8045g tubes

[Guest]

Archived from groups: rec.audio.pro (More info?)

On Tue, 7 Sep 2004 17:20:34 -0400, "Ken Platt"
<kplatt1NEVERSPAM@cogeco.ca> wrote:

>Not a bad suggestion Norm.
>But the guy who gave it 2 us thought it 'needed to be used.'
>Still looking for info on the mod for diff tubes

Hi Ken,

Received your schematic, and it looks extremely straightforward.
There's plenty of bias voltage available, small cathode resistors
to check and adjust bias, and reasonable voltages and load
impedance for KT88/6550 family tubes.

When you examine the output tube sockets, confirm that no pins
are used as convenient tie points for something else. If so,
move them.

Then connect about 100 ohm, a couple watt resistors from pins
3 to 4.

With no output tubes installed, fire it up (preferably with a
Variac, but *SAFETY FIRST* in any case - allow no children or
pets in the room).

Observe voltages at points marked "C1" and C2". Adjust the 30K
ohm bias pots for maximum voltage.

Power off. Observe all supply voltages and wait until they've
fallen to a low level, maybe a coupla volts.

Install your new matched quad of Svetlana or maybe JJ power tubes.
Fire it up again and observe. Everything OK?

Bias is measured at the cathode pins (pin 8). I'd run modern
tubes at between 50 and 70 mA (500 mV and 700mV on pin 8).
The 10K ohm pots are to balance the current in each pair.

Try various bias currents and use the least that doesn't affect
sound quality. And no more than 80mA.

Good fortune,

Chris Hornbeck

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Mike Rivers"
Phil Allison
>
> > > About 2/3 down the page makes the statement below
> > > 6240G See 8045G, also see interchangeable type 6CG7/6FQ7
>
> > ** Which is a ridiculous MISPRINT !!
>
> Hey! How come these guys get a "Misprint" and I'm always an "Idiot"?


** Proof of the difference waits below.


> If it's a misprint, you probably have some idea of what tube should
> have been listed as the alternate.


** See - idiots make asinine assumptions like the one Mike Rivers just
did.


> Care to elucidate?


** And become besotted with them.

Then want others to worship them too.





............ Phil

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

thanks to chris
kp

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in message
news:ujbsj09lg1bhlpdf4qrp4rl0k68h2vi8ti@4ax.com...
> On Tue, 7 Sep 2004 17:20:34 -0400, "Ken Platt"
> <kplatt1NEVERSPAM@cogeco.ca> wrote:
>
>>Not a bad suggestion Norm.
>>But the guy who gave it 2 us thought it 'needed to be used.'
>>Still looking for info on the mod for diff tubes
>
> Hi Ken,
>
> Received your schematic, and it looks extremely straightforward.
> There's plenty of bias voltage available, small cathode resistors
> to check and adjust bias, and reasonable voltages and load
> impedance for KT88/6550 family tubes.
>
> When you examine the output tube sockets, confirm that no pins
> are used as convenient tie points for something else. If so,
> move them.
>
> Then connect about 100 ohm, a couple watt resistors from pins
> 3 to 4.
>
> With no output tubes installed, fire it up (preferably with a
> Variac, but *SAFETY FIRST* in any case - allow no children or
> pets in the room).
>
> Observe voltages at points marked "C1" and C2". Adjust the 30K
> ohm bias pots for maximum voltage.
>
> Power off. Observe all supply voltages and wait until they've
> fallen to a low level, maybe a coupla volts.
>
> Install your new matched quad of Svetlana or maybe JJ power tubes.
> Fire it up again and observe. Everything OK?
>
> Bias is measured at the cathode pins (pin 8). I'd run modern
> tubes at between 50 and 70 mA (500 mV and 700mV on pin 8).
> The 10K ohm pots are to balance the current in each pair.
>
> Try various bias currents and use the least that doesn't affect
> sound quality. And no more than 80mA.
>
> Good fortune,
>
> Chris Hornbeck

 

[Guest]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

On Mon, 06 Sep 2004 16:43:03 +0000, Ken Platt wrote:

> Someone recently gave me a Lux MQ3600 power amp. Unfortunately there is
> one 8045G power tube missing. Finding one seems impossible by my search.
> Does anyone have a source for them? Beyond that, has anyone done the mod
> described below and want to comment on the expense and/or result?

