favorite old gear to buy for parts

[PRR]

> thought that PSU  would have produced a reasonable approximation

You have to enter transformer resistance. Actually there is a default which is in a ballpark for not-small not-large tube-volt PTs, but you should consider how it fits your situation.

PSU has two ways to figure PT resistance. You can put in resistance on both sides. OR you can switch to "Regulation" and enter your PT's VA and estimated regulation. For monster amps this will be 10% to 5%. For dinky preamps it may be as high as 20%. (Double down/up transformer chains may be over 40%.) PSU will work-out the resistance for that regulation and V and A.

The default will, for many cases, throw "rectifier peak current exceeded..." messages. Especially when using grossly over-large cap values. Sometimes when actual DCR values are put in, it passes. Either way, it is the handiest way to check this otherwise mysterious cause of short-term rectifier failures.

[printer2]

> thought that PSU  would have produced a reasonable approximation

You have to enter transformer resistance. Actually there is a default which is in a ballpark for not-small not-large tube-volt PTs, but you should consider how it fits your situation.

PSU has two ways to figure PT resistance. You can put in resistance on both sides. OR you can switch to "Regulation" and enter your PT's VA and estimated regulation. For monster amps this will be 10% to 5%. For dinky preamps it may be as high as 20%. (Double down/up transformer chains may be over 40%.) PSU will work-out the resistance for that regulation and V and A.

The default will, for many cases, throw "rectifier peak current exceeded..." messages. Especially when using grossly over-large cap values. Sometimes when actual DCR values are put in, it passes. Either way, it is the handiest way to check this otherwise mysterious cause of short-term rectifier failures.

Just saying that I measure a transformers open voltage and secondary resistance and plug those numbers in. Never had to bother with the primary resistance and the turns ratio. I'll give them a try on my next amp.

[HotBluePlates]

Just saying that I measure a transformers open voltage and secondary resistance and plug those numbers in. Never had to bother with the primary resistance and the turns ratio.

To be clear, you don't have to do more than what you've been doing.

The net result will be that entered transformer resistance is lower than the effective value for the actual part, resulting rectifier peak current will be higher than in real life, and calculated maximum safe capacitance will be lower than it could be. All that simply adds up to a conservative design, which is never a bad thing.

[Paul1453]

Junk gear parts research and testing day.  PTs and Chokes.
Attached is a pic of my 2 unknown PTs and Chokes with my notes so far.

I mapped out my unknown PTs with resistance measurements.  To be safe I 1st apply 6.6VAC from my bench supply to what I believe should be the primary.
Recorded my resulting VAC measurements, and did some calculations.  Now some questions maybe you can help me with?

On the PT I called Big Boy I'm expecting when I apply 120VAC to the Green and Black primary inputs:
I should get @ 390VAC between pins 1-6 and 1-10 and pin 1 is my CT
I should get @ 12VAC between pins 7--8
Pins 5-9 might be a 5VAC supply
Pins 2-3-4 might be the 6VAC CT supply

On the PT I called Little Boy I'm expecting when I apply 120VAC to the Green and Black primary inputs:
I should get @ 315VAC between pins 6-11 and 6-8 and pin 6 is my CT
I'm not sure what else to expect out of this one
Pins 1-2-3 might be a 6VAC CT supply?
Pins 4-5-Yellow wire might be a 2nd 6VAC CT supply?
Pins 7-10 ???
Pins 9-12 might be another 6VAC supply no CT???
Little Boy is a little odd in that it has Red-Green-Black primary inputs?

I would like to get some feedback from you guys before I hook up 120VAC to the primary inputs.   


The bigger choke has 210 ohms resistance, any way to tell it's H?

The little choke has 5100 ohms resistance, any way to tell it's H?

Thanks for the help guys!   

[PRR]

> Never had to bother with the primary resistance and the turns ratio.

Double the measured secondary resistance. Pretty close.

This is commercially correct for a single-secondary sane-voltage transformer. Both windings add resistance (allow for ratio). It would be silly (and inefficient) to have low-low R in one side with high R in the other. Usually both windings take equal space (best use of window area) which with ratio-leverage gives about equal contribution to total effective resistance. So measure sec and double it.

