# ODR-1



## Chuck D. Bones

This is the Aion Andromeda, it's a Nobels ODR-1 with a BASS control similar to the Timmy's.  PedalPCB sells the Nobleman, which is an exact replica of the ODR-1.  I wanted the BASS control, and rather than mod a Nobelman, I went with the Andromeda.  Aion makes one other optional mod: the hard clipping diodes can be a single anti-parallel pair, like the stock ODR-1, or four diodes in series-parallel for lighter hard clipping.  I built mine with four hard clipping diodes: 1N4003's & 1N4148s.  I fooled around with some of the other semiconductors, using BA482's for the soft clippers (higher Vf) and LM833s for the opamps (quieter than JRC4558's).  I socketed the opamps in case I want to swap them out.  I subbed a 2N5089 for the 2N5088 because that's what I had. 

This pedal is a low-gain overdrive, really a dirty boost, in the same league as the Klon Centaur.  Like the Klon, there are ton of parts for tone shaping.  The ODR-1 is known to be quite bassy, in fact Nobels now offers the ODR-1 with a bass-cut switch inside.  Aion went one better and put a BASS pot on the front panel.  The SPECTRUM control is unique. Below noon it's a mild mid boost and above noon it's a mid cut.  Unlike the Klon, there is no charge pump because none is needed.  Unless you put a boost in front of this pedal, there is no way to saturate the opamps.





Note the complete lack of symmetry in the board layout.  Take note HamishR: I went to special pains to align the main board perfectly in the box. ?


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## Barry

Has that footswitch been soldered? Great looking build!


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## Chuck D. Bones

Yeah, it has.  I checked the pic before posting and I know it doesn't look like it's soldered.  I spot solder on one side of each terminal to minimize the risk of overheating the switch.  It's the side you can't see in this pic.

Thanks!  I love those hammer tone boxes from Tayda.  It's hard to resist using them on everything!


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## music6000

Chuck D. Bones said:


> This is the Aion Andromeda, it's a Nobels ODR-1 with a BASS control similar to the Timmy's.  PedalPCB sells the Nobleman, which is an exact replica of the ODR-1.  I wanted the BASS control, and rather than mod a Nobelman, I went with the Andromeda.  Aion makes one other optional mod: the hard clipping diodes can be a single anti-parallel pair, like the stock ODR-1, or four diodes in series-parallel for lighter hard clipping.  I built mine with four hard clipping diodes: 1N4003's & 1N4148s.  I fooled around with some of the other semiconductors, using BA482's for the soft clippers (higher Vf) and LM833s for the opamps (quieter than JRC4558's).  I socketed the opamps in case I want to swap them out.  I subbed a 2N5089 for the 2N5088 because that's what I had.
> 
> This pedal is a low-gain overdrive, really a dirty boost, in the same league as the Klon Centaur.  Like the Klon, there are ton of parts for tone shaping.  The ODR-1 is known to be quite bassy, in fact Nobels now offers the ODR-1 with a bass-cut switch inside.  Aion went one better and put a BASS pot on the front panel.  The SPECTRUM control is unique. Below noon it's a mild mid boost and above noon it's a mid cut.  Unlike the Klon, there is no charge pump because none is needed.  Unless you put a boost in front of this pedal, there is no way to saturate the opamps.
> 
> View attachment 4309
> 
> Note the complete lack of symmetry in the board layout.  Take note HamishR: I went to special pains to align the main board perfectly in the box. ?
> 
> View attachment 4310


Nice Build,  ODR-1 Overdrive. It's my Mates Number 1!!!!
He recently moved back to Perth, Australia but for 5 years lived in Hamburg, Germany & has toured there every year for 20 years.  
The Original designer Bernhard Kurzke is good friends with him & Gave him the ODR-1 & recently the Mini.


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## cooder

Nice one! Have to check it out, a classic espeially amongst Nashville studio cats I believe.


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## music6000

Chuck D. Bones said:


> I love those hammer tone boxes from Tayda.  It's hard to resist using them on everything!