AFAIK, an 8045G IS a 6550 wired as a triode (by jumpers in the base).
See: http/www.triodeel.com/images/8045.gif

Most of the "8045G" labelled tubes I've seen were US made 6550's
with jumpers added in the base.

> This may be a difficult and expensive
> change, though less expensive than finding new 8045Gs.

Wiring the socket for a 6550 or KT88 is not difficult,
nor should it be expensive.

--
Ned Carlson Triode Electronics Chicago,IL USA
www.triodeelectronics.com

 

[Guest]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

On 12 Sep 2004 03:53:16 -0500, "Ned Carlson" <postmaster@triodeel.com>
wrote:

>AFAIK, an 8045G IS a 6550 wired as a triode (by jumpers in the base).
>
>See: http/www.triodeel.com/images/8045.gif
>
>Most of the "8045G" labelled tubes I've seen were US made 6550's
>with jumpers added in the base.

If a very large number of so-called 8045G's were "modified" tetrodes, the
real McCoy was a native triode, developped at the request of Tim de
Paravicini, then star designer at Lux, by NEC.

 

[Guest]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

"François Yves Le Gal" <flegal@aingeal.com> wrote in message
news:6978k0lhm31ipukhp4v5accniui7j8ak6p@4ax.com...
> On 12 Sep 2004 03:53:16 -0500, "Ned Carlson" <postmaster@triodeel.com>
> wrote:
>
> >AFAIK, an 8045G IS a 6550 wired as a triode (by jumpers in the base).
> >
> >See: http/www.triodeel.com/images/8045.gif
> >
> >Most of the "8045G" labelled tubes I've seen were US made 6550's
> >with jumpers added in the base.
>
> If a very large number of so-called 8045G's were "modified" tetrodes, the
> real McCoy was a native triode, developped at the request of Tim de
> Paravicini, then star designer at Lux, by NEC.

With a very differently-shaped envelope, resembling some transmitting tubes.

Peace,
Paul

 

[Guest]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

Paul Stamler wrote:

> "François Yves Le Gal" <flegal@aingeal.com> wrote in message
> news:6978k0lhm31ipukhp4v5accniui7j8ak6p@4ax.com...
>
>>On 12 Sep 2004 03:53:16 -0500, "Ned Carlson" <postmaster@triodeel.com>
>>wrote:
>>
>>
>>>AFAIK, an 8045G IS a 6550 wired as a triode (by jumpers in the base).
>>>
>>>See: http/www.triodeel.com/images/8045.gif
>>>
>>>Most of the "8045G" labelled tubes I've seen were US made 6550's
>>>with jumpers added in the base.
>>
>>If a very large number of so-called 8045G's were "modified" tetrodes, the
>>real McCoy was a native triode, developped at the request of Tim de
>>Paravicini, then star designer at Lux, by NEC.
>
>
> With a very differently-shaped envelope, resembling some transmitting tubes.
>
> Peace,
> Paul
>
>

Lots of 6550's available at various prices here. Nothing on the 8045G.
http/www.tubesandmore.com/

--
Art Jackson W4TOY Owensboro, KY USA
Life is God's open book test. In order to pass,
you must open His book to find the answers.

 

[Guest]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

Ken Platt wrote:
> Someone recently gave me a Lux MQ3600 power amp. Unfortunately there is one
> 8045G power tube missing. Finding one seems impossible by my search. Does
> anyone have a source for them? Beyond that, has anyone done the mod
> described below and want to comment on the expense and/or result?
>
> *8045G--power triode, made in Japan by NEC especially for a 1970s-model
> Luxman amplifier. Long out of production, scarce and expensive. Unlikely to
> be manufactured again. There may have been a version marketed by Golden
> Dragon recently. We recommend having the amplifier modified to accept a
> triode-connected EL34 or KT88. This may be a difficult and expensive change,
> though less expensive than finding new 8045Gs. Please consult with an
> experienced service technician.*
>
> Thanks, Ken
>
>
Hi Ken
Very easy to change to KT88. I would not consider El34's

 

