Hello to all
Actually I have a 33 preamp (SN 89456) on which I made a total
recapping and thought about transistor substitution on preamplifier boards 12017 and 12019.
But there is a small problem: any transistor have marked number model on case.
I see on schematics them seems to be all BC109 but on my boards transistors have TO-92 plastic cases really different from TO-18 metal case of BC109.
I thought about BC546B as substitute for BC109 but I prefer take more infos before make a disaster
Anyone have suggest for this?
Thanks in advance
MArco - Turin - Italy
Actually I have a 33 preamp (SN 89456) on which I made a total
recapping and thought about transistor substitution on preamplifier boards 12017 and 12019.
But there is a small problem: any transistor have marked number model on case.
I see on schematics them seems to be all BC109 but on my boards transistors have TO-92 plastic cases really different from TO-18 metal case of BC109.
I thought about BC546B as substitute for BC109 but I prefer take more infos before make a disaster
Anyone have suggest for this?
Thanks in advance
MArco - Turin - Italy
Hello,
In the Quad 33 units I have seen, there were BC109C, BC 109B, BC 114, E5270.
The BC109C is still available but I had a good experience with the BC550C, costing one-third of the BC109C. Especially on the disc pre-amp board, you would use a low-noise variety of transistor.
I am experimenting with op-amp based circuits to replace the disc pre-amp, tape I/O and tone control amplifiers. Of course, the Quad 33 has no symmetrical power supply and single 12V isn't exactly ideal for OPA604-based circuits, so I had to squeeze a new transformer and a +/-15V power supply in the confined space.
Sacrilegious acts, I know, but the unit had already been tampered with anyway.
Can anyone point at a decent replacement for the stereo 2x50K Log volume potentiometer-with-mains-switch? The Quad representative in the Benelux has one for 40 euro...
Cheers,
Jacques
In the Quad 33 units I have seen, there were BC109C, BC 109B, BC 114, E5270.
The BC109C is still available but I had a good experience with the BC550C, costing one-third of the BC109C. Especially on the disc pre-amp board, you would use a low-noise variety of transistor.
I am experimenting with op-amp based circuits to replace the disc pre-amp, tape I/O and tone control amplifiers. Of course, the Quad 33 has no symmetrical power supply and single 12V isn't exactly ideal for OPA604-based circuits, so I had to squeeze a new transformer and a +/-15V power supply in the confined space.
Sacrilegious acts, I know, but the unit had already been tampered with anyway.
Can anyone point at a decent replacement for the stereo 2x50K Log volume potentiometer-with-mains-switch? The Quad representative in the Benelux has one for 40 euro...
Cheers,
Jacques
Hello Jaques
>Especially on the disc pre-amp board, you would use a low->noise variety of transistor.
It is my goal, I think after a caps replacement that this phono section could be upgraded with new modern transistor change..
>Can anyone point at a decent replacement for the stereo 2x50K >Log volume potentiometer-with-mains-switch? The Quad >representative in the Benelux has one for 40 euro...
I saw sometimes on USA EBay shops this volume pot, other choose could be a simple pot with an external main-switch or considering a low current absorption no switch.
All the best..
MArco - Turin - Italy
>Especially on the disc pre-amp board, you would use a low->noise variety of transistor.
It is my goal, I think after a caps replacement that this phono section could be upgraded with new modern transistor change..
>Can anyone point at a decent replacement for the stereo 2x50K >Log volume potentiometer-with-mains-switch? The Quad >representative in the Benelux has one for 40 euro...
I saw sometimes on USA EBay shops this volume pot, other choose could be a simple pot with an external main-switch or considering a low current absorption no switch.
All the best..
MArco - Turin - Italy
In the Quad 33 units I have seen, there were BC109C, BC 109B, BC 114, E5270.
The BC109C is still available but I had a good experience with the BC550C, costing one-third of the BC109C. Especially on the disc pre-amp board, you would use a low-noise variety of transistor.
--------------------------------------------------------------------------------
Hello Jaques
after reading your useful infos this evening I have observe 33 board using a magnifing lens and I have seen that some of the transistors are really marked E5270 and now I have another question for you and others:
are BC550 /BC546B pins compatible with this old trans?
I make a search on Net but I haven't found nothing, obviously I could follow the PCB traces to identify which are Emitter or Collector but if someone could or would help me I'll be really glad.
Have a nice night all.
MArco
The BC109C is still available but I had a good experience with the BC550C, costing one-third of the BC109C. Especially on the disc pre-amp board, you would use a low-noise variety of transistor.
