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

[tommypiper]

Yeah I'm almost completely finished sourcing parts. Mouser has about 95% of the parts. Some of the other harder parts I got from ebay. After completion of this build I'll go ahead and post a US "updated BOM list".

Any chance to see this?  thanks

 

[tommypiper]

+1 for using 1/4" standoffs for the TO-66 transistors.
Anybody have a source for the ELMA switches?  I need 4.
Best,
Bruno2000

Did you manage to find them?  Maybe we can do a small group buy direct from Elma.  I've bought direct from them before and picked up directly at their office.

 

[tommypiper]

Some dumb questions: 

what does A.O.T. mean?  (Is it a form of calibration?  )

How do you calibrate?  (I'm not even close, just wondering)

I don't quite understand the bypass board.  (I know it's to create options for iron etc, and uses relays and op amps?.)  Do I NEED to use it?  Do I need to use op amps?  Can't I just hook up the unit without the bypass board, with iron in and out, or direct without iron and without the bypass board?

What is the scheme for all the connection points on the schematic?  Like "INTR1-4."  (I never understand these codes on any project...)  Where do we find these connections?

 

[bruno2000]

+1 for using 1/4" standoffs for the TO-66 transistors.
Anybody have a source for the ELMA switches?  I need 4.
Best,
Bruno2000

Did you manage to find them?  Maybe we can do a small group buy direct from Elma.  I've bought direct from them before and picked up directly at their office.

Yes, i got some, thanks! There has already been a small group buy.
Best,
Bruno2000

 

[tommypiper]

All right... I guess I'm still playing catch up.  I had no idea there was a group buy.  I seem to be late to the party on everything....  do you have a part number for the Elmas?  Haven't been able to find that either.  thanks.

 

[T-rex]

Finally got mine finished today.  UTC H-13 trannys on the input, Nishaminy AF-672 on the outputs (UTC A-20 clones).  OPA134 opamps on the bypass boards, which meant dropping the local board voltage to +/-18V.  NOS output transistors and OA202 diodes from electrochronic.  The meters had to be disassembled to replace the scale.  I was going to repaint them black, but when I stripped off the old finish with steel wool and mineral spirits, I liked the look so much that I left them in that "worn" state.  The front panel is Rustoleum Dark Bronze Hammered finish that I had laser engraved.  Then I put a coat of car wax on it and buffed it to a shine.

So how does it sound?  Are you happy with it?

 

[wmtunate]

So how does it sound?  Are you happy with it?

I'm really happy with it.  You can dial as much or as little grit as you want.  The transformers give a subtle but useful alternative to the clean option. You've really got to slam the input to make it respond though.  I've been using it on the drum bus this past week and I like what I'm hearing.

 

[electroslut]

wow that looks way cool, are there schematics for these?

 

[T-rex]

So how does it sound?  Are you happy with it?

I'm really happy with it.  You can dial as much or as little grit as you want.  The transformers give a subtle but useful alternative to the clean option. You've really got to slam the input to make it respond though.  I've been using it on the drum bus this past week and I like what I'm hearing.

Thats good to know.  I have two songs left to mix for the album I am working on now and then I start building this beast.  Can't decide whether hold or not.  Maybe input based on what having to drive it hard. . .you both went with Hold right?

 

[Hank Dussen]

Just finished my TG1 but I don't get it to work. The only output I get is some low hum. 20Hz @ -40dB or so. Doesn't seem to make a difference what I do with the controls. Meter doesn't move.
I also couldn't get the negative voltage to anything other then -18,3. No matter which jumper I use.
I'm thinking it might be something with the transistors?
The only ones of which I'm not sure are the BC214's. It's not really clear what's the flat side on them. The base was pre-bend in one direction when I bought them and I just inserted them in that way. But I'm not absolutely sure whether that's the right way.
I tried to identify the emitter and collector but found only a very small difference in the 2 voltage drops or resistance.

Anyway, can any one check the orientation of the BC214's on my boards?
Or give some other advice?

 

[Rob Flinn]

The output transistors get quite hot.  I fabricated some heatsinks out of angle aluminium for mine.

