Re: Building my first amplifier. Where to start?
I would use one and keep the other as a spare, in terms of heat, just the
250W of filament power each will keep the shack warm enough in winter! If
you directly ground the grid and have the input tune adjustable that
should make for efficient driving.
Mike
VK2AMF / G3XEF ?
At 07:41 PM 24/12/2023, you wrote:
toggle quoted message
Show quoted text
Thanks everyone for replying. I
live in Northern Ireland, call sign GI0UTE.? I'm not aware of any
qro builders nearby.? I have ordered a few books as have been
suggested and have stared reading some of the web links posted. There is
plenty to take in!
I agree a single GU5b with it's 2.5kw dissipation rating should be enough
to match my power needs, but perhaps two in parallel would run cooler (
run a quieter fan?), and perhaps deliver more gain? I have a 100w radio
and don't really want to need to run a "driver" amplifier, so
would need a gain of over 10 dB, ideally 13 ish. Not sure how that's
calculated yet from tube characteristics.
I'm in no hurry, and am not tied to using this tube, so am open to
suggestions.
Thanks again all, and merry Christmas! Des, GI0UTE?
Mike Fleetwood
Canberra Australia and Sidcup UK.
Worldwide email address
is:?????
mfleetwood@...
|
Re: Building my first amplifier. Where to start?
Love it!
I run a YC156 in my homebrew amp.? It's way way way overkill but
at 4.3KV, it runs limit power without trouble and I don't have to
worry about breaking the tube.? I've got a number of now-dead amps
that were killed in RTTY contesting; death by a variety of
things.? But the YC156 is pretty much bullet proof save for
needing to keep an eye on the grid current.? At the low B+, it's
the limiting factor from a tube risk standpoint.??
A buddy of mine convinced me to buy his 15K because it will sit
in the same socket and would look great.? I put it in to make sure
it was operational, which it was, but it's operationally no
different than the YC156 and with the lid on, it's hard to see the
cool look feature.?
The funny part is that since I got the FLEX PGXL which will run
So2r and does just fine under RTTY whipping conditions, I hardly
use the old tube amp now.? The Flex is just a lot more convenient.
73/jeff/ac0c
alpha-charlie-zero-charlie
On 12/24/2023 9:37 PM, HaL Mandel
wrote:
toggle quoted message
Show quoted text
Hi Jeff!
?
Merry Christmas.
?
I can just imagine two (2), 3CX15,000A7’s,
in Push-Pull,
?
Modulated with two (2), 3CX15,000A7’s.
?
Riley Hollingsworth would personally lead
the arrest, complete with Thompson .45’s.
?
Some years ago, the main power transformer
was robbed from the Beverly-Ann Coal Tipple
in David, Kentucky.
?
They got a 20,000 pound hunk out of the
mine
with two feet of mud everywhere, and nobody
knows a thing…
?
Best, Jeff.
?
Hal
|
Re: Building my first amplifier. Where to start?
Hi Jeff!
?
Merry Christmas.
?
I can just imagine two (2), 3CX15,000A7’s,
in Push-Pull,
?
Modulated with two (2), 3CX15,000A7’s.
?
Riley Hollingsworth would personally lead
the arrest, complete with Thompson .45’s.
?
Some years ago, the main power transformer
was robbed from the Beverly-Ann Coal Tipple
in David, Kentucky.
?
They got a 20,000 pound hunk out of the mine
with two feet of mud everywhere, and nobody
knows a thing…
?
Best, Jeff.
?
Hal
|
Re: Building my first amplifier. Where to start?
Hal,
If you need a spare 15K, I've got a NIB one here that needs to
find a new home.?
73/jeff/ac0c
alpha-charlie-zero-charlie
On 12/24/2023 4:11 PM, HaL Mandel
wrote:
toggle quoted message
Show quoted text
Steve,
?
In calculating the Anode Iron requirement
for
Class AB1, the beast would weigh 565
pounds.
(25 KVA). (3CX15,000A7)
?
But that was 8 years ago, and now, and now:
“Uh – Uh.”
?
Yon beasties are for the Young’uns.
?
Hal W4HBM
|
Have a good one, fellas.
Best wishes for a happy and safe 2024.
Mni 73,
John VK6JX
|
Re: Building my first amplifier. Where to start?
Yes Jeff.
"Took the words . . . . . ."
73, Alek VK6APK.
