choke into a 3CX3K amp must be a joke.
?
73
Peter,
DJ7WW
?
?
The choke is a lot more robust than you
would think.? I've had a couple of them pop over the years but tracked
that down to a resonance (AKA idiot builder error) each time.? Fix the
resonance (reposition), patch the choke and back in biz.? The size of
the choke wire from a "can it carry the plate current" standpoint is
definitely fine for typical use - unless you are in the fire breathing
realm.?
If you don't believe it and want to feel
better about it, hang a few sizes of mid 30's gauge wire on a constant
current supply and see how just high you have to bump that current to get it
to open up.? You may be surprised.
73/jeff/ac0c
alpha-charlie-zero-charlie
? ?
On 12/2/19
10:13 AM, cturnertuning wrote:
This confirms your choke is the "fuse" in
your amplifier. If you are ok with that Dave, then great. I have one in an
AM plate modulated amplifier with a pair of 4-400s modulated by a pair of
304TLs. The choke has survived. I have had failures but was running them
past the ratings. Did your choke unravel?? That seems to be the type
of failure with these. One good bang and they un wind on the
form.
C
On
11/30/2019 7:15 PM, DAVE WHITE via Groups.Io wrote:
¡°Ratings
are guidelines¡± - yeah that what this guy at Essen Motor Show said this
weekend (picture attached)?
In my
3CX3000A7 amp I used a very similar choke (in fact it looks the same)
bought from RF Parts. ?I think it too is rated at 4kv 1.5A. ?
I¡¯ve had
one failure in 18 years with the amp and that was the choke. ?I use
a glitch resistor and an HRC fuse inthe ?HT line which worked fine
and protected the amp when the insulator at the end of my top band 3/8
inverted L exploded one night, thus leaving the choke ok. ?But one
day about 10 years ago the choke just went BANG. ?I never worked
out why. ?I replaced it with another identical one and (touch wood)
it¡¯s been ok since.?
I know
that B&W used to make a much higher rated choke years ago but they
seem to be unobtainium now. ?I run 5.5kv resting voltage on the
anode so always knew that the plate choke was the weakest
point.?
That looks
like a nice amp in the pictures.
I used two
rollercoasters and two vacuum capacitors as a Pi-L 10-160m, by the way.
?
I bought a mix of A7 and F7 tubes from the
Dayton flea market so bought an A7 socket and removed the filament rings
and flying leads from the F7s with a little heat. ?They¡¯re just
held on there with soft solder. ?The idea was that a tube change is
much easier.?
73 Dave?
On Sunday, December 1, 2019, 2:30
am, Carl <km1h@...>
wrote:
Yep,
while the designer ran a full bore 2 hole AL-1500 with no problems the
company went to a lower rating to minimize warranty
issues.
Note I
also stressed the layout as many Hammy Hambone amp builders havent a
clue about coupling and "parasitic" resonances..Not AG6K
parasitics!?
----- Original Message
-----
Sent: Friday, November 29,
2019 12:27 AM
Subject: Re: [ham-amplifiers]
3CX3000F7 10-80m
Ratings are guidelines.
73, Alek
VK6APK
On 29/11/2019 10:14 AM, cturnertuning wrote:
Not
really. Its rated at 4kv max and 1.5 amp peak. It is the weak link
for sure. But if it works it works. Better have a glitch. One arc
and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G
LTE device
The
Ameritron choke will easily handle 2A?from that tube on CW and
SSB.
It is
also well placed for minimum coupling.
----- Original Message
-----
Sent: Wednesday, November
27, 2019 10:40 AM
Subject: Re: [ham-amplifiers]
3CX3000F7 10-80m
That little Ameritron plate choke
is screaming for its life :) Very cool amplifier!
?
On
11/26/2019 6:53 PM, Mike via wrote:
My
latest amplifier.![]() ![]() ![]()
-- Please let me quote you for your parts needs! I offer a discount on Protunes with parts order! Clark Turner 480-695-2898 ???
? -- >From sunny Binningup ? ? ? Family Businesses: SP Electrical. The Velvet Fox. Smart Design Electrical. Perth Interiors. -- Please let me quote you for your parts needs! I offer a discount on Protunes with parts order! Clark Turner 480-695-2898
|
Some joke, Peter. ?One failure in nearly 20 years.?
The HRC fuse has blown twice during that time - once when the top band antenna broke and once when a gamma matched beam flashed over.
