I have a valve amp and I am clueless
 

Apologies for the length of this post. I have quite recently had
serviced and put into operation a fairly old valve amp and I'm excited
and confused by it. I hope you can help.

It’s a Beam Echo Avantic Type SPA II. It sounds great to me. I
should say I probably don't have the same standards as most on this
newsgroup when it comes to audio - prior to this I was happy enough
with my old NAD 3020i which, while I knew it could be better, was fine
with me. I don’t know if the Avantic is higher quality but it
definitely sounds different to the Nad and I much prefer it. I would
love to know more about this amp and I can find practically nothing
about it on the web or anywhere else I’ve looked, so I'd appreciate
any information and opinions anyone might have. I know Beam Echo was
a British company which I think wound-up sometime in the 1960's. I
also remember reading some time back that this was not a particularly
high-end bit of kit in its day and not particularly well thought of,
Beam-Echo produced other, more expensive, amps. The person who
serviced it for me says it was built in 1959 but couldn’t (or didn't)
tell me too much more. Any knowledge you can share would be very
welcome.

Also if anyone can answer any of these questions I would really
appreciate it:

1) On the back is a dial labelled PU Balance which turns 360
degrees. PU is the phono input but what does this dial do? When I’ve
adjusted it I can’t hear much or any difference but I am nervous about
breaking anything and haven't fiddled much with it.
2) Another dial on the back has an arrow you could set to points
labelled 4, 8 or 16 ohms. But the dial doesn't seem to work, does it
matter?
3) It has a dial on the front labelled Balance but this seems to do
very little, certainly doesn’t act like the balance dial on any other
stereo amps I’ve used which move the sound from one speaker to
another. What is it meant for?
5) The source selector dial on the front has 6 settings - on one side
PU, Tuner and Tape under the heading stereo and and on the other side
the same 3 input choices headed 3D. All six work but can anyone tell
me what the 3D setting is for? I can't tell much difference between
them. If pushed I'd say the stereo settings sound better but that
could just be my imagination.
4) It needs a phono amplifier – I use it with a Thorens 160 MkI with
Shure M75 – do you have any recommendations for a decent one in the
not too pricey range. Currently I have the turntable plugged into the
Nad and the Nad pre-amp outputs plugged into the PU inputs of the
Avantic and I wonder if a dedicated phono stage will make a worthwhile
difference.
5) Finally, any suggestions for an improvement on the Linn Index
speakers I'm using. I understand the Avantic is fairly low powered
and that I need speakers with a reasonable sensitivity (the Linns are
rated 87 or 86db). I don’t understand what the sensitivity measure
means and for what its worth it goes very loud - but always (for me)
with something missing in the bass sounds. Is it worth going for
expensive speakers to improve the bass and generally sound better or,
with this set-up, will it not make an appreciable (by me) difference?

Sorry for being so long-winded, and dim.

Thanks in advance for any help...

Dave

I have a valve amp and I am clueless
 

"Dave" wrote in message
...
Apologies for the length of this post. I have quite recently had
serviced and put into operation a fairly old valve amp and I'm excited
and confused by it. I hope you can help.

It’s a Beam Echo Avantic Type SPA II. It sounds great to me. I
should say I probably don't have the same standards as most on this
newsgroup when it comes to audio - prior to this I was happy enough
with my old NAD 3020i which, while I knew it could be better, was fine
with me. I don’t know if the Avantic is higher quality but it
definitely sounds different to the Nad and I much prefer it. I would
love to know more about this amp and I can find practically nothing
about it on the web or anywhere else I’ve looked, so I'd appreciate
any information and opinions anyone might have. I know Beam Echo was
a British company which I think wound-up sometime in the 1960's. I
also remember reading some time back that this was not a particularly
high-end bit of kit in its day and not particularly well thought of,
Beam-Echo produced other, more expensive, amps. The person who
serviced it for me says it was built in 1959 but couldn’t (or didn't)
tell me too much more. Any knowledge you can share would be very
welcome.

Also if anyone can answer any of these questions I would really
appreciate it:

