Has anyone seen this Dumble before

[pottedplant]

I think i shouldn't post when I haven't slept, but yet there I am doing it now

I'm going to do some reading for sure

[pottedplant]

If you want to build with period correct parts for your own peace of mind, have at it. There are other opinions, but I am personally comfortable with the idea that new parts don't sound significantly different from old parts of the same type.

Fair enough, I'm definitely open to the idea and I'm sure I'll experiment with both kinds of parts

Using old electrolytic capacitors is not a good idea, since their performance deteriorates over time. With careful treatment they can often be brought back to acceptable levels, but in general I think new ones will be more reliable. Ceramic capacitors and resistors (other than carbon composition type) are very stable, so no worries there. I wonder about film capacitors, though, since plastic films are known to deteriorate. I prefer to avoid any of these issues by using new parts. Probably everyone who has been doing this a while has had the experience of a new part being defective, however.

Oh yeah I imagine these old Sprague's would be iffy but it was fun to try and find suitable replacements as well as originals. I suppose I wasn't very clear on my intentions

You can build any of the ODS variants on those boards. The power supply board is configured for a stacked reservoir and individual filters, but you can easily add some eyelets and turn it into the "precision" style with stacked filters. The rectifier/bias board can be wired for a two-phase or FWB rectifier, so it will work for any ODS. The relay power board is configured for a FWB rectifier, with 12VAC input and 12V relays. A FWB should work with 6.3VAC input and 5V relays, provided a low-dropout regulator is used. If you want to build an HRM/Bluesmaster type, then you will need an HRM daughter board.

When you say stacked, does this mean parallel? As in the capacitors are effectively behaving as one large cap whose sum is a combination of both their values? I'm wondering what voltages will the capacitors see at the reservoir? Why do I sometimes see 500v ratings for those 300uF's on layouts and other times 300v? Is it a typo? what kind of b+ voltages are usually seen at these caps and does wiring them in parallel affect the voltage rating of the reservoir?

[pottedplant]

OK so this is a totally different question!

Yeah I'm just asking all kinds of stuff in here I should stop while I'm still ahead lol

If I would have to guess and judging by the overtones and breakup this amp has would indeed be a Bluesmaster and the reason why it sounds different than the Lerche amp I posted is because it looks like he is going into the FET input https://www.instagram.com/p/CXSUJQctbAZ/ and Peters was not Peters was also in the Jazz setting w/ mid boost on

I should have paid attention to the jack he was in
Those cleans in the second video are just incredible. It just seamlessly goes in and out of harmonic feedback!
What causes all those harmonic overtones in a Dumble amp? Is it not any one thing or can you point to some big contributors to this phenomenon? I'm seriously captivated by it

[gktamps]

Stacked = series connected capacitors. Cuts capacitance in half and adds voltage ratings, so for example, 2 100uF 100V caps results in 50uF 200V rating, with the caveat both need to be the same capacitance and voltage ratings so they share equally (though to ensure that, balancing resistors are used).

Quick web search for you:
https://eepower.com/capacitor-guide/app ... in-series/#

[martin manning]

When you say stacked, does this mean parallel? As in the capacitors are effectively behaving as one large cap whose sum is a combination of both their values? I'm wondering what voltages will the capacitors see at the reservoir? Why do I sometimes see 500v ratings for those 300uF's on layouts and other times 300v? Is it a typo? what kind of b+ voltages are usually seen at these caps and does wiring them in parallel affect the voltage rating of the reservoir?

If the capacitance is the same, series connected caps will share the voltage equally, but as gktamps points out, balance resistors are added to make sure by overwhelming any difference in leakage current. Parallel connected caps see the same voltage by definition. The reservoir (first filter) sees the highest voltage when in the amp is in standby, typically something a little under 500V. The #124 schematic has examples of both stacked and paralleled caps:

[talbany]

It just seamlessly goes in and out of harmonic feedback!
What causes all those harmonic overtones in a Dumble amp? Is it not any one thing or can you point to some big contributors to this phenomenon? I'm seriously captivated by it

You mean like this?

https://www.youtube.com/watch?v=qyB4HedEOvs

Tony

[beasleybodyshop]

Welcome to the forum!

Kind of nice to see a fresh face, and still full of the good creative curiosity. Never be afraid to ask questions....every dumb question in the world has been asked here a dozen times! Good luck with your build. Personally, the HRM models seem the hardest to play and tune. But if you love the sound then it just doesn't make sense to start with something else.

[erwin_ve]

Welcome Pottedplant,

The Bluesmaster can also be one of the most modern sounding amps of the Dumble arsenal.
When trying some things with recording I used a 4x12 cab with v30, certainly very modern rock sounding.

My amp is very close to the layout Tony posted.
On the "take off at feedback" I got no clue. Sometimes it happens when finishing a amp and sometimes not. Anybody out there feel free to enlighten me.

[pottedplant]

It just seamlessly goes in and out of harmonic feedback!
What causes all those harmonic overtones in a Dumble amp? Is it not any one thing or can you point to some big contributors to this phenomenon? I'm seriously captivated by it

You mean like this?

https://www.youtube.com/watch?v=qyB4HedEOvs

Tony

Yes exactly, well maybe not as much haha. No but seriously that's incredible. Did you ever find out what contributed to it? I have been doing a lot of reading on here and noticed you posted about it

Welcome to the forum!

