Help with tube compliment of Alamo Amp 6A

Tubefever · Newbie Alert Joined: 22 May 2003 Posts: 2

I recently picked up an old tubeless chassis from an Alamo guitar amp, Model 6A. Can anyone tell me the original tube compliment for this amp? It has sockets for a rectifier (octal), 3 9-pins and 3 octal tubes. One of the octal tubes was a 6SQ7. I'm particularly interested in the output tubes.

TIA

TimC · Posted: Sun May 25, 2003 12:54 am Post subject:

Welcome to the forum tubefever. Do you know the model name of your Alamo amp chassis? It would seem Alamo schematics are hard to come by. On a google search, I found the tube compliment for a Titan, but that dosen't sound like yours. Sounds like maybe the 6SQ7 powers the tremolo.

TimC · Posted: Sun May 25, 2003 4:13 pm Post subject:

If your feeling gutsy tubefever, put a 5AR4 in the isolated octal that the power supply transformer wires connect to. The two octals that are wired the same, stick in some 6L6's. The 6SQ7 goes in the remaining octal. 12AX7's in all the mini's. Connect an 8 ohm speaker. Hit the switch and run like hell. Laughing

Tubefever · Newbie Alert Joined: 22 May 2003 Posts: 2

Thanks for the ideas. From what I've been able to discover, the early Alamo amps (50s and 60s) were named according to the number of tubes they had (so there were Model 3s, Model 4s, Model 5s) This amp is a Model 6A. (Later amps had names like Fury and TItan.)

The 2 output tubes use a common cathode resistor of 220 ohms--makes me think it may have used 6V6s. But the power transformer and the choke look big enough for 6L6s. Any other thoughts?

TimC · Posted: Tue May 27, 2003 8:03 am Post subject:

Examine the tube sockets to see if the wiring matches known pin-out for 6l6/6v6's. Install a 1 amp fast-blo and one at a time, starting with the rectifier tube, try a tube you think will work. There were some odd-ball tubes used in the 50's. Maybe someone here at the forum can help. It might be best to wait awhile and see.

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

I'm new here. Not sure you still need this info but....
I've got an almost mint 52 Amp-6a with an original cover!. It still has the tube chart stapled in the bottom! It's the second one I've had. The first was a 1955 model, I'd sold it in 03. It was soo cool looking I watched eBay for them until one finally popped up. 2 months later the cover surfaced having been seperated from it's 1950 Amp-6.
You're right about the model # revealing the tube compliment. I've yet to see an Amp 4 but I've seen a couple 5's & 6's and a pile of Amp-3's. The Amp 5 has 2 - 6V6's and a 12" Jensen speaker. 6 and 6a had the 15" Jensen. The "a'" in 6a means it has Tremolo.

The tubes left to right are
12AX7 - 12AX7 - 6SL7 - 6L6GA - 6L6GA - 12AX7 - 5U4G

I've subbed 12AU7's in the first 2 holes and they sound good. I also use a glass 6SL7GT instead of the metal one. Tung Sol 5881's for power and a 5AR4 rectifier. The amp is very similar to a TV Pro except in 52 the Fender used metal 6SC7's.

Not a big amp by todays standards but in 1952 it was probably the pride and joy of it's owner. I can easily picture Easy Adams and his band picking out Bandera Waltz on stage at the Caberet Club in Bandera, just west of San Antonio, on any given Saturday night in 1952 with a back line of Amp-6's and Amp 5's and a full dance floor!

TimC · Posted: Tue Aug 21, 2007 5:36 pm Post subject:

Thanks for the help Bigsbyguy, and wecome to the forum.

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

Tim, No Problem, I just noticed you got the chassis only. I'll add some jpgs to the end of this post.
Tube amps are my weakness. Especially the bigger Pro models from the 50's. I prefer Fenders but I'm partial to several models built by the other builders of the era. I play non pedal steel and prefer top 40. Music that was tops in the 40's! Wink

I was informed that I can't post jpgs until I've had 10 posts. After I get there I'll come back and post the pics.

TimC · Posted: Wed Aug 22, 2007 10:32 am Post subject:

Congratulations on scoring that Alamo off ebay. I've given up looking around for old tube amps. They are about all gone or trashed to a condition I don't want to put in the time and money trying to bring them back. I have no experience with buying off ebay. I've heard both good and bad. I'd have a hard time buying an amp that I couldn't try out first.

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

Tim I've bought and sold alot of stuff on eBay. Gotten some great deals and found some really rare stuff, like a cover for an Amp-6! I've only been ripped once and only had a couple deals that were headaches.

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

I have some rules I use there, like if I buy a speaker I always assume it'll need reconing and bid accordingly. I try and walk the seller thru packing if they aren't familiar with shipping gear.

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

I live out in the sticks and I buy just about everything online. It's easier and for me to go to a Home Depot is about 55 miles each way. If I want a Target or a Big 5 say I gotta go 160 miles roundtrip!

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

I've found several amps that have been great deals. I sold my first Amp-6a there for 750 with the Buy it Now option and I scooped the one I got now for 500. The cover was $25 bucks.

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

I'm actually more bummed with eBay. I first sold there in 99 and back then all it cost was the listing fee. Now they have that charge as well as a "final value" fee. That's a percentage of what you sold it for. Then if you wnat to take a Credit Card via Pay Pal, which eBay owns, theres'a fee for that too! When I sell anything over $1000 I don't take Pay Pal but I offer to take personal checks instead. After they clear the item gets shipped.

Bigsbyguy · Tadpole Joined: 21 Aug 2007 Posts: 23 Location: NM

My opinion is that eBAy is a GREAT place to buy but not sell. One other thing that bugs me is when the sellers over inflate the shipping costs. Nothing burns me then to pay 20 for shiupping and when the pkg get here the sticker sayd 6.50 or something!
Ok so I reached 10 posts. Now I gotta wait 7 days Sad

Are you familiar with deciphering Pot codes? That'll help determine the year of your Alamo