[zyx]

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?

[Eeyore]

zyx wrote:

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?

You won't do any harm.

Graham

[Patrick Turner]

zyx wrote:

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?


That should be fine, jam away.

Its always OK to use a higher ohm value for speakers instead of a lower
value
on nearly all amps.

Patrick Turner.

[Lord Valve]

Despite what you may have seen from a couple of
the know-it-alls on this NG, don't do it. Audiophools
rarely stress their gear, and consequently rarely
consider what may happen to it when it is operated
beyond design parameters - as guitar amplifiers
*routinely* are. You risk a condition known as high-
tension flyback if you run a tube guitar amp into a higher
than rated impedance; this will fry your power tube
socket, along with the tube in it. Lower-powered
amps are certainly not immune to this, judging by
the number of tube sockets I've replaced in Fender
Champs and small Gibsons over the years. Get
the correct impedance speaker.

Lord Valve
Expert

VISIT MY WEBSITE: http://www.nebsnow.com/LordValve
I specialize in top quality HAND SELECTED NOS and
current-production vacuum tubes for guitar and
bass amps. Good prices, fast service.
Authorized dealer for QSC amps, Sovtek/Electro-Harmonix,
Behringer, Hammond-Suzuki, Leslie, Rolls, Weber VST, etc.!


- Partial Client List -
* Derek Trucks (Allman Brothers Band/Derek Trucks Band) *
* Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling *
* Kofi Burbridge (DTB) * Tod Smallie (DTB) * Susan Tedeschi *
* Roy Pritts (former head, Audio Engineering Society) *
* Rob Hyckys (guitarist for Commander Cody) * Waky Amps *
* Jamie McLean (guitarist for the Dirty Dozen Brass Band) *
* John Pierce (bassist for Huey Lewis and the News) *
* Rob Eaton (guitarist for Dark Star Orchestra) *
* Detroit Frank DuMont (guitarist, Frank DuMont and the Drivin' Wheels) *
* Coco Montoya * Clint Black * Bill McKay * Mojo Watson * Dick Dale *
* Fleetwood Mac * Tyrin Benoit * Eugene Fodor * Dale Bruning *
* Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps *
* Jim Kelley * Balls Amplification * Roccaforte Amplifiers *
* Gerhart Amplification * Aiken Amplification * Germino Amplification *
* Lots More *

NBS Electronics, 230 South Broadway, Denver, CO 80209-1510
Phone orders/tech support after 1:30 PM Denver time at 303-778-1156

- Our 25th Year -

VISA - MASTERCARD - PAYPAL - DISCOVER

"It ain't braggin', if ya can do it." - Dizzy Dean



zyx wrote:

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?

[FLY135]

Patrick Turner wrote:
zyx wrote:

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?


That should be fine, jam away.

Its always OK to use a higher ohm value for speakers instead of a lower
value
on nearly all amps.

Patrick Turner.

That's nearly all **solid state** amps. The Epi is a tube amp.

[GregS]

In article , Lord Valve wrote:
Despite what you may have seen from a couple of
the know-it-alls on this NG, don't do it. Audiophools
rarely stress their gear, and consequently rarely
consider what may happen to it when it is operated
beyond design parameters - as guitar amplifiers
*routinely* are. You risk a condition known as high-
tension flyback if you run a tube guitar amp into a higher
than rated impedance; this will fry your power tube
socket, along with the tube in it. Lower-powered
amps are certainly not immune to this, judging by
the number of tube sockets I've replaced in Fender
Champs and small Gibsons over the years. Get
the correct impedance speaker.

Lord Valve
Expert


Consider the rated Z is just a nominal figure, and the real Z will rapidly
rise with frequency, every amp would be at risk according to your
advice. The rated Z is at a bass frequency. if you don't play
bass, then its not a relavant issue.


greg

VISIT MY WEBSITE: http://www.nebsnow.com/LordValve
I specialize in top quality HAND SELECTED NOS and
current-production vacuum tubes for guitar and
bass amps. Good prices, fast service.
Authorized dealer for QSC amps, Sovtek/Electro-Harmonix,
Behringer, Hammond-Suzuki, Leslie, Rolls, Weber VST, etc.!