It¡¯s not perfect, I¡¯ll concede that.?
On Monday, December 2, 2019, 8:08 pm, Peter Voelpel <dj7ww@...> wrote:
It?s an expensive fuse, not more.
To install it as an rf choke into a 3CX3K
amp must be a joke.
?
73
Peter, DJ7WW
?
?
The
choke is a lot more robust than you would think.? I've had a couple of
them pop over the years but tracked that down to a resonance (AKA idiot builder
error) each time.? Fix the resonance (reposition), patch the choke and
back in biz.? The size of the choke wire from a "can it carry the
plate current" standpoint is definitely fine for typical use - unless you
are in the fire breathing realm.?
If
you don't believe it and want to feel better about it, hang a few sizes of mid
30's gauge wire on a constant current supply and see how just high you have to
bump that current to get it to open up.? You may be surprised.
73/jeff/ac0c
alpha-charlie-zero-charlie
? ?
On 12/2/19 10:13 AM, cturnertuning wrote:
This
confirms your choke is the "fuse" in your amplifier. If you are ok
with that Dave, then great. I have one in an AM plate modulated amplifier with
a pair of 4-400s modulated by a pair of 304TLs. The choke has survived. I have
had failures but was running them past the ratings. Did your choke
unravel?? That seems to be the type of failure with these. One good bang
and they un wind on the form.
C
On 11/30/2019 7:15 PM, DAVE WHITE via Groups.Io wrote:
¡°Ratings are guidelines¡± - yeah that what
this guy at Essen Motor Show said this weekend (picture attached)?
In my 3CX3000A7 amp I used a very similar choke (in
fact it looks the same) bought from RF Parts. ?I think it too is rated at
4kv 1.5A. ?
I¡¯ve had one failure in 18 years with the amp
and that was the choke. ?I use a glitch resistor and an HRC fuse inthe
?HT line which worked fine and protected the amp when the insulator at the
end of my top band 3/8 inverted L exploded one night, thus leaving the choke
ok. ?But one day about 10 years ago the choke just went BANG. ?I
never worked out why. ?I replaced it with another identical one and (touch
wood) it¡¯s been ok since.?
I know that B&W used to make a much higher rated
choke years ago but they seem to be unobtainium now. ?I run 5.5kv resting
voltage on the anode so always knew that the plate choke was the weakest
point.?
That looks like a nice amp in the pictures.
I used two rollercoasters and two vacuum capacitors as
a Pi-L 10-160m, by the way. ?
I bought a mix of A7 and
F7 tubes from the Dayton flea market so bought an A7 socket and removed the
filament rings and flying leads from the F7s with a little heat. ?They¡¯re
just held on there with soft solder. ?The idea was that a tube change is
much easier.?
73 Dave?
On Sunday,
December 1, 2019, 2:30 am, Carl <km1h@...> wrote:
Yep, while the designer ran a full bore 2 hole AL-1500
with no problems the company went to a lower rating to minimize warranty
issues.
Note I also stressed the layout as many Hammy Hambone
amp builders havent a clue about coupling and "parasitic"
resonances..Not AG6K parasitics!?
----- Original Message -----
Sent: Friday,
November 29, 2019 12:27 AM
Subject: Re:
[ham-amplifiers] 3CX3000F7 10-80m
Ratings are guidelines.
73, Alek
VK6APK
On 29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp peak. It
is the weak link for sure. But if it works it works. Better have a glitch. One
arc and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G LTE device
The Ameritron choke will easily handle 2A?from
that tube on CW and SSB.
It is also well placed for minimum coupling.
----- Original Message -----
Sent: Wednesday,
November 27, 2019 10:40 AM
Subject: Re:
[ham-amplifiers] 3CX3000F7 10-80m
That
little Ameritron plate choke is screaming for its life :) Very cool amplifier!
?
On 11/26/2019 6:53 PM, Mike via
wrote:
My latest amplifier.![]() ![]() ![]()
-- Please let me quote you for your parts needs! I offer a discount on Protunes with parts order! Clark Turner 480-695-2898 ???
?
-- >From sunny Binningup ? ? ? Family Businesses: SP Electrical. The Velvet Fox. Smart Design Electrical. Perth Interiors.
-- Please let me quote you for your parts needs! I offer a discount on Protunes with parts order! Clark Turner 480-695-2898
|
It?s an expensive fuse, not more.
To install it as an rf choke into a 3CX3K
amp must be a joke.