Oh , I hadn't noticed!!!


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## HamishR

Well it's good to see that standards are being adhered to.  I like your idea of using 1N4148s with 1N4003s. I must try that. Did you like the result?

Good stuff.  I chose the Aion board for the same reasons. I like the pedal but don't use it much - you have inspired me to try it again. I just received some Aion boards I ordered well over a month ago so I'm hoping my PedalPCB order from the same time may show up soon too.


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## Chuck D. Bones

Ha ha ha, I got the idea from you!  I don't have another ODR-1 with just 1N4148s to compare with it, and the circuit barely tickles the hard clipper except at the very attack of the note. So it may not be the best place to showcase how that diode combo plays.  I do like the ODR-1. It's easy to dial in just a hint of dirt or get more aggressive, and the SPECTRUM control has a whole, well, _spectrum _of tonal possibilities.

I had to pull out my other lower-gain dirt pedals for comparison and I rediscovered my modified BossTone.


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## HamishR

I think you make a good point when you comment on the asymmetry of the circuit layout. Obviously it will affect the sound. Do you find that you feel unbalanced, mentally or physically while playing this pedal? Any nausea, headache or halitosis?

And i have to admit i suspected you got the idea for that diode selection from me.  I got it from Rockett. In a lot of my pedals it just works. LEDs work in some circuits but i find them a bit unnatural sounding in others.


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## Barry

Chuck D. Bones said:


> Yeah, it has.  I checked the pic before posting and I know it doesn't look like it's soldered.  I spot solder on one side of each terminal to minimize the risk of overheating the switch.  It's the side you can't see in this pic.
> 
> Thanks!  I love those hammer tone boxes from Tayda.  It's hard to resist using them on everything!


I love the looks of them, but they don't do well with waterslides


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## HamishR

I dug out my Aion Andromeda after seeing this and tried it again.  It's a very good sounding pedal but a little too compressed for me - probably why it's popular in Nashville. I think the diode combo you went with would probably help.


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## joelorigo

Chuck D. Bones said:


> This is the Aion Andromeda, it's a Nobels ODR-1 with a BASS control similar to the Timmy's.  PedalPCB sells the Nobleman, which is an exact replica of the ODR-1.  I wanted the BASS control, and rather than mod a Nobelman, I went with the Andromeda.  Aion makes one other optional mod: the hard clipping diodes can be a single anti-parallel pair, like the stock ODR-1, or four diodes in series-parallel for lighter hard clipping.  I built mine with four hard clipping diodes: 1N4003's & 1N4148s.  I fooled around with some of the other semiconductors, using BA482's for the soft clippers (higher Vf) and LM833s for the opamps (quieter than JRC4558's).  I socketed the opamps in case I want to swap them out.  I subbed a 2N5089 for the 2N5088 because that's what I had.



Looks nice!

I am building this next. I have already ordered all the parts on the list but what would you say the difference tone-wise was in the LM833 vs the JRC4558, other than being quieter? Same with the diodes you used vs the stock? Based on a build report from the Aion site, I am planning to socket those 2 extra diodes in question, so I can compare with and without them.


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## Chuck D. Bones

I personally was never that keen on the 4558.  It's just a dual 741.  The opamps don't saturate in this circuit, so there is not much, if any, sonic difference besides noise floor.  I did not compare different opamps or diodes in-circuit. My goal with the diodes was to get something in between the stock setup and Aion's four-diode hard clipper.  The soft clipping diodes I used, BA482's, have a higher Vf so the four-diode hard clipper gets hit a little harder.  If you want to explore the differences, then sockets are the way to go.  Make sure you know which diodes are which in the hard clipper, the Aion build docs are ambiguous on this.  Refer to the schematic.  If you want to have two diodes in the hard clipper, you only have to replace one of the four with a jumper.  It doesn't matter which one.  If you omit two diodes and jumper one or both, then you need to get the right pair.