 

[maxwall]

Rob

Hot, Which output transistors ? 2Nxxx or MJExxxx, or TIP31A , 42A ( insulate with Mica insulators for TO-66 types ?)
__________________________________
Hank Dussen
Make sure 2Nxxxx output transistors are mounted with mica insulators or put on short standoffs.
The short standoffs allow the 2Nxxx deviice to cool from underneath, which is good.
With regards to BC214 , should be ECB , pin 1(emitter), 2(base),3(collector)
you can confirm each junction on the transistor using a simple diode test mode on a DVM. Make sure
your BC214 are not L type , then you would expect CEB for the leg orientation which is not recommended
on the TG board.

Check your 2Nxxxx transistors with hfe setting using modified TO-66 socket with wire leads plugged
into your DVM, works great !!! Its not uncommon to come across some bad ones.
_______________________________
WMTunate, nice work !!!
_________________________________

Tommypiper


ELMA rotary 04-1133-20 is correct part for TG

 

[Rob Flinn]

Rob

Hot, Which output transistors ? 2Nxxx or MJExxxx, or TIP31A , 42A ( insulate with Mica insulators for TO-66 types ?)

The 2 big silver ones on the bottom right in the picture above.  Use the mica washers & use some silicon heatsink compound/goo

 

[maxwall]

Rob,

from my experience , consensus from other builders , the TO-66's should be warm , not hot.

this might indicate short of some kind.

 

[Rob Flinn]

Rob,

from my experience , consensus from other builders , the TO-66's should be warm , not hot.

this might indicate short of some kind.

There's not a problem my unit works fine.   I just like to keep my semiconductors cool, especially when they're difficult to get hold of in the first place

 

[Hank Dussen]

Just finished my TG1 but I don't get it to work. The only output I get is some low hum. 20Hz @ -40dB or so. Doesn't seem to make a difference what I do with the controls. Meter doesn't move.
I also couldn't get the negative voltage to anything other then -18,3. No matter which jumper I use.
I'm thinking it might be something with the transistors?
The only ones of which I'm not sure are the BC214's. It's not really clear what's the flat side on them. The base was pre-bend in one direction when I bought them and I just inserted them in that way. But I'm not absolutely sure whether that's the right way.
I tried to identify the emitter and collector but found only a very small difference in the 2 voltage drops or resistance.

Anyway, can any one check the orientation of the BC214's on my boards?
Or give some other advice?

Any one else used BC214's that look like these ones?
How should they be orientated?
Like I said the pins were pre-bend, so I inserted them like that, but maybe it's not correct...

 

[Rob Flinn]

Hank

I used have those ones before, put them in the way the pins are bent.  They work fine.

If you're really really worried about it you can check them in a meter

 

[maxwall]

Hank Dussen,

From closer inspection it appears the silkscreen is labelled correctly on the board for a TO92
standard transistor package, it should read CBE, just as it is silkscreened on the TG board
for VT22 and all others using BC214.

Flat face of the TO92 transistor facing forward. Pin 1 Collector to left, pin 3 Emitter to right.

Hank, the package you have there is not TO92 standard package for that BC214.

I think the BC214 "P" you are using are reversed from normal BC214 , you need
to flip the device opposite the current position

Here is your pin layout for those odd looking BC214's P version (EBC) ?
Pin 1 , Emitter
Pin 2,  Base
Pin 3 , Collector

Normal BC214 is (CBE) for A, B, C and K versions
Pin 1 , Collector
Pin 2 , Base
Pin 3 , Emitter

BC214L version (BCE) L version only (not recommended for TG board -legs must be twisted )
Pin 1 , Base
Pin 2 , Collector
Pin 3,  Emitter

Hope this helps
Let us know if this works ?

 

[Rob Flinn]

I would check them with a meter, because they look like the ones I used, which worked the way the pins were bent.  With the legs bent the way they are it might reverse the pin order for you !

 

[haima]

yep, check them with a meter...

i used the BC214L (the L version) on my igor 2245c - just re-orientated it 45degrees so the legs were in the right holes. worked a treat.

the main thing is you have to check with a meter to know what pinout you have, then just follow the handy silkscreen.