philly amp info needed

[mike hadley]

I recently purchased this philly amp from fleabay, I am 99% sure that it is the one Ben Hase had a while back, the one with jones sockets fitted,

most appears to be original and ties in with the schematics available, choke dc resistances measure ok, the four 6l6's all have the correct value resistors to the right tube pins, all match with the philly schematic's

unfortunately the elves have bee busy with this one,

the -27v rail cap has been wired wrong, with the center tap of the power transformer wired directly to chassis, easy fix,

the caps above chassis two seem to be original, the third has a 1971 date code and appears to be a split type cap, 50 - 50 uf, with both sides used, is this the correct type of cap here ie. split, all but the wrong value,

as the wiring is a little messy and no old solder to give any clue, it would make sense as the early philly chassis has four caps in this location.

Someone has been busy around the 10 way jones socket (speaker connection). lots of fresh solder with some evidence if the wiring been moved, although there are the appropriate connections, field coil, 6l6 anode connections etc.

Also there is something really odd with the fuse holder, one side is wired to ac input, through the fuse to pin 10 on the ten way jones socket via a twisted pair,

the other wire in this twisted pair is connected to pin4 on the (radio chassis) 12 way jones connector, this then leads to a single tag mounted on the chassis near the ac input,

was this for the motor option?

a schematic for this later supply would really help as I would like to put things back to factory,

here are some photo's

jones sockets

-27 v supply cap

10 way jones

12 way jones

loose cap

fuse holder

odd cap

Thanks in advance for any help.

Mike

[David C. Poland]

Mike -  Having spent some time building up the Jones plug version Philharmonic amp (of late 1941) some months ago, I do have some preliminary comments.

-yep, the last of the Philly amps had 3 top side filter caps instead if 4, which makes it look like the Phantom amp at first glance, but having 4 6L6's, (whereas the Phantom has 2 6L6's and 2 6J5 adjacent). 

- AC takes a circuitous route before arriving at the power transformer primary.

-The ac goes through the Speaker Jones plug (pins 1 & 2 as I recall) as a jumper.  A safeguard to assure the speaker is attached during a power up. I do not have a diagram for your Jones plug amp and had to fake it a bit.. But it is worth studying  the diagram for the Scott Laureate for a comparison for it uses Jones plugs, but note the Laureate's 6L6's are in the receiver chassis. The Laureate diagram also shows the tweeter wiring to the band switch. Indeed, the Laureate speaker wiring and plug should be identical to your Philly amp Jones socket as the same standard and optional hi-fi speakers fit them both.

- your amp is designed to feed AC to the receiver power switch on the volume control, a refinement of 1941-2  for the BOL Philharmonic receiver, both the standard and FM version which have the vernier at the top of the dial. 

- the remote control version requires an additional step down transformer mounted inside the amp mid way - where the 4 apron holes are. I don'e see such a transformer among your photos.

Curious, Mike - what version Philly receiver do you have? And what speaker?

[mike hadley]

Dave;

Thanks for the reply,

the chassis is an early philly with a west coast dial, I don't have a speaker so I will be making an adapter box with a ux7 socket for the radio and two umbilicals for the amp, this will remove the need for any modifications to the amp or tuner.

I have attached a pinout list of the jones connectors this does make sense although different to the laureate wiring,

please excuse my scribble, there is also a photo of my philly dial

Mike

[Scott Seickel]

Well, a schematic for the Jones plug version doesn't exist.  Electrically it should be like the latest published version, which I emailed you, with the exception of the Jones plug wiring.

If it were mine, I would just wire it to make it work giving the circumstances, unless you can find another person who has an unmolested PS/amp that is willing to spend the time to trace out the Jones plug wiring.  It is nearly impossible to find an unmolested amp/PS these days. 

[mike hadley]

Scott;

I am beginning to think along these lines because the chassis has been modified, what I really need to know is there is a cap in this chassis that appears to be 50-50uf, split type, this is the black modern cap in the photo, I take it that this is the right type of capacitor for this position, it's all been reworked badly in this area, 

the Jones plug wiring will work as is, just needs tidying up I thought that the power lead from the radio was a ux7, this is not the case as the plug is bigger than this, 

this is my next piece of the puzzle to source,

I found a 3k output transformer in my odd parts, came out of an amp using 4 x el34 tubes, ultra linear type with 43% grid taps, I seem to recall it was from a 60 watt amp, should have more than enough iron.

I will be using modern speakers so I will be substituting the field winding with resistors.

when it's time to run the amp up I will use suitable resistors across the 250v and -27v supplies as a dummy load,

thanks for the later schematic, the output stage is the same, apart from a few electrolytic cap values, but as I'm going to recap I will up the values slightly anyway.

