I have been working on a few projects, and I have come across some very old antique type components.
I cant find a readily available site so identify these vintage components, so I thought I would ask here...
Dont mind the mess in the chassis, I am cleaning up what someone else has done
(large image warning)
Yfrog - img00027200912312251
I am trying to figure out what the red componenes are in the top left corner. They look like packs of firecrackers, and seem to be connected to grounded pins, but I cant figure out what they are exactly. Thanks, sorry for the noob question.
I cant find a readily available site so identify these vintage components, so I thought I would ask here...
Dont mind the mess in the chassis, I am cleaning up what someone else has done
(large image warning)
Yfrog - img00027200912312251
I am trying to figure out what the red componenes are in the top left corner. They look like packs of firecrackers, and seem to be connected to grounded pins, but I cant figure out what they are exactly. Thanks, sorry for the noob question.
Should I leave them in place or can they be safely removed? They are mostly going to randon grounds.
Is there a way to find the values of these components? I am asking since they are in the way and causing some havoc inside the chassis.
Unless you are planning to completely gut and rebuild this amplifier as something else you need to leave them in place. They seem to contain almost all (if not all) of the passive components in that part of the amplifier.
Interesting, now it begs the question, why would they have done this? Oddly, the original stock photo of the underside of this amp never showed those. They seem to have been added, or atleast after the photo was taken the added them.
Two words actually: cost reduction...
In the late 1950s and early 1960s people started to look at ways to cost reduce what was still largely a manual assembly process building electronics. These devices were commonly known as PECs and were designed to reduce the number of components and soldering operations required to implement a circuit. Dynaco was a big fan of these devices in their pre-amps (RIAA and tone control networks) and their tuners (MPX filters and de-emphasis networks.) Using these devices reduced the number of assembly operations required significantly - today of course they are a modder/restorer's nightmare as they are usually mysterious poorly documented devices full of passive components of indifferent quality. (There is a reason why these are never seen in old McIntosh or Marantz gear..)
I agree with these guys, and for particular reasons:
It may take a lot of work to determine what the individual components in the PECs are.
For an 'antique' piece of gear, this thing is in awesome condition! You may want to look at any electrolytic caps, since they do dry out in half a century and much better electros are made nowadays, but I would leave this creampuff as much alone as possible.
Aloha,
Poinz
AudioTropic
It may take a lot of work to determine what the individual components in the PECs are.
For an 'antique' piece of gear, this thing is in awesome condition! You may want to look at any electrolytic caps, since they do dry out in half a century and much better electros are made nowadays, but I would leave this creampuff as much alone as possible.
Aloha,
Poinz
AudioTropic
I see alot of spliced wiring..
unfortunately it was hacked by a previous owner. That was the point of my thread, to see what could be cleaned up.
In the process of tinkering and moving things around, I ran into another issue.... something must have broke or was displaced....
The sound is very dark and muddy now, and it has half the gain/volume as I had before. I suppose I should have left well enough alone.
The only thing I touched was the first and second valve (12AX7's) so I know it most likely has to do with those stages, but I cannot for the life of me figure out what happened...
unfortunately it was hacked by a previous owner. That was the point of my thread, to see what could be cleaned up.
In the process of tinkering and moving things around, I ran into another issue.... something must have broke or was displaced....
The sound is very dark and muddy now, and it has half the gain/volume as I had before. I suppose I should have left well enough alone.
The only thing I touched was the first and second valve (12AX7's) so I know it most likely has to do with those stages, but I cannot for the life of me figure out what happened...
Cold solder joint?
Peace,
Dave
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You may actually be right on the money, I noticed some of the new solder did not mix well with the old solder, and I had a few loose type connections. I am checking more into it. Thanks
Those are not pre-wire modules. They are educational circuit modules used by many of the electronic correspondent vocational schools of the 1950's and 60's, to teach and enhance the student's understanding of circuit design and operation.
Such famous schools National Tech, Cleveland Inst. of Tech., Devey; all used those modules in the training equipment that they sent to their students.
The problem is that they made their way into the shops of electronic equipment makers. But they can be very noisy, if not done correctly. The schools were not looking at the quailty, but the student's ability to understand their lessons.
