¿ªÔÆÌåÓý

Hi,
Pentalab I don't see how this is AMPS related.
BUT I will let it stay as long as there is ROOM in the fileing cabinet.
We are at 37 percent usage and this is a very nice file.

How about some stuff about the FT-2000 PRIVATELY if
you have any.

Thanks..... carry on...

Bob KR4DA retired (So Bell divestiture) ATT computers systems and DATA services customer
services engineer. (That's what they called us... I never thought it should be
engineer in the title)

ham_amplifiers@... wrote:

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the ham_amplifiers
group.

File : /mkvmods1_0.pdf
Uploaded by : pentalab <jim.thomson@telus.com>
Description : Yaesu MK-V ESSB mod document

You can access this file at the URL:


To learn more about file sharing for your group, please visit:


Regards,

pentalab <jim.thomson@telus.com>

-- 
de KR4DA Bob Middleburg, FL
HK0/KR4DA J79DA FG/KR4DA

I wonder if you just wrapped a few turns of wire around the end of the input choke with a pick up probe near the tube this phase shift could be controlled. Also may need a LRC network....just dreaming sounds like something to simulate.

R L Measures wrote:

On Jan 17, 2007, at 2:11 PM, FRANCIS CARCIA wrote:

Check the old RCA transmitting tube handbook showing how to apply RF negative feedback to quad 811s

^^ The trouble with the RCA circuit is that while the feedback is negative at HF, due to phase shift in the associated wiring as frequency increases, the feedback becomes slightly positive c. 95MHz and oscillation can result. Gonset and Heath tried the RCA "neutralization" circuit and dropped it like a hot potato.
...
R. L. Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Jan 17, 2007, at 2:52 PM, hbmandel wrote:

[snip]

Seems to be alot of hams going to the GU84B tubes for their Big
amps over the 8877 or even the old 4-1000.

[snip]

I agree. Here's the breakdown:

The 8877 tube is hellishly expensive and
has a filament that is extremely sensitive
to shortened life because of a few hundredths
of an overvoltage. Additionally, its 25 watt
Grid Dissipation rating makes it vulnerable
if not sutably protected, to damage from
mistuning and arcs.

Judging by the gold-evaporation patterns I've seen on the grid during autopsies, the 8877's grid is damaged by intermittent UHF oscillations wherein the top layer of the gold-plating boils off and forms gold meltballs.

The 4-1000A being a Tetrode, is happiest being
Grid-Driven, but few amateurs have the inclination
to design and experiment with driving and neutralization
techniques, so many of these tubes end up Grounded Grid
at a miserable efficiency.

AB1 grid-driven is slightly less efficient than g-g cathode-driven because the anode's headroom is reduced by the screen potential.

Additionally, the 4-1000A, with a 6KV at 1 Amp

800mA

anode requirement needs a power supply to suit, and
while transformers and diodes are plentiful, adequate
filter caps are not,

Not the case with new-design electrolytics.

and those that are available are
hellishly expensive once the array is gathered to
afford low ripple at maximum amperage.

A 9kV, 25uF, low-ESR filter for an 8170 or 8171 currently costs c. $190 using Panasonic electrolytics.

Hal Mandel
W4HBM
...

R. L. Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Jan 17, 2007, at 3:21 PM, Robert B. Bonner wrote:

The trend is for cheap reliable power. A couple 8877's will make moderate power at medium risk.

** The risk of gold sputtering from the 8877's grid is not small.

A couple 3CX1200A7's will make almost as much power with low risk.

** And sometimes they will even do so with no drive thanks to their feedback-C.

...

R. L. Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

On Jan 17, 2007, at 4:04 PM, 1800 Toll Free wrote:

The 8877 is a waste of money, for the dollars they choose to demand for it.



For the price of a new 8877 you can purchase an 8170 and socket on the
used / pull market.

However, an 8877 is easier to put on 10m/11m than an 8170.

For about the same amount of money you can get all the parts.. Sure, your
power xformer will cost a bit more for the anode voltage, but you will
have a lot more life out of the tube / amp.

Good point, and, as an added FREE bonus, it's instant-on.

cheers, Mr. ______?

The glass tubes aren't being made anymore.... At least, not affordably.
That means it's a waste of money / time to build around them.

It's a reflection of state of the art, or hollow state, if you will. the
russian tubes are being used because they are cheap, not because of any
big difference in technology.


This, of course, is just ramblings from some stupid CBer :)


--Toll_Free







On Wed, 17 Jan 2007 14:28:50 -0800, alphasxsignal <videorov@...>
wrote:

Seems to be alot of hams going to the GU84B tubes for their Big
amps over the 8877 or even the old 4-1000.

--



*Ratings are for transistors, tubes have guidelines*



Yahoo! Groups Links

R. L. Measures, AG6K, 805.386.3734
r@..., rlm@..., www.somis.org

A pair is 1040 US$, 20$ for sockets and they can be rebuilt as well and fit
in a desktop cabinet.
I would not use a pair, but a single tube.

Anode dissipation of the YC-243 is 9KW?