--------------------------------------------------------------------------------
Hello Jaques
after reading your useful infos this evening I have observe 33 board using a magnifing lens and I have seen that some of the transistors are really marked E5270 and now I have another question for you and others:
are BC550 /BC546B pins compatible with this old trans?
I make a search on Net but I haven't found nothing, obviously I could follow the PCB traces to identify which are Emitter or Collector but if someone could or would help me I'll be really glad.
Have a nice night all.
MArco
Buon giorno, Marco!
TO-18 (BC 109) and TO-92 cases are practically pin-compatible. In case of doubt, one can always look up a datasheet (even by Google). Many vendors offer datasheets on-line. Just as an example, search for BC546 on it.farnell.com
This diagram is a bottom view:
Hoping this helps,
Jacques
TO-18 (BC 109) and TO-92 cases are practically pin-compatible. In case of doubt, one can always look up a datasheet (even by Google). Many vendors offer datasheets on-line. Just as an example, search for BC546 on it.farnell.com
This diagram is a bottom view:
Hoping this helps,
Jacques
Attachments
Opamping the Quad 33
Well, I'm doing sort of the same thing.
I've build the Rod Elliot project 6 phono pre amp (single ended version) on the disc adapter board (see attached image) using the opa2134 opamps and polyprop input caps.
The result is really stunning. The sound is much more lively, has more drive and punch and seems rhythmically more correct. Stereo imaging has improved as well as definition. The bass sounds faster and tighter. Rough edges around voices have disappeared. (I could continue, but I think this suffices.) In short, the original boards sound plain dull compared to this design. I never imagined that.
I've also made a new very nifty tape adapter board around the same opamp (see next post). This adapter board is even more versatile than the original.
Next project is adding dual supply rails and output amplifier board. As the disc amplifier board isn't necessary anymore I've plenty of space to put the regulators for the supply.
Marco
Well, I'm doing sort of the same thing.
I've build the Rod Elliot project 6 phono pre amp (single ended version) on the disc adapter board (see attached image) using the opa2134 opamps and polyprop input caps.
The result is really stunning. The sound is much more lively, has more drive and punch and seems rhythmically more correct. Stereo imaging has improved as well as definition. The bass sounds faster and tighter. Rough edges around voices have disappeared. (I could continue, but I think this suffices.) In short, the original boards sound plain dull compared to this design. I never imagined that.
I've also made a new very nifty tape adapter board around the same opamp (see next post). This adapter board is even more versatile than the original.
Next project is adding dual supply rails and output amplifier board. As the disc amplifier board isn't necessary anymore I've plenty of space to put the regulators for the supply.
Marco
Attachments
Op-amping the Quad 33
Hello Marco,
Thanks for your idea to put the pre-amp on the adapter board. Why didn't I think of that!
My idea originated after restoring the disc input circuitry in a second-hand Quad 34 which had been 'adapted' for CD-input into the Disc sockets. All of a sudden, my old Thorens TD126 with an old Ortofon MC20 sounded better than any of my CDs...
I have attempted a circuit with 4 opamps per-stereo channel but I will try Rod Eliott's circuit as well.
Some vendors of op-amp-based upgrade cards for the Quad 33 (such as Net Audio) claim that its original power supply cannot handle several op-amps at once. Have you observed something in this area?
Best regards,
Jacques
Hello Marco,
Thanks for your idea to put the pre-amp on the adapter board. Why didn't I think of that!
My idea originated after restoring the disc input circuitry in a second-hand Quad 34 which had been 'adapted' for CD-input into the Disc sockets. All of a sudden, my old Thorens TD126 with an old Ortofon MC20 sounded better than any of my CDs...
I have attempted a circuit with 4 opamps per-stereo channel but I will try Rod Eliott's circuit as well.
Some vendors of op-amp-based upgrade cards for the Quad 33 (such as Net Audio) claim that its original power supply cannot handle several op-amps at once. Have you observed something in this area?
Best regards,
Jacques
Dear Jacques,
Well, It took me a while to get that idea. I was trying to figure out how the original schematics worked and then I thought ... well, the rest you know.
What i'm doing: Instead of the original disc-amplifier board I'm putting 2 regulators (positive and negative supply, 15V), fed bij an outside pre-regulated pos and neg supply. This is then powering the circuitry in the Q33.
When you go for this option then it is possible to build the normal version of Rod elliot's project 6 instead of the single supply version. I'm convinced that that one will sound better. You can power this phone pre from pin 3 and 4 from the disc amplifier board. (don't know by heart on which pins this comes in at the disc adapter board).
succes, MArco
Well, It took me a while to get that idea.
