100w Bluesmaster HRM new build

[norburybrook]

@talbany, interesting looking at the photo that the resisters marked as koa CF are in fact metal film , that is unless CF used to be blue, which I suppose could be the case as they're blue on the layout.

Marcus
What are you talking about?..The Carlton amp is a Ripper I have not done a layout on a Ripper!
I don't really care either way use whatever resistors you want to use!!

Tony

Tony, I was referning to your Bluesmaster layout. I realise the ripper isn't that! sorry.

M

[talbany]

Marcus
I did that layout 8 years ago! so I really don't remember why I labeled the ones in the layout blue?. But! I highly doubt (given Dumbles track record) he used just Carbon film or Metal films or KOA's or Rodderstien's or Q-lines or RN-series in the PI of every single Bluesmaster that he ever built. Could I be wrong? possibly, because I have not been in every single Bluesmaster that Dumble built..I also highly doubt that just because Dumble used all metal films in the Carlton amp that that's some kind of sign that Dumble used the same all blue MF resistors in every single Bluesmaster amp that Dumble ever built.
The point is that as time passes and new photos are leaked we see certain parts that are on the layout like resistor types, Circuit board material, types of switches and FET's and POT's and Transformers and Chassis, tube types, Polyester, Polypropylene etc could have and quite possibly did change throughout the manufacturing processes of the Bluesmaster line

You're a big boy,I've seen your posts you know your way around an amp and am sure you know the difference between MF and carbons Don't get so hung up on what Dumble used exactly!(you will go nuts!). So trust your ears and the knowledge you've gained here and pick a damn resistor!..

Good Luck with the build!

Tony

[norburybrook]

Marcus
I did that layout 8 years ago! so I really don't remember why I labeled the ones in the layout blue?. But! I highly doubt (given Dumbles track record) he used just Carbon film or Metal films or KOA's or Rodderstien's or Q-lines or RN-series in the PI of every single Bluesmaster that he ever built. Could I be wrong? possibly, because I have not been in every single Bluesmaster that Dumble built..I also highly doubt that just because Dumble used all metal films in the Carlton amp that that's some kind of sign that Dumble used the same all blue MF resistors in every single Bluesmaster amp that Dumble ever built.
The point is that as time passes and new photos are leaked we see certain parts that are on the layout like resistor types, Circuit board material, types of switches and FET's and POT's and Transformers and Chassis, tube types, Polyester, Polypropylene etc could have and quite possibly did change throughout the manufacturing processes of the Bluesmaster line

You're a big boy,I've seen your posts you know your way around an amp and am sure you know the difference between MF and carbons Don't get so hung up on what Dumble used exactly!(you will go nuts!). So trust your ears and the knowledge you've gained here and pick a damn resistor!..

Good Luck with the build!

Tony

tony, indeed and it's ironic we're haivng this conversation as after building a few amps now I've been a big advocate of , it doesn't matter that much what type of componenets are used in builds

I suppose there's still a little part of me wants to believe perhaps that there's the magic in using NOS original parts....




as always thankyou for the photos and work doing the layouts in the first place, I'm eternaly grateful to everyone who here who has contributed to the schematics and layouts and technical help.

right..normal service will now be resumed.


M


p.s. What with the new small orange drops ,resistors generally getting smaller, (I've used MEPCO 1w metal films for the plates which are tiny), the board looks quite strange now compared to the originals.

[norburybrook]

OK ......some more progress today.

I found that the PAB relay board on the screw/bolt standoffs meant there wasn't enough room to manoeuvre them into place without unwiring the mid switch and getting it out of the way!!! Obviously Taylor must use different standoffs and know space is tight, this is the first time I've used his chassis.


Three relays and an HRM board...lots of fiddly stuff to do.

the main boards look messy as they're old used ones I was given. I thought I might as well use them I made the rectifier/HRM/FET boards.

IMG_20180609_161756.jpg

DSC_1827.JPG

M

[talbany]

I suppose there's still a little part of me wants to believe perhaps that there's the magic in using NOS original parts....