With more than two secondaries, it gets tricky. If it were a 1,000VA transformer with a little 10VA winding for a plate supply, then the primary must be so low-R that it can be ignored. But we don't find such transformers in our amps. Typically the heater winding is somewhat smaller than the plate winding, so "double" maybe should be a factor of 1.5X or 1.7X. No great precision is needed. You will allow ample safety margins. Wall-voltage variations are greater than transformer effects.

Very high voltage windings are all paper, and may have more resistance than you expect from simple economic balance. OTOH, high voltage LOW current windings (preamps) "naturally" call for wire too thin to wind at high speed, economics suggest an over-size wire, and resistance may be low (which means the primary may have more effect, and "double" might really be 2.5X or even 3X).

[Paul1453]

While investigating the T-100 2 prong cord it began to crumble to dust in my hand.  Checking the mouse infested bottom, I decided it was safest for me and the components to just gut her and clean all the turds out of her.  So the transformers came off, all components underneath got cut out, and into a hot soapy disinfectant bath she went to soak overnight.  She got a scrubbing this morning, dumped the water, and gave her another hot soapy soak.  After cooling she got another scrubbing, rinsing, and a towel dry.  Took some pics to post and got her hanging in front of a fan for the next day or two to completely dry before I mess with her again.  I'm thinking her chassis and case will still be used to make into a little Champ.

[Ambugaton]

Someone has offered me a Hammond BV. It will be a hassle to move it. Any idea what I can get out of it?

[Paul1453]

Not sure what a BV is?  Have you googled it?  Lot's of people here rave over Hammond organs for conversions.  It should have some good Iron and maybe even some Mullard 12AX7's.  For free?  I'd definitely go through the hassle to get it myself, but that's just the way I am.   

[Willabe]

Someone has offered me a Hammond BV. It will be a hassle to move it. Any idea what I can get out of it?

I just did a quick search and it looks like that's a true 'tone wheel' Hammond with draw bars.

If so, PLEASE DON'T part it out. They are unique instruments that will never be made again.

Many players still love those. Sell it to someone who will take care of it. 

[Paul1453]

V for Vibrato and the B is a tube organ.  As Willabe pointed out this model appears to be a classic.  If it can be fixed, or is in working condition now, the right buyer will pay quite a bit for it. 

Waaaaay more than someone would pay for any kind of guitar amp you could make out of it.  Your location would make finding the right buyer difficult.   

To the right buyer it could possibly go for $10,000 or more!   

[Willabe]

...... this model appears to be a classic.  If it can be fixed, or is in working condition now, the right buyer will pay quite a bit for it.

Yep!   

[Ambugaton]

The offer just came today so I didn't know if anyone had some experience with them off hand. I definitely respect the idea of keeping this thing in tact. I live in Juneau so it is not likely at all that I will find someone willing to pay shipping. I doubt the thing is functional. I will need to get some more info from the guy before I make up my mind. I'm wondering if the thing is destined to rot as furniture on this island or potentially be repurposed.

[Willabe]

Might be someone around there that plays? A church might like it.

Be cheaper for them to pick it up from you or your friend then to have 1 shipped up there.

[PRR]

> A church might like it.

It came OUT of a church. (98% likely.)

Most churches can hardly replace their light-bulbs. Maintaining (not even restoring) a tonewheel machine is far beyond their comfort zone. It was tough even when Hammond had on-call techs.

Today a Roland keyboard is a much more practical hymn machine. Gives zero trouble for a decade. When it does, a new one does not need a major fund-drive. (Play one service on a CasioTone, pass the plate, done.)

I dunno what the rock/blues scene is in Juneau but again I suspect that unless a player LOVES his tonewheels, a Roland etc is a much more practical machine. In Chicago or Nashville you may find a tonewheel guru who would add it to his repair spares and possibly love it for years to come. But unless they split the big city and move to Alaska, shipping is maybe more than they can spare.

The core tonewheel guts are worth more per pound than the case amplifier and speakers. It is not so silly to ship the guts south. Then the dog can sleep in the case and the amplifier can be re-purposed.

[Willabe]

It came OUT of a church. (98% likely.) Most churches can hardly replace their light-bulbs. Maintaining (not even restoring) a tonewheel machine is far beyond their comfort zone. It was tough even when Hammond had on-call techs.

Not if it was your church or mine! 

But.... I guess that's part of what it's come down to now. BUT if you've ever been in a room with a Hammond 'tonewheel machine' run through a real Leslie with a real band, man ain't that the STUFF!!!!!   

