Marlboro - Quadra Sound Blender QBS  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...

Marlboro - Quadra Sound Blender QBS

Postby Zokk » 17 Jan 2012, 02:40

Hey folks

I'm not sure of the manufacturing date of my unit... I hope I post in the good section.

I've done a full recap on my old QSB as it was really too much noisy...
I've not found pictures anywhere, so I've taken some photos of its guts, just for the curious because it is not a real good reverb unit (the only one spring measures around 20 cm and is really "boingy" :mrgreen: ).
After recap' it's dead silent, and I even think I've more headroom, but it's still a bad reverb for guitar: it sounds better when used for dub drum kits :lol:
So here are the pictures before changing the electros (you can see the new caps laying under the unit on one picture: Lelon & Panasonic 105°C hi grade caps, but I'm not sure this effect really worth such a luxury):
You do not have the required permissions to view the files attached to this post.

For this message the author Zokk has received thanks: 3
Blitz Krieg (06 May 2015, 07:36), modman (03 May 2015, 12:48), RnFR (17 Jan 2012, 03:54)
User avatar
Zokk
Solder Soldier
 
Posts: 218
Joined: 05 Jul 2010, 21:00
Location: tantalum shortcut area
Has thanked: 128 times
Have thanks: 52 times

Re: Marlboro QSB guts

Postby Bernardduur » 01 May 2015, 09:41

Nice!

I just scored a Marlboro G50-R amp which is a 2x10 SS amp with a QSB already inside it!

The amp sounds just wonderfull. A bit of hissssss so I'll also do a cap job.The amp sounds remarkable tube like with enough volume. The bright input works perfect for my HB guitars, the normal for my SC guitars and the mellow is just dark, dark and bassy. With bass it is just a bit too much!

The reverb is also a bit boingy and feeds back a bit on the highest settings

The QSB effect is a weird one;
- The tremolo is a hard, choppy tremolo with maximum depth
- The vibrato is a less choppy tremolo (same as above with lower depth setting)
- The echo setting is tremolo on the reverb so you'll get a reverb wash that is cut on volume SIMULATING an echo sound

Sounds nice! Schematic will follow when I get the time to trace it!
'No more....... loud music.......'
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro QSB guts

Postby soulsonic » 01 May 2015, 15:12

Bernardduur wrote:- The echo setting is tremolo on the reverb so you'll get a reverb wash that is cut on volume SIMULATING an echo sound

:!:
This is a really cool idea for a standalone pedal! I'm now imagining doing something like this with a Belton brick.... :idea:
User avatar
soulsonic
Old Solderhand
 
Posts: 3503
Joined: 27 Jun 2007, 04:38
Location: Ithaca, NY
Has thanked: 53 times
Have thanks: 248 times

Re: Marlboro QSB guts

Postby Intripped » 01 May 2015, 16:52

something like this?
You do not have the required permissions to view the files attached to this post.
Intripped
Resistor Ronker
 
Posts: 435
Joined: 25 Aug 2009, 02:03
Has thanked: 461 times
Have thanks: 201 times

Re: Marlboro QSB guts

Postby Zokk » 01 May 2015, 19:54

Nope, the tremolo is located after the reverb tank, inorder to chop the reverb tail :wink:

For this message the author Zokk has received thanks: 2
Intripped (02 May 2015, 02:34), soulsonic (01 May 2015, 20:18)
User avatar
Zokk
Solder Soldier
 
Posts: 218
Joined: 05 Jul 2010, 21:00
Location: tantalum shortcut area
Has thanked: 128 times
Have thanks: 52 times

Re: Marlboro QSB guts

Postby Bernardduur » 02 May 2015, 20:43

Yep! The decaying reverb wash is chopped by the tremolo. You can spot that on the higher tremolo settings: the wash is still going strong (although the reverb isn't that great........ I think I need to upgrade that one!!
'No more....... loud music.......'
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro QSB guts

Postby Bernardduur » 02 May 2015, 20:57

DSCF5328.jpg
DSCF5329.jpg
DSCF5330.jpg
You do not have the required permissions to view the files attached to this post.
'No more....... loud music.......'
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby soulsonic » 03 May 2015, 16:41

I'm definitely going to start on a design for a pedal version of the weird echo-reverb from this.
User avatar
soulsonic
Old Solderhand
 
Posts: 3503
Joined: 27 Jun 2007, 04:38
Location: Ithaca, NY
Has thanked: 53 times
Have thanks: 248 times

Re: Marlboro - Quadra Sound Blender QBS  [schematic]

Postby Bernardduur » 05 May 2015, 19:28

Schematic time:

Preamp.JPG
Reverb.JPG
Tremolo.JPG
You do not have the required permissions to view the files attached to this post.
'No more....... loud music.......'

For this message the author Bernardduur has received thanks: 6
abogicevic (13 Jan 2017, 12:19), Blitz Krieg (06 May 2015, 07:37), modman (06 May 2015, 00:06), Moonsun (06 May 2015, 07:03), soulsonic (05 May 2015, 20:50), Zokk (05 May 2015, 21:47)
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Bernardduur » 05 May 2015, 19:29

PSU.JPG
Poweramp.JPG


Much simpeler then I would guess.........