- Partial Client List -
* Derek Trucks (Allman Brothers Band/Derek Trucks Band) *
* Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling *
* Kofi Burbridge (DTB) * Tod Smallie (DTB) * Susan Tedeschi *
* Roy Pritts (former head, Audio Engineering Society) *
* Rob Hyckys (guitarist for Commander Cody) * Waky Amps *
* Jamie McLean (guitarist for the Dirty Dozen Brass Band) *
* John Pierce (bassist for Huey Lewis and the News) *
* Rob Eaton (guitarist for Dark Star Orchestra) *
* Detroit Frank DuMont (guitarist, Frank DuMont and the Drivin' Wheels) *
* Coco Montoya * Clint Black * Bill McKay * Mojo Watson * Dick Dale *
* Fleetwood Mac * Tyrin Benoit * Eugene Fodor * Dale Bruning *
* Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps *
* Jim Kelley * Balls Amplification * Roccaforte Amplifiers *
* Gerhart Amplification * Aiken Amplification * Germino Amplification *
* Lots More *

NBS Electronics, 230 South Broadway, Denver, CO 80209-1510
Phone orders/tech support after 1:30 PM Denver time at 303-778-1156

- Our 25th Year -

VISA - MASTERCARD - PAYPAL - DISCOVER

"It ain't braggin', if ya can do it." - Dizzy Dean



zyx wrote:

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?

[Ian Iveson]

zyx wrote

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want
to try it on a 12" speaker which is 8 ohms.

Jam away?

A bit risky. Anode voltage may rise higher than some parts can cope
with reliably.

As a general rule, SS amps don't care too much about a higher load
impedance, and valves are tolerant of a lower one.

cheers, Ian

[Ian Iveson]

greg said:

Consider the rated Z is just a nominal figure, and the real Z will
rapidly
rise with frequency, every amp would be at risk according to your
advice. The rated Z is at a bass frequency. if you don't play
bass, then its not a relavant issue.

Perhaps you might, step by step, check the logic of your argument.

Assuming similar characteristics, an 8 ohm speaker will rise to a
maximum impedance of twice that of the 4 ohm speaker. An amp designed
to be reliable at the maximum impedance of the 4 ohm speaker may not
be reliable at the maximum impedance of an 8 ohm speaker.

It would be OK if you stuck to bass.

cheers Ian

[Eeyore]

Lord Valve wrote:

Despite what you may have seen from a couple of
the know-it-alls on this NG, don't do it. Audiophools
rarely stress their gear, and consequently rarely
consider what may happen to it when it is operated
beyond design parameters - as guitar amplifiers
*routinely* are. You risk a condition known as high-
tension flyback if you run a tube guitar amp into a higher
than rated impedance; this will fry your power tube
socket, along with the tube in it. Lower-powered
amps are certainly not immune to this, judging by
the number of tube sockets I've replaced in Fender
Champs and small Gibsons over the years. Get
the correct impedance speaker.

From just a 2:1 change in load impedance ?

You jest surely. Having an open on the output is another matter entirely of
course.

Graham

[Eeyore]

Ian Iveson wrote:

zyx wrote

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want
to try it on a 12" speaker which is 8 ohms.

Jam away?

A bit risky. Anode voltage may rise higher than some parts can cope
with reliably.

Oh puhleeze ! Is that nonsense or what ?


As a general rule, SS amps don't care too much about a higher load
impedance, and valves are tolerant of a lower one.

Tolerant to a point ! I wouldn't advise it. In fact I doubt any valve amps will
drive a 1 - 2 ohms load very well, yet many SS amps do it admirably.

Graham

[Eeyore]

Ian Iveson wrote:

greg said:

Consider the rated Z is just a nominal figure, and the real Z will
rapidly
rise with frequency, every amp would be at risk according to your
advice. The rated Z is at a bass frequency. if you don't play
bass, then its not a relavant issue.

Perhaps you might, step by step, check the logic of your argument.

Assuming similar characteristics, an 8 ohm speaker will rise to a
maximum impedance of twice that of the 4 ohm speaker. An amp designed
to be reliable at the maximum impedance of the 4 ohm speaker may not
be reliable at the maximum impedance of an 8 ohm speaker.

Do tell me more about this reliability Ian !

Especially when a speaker's impedance can rise at some frequencies to easily TEN
TIMES the 'nominal' figure.

By your argument, driving the amplifier at such frequencies will destroy it.


It would be OK if you stuck to bass.

It would be OK if you stuck to not making stuff up about which you know nought.