The price of the Svetlana YC-243 equivalent is 650US$ here

73
Peter


________________________________

From: ham_amplifiers@... [mailto:ham_amplifiers@...]
On Behalf Of pentalab


### How much is 400 Euro's in US dollars ?? Think it's at least
$600-$700.... + socket. $1400.00 for 2 of em.... not a
chance... no bargain there. A YC-243 is still a way better deal
at $1100- $1200.... and is the electrical eq of 6 x 8877's. The
YC-243 can also be rebuilt over and over.

## Have fun trying to play "matched pair" with 8877's.

All,

Any that has a Harbor Freight close, they have a tool sale now with
some good prices on some stuff used in building amps. You need some
coupons to get the best pricing, so a link is below to most. I have a
coupon also for a pack of 100, 7-7/8 L x 3/16" W white wire ties for
$0.99 a pack. The regular price is $3.99 a pack. I bought the cupon
limit of 5 packs, and they are good wire ties. If any wants this
coupon, e-mail me and I will forward it to you.

I purchased a Dremel type hand grinder tool they have which is
rechargable. It also has a flex shaft with it about 30 inches long.
It comes with some attachments in a blow molded case with the
charger. I bought this for $19.99 and it is well worth it. It has a
continuosly variable speed, and not set ones like Dremel has on some.
The only problem I seen is the whine it produces at slow speed due to
the AC solid state speed control. It's not loud, just annoying. This
is not the el-cheapy ones they carry. The regular price is $40. The
coupon for it is at the link below.

There's a 3/4" ro 2-1/2" hole saw set for $2.99 which is all steel.
Regular price is $11.99. No plastic used in the saw anywhere. I
bought this and am totally satisfied with it.

For any with air in the shop, there's a 3/8" air drill for $9.99 that
is well made. I looked it over.

I bought a pneumatic pop-rivet gun that's now on sell for $29.00. No
coupon is needed for it. It will pull up to a 3/16" pop rivet. This
is a steal as these things are down right expensive anywhere you look.

They also have a good deal on a 8" digital caliper for layout work at
$19.99.

Link;



Best,

Will

¿ªÔÆÌåÓý

--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote:

The chinese 8877 at 400 Euros seems to be a good choice,
a company nearby uses about 50 of those for two years without any

trouble

73
Peter

### How much is 400 Euro's in US dollars ?? Think it's at least
$600-$700.... + socket. $1400.00 for 2 of em.... not a
chance... no bargain there. A YC-243 is still a way better deal
at $1100- $1200.... and is the electrical eq of 6 x 8877's. The
YC-243 can also be rebuilt over and over.

## Have fun trying to play "matched pair" with 8877's.

later....... Jim VE7RF

-----Original Message-----
From: ham_amplifiers@...

[mailto:ham_amplifiers@...]

On Behalf Of 1800 Toll Free


The 8877 is a waste of money, for the dollars they choose to

demand for it.

For the price of a new 8877 you can purchase an 8170 and socket on

the used

/ pull market.

--- In ham_amplifiers@..., "Peter Voelpel" <df3kv@...>
wrote:

I guess the YC-243 is the same tube with a different socket

73
Peter

######### The YC-243 is a SOCKETLESS tube. They took a 3CX-
4500F3 industrial heater tube [looks identical to a 3x6.. except it
has no socket, is low mu and has a grid flange.. and lugs for fil]
and stuffed a hi mu grid in it.

### I have been teying to get through Eimac's head that sockets are
a pain in the ass... and are failure prone components... just ask
any broadcast engineer. The sveltlana 6000A7 is an excellent
tube.... u just won't be able to find anybody to rebuild one in the
USA.

### The socket for the 3x3 and 3x6 is now up to $375.00 from RF
parts [includes the grid ring]

### The EIMAC YC-243 sells for LESS than the EIMAC 3x6 .

### I posted a PDF I got from Eimac... on the YC-243...
under "files" on this site. It does have some minor errors in
it... which will get corrected.

### I paid $1100.00 for mine a few yrs back..... which is same
price as buying a 3CX-3000A7 + socket ... and way less than a 3x6 +
socket. In fact the YC-243 was less than the socketed Eimac 3x6.
Both the 3x6 and the YC-243 are an easy 9700 w CCS anode diss
too...... the sleeper of the year.

## Sockets are dead.. dead... toast, obsolete.

## Throw away tubes like 8877's are a joke. Even Ted Henry said
u gotta be nuts to buy one new. A new 3CX-3000A7 is exactly $50.00
more than a new 8877. [the 3x3 is rebuildable]...... which would
you want? A 3x3 with 50 w of drive will do 1500 w out.... and
200w of drive will give u 5200 w out... and very clean imd.

### The 3x6 and esp the YC-243 imo.. blow em all away. It's the
biggest bang for the buck bar none. None of the rebuider's have
ever seen a YC-243 with a blown out grid either.

### we are not gonna even discuss stuff like 3CX-800A7's or 3CPX-
800A7's.

## The russian 4CX-800A7's while cheap..for now... suck huge idle
current. Ask anybody with a QRO amp.... 450 ma zsac... and 675 ma
on the 3 x holer.

