1s1588 Test

[jwin615]

Vf is relative to the testing current.
If you measure Vf with one device and someone else on TGP measures it with a different device, it is very likely that you have near identical parts and very different measurements as the devices will use different currents for their tests. Unless you are curve tracing them, any othe measurement is arbitrary except measuring at the current(s) speced in the datasheet.

Also. There are a TON of curve traces of the Vf of diodes here and elsewhere. Most pedal specific diodes have been traced.
There are no transistors in a D+ so I don't know what you are looking for in hfe measurements and hFE measurements take expensive specialty equipment.
A lot of things determine the actual gain of a transistor in a circuit.

Has anyone actually pulled and tested vintage components so we know 100% what the hell the actual readings are, say Hfe or Vf?!??

I found out this the hard way with the whole MXR RR-104 fiasco. They released a limited run of D+ pedals supposed to be 100% to Randy Rhoads original pedal spec and finally put to rest rumors that his pedal may have been modified.

I purchased 2pc not knowing they were going to be limited, but one to keep in the box or give as gift to another Rhoads enthusiast and the other to play.

My pedal although nice and heavy, sounded nothing like my vintage 1978 and 1980 D- pedals! When investigated...what I found out was the Vf in the 0.6xx to 0.8xx range. The original pedals only run like 0.320 to 0.360-ish, so much more clipping and distortion and no wonder the thing sounded like shit and cleaner and not enough gain! This was inconsistent throughout the run with some having the correct range and many, including both of mine way out of spec, so I ended up selling both off!

I really would like someone....may do it myself have a dedicated page to these vintage pedals....TS9, OD-1, SD-1, D+, etc. and test the components and provide the specs of the transistors and diodes so that people can match them up instead of people saying....just throw in a 914, or 4148 or whatever and you end up with a similar situation above and the Vf supposed to be 0.350, but is more like 0.650 and you're wondering why the fuck it sounds like shit!!

Likewise, this will protect against bogus parts. I had a recent example of this when I decided to just twist up a Distortion+ and wanted vintage specs. I picked up 1N270 from 2 sources and the diode Vfs were off and again, sounded like shit! I found a source of 1n34a's, which should be like 1N270s and the guy suggested testing in the 0.340 range. I picked up a set of 20pc and sure enough, they tested in the 0.340V range, so he was right and these part exactly to proper spec and sound great!!....but we HAVE to know what the original pedal specs are!

 

[owlexifry]

There are a TON of curve traces of the Vf of diodes here

https://thomasbe86.github.io/plotly-plot/Diodes_Avg_Plotly.html

 

[jwin615]

https://thomasbe86.github.io/plotly-plot/Diodes_Avg_Plotly.html

There it is!
TY

 

[Nostradoomus]

Vf is relative to the testing current.
If you measure Vf with one device and someone else on TGP measures it with a different device, it is very likely that you have near identical parts and very different measurements as the devices will use different currents for their tests. Unless you are curve tracing them, any othe measurement is arbitrary except measuring at the current(s) speced in the datasheet.

Also. There are a TON of curve traces of the Vf of diodes here and elsewhere. Most pedal specific diodes have been traced.
There are no transistors in a D+ so I don't know what you are looking for in hfe measurements and hFE measurements take expensive specialty equipment.
A lot of things determine the actual gain of a transistor in a circuit.

 

[ICTRock]

lol which way you want it? fluke or atlas?
not sure why my word wasn't good enough the first time (about something which I gain nothing from lying about) but here we are

 

[Aentons]

To be fair, the makers can be fakers. The Ibanez SM9 has leds that look like regular diodes.

 

[equinox]

Vf is relative to the testing current.
If you measure Vf with one device and someone else on TGP measures it with a different device, it is very likely that you have near identical parts and very different measurements as the devices will use different currents for their tests. Unless you are curve tracing them, any othe measurement is arbitrary except measuring at the current(s) speced in the datasheet.

Also. There are a TON of curve traces of the Vf of diodes here and elsewhere. Most pedal specific diodes have been traced.
There are no transistors in a D+ so I don't know what you are looking for in hfe measurements and hFE measurements take expensive specialty equipment.
A lot of things determine the actual gain of a transistor in a circuit.

Thanks and understood.
The unit I use and test with is a Peak Atlas DCA75 which does have a curve tracer function.
Then I tested a myrid of RR-104 pedals and then compared them to my original vintage 1978 and 1980 D+ pedals, they were all tested with my DCA75, so when I was seeing some RR-104s in the 0.611 and 0.829V range and others in the 0.391 and 0.383 range...I was pissed, because it's significant and enough to hear! The 1978 and 1980 tested at around 0.340V, so some of the RR-104s were correct and others way off! With the DCA75, the readings are at 5.00mA.

I found this other link yesterday which has a lot of information and comparison to it - https://www.guitarpedalx.com/news/news/a-brief-hobbyist-primer-on-clipping-diodes

 

[jwin615]

Thanks and understood.
The unit I use and test with is a Peak Atlas DCA75 which does have a curve tracer function.
Then I tested a myrid of RR-104 pedals and then compared them to my original vintage 1978 and 1980 D+ pedals, they were all tested with my DCA75, so when I was seeing some RR-104s in the 0.611 and 0.829V range and others in the 0.391 and 0.383 range...I was pissed, because it's significant and enough to hear! The 1978 and 1980 tested at around 0.340V, so some of the RR-104s were correct and others way off! With the DCA75, the readings are at 5.00mA.

I found this other link yesterday which has a lot of information and comparison to it - https://www.guitarpedalx.com/news/news/a-brief-hobbyist-primer-on-clipping-diodes

If you have this knowledge and tools, why not just put the correct(in your opinion) diodes in the pedal? If you have already desoldered them to measure them, it seems trivial to put them back in...
Or just make a D+ that you want.
I don't really see what the issue is here
The OEM didn't use diodes to your spec?
Also. I, and I assume others, would be interested in seeing your traces.

 

[ICTRock]

man I've been distracted ... this is the distortion+ clown hijacking a thread about diodes unrelated to his precious

sometimes the shortest path between two points is a straight line in the opposite direction ... get some help, you've been ranting about your distortion+ diodes longer than it is healthy to do so and replacing them with your diodes of choice has been available to you this entire time

 

[jwin615]

man I've been distracted ... this is the distortion+ clown hijacking a thread about diodes unrelated to his precious

sometimes the shortest path between two points is a straight line in the opposite direction ... get some help, you've been ranting about your distortion+ diodes longer than it is healthy to do so and replacing them with your diodes of choice has been available to you this entire time