On 25/12/2023 1:09 am, Jeff AC0C wrote:
toggle quoted message
Show quoted text
A single GS35b is a nice choice as well per your original power
objectives.? And at 4.7KV it will have pretty nice efficiency.?
I ran one here at 4.4KV for years.? Minimal heater current
requirements.? A socket can be built with minimal mechanical
hassle.
73/jeff/ac0c
alpha-charlie-zero-charlie
On 12/24/2023 10:22 AM, bill steffey
NY9H wrote:
20 + amps at 12 volts??? just to light up 1 tube ,,,,,???? 2
tubes would be 40+ AMPS !!!!!
On 12/24/2023 3:41 AM, desmond auld
wrote:
Thanks everyone for replying. I live in Northern Ireland, call
sign GI0UTE.? I'm not aware of any qro builders nearby.? I
have ordered a few books as have been suggested and have
stared reading some of the web links posted. There is plenty
to take in!?
I agree a single GU5b with it's 2.5kw dissipation rating
should be enough to match my power needs, but perhaps two in
parallel would run cooler ( run a quieter fan?), and perhaps
deliver more gain? I have a 100w radio and don't really want
to need to run a "driver" amplifier, so would need a gain of
over 10 dB, ideally 13 ish. Not sure how that's calculated yet
from tube characteristics.?
I'm in no hurry, and am not tied to using this tube, so am
open to suggestions.?
Thanks again all, and merry Christmas! Des, GI0UTE?
--
link to my QRZ listing
|
Re: Building my first amplifier. Where to start?
Steve,
?
In calculating the Anode Iron requirement for
Class AB1, the beast would weigh 565 pounds.
(25 KVA). (3CX15,000A7)
?
But that was 8 years ago, and now, and now:
“Uh – Uh.”
?
Yon beasties are for the Young’uns.
?
Hal W4HBM
|
Re: Building my first amplifier. Where to start?
Here at my off-the-grid, solar-charged, battery-powered QTH, I'd
need a submarine fulla good batteries just to run the heater on
onna those, let alone leaving a brick on the key all day. ===8-O
Steve, K0XP
On 12/24/2023 12:59 PM, HaL Mandel
wrote:
Hullo Bill,
?
So you’re squeamish about 20 or 40 amps on
the heaters, aye?
?
Well, wait ‘til ye graduate to Valves with
Lifting Handles!
?
Some of those babies need 165 amps to warm
them up.
?
Rich Measures fooled around with Handles.
?
He sure did.? But he remembered to start
each
of his Clandestine Jobs with Step: One
(Budget).
?
I’ve been sitting on three monsters
currently
in the parts shed. Got the tubes, etc.
But cannot meet Step: One any more.
?
Hal
W4HBM
--
See my QRZ.com page at
|
Re: Building my first amplifier. Where to start?
Hullo Bill,
?
So you’re squeamish about 20 or 40 amps on
the heaters, aye?
?
Well, wait ‘til ye graduate to Valves with
Lifting Handles!
?
Some of those babies need 165 amps to warm
them up.
?
Rich Measures fooled around with Handles.
?
He sure did.? But he remembered to start each
of his Clandestine Jobs with Step: One (Budget).
?
I’ve been sitting on three monsters currently
in the parts shed. Got the tubes, etc.
But cannot meet Step: One any more.
?
Hal
W4HBM
|
Re: Building my first amplifier. Where to start?
A single GS35b is a nice choice as well per your original power
objectives.? And at 4.7KV it will have pretty nice efficiency.? I
ran one here at 4.4KV for years.? Minimal heater current
requirements.? A socket can be built with minimal mechanical
hassle.
73/jeff/ac0c
alpha-charlie-zero-charlie
On 12/24/2023 10:22 AM, bill steffey
NY9H wrote:
toggle quoted message
Show quoted text
20 + amps at 12 volts??? just to light up 1 tube ,,,,,???? 2
tubes would be 40+ AMPS !!!!!
On 12/24/2023 3:41 AM, desmond auld
wrote:
Thanks everyone for replying. I live in Northern Ireland, call
sign GI0UTE.? I'm not aware of any qro builders nearby.? I have
ordered a few books as have been suggested and have stared
reading some of the web links posted. There is plenty to take
in!?