## If the engine under ur hood of ur car isn't big enough... get a
bigger one... don't stuff 3 x engines in there.

### Svetlana does make a 3000F7.. which has flex leads for the fil..
and also a flex lead for the grid. Fellows will toss the grid flex
lead... and replace with a vac cap flance or a 2 x piec clamping
block. Eimac still makes a 3CX-3000F7 as well.

## If Svetlana now makes a socketless 6000A7... that's news to me...
or a mis print. Where did u see it ??

Later... Jim VE7RF

-----Original Message-----
From: ham_amplifiers@...

[mailto:ham_amplifiers@...] On Behalf Of 1800 Toll Free

After having conversed with Jim over the last few days via email,

I'm

inclined to believe the new "tube of choice" is going to be the YC-

243...

It seems like the way to go.

Not to mention, the 11 meter market will probably sustain the

existance of the tube :) lol

--Toll_Free



On Wed, 17 Jan 2007 15:38:33 -0800, Peter Voelpel <df3kv@...>
wrote:

A reliable and not too expensive solution might be this version

of

3CX6000A7 by Svetlana:


"Better mechanical rigidity and long lasting concentricity of

the

filament is obtained from the improved mesh filament design

contributing

to a longer life. Flexible leads connect to the filament

terminals and a

flange is connected to the grid. The flange provides a

convenient way to

mount the tube."
Product ID: SKU15665

Price: ???594.94
including VAT 19% (???94.99)
[plus shipping]


Unfortunately not in stock at the moment
73
Peter


________________________________

From: ham_amplifiers@...
[mailto:ham_amplifiers@...] On Behalf Of Robert B.

Bonner

The trend is for cheap reliable power.

--



*Ratings are for transistors, tubes have guidelines*



Yahoo! Groups Links

The chinese 8877 at 400 Euros seems to be a good choice,
a company nearby uses about 50 of those for two years without any trouble

73
Peter

I guess the YC-243 is the same tube with a different socket

73
Peter

After having conversed with Jim over the last few days via email, I'm inclined to believe the new "tube of choice" is going to be the YC-243... It seems like the way to go.

Not to mention, the 11 meter market will probably sustain the existance of the tube :) lol




--Toll_Free

--



*Ratings are for transistors, tubes have guidelines*

The 8877 is a waste of money, for the dollars they choose to demand for it.



For the price of a new 8877 you can purchase an 8170 and socket on the used / pull market.


For about the same amount of money you can get all the parts.. Sure, your power xformer will cost a bit more for the anode voltage, but you will have a lot more life out of the tube / amp.



The glass tubes aren't being made anymore.... At least, not affordably. That means it's a waste of money / time to build around them.

It's a reflection of state of the art, or hollow state, if you will. the russian tubes are being used because they are cheap, not because of any big difference in technology.


This, of course, is just ramblings from some stupid CBer :)


--Toll_Free

--



*Ratings are for transistors, tubes have guidelines*

What bites is when the manufacturer purposely keeps it out of stock to make it look like it is a good thing and drive the price up.

BOB DD

Yeah Peter,

For some reason, the good stuff is never in stock.

BOB

A reliable and not too expensive solution might be this version of 3CX6000A7 by Svetlana:


"Better mechanical rigidity and long lasting concentricity of the filament is obtained from the improved mesh filament design contributing to a longer life. Flexible leads connect to the filament terminals and a flange is connected to the grid. The flange provides a convenient way to mount the tube."

Product ID: SKU15665

Price: €594.94
including VAT 19% (€94.99)
[plus shipping]


Unfortunately not in stock at the moment

73
Peter


________________________________

From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of Robert B. Bonner

The trend is for cheap reliable power.

The trend is for cheap reliable power. A couple 8877's will make moderate power at medium risk. A couple 3CX1200A7's will make almost as much power with low risk. Their limit to maximum power is its plate dissapation. Too bad Eimac didn't widely release the 1500 dissapation (YU whatever) version. It sounds like a great tube. No matter what a guy does. Whether it is a 6L6, 811A or an X2159 if you run it consurvatively with safeguards it will last forever. Push it and watch it go Bye-Bye. BOB DD
Sent From Mobile Device

[snip]

Seems to be alot of hams going to the GU84B tubes for their Big
amps over the 8877 or even the old 4-1000.

[snip]

I agree. Here's the breakdown:

The 8877 tube is hellishly expensive and
has a filament that is extremely sensitive
to shortened life because of a few hundredths
of an overvoltage. Additionally, its 25 watt
Grid Dissipation rating makes it vulnerable
if not sutably protected, to damage from
mistuning and arcs.

The 4-1000A being a Tetrode, is happiest being
Grid-Driven, but few amateurs have the inclination
to design and experiment with driving and neutralization
techniques, so many of these tubes end up Grounded Grid
at a miserable efficiency.

Additionally, the 4-1000A, with a 6KV at 1 Amp
anode requirement needs a power supply to suit, and
while transformers and diodes are plentiful, adequate
filter caps are not, and those that are available are
hellishly expensive once the array is gathered to
afford low ripple at maximum amperage.

Hal Mandel
W4HBM