That set up can coooo like a dove and whisper softness, cry like a baby and scream like an eagle, and every thing in between! 

(Play one service on a CasioTone, pass the plate, done.)

    Yeah I'd throw cash money in the plate too! 

[trobbins]

The bigger choke has 210 ohms resistance, any way to tell it's H?

The little choke has 5100 ohms resistance, any way to tell it's H?

I use this technique:
http://dalmura.com.au/projects/Choke%20measurement.pdf


I would also rate the Hammond BV as rare, and imho should not be parted out.  It actually doesn't have much valve gear in it, so best to try and find someone really keen on electro-mechanical restoration, as it is likely to be an onerous job.

[Ambugaton]

Some more info on the organ. It was purchased from a Church quite a while ago... was never fired up and has been sitting in storage for several years. He stated that the finish was not in ideal condition either. I think I will take a look and maybe reach out for any local interest.

[Paul1453]

So with the simple measurement scheme shown on page 1. 
It would not be a good idea for me to try to just use my adjustable HV bench PS by tying my 6 VAC supply together with my adjustable 0-300 VDC supply and sending that through the resistors and unknown choke?  1st idea, and quickly considered not advisable.   

Better to use like a small 12 VAC transformer from some broken radio or something?
Make a little FW bridge rectifier board from cheap IN4001 diodes and use that with the little 9 or 12 VAC PT to connect to this testing circuit?

I'm still reading and trying to comprehend the full paper. 
I see it shows using 12, 20, 32, and 52 VAC, but the resulting L calculated appears relatively close with each.
So for a general in the ballpark estimate of the unknown chokes H value, I could get by using just a little 9 or 12 VAC PT exclusively?

Thank you for this info, trobbins!   

The bigger choke has 210 ohms resistance, any way to tell it's H?

The little choke has 5100 ohms resistance, any way to tell it's H?

I use this technique:
http://dalmura.com.au/projects/Choke%20measurement.pdf


I would also rate the Hammond BV as rare, and imho should not be parted out.  It actually doesn't have much valve gear in it, so best to try and find someone really keen on electro-mechanical restoration, as it is likely to be an onerous job.

[trobbins]

Coupling AC and DC supplies needs some thought as to the consequences, so the test circuit in that reference uses just a simple secondary winding and bridge rectifier setup to give a combined AC+DC test current.  The main concern is that the secondary winding can supply the test current - if you want to test a choke to 100's of mA then the winding needs to cover that.


If you had a variac mains supply then you can take many measurements to construct a performance curve of the unknown choke.  Otherwise you may need to cobble together a few secondary windings to give say 3-4 test AC voltages.  As you don't know the inductance of the choke, then best to start at a low AC supply voltage and then increase, noting the fall off in inductance.  Estimating the DC power loss, from resistance and the test DC current, you can also guess whether you are pushing the choke in to high dissipation levels.


Over the years I have tested 10's of unknown chokes, so I have some transformers in a case with banana plugs for taps just for this purpose - but I probably have a little more equipment hanging around than you.  One possibility is to get a batch of old 12VAC quartz downlight transformers - they can be used for many applications, even as output transformers if they have split primaries.

[eleventeen]

Thanks for that choke article. Interesting.

[Paul1453]

The Silvertone R-R is now a bedroom Champ! 
Troubleshooting terrible hum started at the rectifier.  Should have +280 V coming out pin 8, got +200. 
OK, swap in a different 6X5 still +200. 
Only the cap can before the 1st resistor to be dropping that V.  Change out the cap can. 
It had a 40-40-40uf 300V can, I only had a 40-40uf 450V can. 
OK so I just leave out the last 40uf cap to see if she's gonna work.  Work??? 
She sounds great with only slight barely noticeable hum. 
She's not very loud, but when I add my 12" 8 ohm speaker to the output jack she does much better on volume.
Put in a distortion pedal and add some gain and she's a Rockin!
Less than $25 in parts total, and my time to fix her.
Not a bad deal.  Pretty sure I can get $75 for her locally the way she is now.

[Willabe]

Nice! 

You might want to add the 40uF cap back in? Just get a single 40uF and strap it in somehow.

[Paul1453]

Nice! 

You might want to add the 40uF cap back in? Just get a single 40uF and strap it in somehow.

