Lafayette LA-55 old pa tube amp - techs step in please

[tweed]

Someone at work had one of these laying around in great shape and just gave it to me. I think its 15 watts? I have no idea if I can turn it into anything cool or not, but it looks like it would be a nice little project to tinker with.

Anyone have any more history on these units or if they are worth modding?

 

[tweed]

Just opened her up here at work.

Tubes
2x 6bq5
1x 6bl8
1x 6ca4
1x 12ax7 (Matsushita T with a circle on it)
1x 6av6

Seems to be in great shape. Looks like all original tubes and parts. Nothing looks warped or blown inside.

 

[tweed]

bump for the nightowl amp guru's

 

[blackba]

I have heard of the brand, and seen a Lafayette stereo receiver, which sounded pretty good. I don't know anything about this model though....

 

[Nigel Tufnel]

I'm not familiar with that exact amp but I'm pretty sure it could be made into something cool, if you posted some pics of it I could get a better idea. The first things that come to mind would be a Vox ac-15, Marshall 18w, or a lower powered Trainwreck rocket or liverpool. Of couse it would just be an adaptation but you could use one of those amps as a basis. You'd be keeping the output tubes and maybe the rectifier tube depending on what kind of filtering you want to do and then add 12ax7's in place of some of the oddballs. But it might be cool as hell with just some 1/4" jacks on the input and output, some of those old pa's sond real cool with a guitar plugged in.

 

[tweed]

Ill try and get some shots of it next week. It's been pouring rain everyday when I leave work, didn't want to try and get it to my truck in the rain.

Here is a webpage that has a few shots of it.

http://www.radiomuseum.org/r/lafayette_la_55la5.html

 

[1big1]

lafayette used to be a mail order electronics supplier back in the day.. 50's..60's and 70's.. along the lines of heathkit. they sold parts.. diy stuff.. mics.. replacement speakers.. etc.
i may have some of those tubes laying around.. should you ever need them.

 

[MOAAH]

Some old type PAs make great guitar amps. I have a bunch. Some examples...
My late 40s Electrohome, converted preamp to Ampeg V4:

My super Bogens(100 watts each) Standard poweramps:

Strongly suggest to just keep the power supply, power amp and PI/driver stages stock, and then just change out the preamp to some vintage design. I have a link somehwere on converting old PAs -> guitar amps. I'll see if I can find it...

 

[MOAAH]

http://www.geofex.com/Article_Folders/old2new.htm
Wow, it's still there after all these years. Great link, hope you enjoy

 

[tweed]

http://www.geofex.com/Article_Folders/old2new.htm
Wow, it's still there after all these years. Great link, hope you enjoy

Thanks for the link!!!

Now I just gotta find time to dig into this amp. It's still at work under my desk

 

[MOAAH]

Just opened her up here at work.

Tubes
2x 6bq5
1x 6bl8
1x 6ca4
1x 12ax7 (Matsushita T with a circle on it)
1x 6av6

Seems to be in great shape. Looks like all original tubes and parts. Nothing looks warped or blown inside.

BTW, 6BQ5 is the American designation for EL84.
&
6BL8 makes a great PI/driver and fairly easy to find. So, no need to change that.

http://www.geofex.com/Article_Folders/old2new.htm
Wow, it's still there after all these years. Great link, hope you enjoy

Thanks for the link!!!

Now I just gotta find time to dig into this amp. It's still at work under my desk

Glad you like Take your time, that last thing you want to do is rush anything.

You should be able to track down the schematic which would be very helpful if you want to mod the input.

Just let me know if you want any help, with any part of it

 

[tweed]

You should be able to track down the schematic which would be very helpful if you want to mod the input.

Just let me know if you want any help, with any part of it

Thanks! sent you a PM.

 

[MOAAH]

lafayette used to be a mail order electronics supplier back in the day.. 50's..60's and 70's.. along the lines of heathkit. they sold parts.. diy stuff.. mics.. replacement speakers.. etc.

"Name: Lafayette Radio Corp; New York (NY) (USA)
Founded: 1920
History: Lafayette Radio Electronics Catalogs were well known in the 40's - for instance the 1949 Lafayette Concord Radio Catalog when they had 3 mail orcer centers (Chicago, New York and Atlanta). According to the catalogue of 1973 they started at the beginning of the 20's to sale via catalogs. Most of Lafayette's models were not the best performers nor were they the worst performers.