?
73
Peter, DJ7WW
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf
Of Jeff AC0C
Sent: Montag, 2. Dezember 2019
18:43
To: [email protected]
Subject: Re: [ham-amplifiers]
3CX3000F7 10-80m
?
The
choke is a lot more robust than you would think.? I've had a couple of
them pop over the years but tracked that down to a resonance (AKA idiot builder
error) each time.? Fix the resonance (reposition), patch the choke and
back in biz.? The size of the choke wire from a "can it carry the
plate current" standpoint is definitely fine for typical use - unless you
are in the fire breathing realm.?
If
you don't believe it and want to feel better about it, hang a few sizes of mid
30's gauge wire on a constant current supply and see how just high you have to
bump that current to get it to open up.? You may be surprised.
73/jeff/ac0c
alpha-charlie-zero-charlie
? ?
On 12/2/19 10:13 AM, cturnertuning wrote:
This
confirms your choke is the "fuse" in your amplifier. If you are ok
with that Dave, then great. I have one in an AM plate modulated amplifier with
a pair of 4-400s modulated by a pair of 304TLs. The choke has survived. I have
had failures but was running them past the ratings. Did your choke
unravel?? That seems to be the type of failure with these. One good bang
and they un wind on the form.
C
On 11/30/2019 7:15 PM, DAVE WHITE via Groups.Io wrote:
¡°Ratings are guidelines¡± - yeah that what
this guy at Essen Motor Show said this weekend (picture attached)?
In my 3CX3000A7 amp I used a very similar choke (in
fact it looks the same) bought from RF Parts. ?I think it too is rated at
4kv 1.5A. ?
I¡¯ve had one failure in 18 years with the amp
and that was the choke. ?I use a glitch resistor and an HRC fuse inthe
?HT line which worked fine and protected the amp when the insulator at the
end of my top band 3/8 inverted L exploded one night, thus leaving the choke
ok. ?But one day about 10 years ago the choke just went BANG. ?I
never worked out why. ?I replaced it with another identical one and (touch
wood) it¡¯s been ok since.?
I know that B&W used to make a much higher rated
choke years ago but they seem to be unobtainium now. ?I run 5.5kv resting
voltage on the anode so always knew that the plate choke was the weakest
point.?
That looks like a nice amp in the pictures.
I used two rollercoasters and two vacuum capacitors as
a Pi-L 10-160m, by the way. ?
I bought a mix of A7 and
F7 tubes from the Dayton flea market so bought an A7 socket and removed the
filament rings and flying leads from the F7s with a little heat. ?They¡¯re
just held on there with soft solder. ?The idea was that a tube change is
much easier.?
73 Dave?
On Sunday,
December 1, 2019, 2:30 am, Carl <km1h@...> wrote:
Yep, while the designer ran a full bore 2 hole AL-1500
with no problems the company went to a lower rating to minimize warranty
issues.
Note I also stressed the layout as many Hammy Hambone
amp builders havent a clue about coupling and "parasitic"
resonances..Not AG6K parasitics!?
----- Original Message -----
Sent: Friday,
November 29, 2019 12:27 AM
Subject: Re:
[ham-amplifiers] 3CX3000F7 10-80m
Ratings are guidelines.
73, Alek
VK6APK
On 29/11/2019 10:14 AM, cturnertuning wrote:
Not really. Its rated at 4kv max and 1.5 amp peak. It
is the weak link for sure. But if it works it works. Better have a glitch. One
arc and its done. In this example its a fuse.:)
Sent from my T-Mobile 4G LTE device
The Ameritron choke will easily handle 2A?from
that tube on CW and SSB.
It is also well placed for minimum coupling.
----- Original Message -----
Sent: Wednesday,
November 27, 2019 10:40 AM
Subject: Re:
[ham-amplifiers] 3CX3000F7 10-80m
That
little Ameritron plate choke is screaming for its life :) Very cool amplifier!
?
On 11/26/2019 6:53 PM, Mike via
wrote:
My latest amplifier.
-- Please let me quote you for your parts needs! I offer a discount on Protunes with parts order! Clark Turner 480-695-2898 ???
?
-- >From sunny Binningup ? ? ? Family Businesses: SP Electrical. The Velvet Fox. Smart Design Electrical. Perth Interiors.
-- Please let me quote you for your parts needs! I offer a discount on Protunes with parts order! Clark Turner 480-695-2898
|