And yes..., the problem of repairing those circuits, with today's solder is not so good.
The solder of that time, was made for the use with heavy wattage soldering irons. Their believe was that with the high voltage, plus heat from the tubes and their sockets, a solder requiring a high heating ranges was needed. So if you use low heat solder, the old solder may crystal up on you.
The best way to repair and mod that project, is to walk out the circuit on paper, remove the modules and mount them on FR4 green fiber board. Then rewire the unit using modern wiring methods. Including good signal lead-in wire and install a dc heater circuit and good SS regulation.
Take Care
Ivey
Such famous schools National Tech, Cleveland Inst. of Tech., Devey; all used those modules in the training equipment that they sent to their students.
The problem is that they made their way into the shops of electronic equipment makers. But they can be very noisy, if not done correctly. The schools were not looking at the quailty, but the student's ability to understand their lessons.
And yes..., the problem of repairing those circuits, with today's solder is not so good.
The solder of that time, was made for the use with heavy wattage soldering irons. Their believe was that with the high voltage, plus heat from the tubes and their sockets, a solder requiring a high heating ranges was needed. So if you use low heat solder, the old solder may crystal up on you.
The best way to repair and mod that project, is to walk out the circuit on paper, remove the modules and mount them on FR4 green fiber board. Then rewire the unit using modern wiring methods. Including good signal lead-in wire and install a dc heater circuit and good SS regulation.
Take Care
Ivey
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Well, that would remove its vintage "vibe"... especially the DC heaters and regulation.
But re-making the PECs would be a good idea, as they are probably made with 10% (or worse) tolerance components, with TC factors of 200ppm or more...
Where did you get this unit?
Ah, well, that is what I see first when I look at a piece of vintage equipment. But you are also correct, when you say that it would improve its sonic qualities. It is a metter of preference, what the user wants to obtain: sound quality or originality. I could probably listen to any old radio (as long as it has a conventional speaker) and be satisfied!
Gain-Wire
Remember Desert Storm?
I and others was sent there to do black box electronic ops for the government.
Private Contactor!
I met this solider, a collector of vintage audio equipment. Talked up a storm.
You know, I got this and I got that, kind of stuff.
Well we returned back to the states, met up in Texas at the base. His wife met someone else, and the man shot himself.
He left her and her new man, thousands and thousands of dollars worth of vintage audio equipment.
Lesson is..., it is only worth something to you, to others, it is something to sell. So mod the hell out of it, while you can brother
Take Care
Ivey
Remember Desert Storm?
I and others was sent there to do black box electronic ops for the government.
Private Contactor!
I met this solider, a collector of vintage audio equipment. Talked up a storm.
You know, I got this and I got that, kind of stuff.
Well we returned back to the states, met up in Texas at the base. His wife met someone else, and the man shot himself.
He left her and her new man, thousands and thousands of dollars worth of vintage audio equipment.
Lesson is..., it is only worth something to you, to others, it is something to sell. So mod the hell out of it, while you can brother
Take Care
Ivey
This was actually purchased from this forum
These items have been removed, but I am sticking to the original components as much as possible.
I am sticking with the AC heater circuit, and the EZ81 tube rectifier not going solid state rectifier, since this is going to be used for a guitar mp.
I have removed these, and I am now following a 18 watt Marshall schematic, using the same topolgy etc and rewiring my amp.
Thanks for all the help so far guys and gals, this forum is a great help!
Using it for a guitar amp?
Sounds like my grandson.
I just hope that he and his band, get their big break that they keep talking of.
I enjoyed tube sound, sitting in the dark, with two 20watt class a's, JBL 15" three way speak system, our own hand built phono and line preamp. Looking that the glow of the tubes, ice cold beer, and a foot long SubWay.
Then your grandson wakes up, and start playing his guitar.
Good night
Ivey
Sounds like my grandson.
I just hope that he and his band, get their big break that they keep talking of.
I enjoyed tube sound, sitting in the dark, with two 20watt class a's, JBL 15" three way speak system, our own hand built phono and line preamp. Looking that the glow of the tubes, ice cold beer, and a foot long SubWay.
Then your grandson wakes up, and start playing his guitar.
Good night
Ivey
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