1) On the back is a dial labelled PU Balance which turns 360
degrees. PU is the phono input but what does this dial do? When I’ve
adjusted it I can’t hear much or any difference but I am nervous about
breaking anything and haven't fiddled much with it.
2) Another dial on the back has an arrow you could set to points
labelled 4, 8 or 16 ohms. But the dial doesn't seem to work, does it
matter?
3) It has a dial on the front labelled Balance but this seems to do
very little, certainly doesn’t act like the balance dial on any other
stereo amps I’ve used which move the sound from one speaker to
another. What is it meant for?
5) The source selector dial on the front has 6 settings - on one side
PU, Tuner and Tape under the heading stereo and and on the other side
the same 3 input choices headed 3D. All six work but can anyone tell
me what the 3D setting is for? I can't tell much difference between
them. If pushed I'd say the stereo settings sound better but that
could just be my imagination.
4) It needs a phono amplifier – I use it with a Thorens 160 MkI with
Shure M75 – do you have any recommendations for a decent one in the
not too pricey range. Currently I have the turntable plugged into the
Nad and the Nad pre-amp outputs plugged into the PU inputs of the
Avantic and I wonder if a dedicated phono stage will make a worthwhile
difference.
5) Finally, any suggestions for an improvement on the Linn Index
speakers I'm using. I understand the Avantic is fairly low powered
and that I need speakers with a reasonable sensitivity (the Linns are
rated 87 or 86db). I don’t understand what the sensitivity measure
means and for what its worth it goes very loud - but always (for me)
with something missing in the bass sounds. Is it worth going for
expensive speakers to improve the bass and generally sound better or,
with this set-up, will it not make an appreciable (by me) difference?

Sorry for being so long-winded, and dim.

Thanks in advance for any help...

Dave

From the 1959 Hi-Fi Year Book:-

Avantic SPA11. 7 watts per channel, 10 watts peak
Distortion 1%
Inputs, tuner and tape 100mV, gram 650mV
Response 40-15000c/s +- 1dB
Output Impedance (means load impedance) 4,8,16 ohms
Output valves: ECL82
Price £ 29/8/-

It sounds from your description that you may have some problems with it. The
balance control should work conventionally, but in those days didn't always
cut off the unwanted channel at full rotation, just reduced the level
somewhat, and acted as a true balance control to swing the image slightly
from L to R.

Regarding the impedance dial, if you start with it set to 4 ohms, and
increase it to 8 and 16, you should get a small increase in volume, probably
accompanied by an increase in distortion. If you don't, then it's quite
possible that it may have been disconnected in the past. It is almost
certainly a switch, so should be stiff to turn.

Using your NAD as a phono stage is fine, but I would plug it into the tuner
or tape input. The PU input on the Avantic is meant for a ceramic cartridge,
and whilst it should have a flat response, it may not have.

With only 7 watts, you will need quite efficient 'speakers. You could always
get some horns, but I find them mostly too colored to be pleasant to listen
to. If you can get hold of some Tannoy Dual Concentrics, you may find that
the 7 watts is quite sufficient, and you get a good sound. If you want to
set up a vintage late 50s, early 60s system, you could look for some
Wharfedale or Goodmans drive units and build some cabinets.

Finally, I have no idea what 3D means either! It could be some sort of
pseudo-stereo to give some effect on mono sources, but who knows!

Nice find though. Have fun with it.

S.



--
http://audiopages.googlepages.com

I have a valve amp and I am clueless
 

In article
,
Dave
wrote:

Afraid I don't have any info on the amp, so the following are just
suggestions based on other designs of similar period.


1) On the back is a dial labelled PU Balance which turns 360 degrees.
PU is the phono input but what does this dial do? When Ive adjusted it
I cant hear much or any difference but I am nervous about breaking
anything and haven't fiddled much with it.

I don't know the amp, but 'balance' here (and below) might mean a dc offset
adjustment, not channel balance. If so, you'd need some other indicator to
get correct adjustment.

Alternatively, PU may be for ceramic PU, so does not act as intended when
fed with a low impedance source.

2) Another dial on the back has an arrow you could set to points
labelled 4, 8 or 16 ohms. But the dial doesn't seem to work, does it
matter?

May not be a rotary control. May be either a switch or a plug. i.e. you may
have to pull to remove the 'dial', rotate it, and plug it back in with the
relevant number beside the arrow. The setting matters for maximum power,
etc. But almost any setting may play OK, depending on how loud you want the
music, and what speakers you are using.

3) It has a dial on the front labelled Balance but this seems
to do very little, certainly doesnt act like the balance dial on any
other stereo amps Ive used which move the sound from one speaker to
another. What is it meant for?

As above. May adjust the bias levels in the amp. So you'd need to observe
something else when adjusting. Incorrect adjustment will degrade
performance and may shorten valve life. Some valve amps have 'test points'
where you connect a meter to monitor the voltages/currents and adjust a
'balance' control to get the correct values.

Or may just be a balance control with a limited range.

If you want more bass or more power, then I suspect your best bet will be a
different amp. :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

I have a valve amp and I am clueless
 

"Dave" wrote in message
...
Apologies for the length of this post. I have quite recently had
serviced and put into operation a fairly old valve amp and I'm excited
and confused by it. I hope you can help.

It’s a Beam Echo Avantic Type SPA II.




Hi Dave

There is some interesting info about Beam-Echo at:

http://www.bal-ami.com/balhtml/beamecho.shtml

Iain

I have a valve amp and I am clueless
 

Thanks very much for your responses. I'm now keeping a look out for
some Tannoy dual concentrics and taken your advice on the PU input.
Further investigation revealed that ther is a plug beneath the "ohms
dial" with sockets for the different ratings - I've left it as it is.