On further search one of the speakers is dead........ see if I can revive that one :)
You do not have the required permissions to view the files attached to this post.
'No more....... loud music.......'

For this message the author Bernardduur has received thanks: 5
abogicevic (13 Jan 2017, 16:03), allesz (06 May 2015, 08:58), Blitz Krieg (06 May 2015, 07:38), modman (06 May 2015, 00:06), Zokk (05 May 2015, 21:48)
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby allesz » 06 May 2015, 09:03

Hallo, thank you for the schematic.
It's so simple I would like to try it myself, always wanted to try a spring reverb pedal, and the tremolo, quasi echo, idea would be a nice one to try.
Mr Bernaddurr, can you tell me the voltages V1, V2 and V3 coming from the power supply?
allesz
Cap Cooler
 
Posts: 523
Joined: 15 Jun 2009, 17:29
Location: Italy
Has thanked: 46 times
Have thanks: 114 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Bernardduur » 06 May 2015, 10:43

allesz wrote:Hallo, thank you for the schematic.
It's so simple I would like to try it myself, always wanted to try a spring reverb pedal, and the tremolo, quasi echo, idea would be a nice one to try.
Mr Bernaddurr, can you tell me the voltages V1, V2 and V3 coming from the power supply?


Not yet, I'll first recap the unit and then measure some voltages.
'No more....... loud music.......'
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby tube-exorcist » 06 May 2015, 13:39

The emitter resistors of the output transistors probably will be 0,51 Ohm instead of 0,15 Ohm.

The output driver dransformer is drawn wrong. The primary winding doesn´t have a tap (and no connection to the lower trimmer. The secondary winding doesn´t have a tap there are two seperate windings. The upper is shown correct but no connection to the base of the lower output transistor. The second winding is between the lower trimmer and the lower base, identical to the upper half.
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."

For this message the author tube-exorcist has received thanks:
Blitz Krieg (07 May 2015, 07:16)
tube-exorcist
Cap Cooler
 
Posts: 462
Joined: 05 Jul 2007, 21:09
Has thanked: 210 times
Have thanks: 75 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Bernardduur » 06 May 2015, 13:58

I'll look into it!
'No more....... loud music.......'
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Bernardduur » 06 May 2015, 19:40

I think you are right!

I was guessing the transformer wiring as there are many (also unused) pads on the print. They are all filled with solder. I desoldered the unit.

Poweramp.JPG


Better?
You do not have the required permissions to view the files attached to this post.
'No more....... loud music.......'
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Bernardduur » 25 May 2015, 12:25

Now the PSU with voltages!
PSU.JPG
You do not have the required permissions to view the files attached to this post.
'No more....... loud music.......'

For this message the author Bernardduur has received thanks:
Blitz Krieg (26 May 2015, 06:42)
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby tube-exorcist » 25 May 2015, 17:27

Bernardduur wrote:I think you are right!

I was guessing the transformer wiring as there are many (also unused) pads on the print. They are all filled with solder. I desoldered the unit.

Poweramp.JPG


Better?


Much better....
"I've noticed there's an inverse relationship between cost of gear and talent. If you need the most expensive gear to get decent tones, then you suck as a player."
tube-exorcist
Cap Cooler
 
Posts: 462
Joined: 05 Jul 2007, 21:09
Has thanked: 210 times
Have thanks: 75 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Intripped » 25 May 2015, 23:00

Am I wrong if I say that you had better take those two 20n capacitors off?
I mean C1 and C2, aren't they two "death caps"?
Intripped
Resistor Ronker
 
Posts: 435
Joined: 25 Aug 2009, 02:03
Has thanked: 461 times
Have thanks: 201 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Bernardduur » 26 May 2015, 06:50

Yep, and already done!

They were also part of the noise in my unit
'No more....... loud music.......'
Bernardduur
Transistor Tuner
 
Posts: 1139
Joined: 24 Aug 2007, 08:36
Location: Losser.........
Has thanked: 85 times
Have thanks: 448 times

Re: Marlboro - Quadra Sound Blender QBS

Postby Mattyr » 04 Apr 2016, 00:35

I've used a qsbII for many years and I love it. Recently my reverb broke and upon inspection I found that the small wires that hold the spring had broken. The wires have what appears to be a small magnet that sits between the two bars connected to the transducer. How can I repair this and where would I get parts, including a new spring as I would like to alter the effect slightly. I have no education in electronics but I'm not stupid so I think with some direction I should be able to do this. Any input would be greatly appreciated.
Mattyr
 
Posts: 2
Joined: 04 Apr 2016, 00:25
Has thanked: 0 time
Have thanks: 0 time

Next

Return to Vintage Stompbox Corner ( ... - 1975)

Who is online

Users browsing this forum: No registered users and 4 guests