Marcus
I don't want to talk about the parts thing again and really want to get back to the building. However, I don't want you to get the wrong impression in my above post that "

it doesn't matter that much what type of components are used in builds"

There are certain parts that can and IMO do affect the overall sound of your ODS...There are also certain parts that as you say does not matter much IMO..The ones that do matter most are certainly going to be in the direct signal path!, these are the parts you want to consider most. The ones that are most sensitive to the operational specs of the amp and are out of the audio path are chosen for different reasons and might include his precision MF's parts that he does not want to drift in high temps or years of use.
As you know Dumble used both types in the signal path of the same generation amps why?. Of coarse only Dumble knows the answer for sure . My impression would be the same as to why he used different types of caps.He knew which combination of both caps and resistors to use to help shape the overall sound of any given amp to suit a given players style and sound and was part of his customizing process.IMO this is the true art form of amp building!! and why his amps were so sought after by many great players!
So with that said?
I have a couple questions for you!..Do you prefer to use a set of NTE WH's on the grids of your new Bluesmaster amp build? or a set NOS Dralorics (Pihers) or would it suit you better to mix them up
What about plate resistors?..RN series or Rodderstiens? or KOA..Do you prefer all Draloric in the PI or all Metal films?
These would all be the things Dumble would consider after you tell him what it was you were chasing. Sometimes he can just hear you play and know the answers of these questions I asked you!..
This is why the parts selection would vary greatly from say the Carlton amp vs say the ODS that Eric Johnson used on his recording of the song ZAP!..So you see why looking at a gut shot of 1 ODS specimen might not be the one you would prefer to chase!
I am sure there are plenty of amp builders here who have experimented and built many amps over many years. Some if not most keep this info to themselves due to the time and energy and money spent to obtain it if you have not already gone nuts in the process
So hopefully now you better understand why I said what I said in my previous post!.

BTW..It's a good day when anyone tells me they appreciate my work Even more so from a great player like yourself!
Again Back to building your amp!

Tony

[talbany]

p.s. What with the new small orange drops, resistors generally getting smaller, (I've used MEPCO 1w metal films for the plates which are tiny), the board looks quite strange now compared to the originals.

Unfortunately with the electronics industry getting smaller and more portable so do the parts..I am sure there will come a time where all the key parts used to build a good sounding ODS will no longer become available to us How the newer "smaller" parts available perform and will we like them is still unknown since we are now just in the transition phase of the next generation being brought on by the new 5G technology might play a bigger role. Like I said in the above post the precision resistors out of the signal path are not so much going to be as big a problem as the ones that are in the path.. How do the new ones sound in the path are still AFAIK unknown..I went nuts and got out of amp manufacturing and have not experimented with these new parts yet so I have no opinion yet..This is where places like the Garage will hopefully help with that transition
So let us know what you think of your new Mepco resistors in the plates of your BM amp..
BTW I am using the smaller RN series Dales in the cathodes of my new Ultrasound ODS so we'll see!

Tony

[martin manning]

It's very hard to tell if people are listening with their psyche as opposed to their ears in these discussions.

IMO HAD used CF and MF resistors because they produced less noise, were more precise, and didn't drift- unlike like the CC's that were commonly used at the time. As "better" resistors became available, I believe CF were more common than MF, so the MF's were first used in the places where it mattered most for noise floor and precision: plate loads and biasing. Again, IMO, there is no reason not to use modern MF's everywhere, as they are cheap and widely available in 1% tolerance.

Regarding caps, I accept that different dielectric materials can be responsible for coloring the sound. 715P and 716P are polypropylene, and they are said to be the most "Hi-Fi" and "sterile" sounding (?). Differences between the two are 716P is pressed (flattened), and has tinned solid copper leads, where 715P is round and has tinned copper plated steel heads. The dielectrics used seem to be the same. Maybe this is the reason (right or wrong) that they are accepted in the PI of an amp that gets its distortion character from the preamp stages. They are also the most stable from a temperature and moisture absorption standpoint. Types 6PS, 225P, and 418P are all polyester film/foil, and should be more-or-less equivalent. Close examination of the data sheets shows differences in dissipation factor and maximum pulse rise time, which leads me to believe that they are made using different materials.

[talbany]

It's very hard to tell if people are listening with their psyche as opposed to their ears in these discussions.

Martin
To be perfectly clear!!.I listen with my ears!!

there is no reason not to use modern MF's everywhere, as they are cheap and widely available in 1% tolerance.

I totally agree if anyone prefers's the sound MF (or doesn't notice a difference)and wants to use them in the entire amp. Knock yourself out

Btw. Ceramic capacitors are the worst at stability and drift/leakage/ microphonics yet Dumble still uses them throughout the amplifier?
Tony

[martin manning]

Btw. Ceramic capacitors are the worst at stability and drift/leakage/ microphonics yet Dumble still uses them throughout the amplifier?

