tubes, tubes and... tubes / HELP!

[John]

Hey Guys,
I own a Ampeg B1 combo (see posting 6 september) and I am about to change
the tubes. This is the first time I've ever done this.... so please help me
out.

When I open up the amp itself, the 2 tubes in it feature:
"hot rods slm electronics / 95-134-01 made in yugoslavia"

The manual says:
TUBE COMPLIMENT: 12AX7 (3)
(funny thing about the 3, it only has 2 tubes in it!!)

When I do a google on "hot rods slm electronics / 95-134-01 made in
yugoslavia" nothing appears. When I google on 12AX7, the listings are long..

Now, as a bassplayer, and so are you, what kind of tubes should I buy??
I really want the authentic Ampeg sound, and no crap from Mesa Boogie or so
;)

Thanks for the help.
John

[Todd H.]

Post by John
Hey Guys,
I own a Ampeg B1 combo (see posting 6 september) and I am about to change
the tubes. This is the first time I've ever done this.... so please help me
out.
"hot rods slm electronics / 95-134-01 made in yugoslavia"
TUBE COMPLIMENT: 12AX7 (3)
(funny thing about the 3, it only has 2 tubes in it!!)

Any 12AX7 will do, and the ampeg sound has more to do with the design
tan with individual tubes. Boogie tubes are pretty decent. Groove
Tubes are the monster cable of tubes, from what I've heard from
folks.

Tube manufacturers are a subject of much religious debate in the
alt.guitar.amps group. How much heat vs light is in those debates,
it's hard to say.

Anything new is likely to be an eye openeing improvement over what you
have!

[John]

Post by Todd H.
Any 12AX7 will do, and the ampeg sound has more to do with the design
tan with individual tubes. Boogie tubes are pretty decent. Groove
Tubes are the monster cable of tubes, from what I've heard from
folks.
Tube manufacturers are a subject of much religious debate in the
alt.guitar.amps group. How much heat vs light is in those debates,
it's hard to say.
Anything new is likely to be an eye openeing improvement over what you
have!
--
/"\ ASCII Ribbon Campaign | Todd H
\ / | http://www.toddh.net/
X Promoting good netiquette | http://triplethreatband.com/
/ \ http://www.toddh.net/netiquette/ | "4 lines suffice."

Thank you Todd.
I did a review search and the Electro Harmonix 12AX7 tubes are most
recommended for Ampeg.
In deed, a subject of deepest religious debates.... because another says the
JJ's are better.

John.

[John Shaughnessy]

Just wait untill you have to change your power tubes...
--
Learning funk bass? visit www.js3jazz.com/store.htm
Conservatives are not necessarily stupid,
but most stupid people are conservatives."
- John Stuart Mill

Post by John

Post by Todd H.
Any 12AX7 will do, and the ampeg sound has more to do with the design
tan with individual tubes. Boogie tubes are pretty decent. Groove
Tubes are the monster cable of tubes, from what I've heard from
folks.
Tube manufacturers are a subject of much religious debate in the
alt.guitar.amps group. How much heat vs light is in those debates,
it's hard to say.
Anything new is likely to be an eye openeing improvement over what you
have!
--
/"\ ASCII Ribbon Campaign | Todd H
\ / | http://www.toddh.net/
X Promoting good netiquette |

http://triplethreatband.com/

Post by John

Post by Todd H.
/ \ http://www.toddh.net/netiquette/ | "4 lines suffice."

Thank you Todd.
I did a review search and the Electro Harmonix 12AX7 tubes are most
recommended for Ampeg.
In deed, a subject of deepest religious debates.... because another says the
JJ's are better.
John.

[RB]

Post by John Shaughnessy
Just wait untill you have to change your power tubes...

I think this a hybrid amp, so SS output. worse than changing tubes,
potentially....

[RB]

Post by John
"hot rods slm electronics / 95-134-01 made in yugoslavia"
TUBE COMPLIMENT: 12AX7 (3)

Hi John,

I don't see a B1 on the Ampeg site, so can't get a schematic for you,
but I would say that the writing you describe is on the tubes, and there
are two 12AX7's, right? As far as there being 3... unless you see an
empty tube socket, this must be a typo.

Others here could provide good advice on replacement brands...

[Larry Shaw]

http://www.radio-electronics.com/info/data/valve/tube_equivalents/tube_equivalents.php

That's a link to a tube equivelent look-up table may be of some use !

Post by RB

Post by John
"hot rods slm electronics / 95-134-01 made in yugoslavia"
TUBE COMPLIMENT: 12AX7 (3)

Hi John,
I don't see a B1 on the Ampeg site, so can't get a schematic for you,
but I would say that the writing you describe is on the tubes, and there
are two 12AX7's, right? As far as there being 3... unless you see an
empty tube socket, this must be a typo.
Others here could provide good advice on replacement brands...