Graham

[zyx]

"zyx" wrote in message
...
I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?


Such mixed results.

who to believe... who to believe...

any links to learn more about it? By the way I already have an 12" 8 ohm
speaker so I asked.

[Lord Valve]

GregS wrote:

In article , Lord Valve wrote:
Despite what you may have seen from a couple of
the know-it-alls on this NG, don't do it. Audiophools
rarely stress their gear, and consequently rarely
consider what may happen to it when it is operated
beyond design parameters - as guitar amplifiers
*routinely* are. You risk a condition known as high-
tension flyback if you run a tube guitar amp into a higher
than rated impedance; this will fry your power tube
socket, along with the tube in it. Lower-powered
amps are certainly not immune to this, judging by
the number of tube sockets I've replaced in Fender
Champs and small Gibsons over the years. Get
the correct impedance speaker.

Lord Valve
Expert

Consider the rated Z is just a nominal figure, and the real Z will rapidly
rise with frequency, every amp would be at risk according to your
advice. The rated Z is at a bass frequency. if you don't play
bass, then its not a relavant issue.

Sorry, realworld experience puts the lie to your statement. No offense.

LV






greg

VISIT MY WEBSITE: http://www.nebsnow.com/LordValve
I specialize in top quality HAND SELECTED NOS and
current-production vacuum tubes for guitar and
bass amps. Good prices, fast service.
Authorized dealer for QSC amps, Sovtek/Electro-Harmonix,
Behringer, Hammond-Suzuki, Leslie, Rolls, Weber VST, etc.!


- Partial Client List -
* Derek Trucks (Allman Brothers Band/Derek Trucks Band) *
* Meatloaf * Catherine Wheel * Yo La Tengo * Let's Go Bowling *
* Kofi Burbridge (DTB) * Tod Smallie (DTB) * Susan Tedeschi *
* Roy Pritts (former head, Audio Engineering Society) *
* Rob Hyckys (guitarist for Commander Cody) * Waky Amps *
* Jamie McLean (guitarist for the Dirty Dozen Brass Band) *
* John Pierce (bassist for Huey Lewis and the News) *
* Rob Eaton (guitarist for Dark Star Orchestra) *
* Detroit Frank DuMont (guitarist, Frank DuMont and the Drivin' Wheels) *
* Coco Montoya * Clint Black * Bill McKay * Mojo Watson * Dick Dale *
* Fleetwood Mac * Tyrin Benoit * Eugene Fodor * Dale Bruning *
* Komet Amplification * Dr. Z * Maven Peal * Blockhead Amps *
* Jim Kelley * Balls Amplification * Roccaforte Amplifiers *
* Gerhart Amplification * Aiken Amplification * Germino Amplification *
* Lots More *

NBS Electronics, 230 South Broadway, Denver, CO 80209-1510
Phone orders/tech support after 1:30 PM Denver time at 303-778-1156

- Our 25th Year -

VISA - MASTERCARD - PAYPAL - DISCOVER

"It ain't braggin', if ya can do it." - Dizzy Dean



zyx wrote:

I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try
it on a 12" speaker which is 8 ohms.

Jam away?

[Lord Valve]

Eeyore wrote:

Lord Valve wrote:

Despite what you may have seen from a couple of
the know-it-alls on this NG, don't do it. Audiophools
rarely stress their gear, and consequently rarely
consider what may happen to it when it is operated
beyond design parameters - as guitar amplifiers
*routinely* are. You risk a condition known as high-
tension flyback if you run a tube guitar amp into a higher
than rated impedance; this will fry your power tube
socket, along with the tube in it. Lower-powered
amps are certainly not immune to this, judging by
the number of tube sockets I've replaced in Fender
Champs and small Gibsons over the years. Get
the correct impedance speaker.

From just a 2:1 change in load impedance ?

You jest surely. Having an open on the output is another matter entirely of
course.

Graham



Sorry, realworld experience puts the lie to your statement.

Hope you are *profoundly* offended, you America-hating
****tard.

Lord Valve
Expert

[Hit by A Busch Lite]

zyx wrote:

who to believe... who to believe...

In the big picture of life, your likely do more damage to
your hearing than the speakers.

Without a matching load ( 4 == 4 , 8 == 8) the efficiency of the amp's
output won't be met and your end up with less power output
than what it is ideally capable of producing.