Products ranged from tranceivers for Hams and CBers, and shortwave listeners to normal stereo gear - as can be seen on the front page of "1955 Lafayette Radio Electronics Catalog". Then they claimed to be: "The worlds greatest radio, TV and Hi-Fi center" (Catalog 10-55). They marketed many types with special functions, such as VHF receivers for police and fire channels built into a CB radio - but also already in 1955 "Transistor Parts". A complete model line included many models and brand names to choose from for just about any purpose, as opposed to just a few. The product line also covered other manufacturers' products through seasonal catalogs. The company's best selling products were often shortwave receivers, parts, and portable radios. In the 1960s, most Lafayette brand radios were rebranded Trio-Kenwood sets, which were of moderate performance and build quality.

The downfall of LaFayette Radio began in the early 1970s, following the poor choice to invest in 23-channel CB radios, rather than the 40-channel CB radios approved by the FCC. With less than 100 stores, far fewer than the aggressively expanding Radio Shack's thousands of local outlets, Lafayette Radio remained more of a dedicated enthusiasts' store than a mass marketer.

The banned 23 channel CB radios became illegal for sale, resulting in unsold stock in the company's warehouses. The next blow to the company was the upcoming of electronics retailers relying on aggressive marketing techniques and competitive pricing in the late 1970s. Formerly a national chain, the remaining Lafayette stores in the state of New York closed by the end of 1979. Some local Lafayette stores remained open until 1981. For example, the Long Branch, New Jersey store finally closed in the Fall of 1981. Unsold inventory was literally shovelled into dumpsters overnight to vacate the store."
Quote from:
http://www.radiomuseum.org/dsp_herstell ... any_id=734

 

[MOAAH]

You should be able to track down the schematic which would be very helpful if you want to mod the input.

Just let me know if you want any help, with any part of it

Thanks! sent you a PM.

Cool on the PM.

First, lets see if we can find a free schematic. Or, haha, if you're feeling rich, just pay for one

With the original schematic I can draw you up a new one, just changing out the preamp with the new mod. For a clean small amp, either vintage Ampeg or Fender preamps are great. The Fender being the easiest, but the Ampeg used hifi tone controls which may match up with what you have already.

And when you can, post a clear close up of the guts.

And FWIW, it is prolly(well no, definitely!) best to get the amp working stock before starting to cut it up. Just give it a test run first. Report back with any bad hum, motor boating and the like.

Talk soon and take care,

R.

 

[tweed]

Haven't had time to plug her in yet, but I did get some pics

oustide

 

[tweed]

inside

 

[tweed]

I have more, but that should just about do it I think...

 

[1big1]

thanks for the info on lafayette. i thought after i had posted that they were more like radio scrap than heathkit.

 

[MOAAH]

thanks for the info on lafayette. i thought after i had posted that they were more like radio scrap than heathkit.

You are most welcome.
FWIW, Radio Shack was the shit, after WW2. Many of the radio techs we trained to beat the Nazis later went on to produce and promote HiFi and HAM stuff. IMO, RS was pretty dang good up until the early 70s. Then, like a lot of great American initiatives, they started out sourcing and went to poo shortly after. I wonder if they still honor the life time warranty of the gold pin tubes they produced back in the day

 

[MOAAH]

I have more, but that should just about do it I think...

Good stuff! Hot dang, look at that, real PTP wiring. The unit looks in very good shape, may want to keep it as stock looking as possible, but that's your call.

When you plug it in really keep a close eye on your OP tubes! Those old oil caps have a habit of leaking after all these years, so keep looking for red plates.

One of my first stereos was a Nytone, with all the same make of parts inside. Besides scratchy pots(spray cleaner, not from RS, LOL) the only big prob was the coupling(AKA blocking) caps connecting the Driver/PI to the OP tubes.

Also listen for any excessive hum or what is called motorboating(put put put).

You won't need an input signal for the first test. If there is no funny noises or the plate seem fine after 20 minutes or so, try hooking up a CD to the AUX in. If there is no terrible distortion(not from diming it) then you are ready to go to the next step.

I searched a bit for a free schematic, no luck yet but I try some more. I guess it's only $20 to buy one. Maybe the way to go, what ya think?

Sometimes, but not always, you can get a decent sound just plugging a guitar strait into the mic input. Try that last, if all the early tests go well.

Let me know how stuff goes, &

I'll be back