No new ones in my current inventory, might need to check my junk pile for something usable.
I'm thinking of taking it to Jeff, a local music store owner who does consignment deals for me.
He'll write me a ticket for $75 and when he sells it for whatever he gets, I come pick up my cash.
The way it sounds just as it is, I think he can turn it for $100 in a week or 2 max.
It is an all tube 6V6 12AX7 amp.  Cheap enough for Mom and Dad to get their Kid a tube amp, and not too loud.
My junk pile is getting a little big, time to lighten the load and restock up on ammo.   

[Paul1453]

I got set up to safely put 120VAC into my unknown PTs.

Some results were as expected, others not so much:

Big Boy has:
380-0-380 CT on pins 6-1-10
5VAC on pins 5-9
Very good so far, now the unexpected results
2.5VAC on pins 2-4 pin 3 is CT with 1.2 VAC on each side
2.2VAC on pins 7-8 Yellow wire is CT with 1.1 VAC on each side

Little Boy has:
300-0-300 CT on pins 8-6-11
5VAC on pins 1-5 pin 2 is CT
OK so far, now the unexpected results
2.4VAC on pins 4-5 Yellow wire is CT with 1.2 VAC on each side
1.3VAC on pins 7-10
4.6VAC on pins 9-12

No 6.3VAC on either, but maybe there is a way to make that without adding a 2nd filament PT?
That is if these different voltage windings can be somehow paired up and still meet the heavy current demands of the 6.3 supply.

Any suggestions, or just get some filament PTs to go with the Boys?

I've saved more than enough to do that on these.  I got this lot of 5 unknown transformers for $25.50 including shipping.
So I got the Boys with their oddball voltages, the 2 unknown chokes that appear good, and a blown PP OT.
I saw that thread with someone fixing their blown OT.  I'll have to check and see if I can attempt that too.

I appreciate your suggestions on how I can use these PTs.   

Thank you!

[Paul1453]

Nice! 

You might want to add the 40uF cap back in? Just get a single 40uF and strap it in somehow.

I found an 8 uf 250V cap in my junk parts pile and put it in. 
Maybe it has less hum now, it didn't have much to begin with after putting in that new cap can. 
Before that it was a complete HHHUUUMMM amplifier.

The tiny 4" speaker it contains doesn't do well with low bass frequencies.
When you connect an external, in my case 12" speaker, both play and it seems to send the bass to the external speaker.
This thing actually sounds pretty good for recently being an old piece of junk!   

[Paul1453]

Hi, my name is Paul and I'm a junk tube gear addict.   

What can I do when I see gear like this?  I have to buy it.
This should have Philips MiniWatts from Holland in it.
A 12AX7 or 6BQ5 Miniwatt goes for just about what I paid.
Maybe the PT is fried and all the tubes dead?
I still have to take the shot.

Hi, my name is Paul and I'm a junk tube gear addict.   

A signal generator is used troubleshoot and calibrate guitar amps, right?
I'll have to see if I can fix that 1st before just harvesting its high-quality parts.
Since he had that and the old Intercom ending at the same time, what the heck I guess I'll take that too.
The transformers look to be worth $15 and maybe I saved him a few $ in shipping.

My name is Paul and I'm a junk tube gear addict.   

[Toxophilite]

Lost it today and bought a bunch of stuff

Paid $75 Can (about $5 US)
I was intending to go buy a AO-43 and an AO-29 the fellow had listed with tubes both for $125, The high end of what I would spend. Turned out the guy(nice guy, older , not dishonest, just disorganized ) only had the AO-29  and couldn't find or had already sold the AO-43
So I bought some other junk off him to make the trip worthwhile:


-Got the AO-29 with tubes
-A mystery guitar power amp that allegedly used a unusual power tube..some 7 number ...looks like a boat anchor(anybody recognize it???)clearly used to have a cage over the tubes
-a gibbs or accutronics reverb tank in a bag(handy)
- some weird unit which is at least useful for the jacks etc
-a hammond pushpull OT
and a huge bin of old organ and hifi junk including some okay tools pots, wire, jacks, pilot lights
- 3 decent vintage 6V6Gt (now tested0 and a 12ax7 (also good)


oh and a big storage bin


I figure I got my moneys worth and it was an interesting jaunt

[Paul1453]

Glad to know I wasn't the only one bingeing today.   

Looks like we spent about the same, but I think you did better.

