Ampeg Amps to Get that ‘50s Jazz Guitar Sound

**Greentone** · 03-06-2019, 01:48 PM

HT,

+1 regarding the B15n and the SVT. They will set you back. I have a B15 and it's going nowhere. My son used to have a SVT. Great amp, but impractical for a variety of reasons--if you don't have a road crew and big bucks for maintenance. He sold it and uses smaller amps.

They sure are collectible though.

FWIW, I think the B12 is the right Portaflex to have, though I don't have one at the present time. (Almost bought yours a couple of years back, though.)

**Hammertone** · 03-06-2019, 02:03 PM

Originally Posted by Greentone

HT,
+1 regarding the B15n and the SVT. They will set you back. I have a B15 and it's going nowhere. My son used to have a SVT. Great amp, but impractical for a variety of reasons--if you don't have a road crew and big bucks for maintenance. He sold it and uses smaller amps.
They sure are collectible though.
FWIW, I think the B12 is the right Portaflex to have, though I don't have one at the present time. (Almost bought yours a couple of years back, though.)

The B12 is great because it's so simple. I'd go for a clean helmethead B12 just to satisfy my helmethead OCD, but I'm not chasing one - too much stuff to clear out first. Variants on the B15N are not worth the same $$$. I much prefer my B-15S - larger, way more power, but no blue Tolex, so they sell for less.

My best-sounding Ampeg guitar amp is my 60 watt, tube rectified '68 B-12XT, in black Tolex. It's not particularly portable for a Portaflex. These aren't cheap (possibly because they are fairly unusual and a bit over-the-top) but they are definitely worth it. Here it is, without the caster dolly on it. Which reminds me, I need a cast Ampeg logo for it.

**Greentone** · 03-06-2019, 03:48 PM

The B-12XT is one of the best Ampegs--heck, best amplifiers--I have ever played.

Still, for simplicity's sake and all-around versatility, I like the B-12sb. It was designed for the upright bass player, but it is a tremendous all-around amplifier. I believe you could amplify anything through it. I used to use it with a Gretsch CA 6120 guitar. The pair sounded tremendous.

The 12" Jensen speaker that came in the amp, IIRC, was just a sweet speaker. As I recall, you offered one for sale a few years back that I was SORELY tempted to buy. Your price was right and the amp was in VERY good condition. I shouldda...

**Hammertone** · 03-07-2019, 04:33 AM

This one.

**Greentone** · 03-07-2019, 07:56 AM

That's the amp. I used to use one for both guitar and bass and still wish I had it.

**powerwagonjohn** · 03-07-2019, 05:18 PM

When I bought my Ampeg Gemini II it sounded good and still had the orig. Jensen Concert speaker. The speaker had been reconed with a heavy ribbed cone unlike the orig. light seamed paper cone. I tried several speakers including a P15N with orig. style cone, JBL D130, alnico Jensen Vibranto, Jensen and CTS ceramic speakers and finally settled on the Altec 418 alnico speaker. It really opened the amp up. Unfortunately, I recently passed on an M-15 because it sounded so close to my Gemini, I don't have room to become an amp collector. Eight amps and 14 guitars is enough, as least that is what I keep telling my self! I think your going to enjoy your old amp!
Thanks John

**rpjazzguitar** · 03-07-2019, 05:35 PM

Many years ago, I blew out the original speaker in my 64 Reverberocket.

I can no longer recall how I picked the replacement. It may have been at random. It's a Celestion G12 L 35. Sounds great.

**SandChannel** · 03-08-2019, 12:38 PM

Originally Posted by powerwagonjohn

I don't have room to become an amp collector. Eight amps and 14 guitars is enough, as least that is what I keep telling my self!

Pssst. You are an amp collector!

**Herbie** · 03-08-2019, 01:40 PM

If JS plugged straight into the console there was a plenty of tubes warming the sound before the tape. The first solid state recording console didn’t came until Beatles’ Abbey Road in 1969.