I'm be more leery of the wattage of the speaker than the mismatch of Z
but with a epi your ok.


any links to learn more about it? By the way I already have an 12" 8 ohm
speaker so I asked.


Trust me ! .. This *is* the internet you know !This topic is discussed
to death in most nwes groups.

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
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[Ian Iveson]

zyx wrote

who to believe... who to believe...

You will have the same problem wherever you go, I'm afraid. Sometime
you will need to make a judgement. May as well be now.

It should be obvious that this "eeyor" either can't read or has no
grasp of simple logic, or both. Neither has he any real experience,
and seems not to know the meaning of the word "unreliable". Greg's
argument is clearly half-boiled.

My logic is unassailable, and what you propose is a bit risky. Whether
the risk is worth taking or not depends partly on the design of your
amp, the quality of its components, and the state it is in, and partly
on your propensity for taking risks.

Lord Valve is a professional with many years of relevant experience.
He seems to say the risk is not worth taking.

Personally, if the amp is in good, clean condition and is well made to
a sensible design, I wouldn't worry much about trying an 8 ohm
speaker. I would expect the sound to be compromised though because of
the shift in bandwidth and change in distortion content.

Consider: everyone agrees that an open circuit is not a safe load for
your amp. Everyone agrees that a 4 ohm speaker is a safe load.
Somewhere in between a 4 ohm speaker and infinity, your amp will
become seriously unreliable.

*No-one here knows where that point is*. The consequence of you
loosing the bet is potentially catastrophic. There is an outside
chance of carnage in microseconds.

The best speaker will be 4 ohms, without a doubt. Why mess about? Get
a 4 ohm speaker. Why take a risk in the meantime, even if you judge it
to be small?

any links to learn more about it? By the way I already have an 12" 8
ohm speaker so I asked.

Depends on what you already know, and how confident you are to apply
it to new situations. Ohm's law should suggest that, for the same
power output, a higher output impedance must lead to a higher voltage
across it. This higher voltage will be reflected to the primary side
of the transformer, leading to a higher maximum voltage at the valve
anodes and transformer primary winding.

An understanding of simple filters will explain why the bandwidth will
shift.

Some understanding of valve characteristics should explain why the
distortion content will change.

Nothing except experience will tell you whether this particular amp is
likely to be OK with an 8 ohm speaker, or whether it's sound will be
pleasing to you.

That's why Lord Valve is your best bet.

cheers, Ian

[Phread]

"zyx" wrote in message ...

"zyx" wrote in message ...
I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try it on a 12" speaker which is 8 ohms.

Jam away?


Such mixed results.

who to believe... who to believe...

Dude!

Who to believe? Lord Valve is a musician who's been fixing guitar amps
for longer than you've been on the planet, most likely. Graham is a blow
hard know-it-all who responds to every question posted here even though
his actual knowledge of tube equipment is exactly zero.

I've been building and repairing tube equipment for 50 years, including guitar
amps, home stereo & PA amps, and ham radio transmitters and receivers.
Lord Valve is right. Doubling the load impedance on a tube guitar amp will
cause much larger voltage swings in the primary of the output transformer
(swings of thousands of volts!) which can cause arcs in the output tubes,
tube sockets and tranny.

Fred

any links to learn more about it? By the way I already have an 12" 8 ohm speaker so I asked.

[Eeyore]

Phread wrote:

"zyx" wrote in message
"zyx" wrote in message
I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to try it on a 12" speaker which is 8 ohms.


Jam away?


Such mixed results.

who to believe... who to believe...

Dude!

Who to believe? Lord Valve is a musician who's been fixing guitar amps
for longer than you've been on the planet, most likely. Graham is a blow
hard know-it-all who responds to every question posted here even though
his actual knowledge of tube equipment is exactly zero.

Oh really ?

I'm a pro-audio designer with 35 yrs experience in the business and have plenty of knowledge of tube circuitry and I
even played a part in getting one tube guitar amp into volume production.


I've been building and repairing tube equipment for 50 years, including guitar
amps, home stereo & PA amps, and ham radio transmitters and receivers.
Lord Valve is right. Doubling the load impedance on a tube guitar amp will
cause much larger voltage swings in the primary of the output transformer
(swings of thousands of volts!) which can cause arcs in the output tubes,
tube sockets and tranny.

