SSS002 build happiness

[rccolgan]

quick tone report after changing the filters to 1000pf silver mica and 1000pf orange drop. I can hear a difference too! I was pretty surprised!

I revisited the reverb 2.2m before and after the 10k. (I currently have a 5751 reverb driver because the voltages matched the Japanese schematic and Dumble was known to use 5751s here. I also have a 4AB3C1B tank) The reverb becomes much brighter with the 2.2m before the 10k. Too bright in my opinion as it gets in the way of the guitar and the tail is very long. Personally, I liked the 2.2m after the 10k. I experimented with different tanks and landed on 9AB2C1B as my preference which reduced the tail a little further. I have not tried a 12AT7 yet however, I am very happy with the 5751/9AB3C1B combo now.

Does anyone have new thoughts about V1 voltage? The only way I can get V1 to match V2 like the Japanese schematic is to put a 5751 in V1. 12AX7 puts me at around 234vdc.

[Richard1001]

quick tone report after changing the filters to 1000pf silver mica and 1000pf orange drop. I can hear a difference too! I was pretty surprised!

I revisited the reverb 2.2m before and after the 10k. (I currently have a 5751 reverb driver because the voltages matched the Japanese schematic and Dumble was known to use 5751s here. I also have a 4AB3C1B tank) The reverb becomes much brighter with the 2.2m before the 10k. Too bright in my opinion as it gets in the way of the guitar and the tail is very long. Personally, I liked the 2.2m after the 10k. I experimented with different tanks and landed on 9AB2C1B as my preference which reduced the tail a little further. I have not tried a 12AT7 yet however, I am very happy with the 5751/9AB3C1B combo now.

Does anyone have new thoughts about V1 voltage? The only way I can get V1 to match V2 like the Japanese schematic is to put a 5751 in V1. 12AX7 puts me at around 234vdc.

Does the 1000pf / 1000pf difference resemble the Dumbleland special 009 video? This would be unexpected and would realy surprise me.

I noticed with the 5751 in my amp, the kathode voltage would be 4 volt. With a 12at7 it is 7 volt in my amp which imo would match the input voltage of the driver better.

To match voltages, buy a few TAD 12ax7-c tubes. Their matching is al over the place.

I use a amperex 12ax7 in V1, a Sylvania 12at7 for reverb and for the rest i use Chinese 6n4 tubes.

[rccolgan]

quick tone report after changing the filters to 1000pf silver mica and 1000pf orange drop. I can hear a difference too! I was pretty surprised!

I revisited the reverb 2.2m before and after the 10k. (I currently have a 5751 reverb driver because the voltages matched the Japanese schematic and Dumble was known to use 5751s here. I also have a 4AB3C1B tank) The reverb becomes much brighter with the 2.2m before the 10k. Too bright in my opinion as it gets in the way of the guitar and the tail is very long. Personally, I liked the 2.2m after the 10k. I experimented with different tanks and landed on 9AB2C1B as my preference which reduced the tail a little further. I have not tried a 12AT7 yet however, I am very happy with the 5751/9AB3C1B combo now.

Does anyone have new thoughts about V1 voltage? The only way I can get V1 to match V2 like the Japanese schematic is to put a 5751 in V1. 12AX7 puts me at around 234vdc.

Does the 1000pf / 1000pf difference resemble the Dumbleland special 009 video? This would be unexpected and would realy surprise me.

I noticed with the 5751 in my amp, the kathode voltage would be 4 volt. With a 12at7 it is 7 volt in my amp which imo would match the input voltage of the driver better.

To match voltages, buy a few TAD 12ax7-c tubes. Their matching is al over the place.

I use a amperex 12ax7 in V1, a Sylvania 12at7 for reverb and for the rest i use Chinese 6n4 tubes.

I'll have to give that a shot! I'm about 25v too high if I'm comparing like the Japanese schematic.

The comparison of my filters is close to the Dumbleland now between the two 1000pf/1000pf but I'm going to guess one of the 1000pf is swapped out with something between 330pf and 1000pf based on what I hear in the demo video on YouTube

[hermannbjorgvin]

Checking in with a quick brief. Got one of the original #002 run and implemented the following changes:

• V1 LNFB lowered resistor changed from 1M to 100K

• Entrance to filters changed .01uf first and then the .001 network

• Reverb LNFB was already 100K in my build by chance

• Added reverse polarity protection diode

Things I skipped out on for now:

• Chose not to implement the 2.2M resistor before the 10K on the reverb

• Didn't have a 60uf cap on hand for the power stage

For reference I have a RCA ECC83 in V1 (new logo box) and it measures around 240 but my mains voltage is high.