Thanks again, I now feel a bit less clueless.

Dave

I have a valve amp and I am clueless
 

"Dim Dave" wrote in message
news:2008082018130716807-davesworld100scram@hotmailcom...
Thanks very much for your responses. I'm now keeping a look out for some
Tannoy dual concentrics and taken your advice on the PU input. Further
investigation revealed that ther is a plug beneath the "ohms dial" with
sockets for the different ratings - I've left it as it is.

Thanks again, I now feel a bit less clueless.


Your Beam-Echo amp and a pair of Tannoys make an
excellent combination. If you are buying second hand,
a pair of LRMs (Little Red Monitors) will, I feel,
give a very pleasing musical experience.


Good luck.
Iain

I have a valve amp and I am clueless
 

The Avantic is a superb toy - a lovely retro machine.

For all that, if I wanted the best sound possible I'd buy some big
full range ribbon speakers - the bigger the better. I happen to know
of a pair of Apogee Caliper Sigs coming up for sale on ebay and you
might just get them before they're listed by phoning Rupert on
07920054344 in the next couple of days.

You'd need at least 15 watts to drive them properly - push pull 300b
should do it.

You could use the Avantics for the treble and bi-amp, but I'd be
tempted to sell them for a good price and get a push pull 300b amp
instead. All that assumes a preference for good sound over tasty retro
amps - a big gimme.

Andy

I have a valve amp and I am clueless
 

In article
,
Andy
Evans wrote:


For all that, if I wanted the best sound possible I'd buy some big full
range ribbon speakers - the bigger the better. I happen to know of a
pair of Apogee Caliper Sigs coming up for sale on ebay and you might
just get them before they're listed by phoning Rupert on 07920054344 in
the next couple of days.

You'd need at least 15 watts to drive them properly - push pull 300b
should do it.

You could use the Avantics for the treble and bi-amp, but I'd be tempted
to sell them for a good price and get a push pull 300b amp instead. All
that assumes a preference for good sound over tasty retro amps - a big
gimme.

Makes me wonder about situations where the loudspeaker impedance may be
lower than the output impedance of the power amp... :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

I have a valve amp and I am clueless
 

In article ,
Jim Lesurf wrote:
Makes me wonder about situations where the loudspeaker impedance may be
lower than the output impedance of the power amp... :-)

That's how you get that distinctive 'valve sound' ;-)

--
*Why isn't 11 pronounced onety one? *

Dave Plowman London SW
To e-mail, change noise into sound.

I have a valve amp and I am clueless
 

Jim Lesurf wrote:

In article
,
Andy
Evans wrote:

For all that, if I wanted the best sound possible I'd buy some big full
range ribbon speakers - the bigger the better. I happen to know of a
pair of Apogee Caliper Sigs coming up for sale on ebay and you might
just get them before they're listed by phoning Rupert on 07920054344 in
the next couple of days.

You'd need at least 15 watts to drive them properly - push pull 300b
should do it.

You could use the Avantics for the treble and bi-amp, but I'd be tempted
to sell them for a good price and get a push pull 300b amp instead. All
that assumes a preference for good sound over tasty retro amps - a big
gimme.

Makes me wonder about situations where the loudspeaker impedance may be
lower than the output impedance of the power amp... :-)


What needs to be examined is the speaker sensitivity and ohms when
considering a tube amp.

Most 300B PP amps will have a load on the anode circuit of about 5k. The
300B anode resistance total = 1,600 ohms and if the sec load outlet
match "is for" 6 ohms, then the OPT ratio = 5,000 / 6 = 833 : 1 so the
Ra-a appears as 1,600 / 833 = 1.92 ohms to which we add the OPT winding
resistance of perhaps 0.2 ohms so Rout of the 300B PP amp = 2 ohms.

If 12dB of global NFB is used the Rout will become about 0.5 ohms giving
an DF better than 10 with a 6 ohm load.

Using 300P in SE, or PP or using triode connected KT88, 6550, KT90, the
Rout without NFB is around the 2 ohm mark and will NOT be higher than
the speaker impedance unless some fuctard designed them with Z dipping
to very silly low ohm values.
In that case, if there is a tap on the OPT to give a load match to 3
ohms, the Rout without NFB will be 1 ohm, and loads below 4ohms nominal
will be tolerated OK.

25Watts class AB1 is easy from 300B and if speaker sensitivity is above
88dB/W/M, sound is OK but the higher the sensitivity the better.

What's so great about ribbons though?

Patrick Turner.


Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

I have a valve amp and I am clueless
 

On 2008-09-29 23:35:18 +0100, Andy Evans said:

The Avantic is a superb toy - a lovely retro machine.