Utter garbage. The voltage swings on the primary of the output transformer are typically well *under* a thousand
volts. They cannot in any case exceed 2 x B+ in normal operation.

How many transformers have you designed btw ?

Graham

p.s.

to zyx, there are lots of amateurs here who reckon they know it all and dislike those with professional knowledge.
They regularly make fundamental errors of fact and interpretation.

There are only 2 professional designers here and they are Patrick Turmer and myself.

Lord Valve is a very experienced tube expert at the practical level but has no design experience AFAIK.

[Eeyore]

Ian Iveson wrote:

zyx wrote

who to believe... who to believe...

You will have the same problem wherever you go, I'm afraid. Sometime
you will need to make a judgement. May as well be now.

It should be obvious that this "eeyor" either can't read or has no
grasp of simple logic, or both. Neither has he any real experience,
and seems not to know the meaning of the word "unreliable". Greg's
argument is clearly half-boiled.

My logic is unassailable

No, you're an utter cretin who can barely make a single post without some
serious error.

Graham

[Chris Hornbeck]

Despite what you may have seen from a loud-mouthed
know-it-all on this NG, don't worry.

Loudspeaker impedances are only the roughest kind
of estimate, good within a factor of ten, maybe.

Operation without load is dangerous because it can
cause (somewhat indirectly, but "cause") high
voltage arcing, often in the output transformer's
windings' insulation.

Operation with any load even remotely like a speaker
attached is safe. Never operate without a speaker
attached, but don't worry about some bogus number.

All good fortune,

Chris Hornbeck
"History consists of truths which in the end turn into lies,
while myth consists of lies which finally turn into truths."
- Jean Cocteau

[tubegarden]

Hi RATs and zyx!

Just get another 8 ohm speaker and wire them in parallel.

This NG would rather trade insults than help you solve your problem.

Yes, an 8 ohm resistor would work, sort of, but you can't hear the
resistor's heat output

Happy Ears!
Al

[John Byrns]

In article ,
Eeyore wrote:

Phread wrote:

"zyx" wrote in message
"zyx" wrote in message
I have an epi valve jr combo with 8" speaker that is 4 ohms. I want to
try it on a 12" speaker which is 8 ohms.

Jam away?

Such mixed results.

who to believe... who to believe...

Dude!

Who to believe? Lord Valve is a musician who's been fixing guitar amps
for longer than you've been on the planet, most likely. Graham is a blow
hard know-it-all who responds to every question posted here even though
his actual knowledge of tube equipment is exactly zero.

Oh really ?

I'm a pro-audio designer with 35 yrs experience in the business and have
plenty of knowledge of tube circuitry and I
even played a part in getting one tube guitar amp into volume production.

I've been building and repairing tube equipment for 50 years, including
guitar
amps, home stereo & PA amps, and ham radio transmitters and receivers.
Lord Valve is right. Doubling the load impedance on a tube guitar amp will
cause much larger voltage swings in the primary of the output transformer
(swings of thousands of volts!) which can cause arcs in the output tubes,
tube sockets and tranny.

Utter garbage. The voltage swings on the primary of the output transformer
are typically well *under* a thousand
volts. They cannot in any case exceed 2 x B+ in normal operation.

Oh really ?

Are you sure about that 2 x B+ stuff? Have you ever considered that the
transformer presents an inductive impedance to the tube(s) and if it is
not sufficiently damped the anode voltage can easily exceed 2 x B+ when
the tube is suddenly cut off?

How many transformers have you designed btw ?

to zyx, there are lots of amateurs here who reckon they know it all and
dislike those with professional knowledge.
They regularly make fundamental errors of fact and interpretation.

There are only 2 professional designers here and they are Patrick Turmer and
myself.

What evidence do you have that there are only two "professional
designers" here, there may be more than you suspect? Besides the fact
that someone is a "professional designer" doesn't guarantee that they
know what they are doing.

Lord Valve is a very experienced tube expert at the practical level but has
no design experience AFAIK.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Chris Hornbeck]

On Wed, 17 Jan 2007 17:53:35 +0000, Eeyore
wrote:


Especially when a speaker's impedance can rise at some frequencies to easily TEN
TIMES the 'nominal' figure.

By your argument, driving the amplifier at such frequencies will destroy it.