Lots of heavy metal in your pile, and a boatload of do-dads to go with it.

Very nice!   

Since the Holidays are coming up, I hope my music store guy can move a few bedroom amps for me.   

[DummyLoad]

went to visit an old friend today. picked up a NOS thordarson 22r36 PT - 1200VCT @ 200mA couldn't resist for 20 bux. i have NO idea what i'm going to do with it. maybe class AB with x-mitter tube?

also picked up a webster electic SP-3 for 5 bux.

the original 7189 is gassed out so he sold me a NOS IEC for 10 bux. when i got it home i opened it up and noticed that the OT primary lead to main filter cap was burned in two. still measures ~190R but i have reservations. also, one of the cement power resistors crumbled. it has 3 12AU7, 1 6DJ8, 1 7189, and 1 6CA4. rear panel states 5W output. PT measures good.

like this one... i'm thinking tweed princeton

--pete

[trobbins]

1200VCT @ 200mA , brings to mind choke input allow a wide variety of heft power tubes.

[Paul1453]

This one looks in rough shape but for $23 and whatever time and parts it needs to be fixed, it could be a little bedroom amp easily.  Ends in 6 hours, and I'm out of ammo again.

http://www.ebay.com/itm/371485587181?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Do your own research before spending your money.  Careful, this junk gear can be addicting.   

OK, nobody wanted to take the shot I guess.
Even in it's rough shape it should have had a useable PT, OT, and some still good tubes.
The Silvertone R-R I got just needed a new cap can and it was a Champ 600 with a tube PS.  It sounds really good with an external speaker connected now.
If I wasn't out of ammo, for $23 including shipping, I would have taken that shot.   

[DummyLoad]

1200VCT @ 200mA , brings to mind choke input allow a wide variety of heft power tubes.

it does that and a lot of added weight.  5Hy @ 500mA is not inexpensive or light weight. very likely i'll flip it on fleabay.

--pete

[Paul1453]

You take your shots and live with the results.
Someone already got to the Miniwatts I was hoping were still in here.   

I'll have to try to find the full schematic for this online, and see if I'm better off sticking some tubes in it to fix for resale or just harvesting the parts.

It does have a PT (labelled 250mA) and maybe an OT that could be used.
Gutted and re-engineered it could fit a 6" speaker in for another unique little bedroom amp.
I need to find a schematic before I get too crazy with this.
It's a Norelco EL3951 if you have an idea where to find a schemo.  I'm going searching now.
It might be worth more to someone else if I fix it then a bedroom amp would be.   

[Ed_Chambley]

You take your shots and live with the results.
Someone already got to the Miniwatts I was hoping were still in here.   

I'll have to try to find the full schematic for this online, and see if I'm better off sticking some tubes in it to fix for resale or just harvesting the parts.

It does have a PT (labelled 250mA) and maybe an OT that could be used.
Gutted and re-engineered it could fit a 6" speaker in for another unique little bedroom amp.
I need to find a schematic before I get too crazy with this.
It's a Norelco EL3951 if you have an idea where to find a schemo.  I'm going searching now.
It might be worth more to someone else if I fix it then a bedroom amp would be.   

Here is a link to info on your unit.

http://www.radiomuseum.org/r/philips_el3581_50r.html?language_id=2

You will need to join the radio museum to get the schematic, but this will let you see it. 

[Paul1453]

Thank you Ed!

The Philips support person got me a link for a Hi-Fi web site that had a schemo in German for that model you listed. 
The 3951 doesn't seem to be out there anywhere, yet. 
That model seems close enough in that it has only two tubes, 1 9 pin and 1 7 pin. 
The schemo did not identify the tubes though.  9 pin shows heater pins 4,5 and 9, I'm thinking that means 12AX7. 
Appears the 7 pin is the output tube and I'm thinking that means 6AQ5. 
I sure wish those MiniWatts had been in there.  With just those two premium tubes I would have considered this a good deal! 
Now I'll have to really work to try to make it into one. 
All part of the adventure though.   

[HotBluePlates]

That model seems close enough in that it has only two tubes, 1 9 pin and 1 7 pin. 
The schemo did not identify the tubes though.  9 pin shows heater pins 4,5 and 9, I'm thinking that means 12AX7. 
Appears the 7 pin is the output tube and I'm thinking that means 6AQ5. 

