Fender HRDX to ODS Build
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GuitarsByDelaney
- Posts: 28
- Joined: Fri May 17, 2019 5:52 pm
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Re: Fender HRDX to ODS Build
I'm not a beginner, per se - more a dangerously informed but conceptually needing neophyte.

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GuitarsByDelaney
- Posts: 28
- Joined: Fri May 17, 2019 5:52 pm
Re: Fender HRDX to ODS Build
Finished all the wiring save the FX loop but fired her up to make an unloaded voltage chart -
HRD2ODS
V1.1 - 459.1
V1.2 - 0
V1.3 - 0
V1.4-5 - 3.668VAC
V1.6 - 454.5
V1.7 - .324VAC
V1.8 - 0
V1.9 - 3.666VAC
V2.1 - 455.6
V2.2 - 0
V2.3 - 0
V2.4-5 - 3.666VAC
V2.6 - 452.4
V2.7 - 0
V2.8 - 0
V2.9 - 3.661VAC
V3.1 - 475.3
V3.2 - 0
V3.3 - 0
V3.4-5 - 3.660VAC
V3.6 - 476.1
V3.7 - .030VAC
V3.8 - 0
V3.9 - 3.665VAC
V4.1 - null
V4.2 - 3.665VAC
V4.3 - 485.8
V4.4 - 485.3
V4.5 - -49.62
V4.6 - -49.68
V4.7 - 3.666VAC
V4.8 - 0
V5.1 - null
V5.2 - 3.660VAC
V5.3 - 485.0
V5.4 - 485.2
V5.5 - -49.63
V5.6 - -49.64
V5.7 - 3.662VAC
V5.8 - 0
I did not enjoy wiring the switches and we shall never speak of it again.



Anything I'm missing?
HRD2ODS
V1.1 - 459.1
V1.2 - 0
V1.3 - 0
V1.4-5 - 3.668VAC
V1.6 - 454.5
V1.7 - .324VAC
V1.8 - 0
V1.9 - 3.666VAC
V2.1 - 455.6
V2.2 - 0
V2.3 - 0
V2.4-5 - 3.666VAC
V2.6 - 452.4
V2.7 - 0
V2.8 - 0
V2.9 - 3.661VAC
V3.1 - 475.3
V3.2 - 0
V3.3 - 0
V3.4-5 - 3.660VAC
V3.6 - 476.1
V3.7 - .030VAC
V3.8 - 0
V3.9 - 3.665VAC
V4.1 - null
V4.2 - 3.665VAC
V4.3 - 485.8
V4.4 - 485.3
V4.5 - -49.62
V4.6 - -49.68
V4.7 - 3.666VAC
V4.8 - 0
V5.1 - null
V5.2 - 3.660VAC
V5.3 - 485.0
V5.4 - 485.2
V5.5 - -49.63
V5.6 - -49.64
V5.7 - 3.662VAC
V5.8 - 0
I did not enjoy wiring the switches and we shall never speak of it again.