I agree a single GU5b with it's 2.5kw dissipation rating should
be enough to match my power needs, but perhaps two in parallel
would run cooler ( run a quieter fan?), and perhaps deliver more
gain? I have a 100w radio and don't really want to need to run a
"driver" amplifier, so would need a gain of over 10 dB, ideally
13 ish. Not sure how that's calculated yet from tube
characteristics.?
I'm in no hurry, and am not tied to using this tube, so am open
to suggestions.?
Thanks again all, and merry Christmas! Des, GI0UTE?
--
link to my QRZ listing
|
Re: Building my first amplifier. Where to start?
20 + amps at 12 volts??? just to light up 1 tube ,,,,,???? 2
tubes would be 40+ AMPS !!!!!
On 12/24/2023 3:41 AM, desmond auld
wrote:
Thanks everyone for replying. I live in Northern Ireland, call
sign GI0UTE.? I'm not aware of any qro builders nearby.? I have
ordered a few books as have been suggested and have stared reading
some of the web links posted. There is plenty to take in!?
I agree a single GU5b with it's 2.5kw dissipation rating should be
enough to match my power needs, but perhaps two in parallel would
run cooler ( run a quieter fan?), and perhaps deliver more gain? I
have a 100w radio and don't really want to need to run a "driver"
amplifier, so would need a gain of over 10 dB, ideally 13 ish. Not
sure how that's calculated yet from tube characteristics.?
I'm in no hurry, and am not tied to using this tube, so am open to
suggestions.?
Thanks again all, and merry Christmas! Des, GI0UTE?
--
link to my QRZ listing
|
Re: Building my first amplifier. Where to start?
Thanks everyone for replying. I live in Northern Ireland, call sign GI0UTE.? I'm not aware of any qro builders nearby.? I have ordered a few books as have been suggested and have stared reading some of the web links posted. There is plenty to take in!?
I agree a single GU5b with it's 2.5kw dissipation rating should be enough to match my power needs, but perhaps two in parallel would run cooler ( run a quieter fan?), and perhaps deliver more gain? I have a 100w radio and don't really want to need to run a "driver" amplifier, so would need a gain of over 10 dB, ideally 13 ish. Not sure how that's calculated yet from tube characteristics.?
I'm in no hurry, and am not tied to using this tube, so am open to suggestions.?
Thanks again all, and merry Christmas! Des, GI0UTE?
|
12 KW CCS ON 160-15M...USING THE 3CX-6000A7... PART 9
Here, the paralleled pair of Jennings? RJ2B output vac relays are installed.....along with the 7-16 DIN output connector.
Also installed is the 1/2" silver plated tubing coil, used for 20 + 15m.? ?Also installed is the hb? 3/8" tubing coil, used for? 80+40m.? The hb cu discs
?are cut and installed for the vac tune and vac load caps.? The? hb 1/4"? ?tubing coil (used for 160m) is wound, but not yet installed, nor the 100mm diam Draloric plate block cap.? On the rear apron,? you can also see the pair of 100 amp, superior electric ...'supercon connectors', used to terminate the cables for the 7.0 vac @ 78 amp fil supply.? It's progressing pretty good.? The entire B+ supply has yet to be built... but is a straight forward project, since it's already been done several times before.? ?
|
Re: Building my first amplifier. Where to start?
Stated he was in The UK. Mike
On Saturday, December 23, 2023 at 06:20:08 PM EST, Dave w6de <w6de@...> wrote:
You don’t say where you are located or provide a call sign so those of us replying don’t know where you are for parts recommendations.
?
The Eimac book “Care and feeding of power grid tubes” book has a lot of good information.?
This book should be in all Amplifier Builder’s and Modifier’s libraries.
?
There is a copy on-line from CPI (owners of Eimac) in six sections.
?
Start by looking at Section-3 “Electrical Design Considerations.?
For instance, In section 3 it has sections on Lead Length, Filament Bypassing, Keying, and more.?
Section 3 also talks about Class A, AB, B, and C amplifier characteristics.
?
If you find it useful.?
I’d suggest buying a book on-line.?
eBay USA has several for sale. ?
?
73,
Dave, w6de
?
From: [email protected] <[email protected]>
On Behalf Of desmond auld via groups.io
Sent: 23 December, 2023 10:56
To: [email protected]
Subject: [ham-amplifiers] Building my first amplifier. Where to start?
?