**Bill Eisele** · 03-09-2019, 02:24 AM

Hi All,

Just to let you know, the Ampeg M-15, “Big M”, arrived today (photos below, but wish I could figure out how to rotate them). Everything appears to be operational. There is some noise at higher volume levels that might be tube rattle or perhaps a speaker or cabinet issue. It looks like five out of the six tubes are Ampeg branded tubes so I’m assuming they might be original to the amp. The tolex is in very good, almost new condition in places , so I’m assuming it was recovered at some point. The Ampeg logo is missing which further indicates the tolex isn’t original. As previously mentioned, the speaker is a JBL D-140F and isn’t original to the amp. According to the book, “Ampeg, The Story Behind the Sound,” the original speaker for this amp was a Jensen P15N with variations including the Jensen C15N and the JBL D-130F.

I’m still sorting out the tone, but my first impressions are that it is neutral and clean sounding with a slight bias towards the warm end of the tonal spectrum. I’m not getting a good sense of the tone at higher volume levels due to the noise issue. And, the missing piece of that 50’s sound still not in the house is a single coil pickup. I will have a friend bring over one of his archtop guitars with a single coil pickup to see how that sounds.

I will take the amp to a tech to have him check it out for the noise issue, and to install a power cord with a three prong plug to properly ground the chassis. I will probably have the tech retube the amp even if the tubes aren’t the source of the noise issue. And, I might try a new Jensen P15N speaker in lieu of the JBL D-140F. And the casters are just sitting in holes in the floor of the cabinet so I might glue in wood blocks in the bottom of the cabinet corners and install proper casters attached with wood screws.

If there’s anything else I should consider doing to the amp, please let me know.

Thanks,

Bill

**rpjazzguitar** · 03-09-2019, 02:34 AM

Congrats on the new amp.

In my old Reverberocket I had a noise problem. It was intermittent and took a long time to diagnose. It turned out to be the connector to the reverb tank. It was pushed all the way in, but the little wings on the connector weren't making good contact.

The thing about these amps that might be helpful to consider is that they are built like tanks. When you have a noise problem I'd suggest checking every non-original thing in the amp. Wiggle the speaker wires. Tap the tubes gently. Stuff like that.

**Hammertone** · 03-09-2019, 04:32 AM

Originally Posted by Bill Eisele

...The tolex is in very good, almost new condition in places , so I’m assuming it was recovered at some point. The Ampeg logo is missing which further indicates the tolex isn’t original...

Could be original. Check for tiny holes in the front where the cast logo would go.

Originally Posted by Bill Eisele

... And the casters are just sitting in holes in the floor of the cabinet so I might glue in wood blocks in the bottom of the cabinet corners and install proper casters attached with wood screws.

Consider a metal pop-in caster assembly if it will fit - these work really well. Something like this:
Amazon.com - Fender Pop-in Amplifier Casters 4-pack - Instrument Amplifier Stands

Originally Posted by Bill Eisele

If there’s anything else I should consider doing to the amp, please let me know.

Jumper the channels, so you can adjust the sound using both sets of volume/tone controls. This gives you much more tonal flexibility.

**Bill Eisele** · 03-09-2019, 06:21 PM

Originally Posted by rpjazzguitar

Congrats on the new amp.

In my old Reverberocket I had a noise problem. It was intermittent and took a long time to diagnose. It turned out to be the connector to the reverb tank. It was pushed all the way in, but the little wings on the connector weren't making good contact.

The thing about these amps that might be helpful to consider is that they are built like tanks. When you have a noise problem I'd suggest checking every non-original thing in the amp. Wiggle the speaker wires. Tap the tubes gently. Stuff like that.

Thanks!

Also, appreciate the troubleshooting tips. Will have a go at it.

**Bill Eisele** · 03-09-2019, 06:29 PM

Originally Posted by Hammertone

Could be original. Check for tiny holes in the front where the cast logo would go.

Consider a metal pop-in caster assembly if it will fit - these work really well. Something like this:
Amazon.com - Fender Pop-in Amplifier Casters 4-pack - Instrument Amplifier Stands

Jumper the channels, so you can adjust the sound using both sets of volume/tone controls. This gives you much more tonal flexibility.

Thanks for the information and ideas, Hammertone! I actually did find a couple tiny holes on the front area where the logo would go. Didn’t see them at first because they are so small and blend into the pattern. I have a replica cast logo on the way from Fliptops. And, a set of casters like you suggested are on the way. I will ask the amp tech to jumper the channels when I take the amp in for its service.

**wzpgsr** · 03-09-2019, 07:22 PM

If you don’t keep the original Ampeg-branded tubes you might be surprised how much you can sell them for.