And furthermore a nominally stable (with nominal load) amplifier,
with nominal levels of voltage feedback, which includes conventional
guitar amplifiers, have very, very largely the same circuit voltages
irrespective of load, over a wide range.

The very real danger that has promulgated these myths is
with an unstable amplifier, for example a legacy pentode-
output guitar amplifier that oscillates when driven hard
unloaded; not unknown for lots of classic designs.

Oscillation, or even just overdrive, rapidly puts the
output valves into class C; dI/dT makes multi-kiloJolt
spikes across the output transformer when unloaded.

Any remotely reasonable load keeps dI/dT to as safe a
level as any other remotely reasonable load.

Much thanks, as always,

Chris Hornbeck
"History consists of truths which in the end turn into lies,
while myth consists of lies which finally turn into truths."
- Jean Cocteau

[Phil Allison]

"Eeysore the IDIOT "


Utter garbage. The voltage swings on the primary of the output transformer
are typically well *under* a thousand
volts. They cannot in any case exceed 2 x B+ in normal operation.


** Really ?????

Says an utter fool who has obviously NEVER tested * that * naive theory.

Eg, any Marshall valve amp can easily be made to exhibit +/- 5 kV spikes
on the output plates when operating into a speaker cab.

LVs phrase " high tension flyback " is a very apt one - cos it don't
happen with a resistive load.



How many transformers have you designed btw ?


** More Red Herrings - anyone ??




........ Phil

[Eeyore]

John Byrns wrote:

Eeyore wrote:
Phread wrote:

Doubling the load impedance on a tube guitar amp will
cause much larger voltage swings in the primary of the output transformer
(swings of thousands of volts!) which can cause arcs in the output tubes,
tube sockets and tranny.

Utter garbage. The voltage swings on the primary of the output transformer
are typically well *under* a thousand
volts. They cannot in any case exceed 2 x B+ in normal operation.

Oh really ?

Are you sure about that 2 x B+ stuff?

100%


Have you ever considered that the
transformer presents an inductive impedance to the tube(s) and if it is
not sufficiently damped the anode voltage can easily exceed 2 x B+ when
the tube is suddenly cut off?

The transformer will look like an inductor when there's no load.

When there's a load on the secondary you will see a load on the primary. That's
what transformers *DO* !

The load 'damps' the transformer's own inductance if you want to look at it like
that.


How many transformers have you designed btw ?

to zyx, there are lots of amateurs here who reckon they know it all and
dislike those with professional knowledge.
They regularly make fundamental errors of fact and interpretation.

There are only 2 professional designers here and they are Patrick Turmer and
myself.

What evidence do you have that there are only two "professional
designers" here,

Experience of the posters here.


there may be more than you suspect?

Not to my knowledge.


Besides the fact that someone is a "professional designer" doesn't guarantee
that they know what they are doing.

Patrick and I do.

Graham

[Eeyore]

Phil Allison wrote:

"Eeysore the IDIOT "

Utter garbage. The voltage swings on the primary of the output transformer
are typically well *under* a thousand
volts. They cannot in any case exceed 2 x B+ in normal operation.

** Really ?????

Says an utter fool who has obviously NEVER tested * that * naive theory.

Eg, any Marshall valve amp can easily be made to exhibit +/- 5 kV spikes
on the output plates when operating into a speaker cab.

In which case it's nothing to do with whether the load is a nominal 4 ohms or 8
ohms is it ?

Note that I did say 'in normal operation'. If you grossly abuse an amplifier,
all sorts of stuff can happen.

Graham

[Phil Allison]

" Eeysore the LYING POMMY CHARLATAN "


Utter garbage. The voltage swings on the primary of the output
transformer
are typically well *under* a thousand
volts. They cannot in any case exceed 2 x B+ in normal operation.

** Really ?????

Says an utter fool who has obviously NEVER tested * that * naive
theory.

Eg, any Marshall valve amp can easily be made to exhibit +/- 5 kV
spikes
on the output plates when operating into a speaker cab.

LVs phrase " high tension flyback " is a very apt one - cos it
don't
happen with a resistive load.



In which case it's nothing to do with whether the load is a nominal 4 ohms
or 8
ohms is it ?


** WRONG !

The higher Z value, if mismatched at the output, will induce larger spikes.

At some stage, insulation in the OT, the valves or sockets gives up, with a
BANG.



Note that I did say 'in normal operation'.