ECC83/12AX7 and EL95. See below from the RadioMuseum website Ed linked.

[Paul1453]

Thank you HBP!

My Army network isn't allowing me to go to that site.
It's odd which sites it will and won't allow.  At least this one works.   

So I guessed the 12AX7 correctly, but an EL95/6DL5 wasn't on my radar.
I'll have to check my tube supply.  I don't know that I have that one.

Thanks for the help guys!   

[Paul1453]

Reading some threads on another site about low output problem with EL95 PP setup.

Seemed to indicate he did a direct swap with 6AQ5s and got full output power.

I haven't checked the tube data sheets for these tubes yet, but do any of you know if you can just swap a 6AQ5 in for an EL95/6DL5?   

I've got lots of 6AQ5s.   

[Paul1453]

I've added a poll to give me a better idea of people's interest in this topic.

With my obvious response already tallied.   

[PRR]

I have never seen such a minimalist tape player with speaker and record.

It is, as-expected, largely a Champ with far too much added switching (much omitted here).

There's certainly no 250mA in the B+. You may have found the relay supply.

That is a 6P2T relay; you can't hardly buy one today. Before you bulldoze, find out what the coil voltage is.

[Paul1453]

No plans to bulldoze, yet.

That EL95/6DL5 does not seem to be very common.  I don't have any of those in stock.
Lots of 6AQ5s, a 6CU5 and a 6EH5 which look similar, but not a 6DL5 in sight.

This thing looks pretty clean inside, and I see others like it being offered at $100+ on Ebay.
I can put a 12AX7 in, was hoping it was a 6AQ5 to put back in, test and verify it's working and put in back out there with a starting bid that nets me a small profit.
I don't know if that's feasible now.  You say there is a hard to come by relay in there?

Here's a pic of the PT.  I'm guessing the 250mA is total for the PT?

[Paul1453]

Checked the data sheets.  Pinouts are exactly the same.

Differences noted:
AQ uses more than 2x heater current 450mA vs 200mA.
With just two tubes in this, heater current should not be an issue?
Max Plate dissipation DL = 6W,  AQ = 10W
Plate current DL = 24mA,  AQ = 45mA
Load Resistance DL = 10K,  AQ = 5K
Max output power DL = 3W,  AQ = 4.5W

Please tell me if my analysis of this data is wrong.
I guess that as long as the PS can supply the extra heater and plate current, a direct swap is OK?
The Load resistance through the OT needs to be 1/2 as much for the AQ.
So connecting a 4 ohm speaker to an 8 ohm output jack would work for the AQ swap?

Anything else I should be concerned about?

Any reason I should not just stick a 6AQ5 in with a 12AX7 and test this thing?

[Paul1453]

Thanks Ed!

That is a better schemo than I got through Philips.  It labels the tubes and gives some voltage readings.

Any feedback on me subbing in a 6AQ5 for the 6DL5?   

I don't think it would destroy anything, but I could be wrong if it exceeds the heater current available from the PT.
It is about 250mA more current required than if I had a 6DL5 to put in there.

I got the rest of my weekend junk gear purchases delivered today.
Cleaning them up, and will likely post a pic or two after work tonight.   

[Ed_Chambley]

Thanks Ed!

That is a better schemo than I got through Philips.  It labels the tubes and gives some voltage readings.

Any feedback on me subbing in a 6AQ5 for the 6DL5?   

I don't think it would destroy anything, but I could be wrong if it exceeds the heater current available from the PT.
It is about 250mA more current required than if I had a 6DL5 to put in there.

I got the rest of my weekend junk gear purchases delivered today.
Cleaning them up, and will likely post a pic or two after work tonight.   

I would simply plan for the tube you prefer within reason.  Most Transformers will exceed expectations.  If it heats up too much a heater tranny to me is cheap enough to let me build what I want.

[Paul1453]

These are the major parts resulting from my $50 purchase last weekend.

Based only on these quality parts alone, not the other pots, caps, power resistors, etc. , I consider this to have been a good deal.   

[Ed_Chambley]

That large tranny has a lot of 6.3 supply.  it is a 115v at 290-0-290 which is a nice unit to have.  You can build anything from 15 watts to 40.  Looks perfect for a Vibroverb.

Do you know what the Philco Trannys came out of or did you find the specs on them?  You have collected some parts, but have you built anything yet?