Have to look and see what kind were used. Maybe you or someone else here knows? Some ceramics (Class 3 and 4) are pretty bad, Class 2 are pretty good, and Class 1 (NP0, e.g.) are better than polypropylene film types. Multilayer ceramics are all the rage now due to their small size, and they will likely continue to reduce the availability of disc ceramics. Something else to worry about...

[erwin_ve]

For ceramics: on the mid switch and the snubbers I saw multiple pictures of x5f ceramics, including #124.

In the past I had a some murata ceramics with a J, 1KV, 84 marking, that I used on the mid switch. As soon as I replaced them by x5f ceramics the tone became a lot better. The murata had some really weird, not pleasant, overtones.
I have no clue what causes this behavior. On paper there are better ceramics specs.

[talbany]

I have no clue what causes this behavior.

Probably Microphonic.

Dumble used several different types of ceramics the most popular were/ are?

X5F's (like in 124) and are epoxy-ed were the best quality ceramics I have seen in a Dumble amp..You find these mostly in the typical 3rd and 4th generation amps and scattered throughout the rest.
The others were pretty standard fare ceramic caps (like you would see in a typical Fender amp).
The worst ones were in a Bluesmaster.The real tiny ones with just PF rating on them.(cannot remember the type)We got a bag of 100 once for 2 bucks (I think you can get them from China for less)
My guess would be Dumble liked the gritty (harmonically complex)overtones that they provided in his more aggressive sounding amps.
Dumble did, however, use micas in certain amps however the most by far I have seen were Ceramics!
I have never seen a Polystyrene or a Monolithic anywhere near a Dumble amp..The ones you really want to stay away from are X7R and Z5U types

BTW. I will not ever use those cheap Xicon radial filter caps in any of my power supplies..We tried those in a few protos and immediately pulled them and used them in things like the switching networks!!
Here is Aiken on Ceramic Caps

Silver mica or polystyrene film capacitors are the best choices. They have the best temperature stability and most transparent tone. However, the polystyrene film caps in the pF range usually have very tiny leads, which may not be robust enough to stand up to the rigors of road use. There are very few capacitor manufacturers making low-pF value film capacitors in other dielectrics, such as polypropylene or polyester, and they are nearly impossible to find. Ceramic capacitors should be avoided, as they are usually horribly microphonic, have very high odd-order harmonic distortion (the "bad, or harsh-sounding" kind), typically mostly 3rd and 5th and 7th harmonics, and have poor temperature stability.

Tony

[erwin_ve]

I have no clue what causes this behavior.

Probably Microphonic.

The ones you really want to stay away from are X7R and Z5U types

Maybe microphonic or high odd order harmonic distortion as decribed by Aiken.
Z5U; you know they are in several ODS but not in the signal path

[norburybrook]

I have no clue what causes this behavior.

Probably Microphonic.

The ones you really want to stay away from are X7R and Z5U types

Maybe microphonic or high odd order harmonic distortion as decribed by Aiken.
Z5U; you know they are in several ODS but not in the signal path

Aitken also says screen grid stoppers should be at least 1k.....Dumble ignores that. I've gone with 560R on this build, closest I could get to 470 in the right direction. Interesting that nick at Ceriatone uses 1.5K in his BM.


I'll be back doing some more tomorrow. Met up with Aaron (sleepwalker amps) today and had a look round the guitar stores in London.


Great to actually meet a fellow TAG member I the flesh...especially as he's from the other wide of the world.

M

[erwin_ve]

Probably Microphonic.

The ones you really want to stay away from are X7R and Z5U types

Maybe microphonic or high odd order harmonic distortion as decribed by Aiken.
Z5U; you know they are in several ODS but not in the signal path

Aitken also says screen grid stoppers should be at least 1k.....Dumble ignores that. I've gone with 560R on this build, closest I could get to 470 in the right direction. Interesting that nick at Ceriatone uses 1.5K in his BM.


I'll be back doing some more tomorrow. Met up with Aaron (sleepwalker amps) today and had a look round the guitar stores in London.


Great to actually meet a fellow TAG member I the flesh...especially as he's from the other wide of the world.

M

So you had a mini international ampgarage meeting, nice!

Screen grid stoppers of grid stoppers? Screen grid stoppers vary with the kind of tube used. 470 Ohm is typical and safe for a 6L6GC, for a EL34 a 1K is typical and safe for a Ods with 420-440v on the plates.
Could you point me to that specific Aiken article?

[norburybrook]

Erwin

here you are.

http://www.valvewizard.co.uk/gridstopper.html


M