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DIY Stompboxes => Building your own stompbox => Topic started by: Dimitree on February 12, 2019, 09:44:17 AM

Title: small stone using LM13700
Post by: Dimitree on February 12, 2019, 09:44:17 AM
hello,
can I use LM13700 instead of CA3094 on the Small Stone?
would that work without modifications and give the same results (except less noise luckly)?

thank you
Title: Re: small stone using LM13700
Post by: Kevin Mitchell on February 12, 2019, 10:15:23 AM
I believe it'll work in all places but the LFO since the collector of the buffer is shorted internally to V+ in the LM13700. The Small Stone schematic shows that pin connecting to one of it's own inputs. You could simply use an external darlington buffer and accommodate the connection.
Small Stone schematic here (http://www.montagar.com/~patj/smlstone.gif)

There is already a version of the Small Stone that uses LM13600. Not sure if there's a project file available for this. But worth looking.
(https://i.postimg.cc/JDnYfbpX/st.png) (https://postimg.cc/JDnYfbpX)
Title: Re: small stone using LM13700
Post by: Scruffie on February 12, 2019, 10:52:05 AM
Schematic http://lectric-fx.com/wp-content/uploads/2018/03/SH2.pdf
Title: Re: small stone using LM13700
Post by: Kevin Mitchell on February 12, 2019, 10:59:49 AM
Quote from: Scruffie on February 12, 2019, 10:52:05 AM
Schematic http://lectric-fx.com/wp-content/uploads/2018/03/SH2.pdf
Looks like I was on the right track  8)
Title: Re: small stone using LM13700
Post by: Dimitree on February 13, 2019, 04:36:45 AM
than you,
one thing I noticed on those LM13700/13600 schematic adaptions it that the + and - input pins on the OTA are inverted, compared to the original schematic with CA3094. Any reason for that?
Title: Re: small stone using LM13700
Post by: Scruffie on February 13, 2019, 01:43:45 PM
Quote from: Dimitree on February 13, 2019, 04:36:45 AM
than you,
one thing I noticed on those LM13700/13600 schematic adaptions it that the + and - input pins on the OTA are inverted, compared to the original schematic with CA3094. Any reason for that?
If you're referring to this schematic;

(http://www.montagar.com/~patj/smlstone.gif)

It's because whoever drew it labelled the + & - wrong  :)
Title: Re: small stone using LM13700
Post by: Marcos - Munky on February 13, 2019, 02:45:37 PM
There's the Tonepad Ross Phaser project, which uses LM13600:
http://tonepad.com/getFileInfo.asp?id=99

Btw,
Quote from: Dimitree on February 12, 2019, 09:44:17 AM
can I use LM13700 instead of CA3094 on the Small Stone?
The Small Stone uses CA3080, not 3094.
Title: Re: small stone using LM13700
Post by: Scruffie on February 13, 2019, 02:51:56 PM
Quote from: Marcos - Munky on February 13, 2019, 02:45:37 PM
Btw,
Quote from: Dimitree on February 12, 2019, 09:44:17 AM
can I use LM13700 instead of CA3094 on the Small Stone?
The Small Stone uses CA3080, not 3094.
The Tonepad Small Stone uses the CA3080, the original uses the CA3094 (house stamped as EH1048).
Title: Re: small stone using LM13700
Post by: Marcos - Munky on February 13, 2019, 03:43:26 PM
Ah didn't knew on that. Every schematic I saw asks for 3080, so I assumed it was the one that was used on the original.