Anything I'm missing?
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GuitarsByDelaney
- Posts: 28
- Joined: Fri May 17, 2019 5:52 pm
Re: Fender HRDX to ODS Build
Tried preamp tubes first and with that load the voltages dropped to a range you'd expect, as did the power tubes when I put them in.
It clean sounds really quite fantastic but it's also very quiet. Quiet like, I can dime the MV and Volume and it's a pretty casual volume level, not enough for a bar gig.
The OD channel is wonky too - sounds crazy spongy and starved. I played with the bias and OD level trimmer but those didn't address the issue of whatever's sucking volume.
I can tell this is going to be a really, really great amp once I sort the volume gremlins!
It clean sounds really quite fantastic but it's also very quiet. Quiet like, I can dime the MV and Volume and it's a pretty casual volume level, not enough for a bar gig.
The OD channel is wonky too - sounds crazy spongy and starved. I played with the bias and OD level trimmer but those didn't address the issue of whatever's sucking volume.
I can tell this is going to be a really, really great amp once I sort the volume gremlins!
- JazzGuitarGimp
- Posts: 2357
- Joined: Mon Jul 23, 2012 4:54 pm
- Location: Northern CA
2 others liked this
Re: Fender HRDX to ODS Build
Hi Evan,
If you hadn’t wired the efx loop jacks before you played the amp, that’s your problem. You would need to run a short jumper from the send point to the return point (like your red jumper at the standby switch connector), otherwise the preamp output is not connected to the power amp input, and you are just hearing bleed from one signal path to the other.
Ciao,
Lou
If you hadn’t wired the efx loop jacks before you played the amp, that’s your problem. You would need to run a short jumper from the send point to the return point (like your red jumper at the standby switch connector), otherwise the preamp output is not connected to the power amp input, and you are just hearing bleed from one signal path to the other.
Ciao,
Lou
Lou Rossi Designs
Printed Circuit Design & Layout,
and Schematic Capture
Printed Circuit Design & Layout,
and Schematic Capture
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GuitarsByDelaney
- Posts: 28
- Joined: Fri May 17, 2019 5:52 pm
Re: Fender HRDX to ODS Build
Ah! Wonderful! A simple fix from a minor oversight - that's great!JazzGuitarGimp wrote: ↑Tue Mar 31, 2020 11:19 pm Hi Evan,
If you hadn’t wired the efx loop jacks before you played the amp, that’s your problem. You would need to run a short jumper from the send point to the return point (like your red jumper at the standby switch connector), otherwise the preamp output is not connected to the power amp input, and you are just hearing bleed from one signal path to the other.
Ciao,
Lou
Re: Fender HRDX to ODS Build
I can’t believe you got any sound at all!
I build and repair tube amps. http://amps.monkeymatic.com
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GuitarsByDelaney
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Re: Fender HRDX to ODS Build
I knew whatever was the matter had to be something, uh, not horrible, because I was definitely hearing the amp and its potential but obviously something was askew.
But...IT IS NOW FINSISHED!
Testing the loop -

Back home again!

Re: Fender HRDX to ODS Build
Oh, DANG! I love a finished product!
How's it sounding?
How's it sounding?
I build and repair tube amps. http://amps.monkeymatic.com
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GuitarsByDelaney
- Posts: 28
- Joined: Fri May 17, 2019 5:52 pm
Re: Fender HRDX to ODS Build
I'm legitimately gobsmacked at how good the clean channel sounds in particular - so musical, articulate, harmonically rich. The V30 was just what the amp had in it and it sounds pretty freakin' good with just that, haven't even tried it with anything else.
The gain channel is very different from what I'm used to and I need to work with the trimmers to balance its EQ and relative output level. It's very aggressive and bright, which aren't bad things just different. Maybe it's the clarity and note definition being retained in the gain that hits my ear so differently.
Any thoughts on optimally dialing it in? I'm kinda curious about playing with the PI balance trimmer but the clean already sounds so good that I feel like I don't want to mess it up.
I think I labeled the FX S/R backwards, oh well. It works and sounds stellar so who cares?

