Help ID'ing Components in Amplifier Schematic

Started by teej, July 23, 2014, 05:05:25 PM

Previous topic - Next topic

teej

First, I should note that this is actually for a Hartke HA1400 bass amplifier, not a pedal. I need help identifying what types of switch and 1/4" jacks I'm looking at here. I cropped the sections of the schematic in question and have posted the images below.

In the schematic, the Compression and Contour switches look like ordinary DPDT switches to me. In addition to the 6 pins, the actual switches have 2 additional pins that connect to a chassis grounding plates that screw into the front panel of the amp. As for the jacks, I know the input, return, send and output are all mono, but the little black arrow throws me off. Does that mean they are switching jacks? And what about the headphone jack? It's got 6 pins with a 7th pin that connects to a black wire (ground?) that is part of a pair of wires (black and white) that connect to the main amp circuit.



Ice-9

From the drawings , the switches are ordinary DPDT and the jacks are mono switched with the headphone looking like a stereo switched.

do they look similar to these

http://www.rean-connectors.com/en/products/1-4-jacks/  
www.stanleyfx.co.uk

Sanity: doing the same thing over and over again and expecting the same result. Mick Taylor

Please at least have 1 forum post before sending me a PM demanding something.

duck_arse

the little black arrows indicate a switch/ing contact, normally closed in all your examples. when you in-plug, the dinger moves away from the arrowed contact - switch open. where they are shown shorted back on the dinger contact suggests their function is not used. "input" and "return" short to ground until you in-plug, then operate normally. as for the headphine, I think that odd draw indicates (as I recently found on a marshall SS) that the in-plug works opens P1//P2, so lifting the ground connection to another section (maybe power out).

extra contacts on those switches (are they slides?) provide mechanical rigidity via the switch frame. I would think.
don't make me draw another line.

tubegeek

Note that the jack JK5 has the same behavior whether anything is plugged in or not. The reason a switching jack was used there is so the manufacturer would only have to stock two types of jacks, a TS switched and a TRS switched.
"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

teej

#4
Quote from: Ice-9 on July 23, 2014, 07:25:53 PMFrom the drawings , the switches are ordinary DPDT and the jacks are mono switched with the headphone looking like a stereo switched.

do they look similar to these?

http://www.rean-connectors.com/en/products/1-4-jacks/
Thanks, everyone! You're a lot more helpful with this than my usual stomping ground (TalkBass forums). Below are photos I just took of the actual circuit boards. I should note that what I'm doing with this amp is converting it into a retro-styled combo by replacing the front panel and and swapping out the jacks, switches and knobs.

Here's the circuit board with the tone contour switch and input, return, and send jacks (in that order, left to right).


And here's the board with the headphone jack and compression switch.

teej

#5
Quote from: duck_arse on July 24, 2014, 09:12:26 AMthe little black arrows indicate a switch/ing contact, normally closed in all your examples. when you in-plug, the dinger moves away from the arrowed contact - switch open. where they are shown shorted back on the dinger contact suggests their function is not used. "input" and "return" short to ground until you in-plug, then operate normally. as for the headphine, I think that odd draw indicates (as I recently found on a marshall SS) that the in-plug works opens P1//P2, so lifting the ground connection to another section (maybe power out).

extra contacts on those switches (are they slides?) provide mechanical rigidity via the switch frame. I would think.
It's funny you mention Marshall because in trying to figure out what kind of jacks these are, I came across a website selling replacement jacks for Marshall amps and they look identical to what I have here. As for those switches, the contour and compression switches are push-button. I plan on replacing all the switches with toggles for this project.

teej

Quote from: duck_arse on July 24, 2014, 09:12:26 AM
extra contacts on those switches (are they slides?) provide mechanical rigidity via the switch frame. I would think.
I took a closer look at the additional pins on those switches and I think you're right on that. It's two pins but attached to the same piece of metal that is secured to the frame of the switch. And I now think that what I thought were grounds that attach to the front panel are actually meant to hold the circuit board in place and prevent the user from pushing the switch into the amp chassis.

duck_arse

well, the jacks in my lead12 are the open plastic type, with the 3 pairs of switched contacts, and the headphone has a special weird-bent extra lug. those in the pic look like the ones I've pulled out hi-fi amplifiers of diff brands.

and the copper-ness of the bracket with the screw through I would reckon is no accident. it probly chosen for conductivity porpoises (?) and the split track under the push switch adds weight to the theory. although I don't know why it needs splitting.
don't make me draw another line.

Ice-9

These jacks were quite common in  cheap 1980's pedals, I really disliked these. They had a very brittle plastic feel about them and at the time were impossible to get replacements in the UK. Should be easy to get now though.
www.stanleyfx.co.uk

Sanity: doing the same thing over and over again and expecting the same result. Mick Taylor

Please at least have 1 forum post before sending me a PM demanding something.

teej

#9
Quote from: Ice-9 on July 25, 2014, 09:25:30 AM
These jacks were quite common in  cheap 1980's pedals, I really disliked these. They had a very brittle plastic feel about them and at the time were impossible to get replacements in the UK. Should be easy to get now though.
I had a bit of a time removing the plastic nut from these plastic jacks because the threads were so brittle and worn. They still work but don't have a solid "snap" or firm connection when plugging in.

Quote from: duck_arse on July 25, 2014, 09:19:23 AM
well, the jacks in my lead12 are the open plastic type, with the 3 pairs of switched contacts, and the headphone has a special weird-bent extra lug. those in the pic look like the ones I've pulled out hi-fi amplifiers of diff brands.

and the copper-ness of the bracket with the screw through I would reckon is no accident. it probly chosen for conductivity porpoises (?) and the split track under the push switch adds weight to the theory. although I don't know why it needs splitting.
Yeah, it wouldn't make a difference since those two pins are one piece of metal. I took the switch apart and noticed that the metal piece in question doesn't make contact with anything within the switch, so it appears to serve no real purpose except to securely hold the switch in place. I'm really starting to think that the extra pins and copper-colored plate are just structural and serve no electrical purpose.