Hi guys, I have been subscribed to this list and reading messages for some time, but I believe this is my first message, so hello all. I am a ham based in the UK and have been interested in amplifiers for some time. I have a somewhat basic
understanding of their operation if I'm honest, and currently own a linear amps UK 811 hunter. It uses 4 off 811 tubes, and runs very well. I understand 811's are somewhat delicate, and so I tread lightly with them.
I have always had a notion of building my own hf multiband amplifier covering 80 to 10 ideally.? I have been gathering parts that might someday be useful such as hv transformers, power supply hv capacitors, door knob caps of various values and some big vacuum
caps etc. I don't have everything, but I guess I'm on the way. This approach makes things seem less expensive :) .
When it comes to tubes, I have also managed to collect some "interesting" items. I have a 3cw 30,000 and some gu5b's. The 3cw30,000 is clearly way too big (is there such a thing :) ) but the gu5b's might be about right.?
With the power supplies I have I can supply options. 2.8kv DC, 4.7kv DC, 5.5kv DC. All from a 20kva rated transformer, and voltages quoted are bridge rectified at zero load, not voltage doubled, so I have plenty of supply capacity.? I could tweak things to
get intermediate voltages if useful. I am yet to collect filament supplies, and the thought of a 6.3v or similar high amp supply puts me off so I guess that rules out the 3cw30,000 or similar.
I have been told to start with a triode amplifier as a tetrode is a much more complex beast, which with it's screen supplies etc I can understand.? I have good metal working tools and equipment (Bridgeport mill and welding kit etc) and some electrical test
kit including HV probes and a nano van and an old scope.?
Anyhow, I'm keen to learn as much as I can before I start off on this adventure, can you recommend any good books that are practical in their approach to hf amplifiers? I don't mind maths, I'm an engineer , but practical examples helps set context in my mind.
I have seen this diagram (attached) to an amplifier based on 2 off gu5b tubes. Obviously input circuits aren't described, but I guess it's a start?
Goal is something that will easily do the new 1kw UK limit. 2kw might be a nice max power rating. Am I mad??
Seasonal greetings all, des.?
|
Re: Building my first amplifier. Where to start?
You don’t say where you are located or provide a call sign so those of us replying don’t know where you are for parts recommendations.
?
The Eimac book “Care and feeding of power grid tubes” book has a lot of good information.?
This book should be in all Amplifier Builder’s and Modifier’s libraries.
?
There is a copy on-line from CPI (owners of Eimac) in six sections.
?
Start by looking at Section-3 “Electrical Design Considerations.?
For instance, In section 3 it has sections on Lead Length, Filament Bypassing, Keying, and more.?
Section 3 also talks about Class A, AB, B, and C amplifier characteristics.
?
If you find it useful.?
I’d suggest buying a book on-line.?
eBay USA has several for sale. ?
?
73,
Dave, w6de
?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]>
On Behalf Of desmond auld via groups.io
Sent: 23 December, 2023 10:56
To: [email protected]
Subject: [ham-amplifiers] Building my first amplifier. Where to start?
?
Hi guys, I have been subscribed to this list and reading messages for some time, but I believe this is my first message, so hello all. I am a ham based in the UK and have been interested in amplifiers for some time. I have a somewhat basic
understanding of their operation if I'm honest, and currently own a linear amps UK 811 hunter. It uses 4 off 811 tubes, and runs very well. I understand 811's are somewhat delicate, and so I tread lightly with them.
I have always had a notion of building my own hf multiband amplifier covering 80 to 10 ideally.? I have been gathering parts that might someday be useful such as hv transformers, power supply hv capacitors, door knob caps of various values and some big vacuum
caps etc. I don't have everything, but I guess I'm on the way. This approach makes things seem less expensive :) .
When it comes to tubes, I have also managed to collect some "interesting" items. I have a 3cw 30,000 and some gu5b's. The 3cw30,000 is clearly way too big (is there such a thing :) ) but the gu5b's might be about right.?
With the power supplies I have I can supply options. 2.8kv DC, 4.7kv DC, 5.5kv DC. All from a 20kva rated transformer, and voltages quoted are bridge rectified at zero load, not voltage doubled, so I have plenty of supply capacity.? I could tweak things to
get intermediate voltages if useful. I am yet to collect filament supplies, and the thought of a 6.3v or similar high amp supply puts me off so I guess that rules out the 3cw30,000 or similar.