[Paul1453]

That large tranny has a lot of 6.3 supply.  it is a 115v at 290-0-290 which is a nice unit to have.  You can build anything from 15 watts to 40.  Looks perfect for a Vibroverb.

Do you know what the Philco Trannys came out of or did you find the specs on them?  You have collected some parts, but have you built anything yet?

10 A on three separate 6.3 VAC taps can heat up a lot of tubes.   

Found a Philco radio site with pretty much info.  My parts appear to have been a 32 model?  The site didn't have specs for my stuff of course.  Still searching.

Of course I have built some things by now.  My problem has been a lack of proper OTs and speaker cabs. 
I have one PP and one SE OT.  It appears I have two more SE OTs now, at around 5W I'm guessing.
I use the 2x12 cab from my pawnshop Peavey Mace as my testing speakers now.

I have a 6V6 PP with 6SJ7 pre and 6SN7 PI that was using my only PP OT.
I end up tearing out the OT from things I have built when I want to try something else.   

That chassis and tubes came out of a Magnavox with a Field Coil Speaker.
The PT in it went bad, so I used my bench supply.  I have a few PTs that could go in it now.  I don't think I want to use this one in it.

That sounds like a project for this weekend.  I need to figure out which PT to use, wire up my 5 rectifier tube, and field coil socket connection.
I could reclaim my one PP OT for a little while at least.  I am interested in how that monster field coil speaker will sound in a guitar amp.
It's at least 12" and might be 15", I didn't measure it.  I was a little leery of running the HV out and back into the amp through that old wiring and unknown speaker.
It's got to be done, so I guess that's what I'll focus on this weekend.

I have a couple of SE EL84 projects that were kind of on hold because I didn't want to play swap the OT on them.
I'm hoping these two new (old) Philco OTs will fit the bill for them.  I could keep my one new SE multi-tap OT for my breadboard projects then.

It would be a whole lot easier to just buy a complete kit from Doug!  More expensive, but nice and clean to work on, and a prettier product in the end.
I don't think I could sell one of those at a profit.     I'm not really looking to build and sell amps though. 
I'm trying to learn, and work through the more difficult challenges presented when repurposing old gear into an amp.   

I'm just looking to sell a couple of these repurposed things now, to keep the steady flow of cheap, high quality part containing, junk gear running through my basement.

I guess you could call it a hobby.   

Added a pic of the rest of the high quality parts harvested from this buy.  Not necessary to try to value any of this stuff, as the PT alone is worth more than $50 IMO.

[eleventeen]

If I didn't mention it before, I reco looking on your local Craigslist for old oscilloscopes. For one...you might get a functional scope if you do have a latter-20th century one. They have to be CHEAP because there are *some* parts that are useful but a lot that ARE NOT.


Power transformer: In a big scope, you'll have as many as 1/2 dozen 6.3 windings. But the B+ ampacity is generally inadequate for amp use. That's because either there are 3 B+ windings and they divide up total device current on 3 diff windings. Or the thing uses 30-50 mils total. So not one of them is really strong current-wise.  So scope transformers are usually really big (heavy, take up lots of chassis footprint) and yet not so great for an amp. In a nice Tek scope, you may well get a 12AX7 or two but most of those 9-pin tubes are 6DJ8s (which are much like 12AX7 with a different base pinout) You will get lots of good hardware from a junked Tek tube scope. Knobs.


A little 1957-1962 3" offbrand scope will furnish an astoundingly small pile of usable parts. KNIGHT kit scopes, however, use 12AX7. Very old Dumont scopes used 12AX7. MOST other scopes use 12AU7 or 6DJ8 and these are tubes you can add to your collection and impress your friends but generally will not use. 

[eleventeen]

Irresistable 2 for $10 deal. 2 Blonder-Tongue line video amps. Nice chassis with cages and princeton sized 350-0-350 tranny. 6BQ5 will not fit under the cages but 6V6 will. Pretty clean.








These would be neat for a dual mono block 6V6-fired stereo. Or brown Princeton or Deluxe. I of course need a project like that. I thought the chassis were inspiring. And duallys!

[Paul1453]

Wow, a very nice find, in stereo.   

Where did you get them?

A slightly bigger cage would be easy enough to make, or just put the cage on stilts.  Those PTs will give you a B+ big enough for 6L6s if that's what you wanted to put in there.