** Normal operation ( for a guitar amp) is the case.



As I said - YOU have NEVER tested it.

Cos YOU are a posturing, pig ignorant, ASD ****ed

POMMY CHARLATAN !!





........ Phil

[Eeyore]

Phil Allison wrote:


As I said - YOU have NEVER tested it.

So how about you tell us how you got it to do this then ?

Graham

[Phil Allison]

"Eeysore the IDIOT "


So how about you tell us how you got it to do this then ?


** Got what to do what - exactly ??





....... Phil

[Eeyore]

Phil Allison wrote:

"Eeysore the IDIOT "

So how about you tell us how you got it to do this then ?

** Got what to do what - exactly ??

Get the amplifier to create 5kV on the OPT primary !

Graham

[Phil Allison]

"Eeysore the ****ING IDIOT "

So how about you tell us how you got it to do this then ?

** Got what to do what - exactly ??

Get the amplifier to create 5kV on the OPT primary !


** Already told you.




........ Phil

[Eeyore]

Phil Allison wrote:

"Eeysore the ****ING IDIOT "

So how about you tell us how you got it to do this then ?

** Got what to do what - exactly ??

Get the amplifier to create 5kV on the OPT primary !

** Already told you.

You did NOT say how you did it.

Graham

[Eeyore]

Phil Allison wrote:

"Eeysore the ****ING IDIOT "

** Got what to do what - exactly ??

Get the amplifier to create 5kV on the OPT primary !

** Already told you.

You did NOT say how you did it.

" Eg, any Marshall valve amp can easily be made to exhibit +/- 5 kV
spikes on the output plates when operating into a speaker cab.

LVs phrase " high tension flyback " is a very apt one - cos it don't
happen with a resistive load. "

" Normal operation ( for a guitar amp) is the case. "

Ok - so *how easily* ?

If you can't provide an answer you'll be seen to be simply posturing.

Graham

[Eeyore]

Phil Allison wrote:

"Eeysore the LYING CHARLATAN "

** Got what to do what - exactly ??

Get the amplifier to create 5kV on the OPT primary !

** Already told you.

You did NOT say how you did it.

" Eg, any Marshall valve amp can easily be made to exhibit +/- 5 kV
spikes on the output plates when operating into a speaker cab.

LVs phrase " high tension flyback " is a very apt one - cos it
don't
happen with a resistive load. "

" Normal operation ( for a guitar amp) is the case. "

Ok - so *how easily* ?

** The question has been answered.

Do your own tests if you want proof.

Do a GG search on " alt .guitar.amps" on the topic of "flyback spikes "
for confirmation the phenomenon is well known.

So you're just making it up ( you can't or refuse to explain it ).

Just as I expected from a toaster repairman.

Graham

[Phil Allison]

"Eeysore the Raving LUNATIC" "



** The question has been answered.

Do your own tests if you want proof.

Do a GG search on " alt .guitar.amps" on the topic of "flyback spikes
"
for confirmation the phenomenon is well known.


So you're just making it up ( you can't or refuse to explain it ).


** What an UTTER non sequitur !!!!!!!!

Someone one ought to shoot this pile of pommy **** right in the head.

Then ask the Queen for a medal for services to the British Empire.




........ Phil

[Eeyore]

Phil Allison wrote:

"Eeysore the Raving LUNATIC" "

** The question has been answered.

Do your own tests if you want proof.

Do a GG search on " alt .guitar.amps" on the topic of "flyback spikes
"
for confirmation the phenomenon is well known.


So you're just making it up ( you can't or refuse to explain it ).

** What an UTTER non sequitur !!!!!!!!

So go-on, what causes the 5kV ?

You don't know do you ?

Graham

[Arny Krueger]

"Eeyore" wrote in
message
Phil Allison wrote:

"Eeysore the LYING CHARLATAN "

** Got what to do what - exactly ??

Get the amplifier to create 5kV on the OPT primary !

** Already told you.

You did NOT say how you did it.

" Eg, any Marshall valve amp can easily be made to
exhibit +/- 5 kV spikes on the output plates when
operating into a speaker cab.

LVs phrase " high tension flyback " is a very apt
one - cos it don't
happen with a resistive load. "

" Normal operation ( for a guitar amp) is the case. "

Ok - so *how easily* ?

** The question has been answered.

Do your own tests if you want proof.