I have been told to start with a triode amplifier as a tetrode is a much more complex beast, which with it's screen supplies etc I can understand.? I have good metal working tools and equipment (Bridgeport mill and welding kit etc) and some electrical test
kit including HV probes and a nano van and an old scope.?
Anyhow, I'm keen to learn as much as I can before I start off on this adventure, can you recommend any good books that are practical in their approach to hf amplifiers? I don't mind maths, I'm an engineer , but practical examples helps set context in my mind.
I have seen this diagram (attached) to an amplifier based on 2 off gu5b tubes. Obviously input circuits aren't described, but I guess it's a start?
Goal is something that will easily do the new 1kw UK limit. 2kw might be a nice max power rating. Am I mad??
Seasonal greetings all, des.?
|
Re: Building my first amplifier. Where to start?
I have found "Valve Amplifiers Explained" by John Fielding
ZS5JF quite helpful, its published by the RSGB.
Mike
VK2AMF / G3XEF.
At 09:56 PM 23/12/2023, you wrote:
Hi guys, I have been subscribed
to this list and reading messages for some time, but I believe this is my
first message, so hello all. I am a ham based in the UK and have been
interested in amplifiers for some time. I have a somewhat basic
understanding of their operation if I'm honest, and currently own a
linear amps UK 811 hunter. It uses 4 off 811 tubes, and runs very well. I
understand 811's are somewhat delicate, and so I tread lightly with
them.
I have always had a notion of building my own hf multiband amplifier
covering 80 to 10 ideally.? I have been gathering parts that might
someday be useful such as hv transformers, power supply hv capacitors,
door knob caps of various values and some big vacuum caps etc. I don't
have everything, but I guess I'm on the way. This approach makes things
seem less expensive :) .
When it comes to tubes, I have also managed to collect some
"interesting" items. I have a 3cw 30,000 and some gu5b's. The
3cw30,000 is clearly way too big (is there such a thing :) ) but the
gu5b's might be about right.
With the power supplies I have I can supply options. 2.8kv DC, 4.7kv DC,
5.5kv DC. All from a 20kva rated transformer, and voltages quoted are
bridge rectified at zero load, not voltage doubled, so I have plenty of
supply capacity.? I could tweak things to get intermediate voltages
if useful. I am yet to collect filament supplies, and the thought of a
6.3v or similar high amp supply puts me off so I guess that rules out the
3cw30,000 or similar.
I have been told to start with a triode amplifier as a tetrode is a much
more complex beast, which with it's screen supplies etc I can
understand.? I have good metal working tools and equipment
(Bridgeport mill and welding kit etc) and some electrical test kit
including HV probes and a nano van and an old scope.
Anyhow, I'm keen to learn as much as I can before I start off on this
adventure, can you recommend any good books that are practical in their
approach to hf amplifiers? I don't mind maths, I'm an engineer , but
practical examples helps set context in my mind.
I have seen this diagram (attached) to an amplifier based on 2 off gu5b
tubes. Obviously input circuits aren't described, but I guess it's a
start?
Goal is something that will easily do the new 1kw UK limit. 2kw might be
a nice max power rating. Am I mad?
Seasonal greetings all, des.?
Mike Fleetwood
Canberra Australia and Sidcup UK.
Worldwide email address
is:?????
mfleetwood@...
|
Re: Building my first amplifier. Where to start?
Dear Des,
?
Welcome to the forum.
?
You can’t do too much better than the collection
Of builders and thinkers hereon.
?
In the amplifier schematic you posted I wonder
If the Input Network Inductor is a roller-type,
And the capacitors mini-vacuum-variables?
?
Oh Boy.
?
Look out Surplus Sales of Nebraska!
?
Best,
?
Hal Mandel
W4HBM
|
Re: Building my first amplifier. Where to start?