Kind of nice to see a fresh face, and still full of the good creative curiosity. Never be afraid to ask questions....every dumb question in the world has been asked here a dozen times! Good luck with your build. Personally, the HRM models seem the hardest to play and tune. But if you love the sound then it just doesn't make sense to start with something else.

Thanks very much! Honestly I'm just glad to find a place that shares the same interest! I've got a ton of dumb questions and speculations in my thoughts that I'll post later

Welcome Pottedplant,

The Bluesmaster can also be one of the most modern sounding amps of the Dumble arsenal.
When trying some things with recording I used a 4x12 cab with v30, certainly very modern rock sounding.

My amp is very close to the layout Tony posted.

That sounds incredible, I love it. Freaking amazing tones.

On the "take off at feedback" I got no clue. Sometimes it happens when finishing a amp and sometimes not. Anybody out there feel free to enlighten me.

Honestly I wish Mr Dumble had been more open to sharing his creations with like-minded people. It's sad that we'll probably never know the secrets. From what I've heard since his passing, he was a very unique person but mostly very kind and accommodating. I think he just appreciated genuine people who weren't trying to make a profit off of his passion. The guy from the podcast who worked at fender said it was like he was creating an amp with the player and it was a shared thing between the two (dumble and the player) and that's how he wanted the other party to feel about it. I can totally relate to that, it sounds like Dumble never lost his passion for making incredible creations and was looking for people who felt the same way he did.

[talbany]

Yes exactly, well maybe not as much haha. No but seriously that's incredible. Did you ever find out what contributed to it? I have been doing a lot of reading on here and noticed you posted about it

So that amp was a High plate Skyliner and it feedback and bloomed similar to your friends Bluesmaster (although he was in the FET channel and had a bit more gain) Dumble's amps (if you build them right)they will all do the feedback thing. (Some a little more than others)
My point? It doesn't have to be a Bluesmaster to do it.
Hope this helps!

Tony

[drew]

I think i shouldn't post when I haven't slept, but yet there I am doing it now

I'm going to do some reading for sure

Suggestion: look up build threads by member "norburybrook." He has built most of the D-amp variants in the last half dozen years or so, offers good commentary, uses the amps in pro settings. Plus Larry Carlton borrows amps from him.

[pottedplant]

Yes exactly, well maybe not as much haha. No but seriously that's incredible. Did you ever find out what contributed to it? I have been doing a lot of reading on here and noticed you posted about it

So that amp was a High plate Skyliner and it feedback and bloomed similar to your friends Bluesmaster (although he was in the FET channel and had a bit more gain) Dumble's amps (if you build them right)they will all do the feedback thing. (Some a little more than others)
My point? It doesn't have to be a Bluesmaster to do it.
Hope this helps!

Tony

It very much does! I'm currently on the hunt for transformers. I have found some TMI made TF-130's not sure if these are desireable though... If you want to share what you think I am very open to suggestions!

I think i shouldn't post when I haven't slept, but yet there I am doing it now

I'm going to do some reading for sure

Suggestion: look up build threads by member "norburybrook." He has built most of the D-amp variants in the last half dozen years or so, offers good commentary, uses the amps in pro settings. Plus Larry Carlton borrows amps from him.

I actually saw that! The post about Larry asking to use his amp like maybe a year ago? Talk about incredible. But yeah, I've been lurking here for quite a while but just never got the courage to post. Thank you for telling me to look into his builds though, I hadn't really thought to do that.

[ijedouglas]

I have found some TMI made TF-130's not sure if these are desireable though... If you want to share what you think I am very open to suggestions!

I can't vouch for TMI. I tried the current MagicParts TF-130 and it didn't stay long in the amp. Not sure if they are the same.

I used Merren transformers http://www.merrenaudio.com/marshall_output_transformers in both a 183, BluesMaster and JTM45 and they are truly amazing. Chris makes some of the best Marshal repro transformers and really knows his stuff.

[Abe5150]

Welcome Pottedplant,

The Bluesmaster can also be one of the most modern sounding amps of the Dumble arsenal.
When trying some things with recording I used a 4x12 cab with v30, certainly very modern rock sounding.

My amp is very close to the layout Tony posted.
On the "take off at feedback" I got no clue. Sometimes it happens when finishing a amp and sometimes not. Anybody out there feel free to enlighten me.

Dang Erwin that sounds really good.

[pottedplant]

I have found some TMI made TF-130's not sure if these are desireable though... If you want to share what you think I am very open to suggestions!

I can't vouch for TMI. I tried the current MagicParts TF-130 and it didn't stay long in the amp. Not sure if they are the same.

I used Merren transformers http://www.merrenaudio.com/marshall_output_transformers in both a 183, BluesMaster and JTM45 and they are truly amazing. Chris makes some of the best Marshal repro transformers and really knows his stuff.

Those merrens look nice but I notice he only makes marshall style transformers, what about fender style power transformers? What would you recommend?