Do a GG search on " alt .guitar.amps" on the topic of
"flyback spikes " for confirmation the phenomenon is
well known.

So you're just making it up ( you can't or refuse to
explain it ).

Ironically, if one takes Phil's advice and searches alt.guitar.amps for
posts about flyback spikes, you find him dodging the same basic question you
asked about generating 5 Kv spikes around 2/25/2003, for example.

Searching further, it looks like people are talking about loose 1/4 plugs,
and the like. Based on what I know about generating inductive spikes, a wide
range of inductances can suffice, and saying that 8 ohm speakers are always
safe with a given amp would be a real stretch.

[Phil Allison]

"Eeysore the Raving CRIMINAL LUNATIC" "


" Normal operation ( for a guitar amp) is the case. "

Ok - so *how easily* ?


** The question has been answered.

Do your own tests if you want proof.

Do a GG search on " alt .guitar.amps" on the topic of "flyback
spikes
"
for confirmation the phenomenon is well known.


So you're just making it up ( you can't or refuse to explain it ).

** What an UTTER non sequitur !!!!!!!!

So go-on, what causes the 5kV ?


** So you have no idea what the term " flyback spikes" refers to ?

But you do now accept that they really exist in valve amps ???


Finally did a little Googling - did we ?






....... Phil

[Lord Valve]

Chris Hornbeck wrote:

Despite what you may have seen from a loud-mouthed
know-it-all on this NG, don't worry.

Well, ****-fire and boy howdy, son...

You're wrong, but you can derive some small solace
from the fact that you're wrong for all the right reasons,
chief among them being ignorance regarding actual
field operating conditions for *guitar* amplifiers.

You've also never seen an Epiphone Valve Junior,
nor the schematic thereto. Right?

So - this amp runs a single EL84, giving an output
of around 4 watts RMS. One 12AX7. SS bridge
rectifier for the HV, as well as one for the heaters.
No screen resistor. The entire shebang - including
the speaker - *retails* for $139, and can often be
had for less than $100, brand new in the box. In
short, it's a cheap-ass piece of Chinese ****,
a bare-bones minimum design intended to sell
for the lowest price possible - less, in fact, than
most audiophools spend on a couple of snob-glass
preamp tubes.

Think any corners were cut?

I've had around a half-dozen of these across my
bench in the last year. All but one had the same
problem: fried socket. Cause: "I hooked it up
to my (brand XYZ) speaker cabinet cuz it wasn't
loud enough for me to play with a drummer."
Said speaker cabinet, of course, was nearly
always an 8-ohm box. One was 16.

This is a 4-watt amp commonly purchased by
the worst gear abusers on the planet: guitar
pickers. Since it's only 4 watts, it is *always*
played at full-bore output clipping, for max
distortion and "blues tone." Its (often short)
life is one of maximum stress, placed upon
the sleaziest components imaginable.

Now, son - you may know what you may
know, and it may well be at odds with what
I've said, but I have hands-on time with this
particular gizmo, and I know for certain it
eats tube sockets when operated into a
higher than spec load. If you want to show
me the math which proves that a bumblebee
can't fly, be my guest. I've seen 'em fly, so
I'll take your "knowledge" with a grain of salt,
if that's OK with you. You don't catch my ass
on this NG telling the audiophools about their
SET 300B snob designs for a fairly good
reason: I know jack **** about 'em. The
difference between me and the audio******s
is that I can admit it.

Lord Valve
Expert Guitar Amp Dude

[Eeyore]

Phil Allison wrote:

"Eeysore the Raving CRIMINAL LUNATIC" "

" Normal operation ( for a guitar amp) is the case. "

Ok - so *how easily* ?

** The question has been answered.

Do your own tests if you want proof.

Do a GG search on " alt .guitar.amps" on the topic of "flyback
spikes
"
for confirmation the phenomenon is well known.


So you're just making it up ( you can't or refuse to explain it ).

** What an UTTER non sequitur !!!!!!!!

So go-on, what causes the 5kV ?

** So you have no idea what the term " flyback spikes" refers to ?

I know exactly.


But you do now accept that they really exist in valve amps ???

If the load's disconnected for sure.


Finally did a little Googling - did we ?

No need.

Now, how did *YOU* get 5kV flyback spikes.

What was the load ?

How hard was the amp being driven ?

What was the input signal ?

Graham