I was trying to figure out how the original schematics worked and then I thought ... well, the rest you know.Well, the phone pre board with two opa2134's works well. Adding the tape-adapter board with an NE5532 works ok too. Replacing this ne5532 with another OPA2134 didn't work anymore. Aparently this one is consuming more power.
What i'm doing: Instead of the original disc-amplifier board I'm putting 2 regulators (positive and negative supply, 15V), fed bij an outside pre-regulated pos and neg supply. This is then powering the circuitry in the Q33.
When you go for this option then it is possible to build the normal version of Rod elliot's project 6 instead of the single supply version. I'm convinced that that one will sound better. You can power this phone pre from pin 3 and 4 from the disc amplifier board. (don't know by heart on which pins this comes in at the disc adapter board).
succes, MArco
Replaced ouput amplifier board
Well finally replaced the output amplifier board with the second gain stage of Rod Elliot's project 88.
It took me a while to get the balance right and I'm still working on the volume control (almost all the action is in the part 0-2). But the result is again simply stunning.
Compared to the original output amplifier boards these give much more detail and transparancy as well as much better sound staging.
Somehow the original output amp boards added something to te sound which has now dissapeared. A definite improvement.
Alas, Alas, I always tought that the Q33 was a fairly decent pre-amp. Never suspected that it was so easy to improve on that with a few decent op-amps ...
Next, I will put some regulators really near to the op-amps, so that each channel has its own regulators...
greetz, MArco
Well finally replaced the output amplifier board with the second gain stage of Rod Elliot's project 88.
It took me a while to get the balance right and I'm still working on the volume control (almost all the action is in the part 0-2). But the result is again simply stunning.
Compared to the original output amplifier boards these give much more detail and transparancy as well as much better sound staging.
Somehow the original output amp boards added something to te sound which has now dissapeared. A definite improvement.
Alas, Alas, I always tought that the Q33 was a fairly decent pre-amp. Never suspected that it was so easy to improve on that with a few decent op-amps ...
Next, I will put some regulators really near to the op-amps, so that each channel has its own regulators...
greetz, MArco
Quad 33 enhancement
Hello and Happy New Year to everybody,
Best wishes of health, success and joy in everything, all dream to turn reals !!!!
I'm using my good old Quad 33 preamp (I've already reniewed it using Dada Electronics DIY kit for the Quad 33) with a GC type amplifier (LM3886 based, non-inverted input, +/- 42 Volts PSU), a Micromega CDF-2 CD player, a Thorens 166MK2 turntable with a high output Moving Coil Dynavector 10x3 cartridge, and Wharfies Diamond 9.6 as loudspeakers.
I've been across many posts looking if there was anything I can project to improve further my Quad preamp. I've read this post, and I am thinking that what deduikertjes have done on his own 33 is of high interest so I'm considering to do the same.
Dear deduikertjes, would it be possible for you (I'm aware that was over 18 months ago !!!) to detail and complete the modification you did ? I've as well planning to make the output amplifier (board #12017) using Rod's Elliot 1st gain stage (its output connecting to pin 5, input of tone control/cancel) and Rod's Elliott 2nd gain stage (input pin 6, output pin 4). I will modify the PSU, making a regulated -15 / +15V one (the +15V rail will use existing voltage layout, the -15V will be brought to boards using wired connectors).
My first problem is the balance control (pin 7): where shall I connect this one ? To pin 1 or Pin 2 of the OPA2134 ? Or shall I completly change the balance layout (using the layout of Elliott) putting it between 1st and 2nd gain stages ?
For the PU board, I am simply thinking to use (again) Elliott's phono preamp design with +/-15 Volts PSU.
For the tape board, I will leave it as is (more complex to bring the -15 Volts rail without loosing the connectivity of the board, except if designing the sensitivity switches outside the preamp), if modifying it I would probably (again) use as starting point 1st gain stage circuit.
Thank you in advance or any information provided,
Best regards,
Michel.
Hello and Happy New Year to everybody,
Best wishes of health, success and joy in everything, all dream to turn reals !!!!
I'm using my good old Quad 33 preamp (I've already reniewed it using Dada Electronics DIY kit for the Quad 33) with a GC type amplifier (LM3886 based, non-inverted input, +/- 42 Volts PSU), a Micromega CDF-2 CD player, a Thorens 166MK2 turntable with a high output Moving Coil Dynavector 10x3 cartridge, and Wharfies Diamond 9.6 as loudspeakers.
I've been across many posts looking if there was anything I can project to improve further my Quad preamp. I've read this post, and I am thinking that what deduikertjes have done on his own 33 is of high interest so I'm considering to do the same.