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## Danbieranowski

If you haven't tried one yet, check out the Wonder Drive. Not a lot of drive on tap in it, but a lot of tone shaping options. It's been one of my go-tos for a while now and I've built a handful for friends. While mostly they are being used for tightening low end for heavy low-tuned stuff, I've found that they sound really good as a sort of gritty boost, and they boost into effects REALLY well, making delays and reverbs sound nice and full.


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## joelorigo

Chuck D. Bones said:


> I personally was never that keen on the 4558.  It's just a dual 741.  The opamps don't saturate in this circuit, so there is not much, if any, sonic difference besides noise floor.  I did not compare different opamps or diodes in-circuit. My goal with the diodes was to get something in between the stock setup and Aion's four-diode hard clipper.  The soft clipping diodes I used, BA482's, have a higher Vf so the four-diode hard clipper gets hit a little harder.  If you want to explore the differences, then sockets are the way to go.  Make sure you know which diodes are which in the hard clipper, the Aion build docs are ambiguous on this.  Refer to the schematic.  If you want to have two diodes in the hard clipper, you only have to replace one of the four with a jumper.  It doesn't matter which one.  If you omit two diodes and jumer one or both, then you need to get the right pair.


The instructions say:

_"If you don’t want to use the additional diodes, you can either run jumper wires across them..."_

Doesn't this mean installing jumpers instead of the diodes? A jumper where the diode would go for each D6 & D7?

_or you can just bridge the two jumper pads to the immediate left of D7._

I don't know what this means


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## dlazzarini

Danbieranowski said:


> If you haven't tried one yet, check out the Wonder Drive. Not a lot of drive on tap in it, but a lot of tone shaping options. It's been one of my go-tos for a while now and I've built a handful for friends. While mostly they are being used for tightening low end for heavy low-tuned stuff, I've found that they sound really good as a sort of gritty boost, and they boost into effects REALLY well, making delays and reverbs sound nice and full.


I love my wonder drive. Do you have a reliable source for those opa2604’s? I lucked out on my first one and didn’t get burned but they no longer have then in stock. Lots of fakes from china


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## Chas Grant

That’s a real beauty! I built an Aion ODR-1 a while back for my daughter. It’s a great little overdrive. I went with the 4558, is the LM833 noticeably quieter? If so I may have to give it a try. After building this pedal I had to bribe her with a new Strat so I could get my Tele back!???


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## Danbieranowski

dlazzarini said:


> I love my wonder drive. Do you have a reliable source for those opa2604’s? I lucked out on my first one and didn’t get burned but they no longer have then in stock. Lots of fakes from china



They are pricey, but you can still get them through Small Bear. Otherwise, you're dealing with sorting through potential fakes or repurposed used ones that people sell as new. The picture on the Small Bear site is for an opa2134, but the ones that arrive will be 2604. I've also built them with 2134s and TL072s, and I don't recall the difference being noticeable sonically. 









						IC OPA2604AP
					

Small Bear Electronics DIY Parts




					smallbear-electronics.mybigcommerce.com


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## dlazzarini

Danbieranowski said:


> They are pricey, but you can still get them through Small Bear. Otherwise, you're dealing with sorting through potential fakes or repurposed used ones that people sell as new. The picture on the Small Bear site is for an opa2134, but the ones that arrive will be 2604. I've also built them with 2134s and TL072s, and I don't recall the difference being noticeable sonically.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> IC OPA2604AP
> 
> 
> Small Bear Electronics DIY Parts
> 
> 
> 
> 
> smallbear-electronics.mybigcommerce.com


Thanks for the info


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## Flying

This makes an interesting read: https://nordland-electronics.de/en/blog/odr-1.html


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## dlazzarini

Flying said:


> This makes an interesting read: https://nordland-electronics.de/en/blog/odr-1.html


Thanks. I’ll check it out when I get home later


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## Flying

I'm just looking at the ODR1 Plus schematic, in particular the boost bit, but not understanding how the boost works, can anyone enlighten me?


