vendors for budget parts?

[boogieWoogie]

Hi Folks,
I'm putting together a bill of materials for a ~2W single-ended amp, in hopes of teaching it as a class at my community arts org.  However, if the materials cost gets too high, they won't offer the class.  So I'm looking for ideas around vendors who sell budget parts, and/or designs that are cheaper to build.

I've done searches, but I bet some of you have some vendors that I haven't discovered for cheap parts, particularly the expensive items, like transformers + chassis.  (Unfortunately, since this is for a class, I need new, off-the-shelf parts, so cost savers like "pull your transformer from a police radio" won't work when I need 10 identical PTs, OTs, + chassis).

My current plan is Terry Dayon's (from D-lab on Youtube) 6CL6 2W amp.

Thanks for any ideas!
BW

[Loomer]

Just to be sure we can help, where are you located?

[scstill]

if you are in US...
For Hammond Transformers:  https://www.hawkusa.com/
For most other parts: https://www.amplifiedparts.com/  or https://www.mouser.com/

[boogieWoogie]

Just to be sure we can help, where are you located?

Good question, thanks: in Massachusetts, United States.  I forgot we've got representatives from all over the world here.

[Loomer]

Good question, thanks: in Massachusetts, United States.  I forgot we've got representatives from all over the world here.

Easily done! I'll let the US folks chime in.
Good luck with getting that course up and running, I'd have loved to see something like that as a course!

[AlNewman]

Best option might be to find an old radio to convert.  2 watt is very attainable.  You'd have the PT, OT, speaker, tubes, and chassis, and half of the course could just be testing everything to see if it works.  $100 all day long, including replacement parts.

[acheld]

Hands down, Mouser is your friend.    HawkUSA.com has consistently good prices (with shipping) for Hammond transformers.

[Joel]

You sir are singing the song of my people!

Budget!  Cost effectiveness!  Cheap!  Economical!  Such beautiful mellifluous words!

May I suggest you check out the following links for reasonable priced inspiration?

Cost Effective 2W valve amp:
https://valveheaven.com/diy-amp-designs/the-lamington-junior/
Grant also has designs for 10W and 18W amps.  He's also an educator and a top bloke.

Theory for using cheap and easily available line matching transformers as valve output transformers:
https://www.ozvalveamps.org/optrans.htm
If you're teaching some theory, this could make a great exercise for students.

They are Australian links (which means they're totally awesome!), but you should be able to use the concepts over the pond in the US of A too.  Please give credit where it's due if you to end up referencing these links in your class.

[kagliostro]

I can say that the idea to use Old Tube Radio (or Reel Recorder or Suitcase Phono)

is a good way to save a lot of money

When you buy it only verify that audio comes out of the units and that the Power transformer is a real Power Transformer and not an AutoTransformer (avoid the units that are feed without a Transformer directly from the line as in olt time happened)

You can recover Power Transformer - Output Transformer and Tubes that are the parts that has the higher price

then may be pots, resistors and caps

However resistors aren't so explensive also if you buy new and the same for e-caps if you use Radial Caps instead of Axial caps


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Using only new parts:

To save money you can also teach your students that two lower voltage e-caps connected in series will see the capacity decreased but the voltage they can afford increased so using two cheaper e-caps you can avoid to buy an expensive high voltage version (obviously use the cheaper radial versions instead of the axial ones)

Another thing you can teach your students is to use Back to Back connected transformers as power transformers (usually toroidal Illumination Transformers are cheaper), our Australian friends (Darryl - TIMBO and others) at https://www.aggh.net often use this way to get Low-cost "Power" Transformers", another way they use are voltage Doublers and Quadruplers

One other thing, a 50W / 100W Illumination Transformer (this time is better it isn't a Toroidal Version also if here they used a Toroidal http://www.diegobarone.it/storico/art1.htm - http://www.diegobarone.it/storico/jpg/Valvolozzo2-2.JPG) with the proper Turn Ratio can be used in a few W (2W as in your example) SE amp as Output Transformer

Franco

[scstill]

I often get old radios just for their PT very cost effective. Sometimes the Transformers need to have wires replaced. Be aware that not all tube radios used power transformers and relied on the wooden cases and plastic knobs to protect from chassis carrying AC - yikes!!!

Also old radio tubes do not often translate into good guitar tubes. Triodes, Rectifiers and Power tubes seem to always work if they are good. Pentodes should be sharp cutoff for guitar, radio uses remote cutoff.

Finding an old tube radio is a great way to learn and get a stash of cheap parts and each of the built amps will be different. Plus rather than following a pre drawn schematic with a parts list, you have to design your own guitar amp. That is where the learning happens.

[kagliostro]

For some components like resistors - pots - e-caps - capacitors give a try to Banggood (and E-Bay)


Also mil Surplus sellers may have components on the cheap


Franco

[kagliostro]

Other way to save money is to build your own chassis

You can use this simple method (borrowed from our friend Heinz)

You need C aluminium bars and sheets

Franco

[Kesi from Hungary]

[/quote] You need C aluminium bars and sheets

Wow. What a fantastic idea

[kagliostro]

Low cost and measures at your taste

Note that tubes can be mounted on the sheet instead that on the C bar if you want

Franco

[EL34]

Make sure you visit the Hoffman Amps store
Hoffman Amps provides this forum.
Enter Hoffman Amps Store

[dogburn]

If you haven't decided on the exact amp project yet, one possibility is Rob Robinette's Champ Micro EF80. You can use a toroidal power transformer (which at about $28 is quite cheap), and the EF80/6BX6 tubes are not made any more but they are stocked at places like Amplified Parts and are quite cheap (like $5). Using solid state rectification, the only other tube you'll need is a 12AY7.