Mike

[Scott Seickel]

Mike,

I do possess the rarest Scott item of all...an unmolested amp/PS chassis...LOL.

It is not the Jones plug one, but a late AM/FM unit.

All 3 original vertical mount capacitors in it are dual 30 uF units.  Not to say that Scott didn't up the capacitors in the last version, which is what you have.  I would be comfortable with either the 30 or the 50 uF units. 

If I recall correctly, those Jones plugs for this set are hard to find.

I guess you are going to mount that output transformer on a separate chassis...

[Scott Seickel]

Here are some pics of my late amp.  Maybe they will be helpful.

As you can see, 2 of the twin 30 uF caps have both sections tied together yielding 60 uF.  If you think it would be helpful, I can email you the full resolution pictures. 

[David C. Poland]

Yes - proper Jones plugs are hard to find.

A socket to fit the receiver cable plug is also hard to find, for it is not a standard 7 pin socket. 

The pointer dial Philharmonic  was the first version. The long shank power switch came out of the amp for mounting on the right side of the cabinet.

[Scott Seickel]

Yes, the early amps had a toggle switch on a 36" or so cord that came out of the amp.  The switch was mounted on the side of the cabinet.  The later versions of the amp had a round 4 pin socket which was used for power switching on the tuner chassis, and also 24v for the remote option.  Last version was the Jones plug- and by far the least common but it did use power switching on the tuner chassis.   

So your Philharmonic volume control doesn't have a power switch on it because the original set was wired with a toggle switch on a cord coming out of the amp.  I have looked and finding these toggle switches with integral wires is impossible to find. 

[mike hadley]

Scott,

after some thought I have decided to go down the route of modification, I will remove the switch option from the radio chassis as there is no switch anyway, the wiring around the hi low switch is suspect, the obvious thing here is to rewire this switch by putting the transformer in the high position and re assigning the switch to on off.

I have suitable jones connectors, maybe I will make something for the seven pin socket if I cant find anything suitable.

Mike

[Scott Seickel]

Yeah, that makes sense.  No use for the Hi-Lo switch these days.  If you ever get a cabinet, then you would want a wire coming out of the set with a toggle switch on the end. 

[Joseph W Strickland]

Scott and Mike;

Was the toggle switch that was mounted on the cabinet a long shank type? I ran into that with a Philco 40-201 set which uses a separate cabinet mounted toggle switch for power on-off. The original toggle switch shank was quite long and I only found two modern ones that came even close to the original. Due to the age of the OEM switch, I did not trust it even though it might have been possible to open it up and reassemble, I suspected significant pitting of the contacts and just did not trust it not to start a fire due to internal arcing. I found these switches I considered:

From: http://www.wellgainelectronics.com/carlingswitchspst6a125vac.aspx

CARLINGSWITCH SPST 6A 125VAC

Manufacturer: Carling (Switch) Technologies

Manufacturer Part No: SPST 6A 125VAC, price was $49.90

From: http://hardwaredistributors.com/switch-toggle-spst-bl-nn.html

Top of Form

SWITCH TOGGLE SPST BL NN

Item Number: 3135746

ACE MEDIUM DUTY LONG SHANK TOGGLE SWITCH *3A/250V *6A/125V *For lamps lamp fixtures *SPST ball handle *Long shank *UL listed CSA certified *Blister carded. Our Price: $7.99 (each) Bottom of Form

Ace 3 A 250 V Medium Duty Long Shank Toggle Switch

Item no: 3135746 | 082901051787

$11.99

The "Ace" referred to is Ace Hardware Stores here in the USA and I ordered through their on-line site.

The above image was the one from Ace Hardware. i removed the screws, soldered wires and placed heat shrink tubing over the wire ends and solder lugs of the switch. In the radio I was restoring I also had to remove about .25" of wood from the back side of the mounting surface and then the switch fit and worked well.

Joe

[mike hadley]

After checking over what I have actually got into, it seems that two of the electrolytics are original, one has all sections joined and gives a total of 160 uf, the other is a single 50uf, the third cap is dated 7106, June 71, both sides connected and wired across the supply to the radio chassis, all of the resistors except one have gone high, one 240k is nearly half a Meg.

I did intend to sympathetically restore the chassis but I am now treating it as a set of parts, this gives me license to perform a clean refit, the wiring is ok and will be reused, 

the Jones sockets are ok, along with the wound components, 

any thoughts on this are most welcome 

Mike