- norburybrook
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Re: Fender HRDX to ODS Build
I've really enjoyed seeing this come together. Congratulations on a great build.
Kudos to Lou and Xtian for such a great concept and product.
M
Kudos to Lou and Xtian for such a great concept and product.
M
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GuitarsByDelaney
- Posts: 28
- Joined: Fri May 17, 2019 5:52 pm
Re: Fender HRDX to ODS Build
Thank you kindly, I'm glad you enjoy it! I really like well-documenting fun and interesting builds.norburybrook wrote: ↑Wed Apr 01, 2020 9:17 am I've really enjoyed seeing this come together. Congratulations on a great build.
Kudos to Lou and Xtian for such a great concept and product.
M
Arron and Lou have been wonderful to work with and very gracious with their time and knowledge.
Re: Fender HRDX to ODS Build
For the OD, I find I need to turn the Treble trimmer down, almost to zero, and boost the mid and low trimmers a little. To set the OD entrance trimmer, first set your Volume control in clean mode where it sounds good (I like mine around noon, maybe a little more). Then adjust the OD trimmer so that you have a good sweep on the OD Drive control.GuitarsByDelaney wrote: ↑Wed Apr 01, 2020 4:13 amThe gain channel is very different from what I'm used to and I need to work with the trimmers to balance its EQ and relative output level. It's very aggressive and bright, which aren't bad things just different. Maybe it's the clarity and note definition being retained in the gain that hits my ear so differently.
Any thoughts on optimally dialing it in? I'm kinda curious about playing with the PI balance trimmer but the clean already sounds so good that I feel like I don't want to mess it up.
Finally, I leave my PI balance centered. My ears could not perceive a whole lot of change, regardless of setting.
I build and repair tube amps. http://amps.monkeymatic.com
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GuitarsByDelaney
- Posts: 28
- Joined: Fri May 17, 2019 5:52 pm
Re: Fender HRDX to ODS Build
A little softening of the top end would definitely help balance it out, I think. Perhaps, or likely, I'm misunderstanding the gain structure of the circuit as my OD Level is 3:00 or higher with the OD similarly high, and the internal trimmer nearly maxed, to perceivably equal the same output of the clean Volume. I feel I may be doing something wrong...but my functional and/operation user issues/qualms aside the amp sounds phenomenal and I find I love the clean channel and pushing that with a fuzz or boost is nirvana.xtian wrote: ↑Wed Apr 01, 2020 4:04 pmFor the OD, I find I need to turn the Treble trimmer down, almost to zero, and boost the mid and low trimmers a little. To set the OD entrance trimmer, first set your Volume control in clean mode where it sounds good (I like mine around noon, maybe a little more). Then adjust the OD trimmer so that you have a good sweep on the OD Drive control.GuitarsByDelaney wrote: ↑Wed Apr 01, 2020 4:13 amThe gain channel is very different from what I'm used to and I need to work with the trimmers to balance its EQ and relative output level. It's very aggressive and bright, which aren't bad things just different. Maybe it's the clarity and note definition being retained in the gain that hits my ear so differently.
Any thoughts on optimally dialing it in? I'm kinda curious about playing with the PI balance trimmer but the clean already sounds so good that I feel like I don't want to mess it up.
Finally, I leave my PI balance centered. My ears could not perceive a whole lot of change, regardless of setting.
This made me curious about revisiting the Tweedle Dee circuit - I'm attracted to the idea of distilling the ODS clean channel into a single channel platform as a condensed grab-n-go.
Re: Fender HRDX to ODS Build
Mine is very different: with my Volume set at noon, OD Drive is around 8:00, OD Level is at 4:00. In OD mode, this give me just a bit of distortion, growl, thicker, more compression.
I build and repair tube amps. http://amps.monkeymatic.com
- norburybrook
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Re: Fender HRDX to ODS Build
The Tweedle Dee is nothing like the clean ODS channel. There's very little true clean headroom before it starts to break up.GuitarsByDelaney wrote: ↑Thu Apr 02, 2020 3:04 pmxtian wrote: ↑Wed Apr 01, 2020 4:04 pmFor the OD, I find I need to turn the Treble trimmer down, almost to zero, and boost the mid and low trimmers a little. To set the OD entrance trimmer, first set your Volume control in clean mode where it sounds good (I like mine around noon, maybe a little more). Then adjust the OD trimmer so that you have a good sweep on the OD Drive control.GuitarsByDelaney wrote: ↑Wed Apr 01, 2020 4:13 amThe gain channel is very different from what I'm used to and I need to work with the trimmers to balance its EQ and relative output level. It's very aggressive and bright, which aren't bad things just different. Maybe it's the clarity and note definition being retained in the gain that hits my ear so differently.
Any thoughts on optimally dialing it in? I'm kinda curious about playing with the PI balance trimmer but the clean already sounds so good that I feel like I don't want to mess it up.
Finally, I leave my PI balance centered. My ears could not perceive a whole lot of change, regardless of setting.
This made me curious about revisiting the Tweedle Dee circuit - I'm attracted to the idea of distilling the ODS clean channel into a single channel platform as a condensed grab-n-go.
It's a great amp but nothing like the clean ODS.
If you're after the clean ODS then just go with the small special, that's the clean only channel of an ODS and I'm sure it would fit in a small grab and go combo.
M