For all that, if I wanted the best sound possible I'd buy some big
full range ribbon speakers - the bigger the better. I happen to know
of a pair of Apogee Caliper Sigs coming up for sale on ebay and you
might just get them before they're listed by phoning Rupert on
07920054344 in the next couple of days.

You'd need at least 15 watts to drive them properly - push pull 300b
should do it.

You could use the Avantics for the treble and bi-amp, but I'd be
tempted to sell them for a good price and get a push pull 300b amp
instead. All that assumes a preference for good sound over tasty retro
amps - a big gimme.

Andy

Andy
Thanks for the tip on the speakers. I know that if I want the best
sound possible I'll need to spend a lot more money than I currently
want to. Also sadly those speakers just wouldn't fit well into my
little pad and I'd rarely get the chance to play them at a suitable
volume anyway. So...I'm very happy for now with the lovely Avantic
(dunno if it's retro, it's younger than me) and would hate to see it up
on ebay just yet. Thanks anyway...

Dave

I have a valve amp and I am clueless
 

In that case, if there is a tap on the OPT to give a load match to 3
ohms, the Rout without NFB will be 1 ohm, and loads below 4ohms nominal
will be tolerated OK.

The impedence of the speakers is around 3 ohms. So as you say you
figure for a low ohm tap on the secondary. I'm getting good sound with
a PPP 6S4A amp with a nominal 8k a-a into 4 ohms, which works out just
about OK. Sounds fine. My brother uses a Nagra VPA 845 PP valve amp,
which sounds great. A friend uses a KT88 amp with feedback. That works
too. All of us have Caliper Sigs, though my friend just upgraded to
Duettas. Drool.


25Watts class AB1 is easy from 300B and if speaker sensitivity is above
88dB/W/M, sound is OK but the higher the sensitivity the better.

Apogees are what, about 85db - something like that.

What's so great about ribbons though?

Have you heard the big Apogees? They're now built down under.
http://www.apogeeacoustics.com/index.html

Are you anywhere near Queensland's "sunshine coast"?

Andy

I have a valve amp and I am clueless
 

In article
,
Andy
Evans wrote:

In that case, if there is a tap on the OPT to give a load match to 3
ohms, the Rout without NFB will be 1 ohm, and loads below 4ohms
nominal will be tolerated OK.

The impedence of the speakers is around 3 ohms. So as you say you figure
for a low ohm tap on the secondary. I'm getting good sound with a PPP
6S4A amp with a nominal 8k a-a into 4 ohms, which works out just about
OK. Sounds fine. My brother uses a Nagra VPA 845 PP valve amp, which
sounds great. A friend uses a KT88 amp with feedback. That works too.
All of us have Caliper Sigs, though my friend just upgraded to Duettas.
Drool.


25Watts class AB1 is easy from 300B and if speaker sensitivity is
above 88dB/W/M, sound is OK but the higher the sensitivity the better.

Apogees are what, about 85db - something like that.

I suspect that may be rather 'optimistic'. :-) If you look at something
like MCs review of the Apogee Caliper in HFN (1986) he reported a 2.86V
sensitivity of just 80dB. Very different to needing 88dB or more! If my
memory isn't playing me false, some other Apogees had even lower
efficiencies and/or impedances.

If you then factor in what Patrick went over (although that wasn't the
actual point of my previous comment which actually took what he
described for granted) you may find an even lower effective sensitivity
for reasons I assume are now obvious! :-)

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

I have a valve amp and I am clueless
 

Andy Evans wrote:

In that case, if there is a tap on the OPT to give a load match to 3
ohms, the Rout without NFB will be 1 ohm, and loads below 4ohms nominal
will be tolerated OK.

The impedence of the speakers is around 3 ohms. So as you say you
figure for a low ohm tap on the secondary. I'm getting good sound with
a PPP 6S4A amp with a nominal 8k a-a into 4 ohms, which works out just
about OK. Sounds fine. My brother uses a Nagra VPA 845 PP valve amp,
which sounds great. A friend uses a KT88 amp with feedback. That works
too. All of us have Caliper Sigs, though my friend just upgraded to
Duettas. Drool.


25Watts class AB1 is easy from 300B and if speaker sensitivity is above
88dB/W/M, sound is OK but the higher the sensitivity the better.

Apogees are what, about 85db - something like that.


With 85dB its getting a bit hard to drive and I'd like to have 50W
available....

What's so great about ribbons though?

Have you heard the big Apogees? They're now built down under.
http://www.apogeeacoustics.com/index.html

I wasn't aware of that.

There is another ribbon company, Ambience on the sth coast NSW.

Are you anywhere near Queensland's "sunshine coast"?

No, I'm in Canberra, 300km sthwest of Sydney.

I prefer really well done dynamic cones and domes.

Patrick Turner.

Andy