Obvious improvement to the bass, it sounds like the two rock signature now. And the LNFB changes to V1 sound great too.

[rccolgan]

Awesome check in!

[rccolgan]

Obvious improvement to the bass, it sounds like the two rock signature now. And the LNFB changes to V1 sound great too.

You mean it sounds like a Dumble

[hermannbjorgvin]

Obvious improvement to the bass, it sounds like the two rock signature now. And the LNFB changes to V1 sound great too.

You mean it sounds like a Dumble

Sounds like a Colgan now

[erwin_ve]

The last update for my amp is with the updated serial cap for the filter instead of the parallel cap.
I had some time to give it a try on a band soundlevel. Recorded with my phone. pls make sure you have the 720p or 1080p setting for better high frequency reproduction.

[10thTx]

Beautiful tone! Thanks for sharing the sound clip.

I'd be very happy with an amp like that.

with respect, 10thtx

[dbharris]

Your amp sounds fantastic Erwin!

-Dan

[Richard1001]

I have a question about LTSpice and hope someone is able to help.
I downloaded Ryans 002 file and corrected the schematic to the latest upgrades.

When simulating the filters i got readings much like the same frequency response graphs as Martin. The low settings are much lower (db) than the treble side which are relative high. Somehow this does not represent what i hear. I dissabled the reverb in the schematic, because i only wanted to measure direct signal, and measured the simulated signal on different points through out the amp. When i did this i noticed that the only place the frequency response graph reacts according to what i am hearing is on both the outputs of the phase inverter. The strange thing is that following the signal to the input of the driver, only one cap further, the frequency response is back to how it was on the input of the PI.

To explain what i mean i here is a foto of the screen: yellow is the PI input, pink is the PI output and red is the CF input. High is on the second position (150p) low on the 4th position)

20210511_213617.jpg

The pink line is what i hear and would expect to see, but this is somehow only present on the output of the PI and nowhere else. Since i am new at LTSpice: am i doing something wrong or is there something wrong with the program?

[rccolgan]

I have a question about LTSpice and hope someone is able to help.
I downloaded Ryans 002 file and corrected the schematic to the latest upgrades.

When simulating the filters i got readings much like the same frequency response graphs as Martin. The low settings are much lower (db) than the treble side which are relative high. Somehow this does not represent what i hear. I dissabled the reverb in the schematic, because i only wanted to measure direct signal, and measured the simulated signal on different points through out the amp. When i did this i noticed that the only place the frequency response graph reacts according to what i am hearing is on both the outputs of the phase inverter. The strange thing is that following the signal to the input of the driver, only one cap further, the frequency response is back to how it was on the input of the PI.

To explain what i mean i here is a foto of the screen: yellow is the PI input, pink is the PI output and red is the CF input. High is on the second position (150p) low on the 4th position)

20210511_213617.jpg

The pink line is what i hear and would expect to see, but this is somehow only present on the output of the PI and nowhere else. Since i am new at LTSpice: am i doing something wrong or is there something wrong with the program?

Hey Richard. It's quite possible my simulation has something weird going on. They can get pretty complicated. If you'd like, maybe we can start a new thread on LTspice simulations of #002 and the Dumbleland so we can join our efforts and keep the momentum going.

I just invested in a arbitrary signal generator and 'scope to run Bode Plots/frequency responses through my amps so I should be able to help verify the simulations are correct or at least close. I'm pretty excited about it

[Max]

... Somehow this does not represent what i hear. ...

Of course, it is possible, or perhaps even likely, that this is due to some software bug. But as far as I know, it is basically the case that our perception of the timbre of a musical instrument does not correlate particularly well with its frequency spectrum. Envelope and starting transients often have an even greater influence on our perception of timbre. Here you can listen to an audio demonstration if you should be interested:

https://www.animations.physics.unsw.edu ... velope.htm

"Quanitfying Sound": https://www.animations.physics.unsw.edu ... index.html

Best regards,

Max

[Richard1001]

Thank you both for your answers. I am aware that the perception of what i hear can differ from the actual frequency spectrum. To me it is just odd how the LT Spice simulations react and wondered if this is a known problem, if the program is limited in its ability to simulate or than i am doing something wrong.
Since a lot of people use it and draw conclusions based on the simulations, it is good to know if these simulations give a real life result or not.

[talbany]

Wrong thread?