6v6 for 50-something Alamo

[Lonely Raven]

I'm expecting an Alamo Model 3 delivered to me in a few days, and I'm researching tubes for the old girl.

I *think* it's a single 6SL7 and 6v6, I'm not sure of the rectifier tube though. The previous owner didn't have much to say about it except that it's working, and it's a little noisy. Judging from the photos, it doesn't look like it's been opened/serviced in 50+ years.

http://www.thegearpage.net/board/showth ... ight=alamo

Any suggestions on a NOS tube compliment for this amp? I'll play what it has if they are good, but I always have a spare set of tubes for every amp I have...plus it's fun to learn a little bit about tubes that aren't mainstream anymore.

Suggestions? Thoughts?

[Andy Le Blanc]

I had an Alamo go across my bench for repairs a few years back
It had Sylvania's..... I cant say that they were original.....
but they were the right age... you will want NOS for a 6sl7
the new are ok but.......
that amp also had a blown power transformer.... so go easy on yours
it also had issues with its coupling capacitors.... so if it starts to go blatt
check the caps.....,

[Lonely Raven]

I had an Alamo go across my bench for repairs a few years back
It had Sylvania's..... I cant say that they were original.....
but they were the right age... you will want NOS for a 6sl7
the new are ok but.......
that amp also had a blown power transformer.... so go easy on yours
it also had issues with its coupling capacitors.... so if it starts to go blatt
check the caps.....,

Thanks Andy.

I figure I'll play it for a bit, but I'm assuming the E-caps are toast at this stage. I want to do as little to it as possible as I'm afraid I'll change the tone. I've had a few early 60's vintage amps that I simply changed the E-caps on, making sure voltages were according to schematics...and the tone was never the same again. (not bad, just not the same)

So even though the power cord has aesthetic mojo, I'll replace that, and the e-caps, and simply play it.

[Andy Le Blanc]

it can be a tough choice..... to fix or keep
I scrounge bits where ever and when ever
to have old parts around the shop
just because the industry or consumer trend is to go
with certain parts IE: orange drops or sprauge this or mallory that
does not not mean that it will hold the right tone for the application
old parts drift with age and ............their old
I had princeton reverb # 6 on my bench a few weeks back
they hadn't gotten the sticker right
it had the model # of a vibro champ
thankfully the only cap that needed to go was it tremelo circuit

[Lonely Raven]

Understood. I won't replace anything I don't have to. But shouldn't the filter caps and power cord be replaced no ifs-ands-or-buts? At least that's what I was taught (from reading books on amp service).

Like I said, besides safety and e-caps to keep the amp healthy, I just want to play it as is.

[Andy Le Blanc]

do replace the power cord....
I've been hit in the mouth on-stage thru the mic
from grounding issues...... it's no fun....
check the filter caps.... before you arbitrarily replace them
they might be good to go..... most old amps were designed around 110 AC
and that might be a real issue.... were I live they push the voltage
today it's 123.5 V ..... it can strain old parts and be a hidden culprit
some say to increase the caps value to reduce hum....
it works but also changes the impedance of the power supply
and the amps tone

[Johnhenry]

LR, A few thing's that I know about Alamo Amp's, the guy that own's the name and Schematic's live's here in S.A. where the amp was made,
There are no Schematic's for these amp's availible to the public, so make a drawing of your amp before changeing anything,
I just finished building a A Class amp with 1 6SL7 and 1 6V6 for power, it really sound's good and i've been playing the heck out of it, I would be interested in seeing the value's inside your amp, + Voltage's !
you really don't need the 3 wire cord anymore, everything is wired back to the common side on today's electrical service,
beside's, you don't have a Polarity switch on these cheap amp's, if one hummed when turned on we just would unplug the amp, spin the plug 180 degrees and plug it back in, that would normally get rid of the hum,
And yes, Like Andy said, any changes and the amp's tone will change, sometime's for the better, but most of the time for worse,
I've serviced a many Alamo amp and some of them can sound very sweet with a service and new tube's,
I have done many cap job's on the older amp's i've serviced, I had good result's by staying with the same value's on the can style replacement cap.
if you have it, you could start by De-oxing the Pot's and Jack's, I've used a lot of stuff for this job through the year's but De-Oxit work's the best for my money,
As for tube's, I'm useing NOS, I just sold 55.000 old Military tube's to a dealer here in S.A.
If you need tube's, Let me know, I would be more than glad to help out on the Tube's.
Johnhenry

[Lonely Raven]

Great info, John, thanks!