[acheld]

I think a better place to look for projects is on Doug's "Kits Page"  https://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&thispage=PartsListIndex.htm&ORDER_ID=!ORDERID!.   

Scroll down so that you can take in the "Project Links" on the right.   These are great projects -- some very simple, others more complex, but all with absolutely first rate schematics, layouts, and BOM.   Each one of these amps has stood the test of time, and more important, the efforts of novice and expert builders alike.   Furthermore, this forum is quite familiar with these amps, as well as their various mods, and routinely supports these projects.

What more could you ask for?

[bmccowan]

I have a few thoughts on this:
I looked into doing this very thing about 10 years ago. I found that there was someone in central Mass teaching such a course at Montachusett Tech in Westminster. They were assembling a champ kit.
Although I agree with all the encouragement expressed here; especially sourcing parts from Doug, I have some cautions. With the dangers involved in novices and high voltage, I would want to use a standard kit. I'm sure your first lessons would be safety, but if something goes wrong, its best to share the blame. The further you get away from a commercial product, with instructions, the more you are personally on the liability hook. Somebody might call Joe. (PRR and other Mainers will know this reference.)
Although I did not move forward, mostly because I decided I needed more experience, I think the idea is splendid. So best of luck.   

[boogieWoogie]

Thanks for the ideas folks!

Vendors
I've regularly used el34world's host, Doug, as well as Mouser and Hawk as vendors, and love 'em all.  Some others that weren't mentioned in replies, but I've found useful, are taydaelectronics.com (great for switches, and HW related to guitar pedals), partsexpress (great for wiring, connectors, heat shrink), partsisparts.net (for repair of commercial git amps).

Designs
Thanks for the mention about Rob's Micro Champ.  His page + designs are terrific.  I considered his Micro Champ, but there are some higher costs w/ that design, so Terry's from D-Lab won out.  Regardless, if I prove myself w/ this org, and can be allowed to spend a bit more on materials in subsequent class offerings, I'd guess we'd do a Rob Rob. amp soon.

As for designs based on used transformers, as I said, I need 10 identical designs + BOM.  I cannot spend time sourcing vintage gear, nor designing real-time in the class.

Novel Cost-Cutting Ideas
I've seen how a sheet-metal brake + sheet-metal can allow you to build a budget chassis.  I unfortunately don't have access to a brake, but if the class is successful, I might invest in one down the road.  The C-channel aluminum, screwed to plate aluminum, does not appear to save $ when compared to a Hammond or Bud chassis (maybe it does for larger chassis, I didn't price that out).

One poster shared valveheaven.com's Lamington amps.  I'd found those in my searches.  Interesting ideas (back-to-back transformers) for keeping costs low.  If buying 2 smaller transformers ends up being cheaper, it still has the drawback of taking more time to mount, and increases the size of chassis (which.. costs more money  ).

So, in the end, I think I'll stick w/ Terry's 6CL6 amp (from D-Lab) + use a 160V non-CT PT from Antek (which also has filament windings) and an output transformer from either tedweber.com or tubesandmore.com.

Regarding "line matching transformers as valve output transformers", I'd watched a video on this recently, but the commenters pointed out that the trans. in question wasn't air-gapped, and so could not tolerate any DC-current.  Since I'm building a single-ended amp, it'll have big DC-current so I believe I can't use them, but the ozvalveamps.org link is appreciated, and will be something I need to study for my next push-pull amp.

Voltage doublers were also mentioned, and on one of Terry's D-lab https://www.youtube.com/watch?v=zt27PPa5KC0&t=66s, he tests their ability to drive a 10W, 1K ohm output, and it works.  Since I don't yet know my true power requirements, I'll save this for a future "just for me" project, but I'm interested in testing this out.

Safety, finally, is of upmost concern, but I've participated in an amp club where no one was hurt over many years, so it can be done.

[kagliostro]

Budget chassis

aluminium C bar + sheet ... expensive ... may be it depends on where you get the materials ....

However ... go to Lamington amps and give a look to the chassis he use



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..... https://www.amazon.it/Teglia-rettangolare-antiaderente-vassoio-cucina/dp/B08BFTBPCR?th=1

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..... but the commenters pointed out that the trans. in question wasn't air-gapped, and so could not tolerate any DC-current.  Since I'm building a single-ended amp, it'll have big DC-current so I believe I can't use them .....

Use a translator and read the link I posted previously

http://www.diegobarone.it/storico/art1.htm


The toroidal transformers in the attached photo are used as OT following the explanation on the preceding link (but you can use the same way an E / I standard PT)


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You have one other way .... as you require materials for many identical project (say 10 or more)

send a PM to Doug and ask if is possible to trade a special offer for the components of a dozen or more amps

Franco

[bmccowan]

Safety, finally, is of upmost concern, but I've participated in an amp club where no one was hurt over many years, so it can be done.

Understood - no doubt it can be and is done - heck we are all survivors here. I was just pointing out the relative liability issues in the unlikely event something does go wrong. My Nephew just defended a lodge that was sued because a guest jumped into the lake and hit a rock. He and the lodge lost.
Anyways cool idea - keep us informed please.

[mresistor]

for those that don't know   Lamington Amps are available at Valve Heaven  https://valveheaven.com/