**wzpgsr** · 03-09-2019, 07:27 PM

Originally Posted by Bill Eisele

Thanks for the information and ideas, Hammertone! I actually did find a couple tiny holes on the front area where the logo would go. Didn’t see them at first because they are so small and blend into the pattern. I have a replica cast logo on the way from Fliptops. And, a set of casters like you suggested are on the way. I will ask the amp tech to jumper the channels when I take the amp in for its service.

The tech doesn’t need to jumper them for you. You just use a guitar cable to connect, say, accordion 1 to accordion 2 while your guitar is plugged in to guitar 1.

**Bill Eisele** · 03-10-2019, 01:09 AM

Originally Posted by wzpgsr

If you don’t keep the original Ampeg-branded tubes you might be surprised how much you can sell them for.

I’m planning on keeping the original tubes but I’m curious as to what they go for. They are 6L6s, 6SL7s, and a
5U4. The 6L6s and the 5U4 were made by RCA and the 6SL7s were made by Sylvania for Ampeg. I haven’t found an Ampeg label on the 6L6s and 5U4 yet as I haven’t pulled the tubes.

**Bill Eisele** · 03-10-2019, 01:11 AM

Originally Posted by wzpgsr

The tech doesn’t need to jumper them for you. You just use a guitar cable to connect, say, accordion 1 to accordion 2 while your guitar is plugged in to guitar 1.

Thanks for the clarification. It was only two weeks ago when I saw someone doing the same thing on a vintage amp. My memory isn’t what it used to be!

**Greentone** · 03-11-2019, 08:06 PM

Bill,

Great amp! Looks to be in "kept in the closet" condition, to me. Just a super amplifier, as I am sure you will soon see/hear.

GT

**Bill Eisele** · 03-11-2019, 10:36 PM

Originally Posted by Greentone

Bill,

Great amp! Looks to be in "kept in the closet" condition, to me. Just a super amplifier, as I am sure you will soon see/hear.

GT

It is a great amp. On closer inspection, you can tell that it’s seen some service, but is in great condition for its age. Had a friend over this afternoon who’s a guitarist and amp guy and he loves the amp. He’s telling me to sell my Rivera Jazz Suprema 55-12 because it doesn’t compare in terms of the vintage tone that I’ve been looking for. And, the Rivera is a great amp, but has a more modern sound.

The Ampeg M-15 is as close as I think I can get to the tone I’ve been looking for. I believe it’s primarily due to the octal tube preamp section and the Ampeg tone stack. It has a rich lushness that I haven’t found before.

I think I will pull the chassis and ship it to Vintage Amp Restoration for a check up. There’s some noise in channel one and I want to have a three prong plug power cord installed to ensure a proper ground for safety purposes.

And a shout-out out to Hammertone for suggesting the M-15!

**Bill Eisele** · 03-15-2019, 08:21 PM

I got around to cleaning up the amp cabinet, installing new casters, and pulling the JBL D140F and installing the Jensen P15N. As it turns out the JBL D140F was reconed and turned into a JBL D130F. The new cone doesn’t have the concentric rings. So, the speaker was turned from a bass speaker to a guitar speaker. I still need to have the amp checked out and a grounded power cord installed.

There is one black and one yellow wire coming from the amp chassis and connected to the D140F terminals. The black wire was connected to the positive terminal and the yellow wire was connected to the negative terminal. This appears to go against common convention where the black wire is the negative side. It’s possible that the speaker was wired out of phase. Does anyone know which what color corresponds to positive and negative for this amp?

Thanks,

Bill

**Hammertone** · 03-15-2019, 08:35 PM

Bill:
With only one speaker, it makes no difference.
Phase is only relevant when it relates to another speaker.

**Bill Eisele** · 03-15-2019, 08:55 PM

Thanks, Hammertone. I’ve heard that some people claim they are sensitive to phase. This is a popular topic that comes up in audiophile discussions. My guess is that the black wire is negative so I will wire it up that way.

**Hammertone** · 03-15-2019, 11:14 PM

Originally Posted by Bill Eisele

Thanks, Hammertone. I’ve heard that some people claim they are sensitive to phase. This is a popular topic that comes up in audiophile discussions. My guess is that the black wire is negative so I will wire it up that way.

I'm no audiophile, I swear, I never touched that knob!