I did some research, and I can't find any info on the Alamo, so I think your right about the schematic. Since I expect it to be as simple of a layout as a 5F1, I figured I'd do my best to measure, draw a schemo, and a good layout. Maybe even make a clone for my dad since he likes little bedrom amps with his '52 RI Tele.

I may need to hit you up for tubes. I've already spoken with KCA, and I trust Mike's opinion, but his choice of "best tube for this amp" always is also his most expensive.

[Johnhenry]

I repaired amp's here in San Antonio for 30 yr's, I know i'm right on the Schematic's, I tried to buy the name and right's to Alamo but he would not sell, i have collected schematic's for 35 yr's and i only have 1 Alamo Schematic !
I would love a copy of your Schemo and layout, and i know the price of old tube's, but for your effort on the drawing's i'll donate you a very good set of tube's for your amp. just P.M. me your mailing info when you findout what the tube's are in your amp.
Johnhenry
P.S. Your Dad will love you for the clone !

[Johnhenry]

If memory serve's me right, I think your model 3 should have a 6SJ7 in the preamp, a 6V6 power and a 5Y3 rectifier, i know a couple of the small amp's used the 6SJ7, but it's been a while since i worked on one !
Johnhenry

[Lonely Raven]

I repaired amp's here in San Antonio for 30 yr's, I know i'm right on the Schematic's, I tried to buy the name and right's to Alamo but he would not sell, i have collected schematic's for 35 yr's and i only have 1 Alamo Schematic !
I would love a copy of your Schemo and layout, and i know the price of old tube's, but for your effort on the drawing's i'll donate you a very good set of tube's for your amp. just P.M. me your mailing info when you findout what the tube's are in your amp.
Johnhenry
P.S. Your Dad will love you for the clone !

No, my Dad is always mad at me, because whatever amp I make him...I'll make something he likes better for myself.

If memory serve's me right, I think your model 3 should have a 6SJ7 in the preamp, a 6V6 power and a 5Y3 rectifier, i know a couple of the small amp's used the 6SJ7, but it's been a while since i worked on one !
Johnhenry

From what little info I can find online, I believe this to be true.

[Lonely Raven]

Bump!

UPDATE!

Ok, I have the Alamo Model 3 at home now.

It's really rough...in fact, I'd classify it as a fire hazard.

I'm pretty sure the Jenson P10T is shot as most notes make it rattle like there is a loose nut under the dust cap.

All that said, I have a good idea of what needs to be replaced. But before I do anything, I'd like to blueprint it, and attempt cloning it with modern parts at stock value so I can get an idea of what this might have sounded like 54 years ago when it was new!

What program should I use to *Draw* out the layout? I want something that will look good, and enable other builders to clearly see what I see and be able to learn from the circuit.

So what's out there that's not too hard to use and looks good?

~Eric~

[Jack Hester]

I know that this is an old thread, but I'm interested in the #3 schematic. Did you ever get around to making a sketch of yours? Thanks.

Jack

[Lonely Raven]

I know that this is an old thread, but I'm interested in the #3 schematic. Did you ever get around to making a sketch of yours? Thanks.

Jack

Hey Jack,

Unfortunately I did not make a layout yet. I had some health issues, and moved into a new house! So it's been sitting in storage since then.

Right after I moved into the house, I was talking with Ted Weber about reconing the speaker, and I think that was just before he passed away...

So all things kinda put a damper on this project.

I still fully intend to draw up a layout and clone this amp (for my Dad)...I keep saying "this winter when I have time" but then it never happens. LOL When I do get around to it, I'll make sure to post about it here!

I also have a '59 Magnatone I need to build a cabinet for, and two 5E3 amps I need to build for an experiment (two amps, all the same common parts - but one with standard caps and wire, and one built with Audiophile caps and wire). And I think I have most of the parts for an XITS X10 clone that I've not even thought about in several years.

So just a few things on the docket.

[Zippy]

Unfortunately I did not make a layout yet. I had some health issues, and moved into a new house! So it's been sitting in storage since then.

Hope you're felling better and getting settled into the new home. I've been going through much the same the last few years - both health issues and moving.

Might you be able to start with some pretty gut shots?