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## Chuck D. Bones

I'll keep this as simple as possible.  The gain of the 1st stage is determined by the impedance of everything between pins 2 & 3, which we'll call Zf, and the impedance of everything between pin 3 & ground, which we'll call Zg.

The gain, G is given by:

G = 1+ Zf / Zg

Notice this if Zg gets smaller, the gain gets larger.  The Boost switch puts R15 & C15 in parallel with R12, R13, C12 & C13.  Engaging the Boost switch makes Zg roughly 3x smaller, which will make the gain approx 3x larger.

Because of the capacitors and diodes, the gain varies with frequency & amplitude, but the general principle is still valid.  Note that this is a gain boost and not a volume boost.  The apparent volume will go up a little when Boost is engaged, but the main effect of Boost is more distortion and sustain.


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## Flying

Thanks Chuck, and for keeping it simple, this boost can so easily be put on a switch and wired into the PCB I think give it a go.

When I saw the 2.2u cap in the boost section I thought it was going to make an already bass 'rich' pedal have even more bass! I appreciate that this because I don't have the knowledge to understand what's going on, so thanks again for clarifying.


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## Chuck D. Bones

Engaging Boost will boost frequencies above 250Hz, based on C15 & R15.


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## Flying

I've just been looking at the schematic for the ODR-S, this is the Bass Mid and Treble eq version, the bit that caught my eye was that the hard clipping diodes are AA112s rather than the 1N4148s I've seen in the other schematics.

These AA112s are germanium, rather expensive and seem to have a higher forward voltage compared to 1N4148, I know that in Aion's version he's suggested 2 1N4148s in series to increase the forward voltage, making me think there is some milage in playing with different diodes in the hard clipping part of the circuit. 

Any suggestions for diodes that might be a good substitute that are not silly money?


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## Chuck D. Bones

A couple of thoughts...

Can you point me to, or share the ODR-S schematic?

AA112 are $0.90 ea at PedalHacker.  Not expensive.  Their advertised Vf is 0.28V-0.29V, which is much less than 1N4148.

Lower Vf in either diode pair increases compression.  There is interaction between the soft and hard clippers which means that the effect of changing Vf in one pair depends on the Vf of the other pair.


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## fig

I'm in!


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## Chuck D. Bones

Hmmmm, interesting.  Thanks.  I stand by my previous statements.


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## Barry

Took me a minute to get my head around the way they do their pots


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## Flying

Interesting, this data sheet has a forward voltage of 0.95v max (no minimum) 

https://datasheetspdf.com/pdf/155557/ETC/AA112/1


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## Chuck D. Bones

Vf = 0.95V max is at If = 10mA.  Small signal diodes like these have fairly high resistance and that's what causes the high Vf at 10mA.  The ODR-S circuit will put less than 0.4mA into the hard clippers, so the Vf given on PedalHacker is more applicable.

This points out the pitfall of comparing Vf without know If.  
I measured an OA74A.  Vf = 0.36V @ 1mA; Vf = 0.84V @ 5mA.
I measured a D18.  Vf = 0.37V @ 1mA; Vf = 0.57V @ 5mA. 
Both are Ge diodes, have about the same Vf @ 1mA, but their V-I curves are very different because the resistance of the D18 is substantially lower.


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## music6000

I used NOS Sylvania 1N34A's in my ODR-S Build!


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## Barry

music6000 said:


> I used NOS Sylvania 1N34A's in my ODR-S Build!


That's exactly what I was thinking about using


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## fig

I thought the ODR-1 had like 7 transistors?

Edit: It does, Nobleman has 2 transistors. OP "exact replica" threw me`, but it's all good.


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## Flying

The ODR-1 is not true bypass and so has a number of transistors doing the switching. Pedal PCB's is true bypass, when the pedal is on it should sound exactly like the original.


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## fig

Right on.


Flying said:


> The ODR-1 is not true bypass and so has a number of transistors doing the switching. Pedal PCB's is true bypass, when the pedal is on it should sound exactly like the original.


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