On 12/23/2023 7:09 AM, Floyd - K8AC wrote: The older ARRL handbooks are a good source of amplifier circuits and info.? I have a 2004 Handbook with some interesting amplifier circuits. I would interject that The Radio Handbook, edited by Bill Orr and/or "Editors & Engineers", is generally much more informative than almost any of the ARRL handbooks for amplifier circuitry, in particular. Various editions are available from time to time on epay at modest prices. The RSGB handbooks can also yield some valuable insight but are generally geared toward legal-limit power levels. Seems to me that just a single GU5B will deliver the legal limit easily. Agreed... they seem rated at 3 kW per tube...?? And all of the specs I've seen indicate the tube should be installed with anode down. I would venture to say that your MOST VALUABLE "insight" would probably be to make friends with a ham/amplifier builder within driving distance who knows what they are about. Yes, easier said than done, especially these days with the older, more-experienced folks dying out left and right... On your side of the pond, for high power schtuff, G8WRB comes to mind, but I haven't heard of nor seen anything from him for years. G3SEK is another but I believe he's mostly-retired from homebrewing..?? Try doing a Yahoo search using the various high power Russian transmitting tube numbers and many other European builders will come up... some of whom are even still around!! 73, Steve K0XP
|
Re: Building my first amplifier. Where to start?
I'm sure you'll get a lot of input from real experts today, but I will give you a few high level comments.? Check out w8ji.com and read everything there about amplifiers.? Tom designed many tube amps for Ameritron and others over the years and is a good source of practical knowledge.? Also, read everything you can find by VE7RF.? He has written a lot on eHam amplifiers forum and elsewhere on building large amplifiers.? The older ARRL handbooks are a good source of amplifier circuits and info.? I have a 2004 Handbook with some interesting amplifier circuits.? On Facebook, look for the group "Amplifier Building and Homebrewing" - lots of good info there and you can converse with W8JI on difficult amplifier questions.??
Seems to me that just a single GU5B will deliver the legal limit easily.? I see that someone in Europe is selling sockets for that tube although they are quite expensive.? One area of concern is always the plate choke and it's a challenge to obtain one or build one that works properly on all the bands without resonances that can destroy them.? W8JI has good info on that.? You probably know that you won't be able to obtain tune and load capacitors at the needed voltage level and the capacitance range shown in your diagram.? Typically fixed capacitors are switched in for the lower band or two.? A good example of a fairly modern tube amp with these considerations covered can be found at AlphaRFSystems.com.? Here's a link to the Alpha 99 schematic:?.? That's a tetrode amp, but the site includes others info on their earlier triode amps such as the Alpha 86 and Alpha 89.??
To the questions "Am I mad?".? Maybe not, but you will be by the time the project is finished!
|
Building my first amplifier. Where to start?
Hi guys, I have been subscribed to this list and reading messages for some time, but I believe this is my first message, so hello all. I am a ham based in the UK and have been interested in amplifiers for some time. I have a somewhat basic understanding of their operation if I'm honest, and currently own a linear amps UK 811 hunter. It uses 4 off 811 tubes, and runs very well. I understand 811's are somewhat delicate, and so I tread lightly with them.
I have always had a notion of building my own hf multiband amplifier covering 80 to 10 ideally.? I have been gathering parts that might someday be useful such as hv transformers, power supply hv capacitors, door knob caps of various values and some big vacuum caps etc. I don't have everything, but I guess I'm on the way. This approach makes things seem less expensive :) .
When it comes to tubes, I have also managed to collect some "interesting" items. I have a 3cw 30,000 and some gu5b's. The 3cw30,000 is clearly way too big (is there such a thing :) ) but the gu5b's might be about right.?
With the power supplies I have I can supply options. 2.8kv DC, 4.7kv DC, 5.5kv DC. All from a 20kva rated transformer, and voltages quoted are bridge rectified at zero load, not voltage doubled, so I have plenty of supply capacity.? I could tweak things to get intermediate voltages if useful. I am yet to collect filament supplies, and the thought of a 6.3v or similar high amp supply puts me off so I guess that rules out the 3cw30,000 or similar.
I have been told to start with a triode amplifier as a tetrode is a much more complex beast, which with it's screen supplies etc I can understand.? I have good metal working tools and equipment (Bridgeport mill and welding kit etc) and some electrical test kit including HV probes and a nano van and an old scope.?
Anyhow, I'm keen to learn as much as I can before I start off on this adventure, can you recommend any good books that are practical in their approach to hf amplifiers? I don't mind maths, I'm an engineer , but practical examples helps set context in my mind.
I have seen this diagram (attached) to an amplifier based on 2 off gu5b tubes. Obviously input circuits aren't described, but I guess it's a start?
Goal is something that will easily do the new 1kw UK limit. 2kw might be a nice max power rating. Am I mad??
Seasonal greetings all, des.?
|
HaL Mandel
Floyd - K8AC