[John]

Post by RB
Hi John,
I don't see a B1 on the Ampeg site, so can't get a schematic for you,
but I would say that the writing you describe is on the tubes, and there
are two 12AX7's, right? As far as there being 3... unless you see an
empty tube socket, this must be a typo.
Others here could provide good advice on replacement brands...

Hi There,
The B1 was discontinued... to bad, because it's a great amp!
There are still some out there,
http://www.google.nl/search?hl=nl&q=%22Ampeg+B-1+combo%22&meta=
http://www.google.nl/search?hl=nl&q=%22Ampeg+B1+combo%22&meta=

Recommend them to all session players who use Ampeg.
The portabass series are also great.... little to expensive for hobby work
;)

[Nigel Goodwin]

Post by John
Hey Guys,
I own a Ampeg B1 combo (see posting 6 september) and I am about to change
the tubes. This is the first time I've ever done this.... so please help me
out.
"hot rods slm electronics / 95-134-01 made in yugoslavia"
TUBE COMPLIMENT: 12AX7 (3)
(funny thing about the 3, it only has 2 tubes in it!!)
When I do a google on "hot rods slm electronics / 95-134-01 made in
yugoslavia" nothing appears. When I google on 12AX7, the listings are long..
Now, as a bassplayer, and so are you, what kind of tubes should I buy??
I really want the authentic Ampeg sound, and no crap from Mesa Boogie or so

It's just a bog standard double triode, you shouldn't notice any
difference between different makes!.

Why are you changing them anyway?, are they faulty?, if so just change
the faulty one!.

12AX7's (and other double triodes only very rarely go faulty), it seems
totally pointless changing a good working valve/tube for an unknown
quality one!. There's been no decent quality valves/tubes made for
something like 30 years! - they are all total crap compared to back
then, they just charge you stupid money for them!.

[John]

Post by Nigel Goodwin
It's just a bog standard double triode, you shouldn't notice any
difference between different makes!.
Why are you changing them anyway?, are they faulty?, if so just change the
faulty one!.
12AX7's (and other double triodes only very rarely go faulty), it seems
totally pointless changing a good working valve/tube for an unknown
quality one!. There's been no decent quality valves/tubes made for
something like 30 years! - they are all total crap compared to back then,
they just charge you stupid money for them!.
--
Nigel.
/------------------------------------------------------------\
| Lower Pilsley | Website : http://www.lpilsley.co.uk |
| Chesterfield | Homepage for WinPicProg |
| England | http://www.winpicprog.co.uk |
\------------------------------------------------------------/

Because:
I've an Ampeg B1 combo, served me well last couple of years on small
sessions. Just got back from abroad, I turn it on, no or just bad sound
coming from it. After a couple of mins., when I fully open the gain and
master I hear this 'dead' bass tone, a little bit groaning.....

so the first thing I came up with, is replacing Tubes.
the combo is nearly 10 yrs old I think, and it was a second hand used very
heavy over the last couple of years!!

I found a review of it online, and its true ;) here it is:

I use an AMPEG B-1 (combo amp, now obsolete). Although an expensive amp when
new (over $900.00 retail), I got mine at a music store close-out for $200.00
(new w/warrenty). This little wonder has got to be the Mesa Boogie of bass
amps! Weighing in around 65 lbs, this box is ready to gig! Transport options
include two Sessions handles on the sides, a top padded strap, and pop-out
casters. A perforated metal grill protects the front ported cast-frame 12"
Eminence speaker and Fostex horn (both units have filter/attenuator
selections on back of amp, as well as a bypassable comp/limiter for
transient protection), standard black Tolex and chrome metal corners wrap-up
the rest of the amp.

The amplifier itself is a single rack space B-1R unit (also obsolete) with a
2-tube pre-amp (all literature incorrectly states it has 3-tubes) with a
foot-switchable "Solo" (i.e. "Lead Boost") gain stage. A Mos-FET power-amp
section w/ torrordial transformer yields a whopping good sounding 150 Watts
RMS! FX Loop, Pre-amp In/Out, and excellent sounding DI (especially in the
post EQ mode) makes connecting this amp to any outboard processing and/or PA
system a breeze!

Although I would have to state it as THE BEST SOUNDING bass amp for a
grab-and-go gig, it will lack a bit of bottom-end when in loud rock band
situations. However, the chances are you will be plugged into a PA system
with sub-woofers so you can bring up these deep lows in the mix, otherwise
an extension cabinet may be necessary.
http://www.vintageguitar.com/bulletin_boards/details.asp?forumID=22&topicID=911


Regards
John, bedtime over here.....