Dear deduikertjes, would it be possible for you (I'm aware that was over 18 months ago !!!) to detail and complete the modification you did ? I've as well planning to make the output amplifier (board #12017) using Rod's Elliot 1st gain stage (its output connecting to pin 5, input of tone control/cancel) and Rod's Elliott 2nd gain stage (input pin 6, output pin 4). I will modify the PSU, making a regulated -15 / +15V one (the +15V rail will use existing voltage layout, the -15V will be brought to boards using wired connectors).
My first problem is the balance control (pin 7): where shall I connect this one ? To pin 1 or Pin 2 of the OPA2134 ? Or shall I completly change the balance layout (using the layout of Elliott) putting it between 1st and 2nd gain stages ?
For the PU board, I am simply thinking to use (again) Elliott's phono preamp design with +/-15 Volts PSU.
For the tape board, I will leave it as is (more complex to bring the -15 Volts rail without loosing the connectivity of the board, except if designing the sensitivity switches outside the preamp), if modifying it I would probably (again) use as starting point 1st gain stage circuit.
Thank you in advance or any information provided,
Best regards,
Michel.
more details
Well, I can try, though I never made any schematics. Just worked from the articles of Rode Eliot and adapted things to my liking.
So from memory:
Since my last post I've revised the phono adapter board. As I did bring symetric power into the Q33, I wanted a new phono. I've build the VSPS (very simple phono clone). I like it more than the old asymetric Rod Eliot P6. It leaves enough space on the board to ad a microphone amp, or an extra CD-in. Makes the Q33 even more versatile.
I've put the second stage of the Rod Eliot preamp on the output amp board. First stage on the tape adapter board. But this one you don't really need. So I've made a possibility to use passive input (by setting jumpers). Bringing symetric power supply to the tape adapter board isn't that difficult. My solution does require to open the Q33 to remove the Tape adapter board. Not that bad as I don't do this often. Look at th picture, left hand bottom side. There is a 4 pin header to put a connector on.
Balance is in the feedback loop of the second gain stage. Works fine, but I've added jumpers to bypass that. As I don't need balance it's always bypassed. In that way the signal doesn't have to travel all the way trough the Q33 to the balance control and then back again. As you've guessed: sounds better without balance.
Each output board has it's own set of regulators. The phone stage has it's own regulators sitting on the not needed phono amp board. On this board are also the requlators for the tape adapter board. So every stage has it's own supply.
All this is fed from an external power supply: 24V regulated symetric.
Hope this helps, Marco
Maybe I can find some pics of output board to post
Well, I can try, though I never made any schematics. Just worked from the articles of Rode Eliot and adapted things to my liking.
So from memory:
Since my last post I've revised the phono adapter board. As I did bring symetric power into the Q33, I wanted a new phono. I've build the VSPS (very simple phono clone). I like it more than the old asymetric Rod Eliot P6. It leaves enough space on the board to ad a microphone amp, or an extra CD-in. Makes the Q33 even more versatile.
I've put the second stage of the Rod Eliot preamp on the output amp board. First stage on the tape adapter board. But this one you don't really need. So I've made a possibility to use passive input (by setting jumpers). Bringing symetric power supply to the tape adapter board isn't that difficult. My solution does require to open the Q33 to remove the Tape adapter board. Not that bad as I don't do this often. Look at th picture, left hand bottom side. There is a 4 pin header to put a connector on.
Balance is in the feedback loop of the second gain stage. Works fine, but I've added jumpers to bypass that. As I don't need balance it's always bypassed. In that way the signal doesn't have to travel all the way trough the Q33 to the balance control and then back again. As you've guessed: sounds better without balance.
Each output board has it's own set of regulators. The phone stage has it's own regulators sitting on the not needed phono amp board. On this board are also the requlators for the tape adapter board. So every stage has it's own supply.
All this is fed from an external power supply: 24V regulated symetric.
Hope this helps, Marco
Maybe I can find some pics of output board to post
Hello Marco !
Thank you for your information; it will take a little while before I will experiment as I have not much time these days (work ..... !). I am planning to make layouts of PCB's (I have a small equipment at home to expose/etch/drill small PCB's).
I'll come back as soon I've got results (will be number of weeks '
').
Best regards,
Michel.
Thank you for your information; it will take a little while before I will experiment as I have not much time these days (work ..... !). I am planning to make layouts of PCB's (I have a small equipment at home to expose/etch/drill small PCB's).
I'll come back as soon I've got results (will be number of weeks '
').Best regards,
Michel.
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