TG1 - advice from any one who has built it...

[salomonander]

thanks majestic.
im using old gardners 600:600 on the output. i dont think there is an offficial recommandation. could you maybe give some rough ballpark values? i would not really know where to start honestly.....
good to know about the opamp. thanks a lot!

 

[Rob Flinn]

thanks majestic.
im using old gardners 600:600 on the output. i dont think there is an offficial recommandation. could you maybe give some rough ballpark values? i would not really know where to start honestly.....
good to know about the opamp. thanks a lot!

Put a square wave through the unit, the look on a scope to see if theere is any ringing happening.  If there isn't you don't need a zobel network.  If there is do some searching & you will find out how to get the right value.  it's a bit trial and error but not difficult.

 

[salomonander]

thanks rob!
ok now maybe for a stupid question.... my frontpanel gives me the option of iron/bypass/clean. i honestly do not care for  transformerless option. although it would be a lot of work - could i have a chandler/emi choice instead? i know id need different transformers but have some carnhills anyways. i guess id need some extra relays to re-configure the input/hold pot but that should be possible.

the only differences are pot arrangement (and value) plus the transformers right? does anyone know which pot chandler used on the tg1? and which carnhills for in and out?

thanks a lot and sorry if this info was already posted....

 

[Rob Flinn]

thanks rob!
ok now maybe for a stupid question.... my frontpanel gives me the option of iron/bypass/clean. i honestly do not care for  transformerless option. although it would be a lot of work - could i have a chandler/emi choice instead? i know id need different transformers but have some carnhills anyways. i guess id need some extra relays to re-configure the input/hold pot but that should be possible.

the only differences are pot arrangement (and value) plus the transformers right? does anyone know which pot chandler used on the tg1? and which carnhills for in and out?

thanks a lot and sorry if this info was already posted....

VTB 9045 on input  VTB1148 on output.  You could probably do this, but you will have to work it out for yourself because I don't think anyone has done this.

 

[bruno2000]

thanks rob!
ok now maybe for a stupid question.... my frontpanel gives me the option of iron/bypass/clean. i honestly do not care for  transformerless option. although it would be a lot of work - could i have a chandler/emi choice instead? i know id need different transformers but have some carnhills anyways. i guess id need some extra relays to re-configure the input/hold pot but that should be possible.

the only differences are pot arrangement (and value) plus the transformers right? does anyone know which pot chandler used on the tg1? and which carnhills for in and out?

thanks a lot and sorry if this info was already posted....

Chandler uses Carnhill mic pre XF on input.
Best,
Bruno2000

 

[salomonander]

VTB 9045 on input  VTB1148 on output.  You could probably do this, but you will have to work it out for yourself because I don't think anyone has done this.

cheers. im well aware that i will be alone on this but it should not be too complicated. anyone know what pot value chandler used on the input?

 

[Rob Flinn]

cheers. im well aware that i will be alone on this but it should not be too complicated. anyone know what pot value chandler used on the input?

10k log

 

[salomonander]

10k log

cheers...

 

[salomonander]

...and im back
slightly insecure about the hold control. in order to be less confused i re-drew the shematic as to what i think is right for an emi type unit. could anyone be so kind as to take a look? is the pots wiper shorted with one side? thanks a lot

 

[salomonander]

...and this for chandler?

 

[salomonander]

can anyone be so nice and comment on my drawings? are they correct? cheers

 

[Rob Flinn]

They look very nice, but I don't have time to check them.  Sorry.

 

[Ilya]

Has anybody have any HS2051 spares left? I'd like to buy some. Preferably the ones that give the unity gain.

As a side note, has anybody actually measured the curve of these zeners?

 

[salomonander]

...i think im missing an important piece of information. does anyone have the TG_FIX.rar file? i cant find it anywhere for download and need the information. cheers

 

[Ilya]

Here you go.
Remove the ".txt" from the extension to make it a proper RAR archive.

 

[salomonander]

cheers mate. i whish i could help you with the diodes but the only source i knew had barely enough for me. if i find another source ill let you know.

 

[salomonander]

gosh this is a tough one for me. i cant use the pcb since my frontpanel is drilled differently (so all switches are on breadboard) and my freaking adhs makes it really tough for me to sort this out. i might be wrong but i think the schematic is drawn wrong in this section.  i tried to make sense of it, redrawing the schematic once again. it would be great if anyone without adhs could chime in and correct me if im wrong.  i drew for a 1:1 emi unit with 10k lin hold. but why is this 270ohms resistor in there? its not in the original schematic.

thanks a lot

 

[Ilya]

I've got a problem with 1N751A zeners from Central Semi.  In the batch that I received from Mouser all zeners are very noisy. When I replace these with another zeners, everything is fine, but with 751A the unit is a noise machine. Has anybody had anything like that?

 

[fripholm]

When I replace these with another zeners, everything is fine, but with 751A the unit is a noise machine.

What type are the other Zeners and did the unit work as expected with these?

 

[Ilya]

What type are the other Zeners and did the unit work as expected with these?

Don't remember which ones, got them in local store. I'm getting  roughly -76dBFS self noise vs -35dBFS with 751A. Unit works as expected, but I get a bit of CV on the signal and can't get rid of that no matter what. Going to tinker a bit more.