[RB]

Ampeg B-1

I recognize it now, and I recall playing through one a few yrs back --
good sounding rig)

This little wonder has got to be the Mesa Boogie of bass
amps!

Not to dis the B-1, but that's a bit of a misnomer. I'd say the "Mesa
Boogie of Bass amps" would be this one:

http://www.mesaboogie.com/Product_Info/Bass_Amps/walkabout/WalkaboutScout
/WalkScout.htm


As far as your amp problem, John, I'd echo other posts in that it's not
necessarily the pre-amp tubes. Is there some way you can swap out (one
at a time) the 12AX7's, before buying same? That way you'll know if
the problem lies elsewhere....

Good luck with it!

[John]

Post by RB

Ampeg B-1

I recognize it now, and I recall playing through one a few yrs back --
good sounding rig)

This little wonder has got to be the Mesa Boogie of bass
amps!

Not to dis the B-1, but that's a bit of a misnomer. I'd say the "Mesa
http://www.mesaboogie.com/Product_Info/Bass_Amps/walkabout/WalkaboutScout
/WalkScout.htm
As far as your amp problem, John, I'd echo other posts in that it's not
necessarily the pre-amp tubes. Is there some way you can swap out (one
at a time) the 12AX7's, before buying same? That way you'll know if
the problem lies elsewhere....
Good luck with it!

You mean I can remove both tubes and then play through the amp? Will I not
blow things up??
I thought of testing that as well, but I am not shure I can remove the tubes
and then turn the amp one?!

John

[RB]

Post by John
You mean I can remove both tubes and then play through the amp? Will I not
blow things up??

I don't think the amp would blow up, likely it just wouldn't work (but
don't do it anyway)

No - by "swap out" I meant literally, trade them (one at a time) for a
tube you know is good. The 12AX7 is a very common pre-amp tube, so
perhaps you have another musician friend who can help you? If not,
maybe you know a reasonable shop that would allow you to do this
experiment BEFORE you pay a shop minimum to put the amp on the bench and
troubleshoot it....

I'm not sure but I assume the reason there are two pre-amp tubes is
because you have some sort of channel switching ability on the amp.
Have you tried running separate channels? If so, and the problem is
there no matter which channel you're going through, then either BOTH
tubes are bad (very unlikely) or the problem lies elsewhere in the amp's
circuitry.

[Nigel Goodwin]

Post by John
I've an Ampeg B1 combo, served me well last couple of years on small
sessions. Just got back from abroad, I turn it on, no or just bad sound
coming from it. After a couple of mins., when I fully open the gain and
master I hear this 'dead' bass tone, a little bit groaning.....
so the first thing I came up with, is replacing Tubes.
the combo is nearly 10 yrs old I think, and it was a second hand used very
heavy over the last couple of years!!

There's always a chance it 'could' be the valves?, but I would have
thought it's not very likely.

Does it have two inputs?, often one valve is used for each input, so try
using the other input, or swap the valves round.

As I mentioned before, it's rare for these valves to fail.

[John]

Post by Nigel Goodwin
There's always a chance it 'could' be the valves?, but I would have
thought it's not very likely.
Does it have two inputs?, often one valve is used for each input, so try
using the other input, or swap the valves round.
As I mentioned before, it's rare for these valves to fail.
--
Nigel.
/------------------------------------------------------------\
| Lower Pilsley | Website : http://www.lpilsley.co.uk |
| Chesterfield | Homepage for WinPicProg |
| England | http://www.winpicprog.co.uk |
\------------------------------------------------------------/

Well..... Now it's getting stranger.... When I connect the balanced out to
my mixing console, it has the sound I always hear!!
But when I connect the speaker output to the combo's speaker input, it's
dead for 80%..... You hear this groaming, very low volume crappy sound....
And the speaker cab itself is new.... So.... what do you think? Speaker
connections.....??

[Nigel Goodwin]

Post by John
Well..... Now it's getting stranger.... When I connect the balanced out to
my mixing console, it has the sound I always hear!!
But when I connect the speaker output to the combo's speaker input, it's
dead for 80%..... You hear this groaming, very low volume crappy sound....
And the speaker cab itself is new.... So.... what do you think? Speaker
connections.....??

Presumably the balanced output is from the preamp only?, so it sounds
like it may be the power amp at fault!.

[RB]

Post by John
So.... what do you think? Speaker
connections.....??

Or... possibly output transistors or other amp circuitry failure. The
fact that the line-out functions means that's it's not the pre-amp
causing the weirdness (so the tubes are off the hook)