[Guest]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

In article <41482e0d$0$24391$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
Philip Lawrence <hitriode@iinet.net.au> wrote:
>Ken Platt wrote:
>> Someone recently gave me a Lux MQ3600 power amp. Unfortunately there is one
>> 8045G power tube missing. Finding one seems impossible by my search. Does
>> anyone have a source for them? Beyond that, has anyone done the mod
>> described below and want to comment on the expense and/or result?
>>
>> *8045G--power triode, made in Japan by NEC especially for a 1970s-model
>> Luxman amplifier. Long out of production, scarce and expensive. Unlikely to
>> be manufactured again. There may have been a version marketed by Golden
>> Dragon recently. We recommend having the amplifier modified to accept a
>> triode-connected EL34 or KT88. This may be a difficult and expensive change,
>> though less expensive than finding new 8045Gs. Please consult with an
>> experienced service technician.*
>>
>> Thanks, Ken
>>
>Hi Ken
> Very easy to change to KT88. I would not consider El34's

Agreed, the KT88 change should be just addition of a jumper and rebiasing
for the most part, and there should be no problems with mechanical fit.
Permit me to recommend the Svetlana 6550C as a great inexpensive KT88-style
tube.

EL34 will require some big bias change and some loss of power. Not a huge
problem, but they aren't really much cheaper than the 6550Cs anyway.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[Guest]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

Thanks for seconding that motion. I think I have decided to do the mod as
opposed to getting into more rare tubes. That said, can anyone recommend
someone in the Hamilton ON or at least southern Ontario area who is
qualified for such a mod. Barring any recommendations I will just ask my
usual guitar (tube) amp guy. Thanks for everyone's help.
ken

"Scott Dorsey" <kludge@panix.com> wrote in message
news:ci9jsf$5pd$1@panix2.panix.com...
> In article <41482e0d$0$24391$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
> Philip Lawrence <hitriode@iinet.net.au> wrote:
>>Ken Platt wrote:
>>> Someone recently gave me a Lux MQ3600 power amp. Unfortunately there is
>>> one
>>> 8045G power tube missing. Finding one seems impossible by my search.
>>> Does
>>> anyone have a source for them? Beyond that, has anyone done the mod
>>> described below and want to comment on the expense and/or result?
>>>
>>> *8045G--power triode, made in Japan by NEC especially for a 1970s-model
>>> Luxman amplifier. Long out of production, scarce and expensive. Unlikely
>>> to
>>> be manufactured again. There may have been a version marketed by Golden
>>> Dragon recently. We recommend having the amplifier modified to accept a
>>> triode-connected EL34 or KT88. This may be a difficult and expensive
>>> change,
>>> though less expensive than finding new 8045Gs. Please consult with an
>>> experienced service technician.*
>>>
>>> Thanks, Ken
>>>
>>Hi Ken
>> Very easy to change to KT88. I would not consider El34's
>
> Agreed, the KT88 change should be just addition of a jumper and rebiasing
> for the most part, and there should be no problems with mechanical fit.
> Permit me to recommend the Svetlana 6550C as a great inexpensive
> KT88-style
> tube.
>
> EL34 will require some big bias change and some loss of power. Not a huge
> problem, but they aren't really much cheaper than the 6550Cs anyway.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

 

[Guest]

Hello
I have two pairs of 8045G . Is anyone going to buy

varfand@yahoo.com

 

[Guest]

I have two 8045g tubes one tests very good while the other is only good. I don't have vintage luxman amplifier, so they are on sale.
pietro.mazzagatti@fastwebnet.it

 

[vt25b]

Archived from groups: rec.audio.pro,rec.audio.tubes (More info?)

Someone recently gave me a Lux MQ3600 power amp. Unfortunately there is one
8045G power tube missing. Finding one seems impossible by my search. Does
anyone have a source for them? Beyond that, has anyone done the mod
described below and want to comment on the expense and/or result?

*8045G--power triode, made in Japan by NEC especially for a 1970s-model
Luxman amplifier. Long out of production, scarce and expensive. Unlikely to
be manufactured again. There may have been a version marketed by Golden
Dragon recently. We recommend having the amplifier modified to accept a
triode-connected EL34 or KT88. This may be a difficult and expensive change,
though less expensive than finding new 8045Gs. Please consult with an
experienced service technician.*

Thanks, Ken

Hi Ken,
I happened to see this lately and reminded me that I had kept for spare a set of tubes (8045Gx2 & 6240Gx2) some 20 years ago. I had tested them on the amp (MQ3600) which I sold then. Since I switch to DHT these tubes are no longer useful to me and I would sell them for say US$400. Let me know if you are interested. I'm in Hong Kong.

Cheers
Brian