100W HRM in the BluesMaster Style?

[oldmacman]

Those values aren't unreasonable - Dumble did the same thing in several amps. It really smooths out the tone. Try it and see what you think.

[mdroberts1243]

Those values aren't unreasonable - Dumble did the same thing in several amps. It really smooths out the tone. Try it and see what you think.

Thanks for the encouragement,

I plan/promise to build this schematic... however it evolves with the group's consensus!

I had great results building a Trainwreck and gleaning all the suggestions from the postings on that forum... I'm looking forward to a similar pleasant experience on this build.

[jelle]

Mark,

Many of us dislike the cap before the post OD tonestack...Larry also mentioned this cap here. My advice is to try it and decide what you like!

How does the amp sound to you when you play it?

Jelle

[mdroberts1243]

EDIT: Schematic updated and removed from this post!

Slight changes in this version...
-- corrected treble caps as suggested (.002 & 390pf)
-- default component values are as per alleged BM
-- bolded values with ??? are common tweaks/improvements (6) noted in other D-Clones... these are things I might try in appropriate combinations.
-- noted my intended component changes in brackets (xxx)[/b]
-- added a mid-boost relay, moved switches to footswitch wiring on power page
-- re-labelled B+ supplies to use standard scheme

Would appreciate some extra eyes on this! One question in particular: will the simplified FET switching work? (the dumble pics seem to note a more complicated scheme with isolated switching jacks)

Thanks,

[mdroberts1243]

EDIT... more recent PDF version further down the line...

In this draft I went to 11x17 paper to get everything on one page. Still seems legible when printed 8.5x11.

Everything now includes another relay (#4) and a dumblelator!

The preliminary power supply is shown, with placeholders for the dropping string, FET input circuit included, etc.

I still have to show panel switches for manual operation of the relays and the 5-pin XLR wiring I plan to use... Then I need to focus on layout.

Feedback & ideas always welcome!

Funk if you're out there... do you have detail shots of the preamp & hrm boards I could use towards the layout?

Thanks,

[heisthl]

Now that I see it drawn out, I see no purpose for the .001 across the bass pot in the "stacked" arrangement. The 2 .022 are doing anything the .001 would do (and more).

[mdroberts1243]

Now that I see it drawn out, I see no purpose for the .001 across the bass pot in the "stacked" arrangement. The 2 .022 are doing anything the .001 would do (and more).

I agree, 10x more cap in series... I'll take it out in the next revision, but it would've added a splash of orange to the POTs area!

[mdroberts1243]

Anybody out there with hints/recommendations/ideas w.r.t. squeezing a fourth preamp tube and the eyelet board for the D'Lator into Funk's standard chassis?

I'm gonna try right between the OD and PI tubes, but it looks awfully tight.

[mlp-mx6]

If you can go with a 50W amp, you can get one of the "octal to 9-pin" conversion plates from Weber and use the first (or fourth, depending on how you count!) octal hole as a 9-pin hole.

[mdroberts1243]

If you can go with a 50W amp, you can get one of the "octal to 9-pin" conversion plates from Weber and use the first (or fourth) octal hole as a 9-pin hole.

Personally, 50W is more than I would need or my gigging friend for that matter... but I haven't tried a 100W build, yet and want to see what the tone is like.

I'm thinking about 2-phase build... straight 100W passive loop but cut the hole for the 4th tube and pre-wire for the D'Lator... maybe a little eyelet board that surrounds the tube (with a punched out circle for the tube) could be added later, supported by the tube socket screws (and raised up quite a bit)... the extra dropping resistors and filter caps would have to be added to the new eyelet board, as it might be difficult to work them into Funk's existing PCB filter board. The send/receive level pots might need to be special (small) panel mount types.

Do you tend to fiddle with send/receive levels or set and forget?

[mdroberts1243]

EDIT: Look for the new version further down the line...


Nothing much new in this rev... removed the tonestack bass pot bypass cap, spec'd 250kA pots in both send & receive of D'Lator, up'd the Bass trimmer in the HRM to 1M ohm, changed the FX Send jack to non-shorting (that way the receiver is never open circuit if you just tap into the send).

Main purpose of this post is to try a PDF version of the schematic... I think it will display and print better... what do you prefer? (The JPG quality was getting poor for the size of the file).

[mdroberts1243]

It looks like relay boards could be in short supply... AmpDoc is out according to brown-note forum and Funk supplies two, only in full sets with his boards... so... here is an experimental post.

I've created a little 4-relay board (untested, but I've gotten as far as ordering a set) using ExpressSCH and ExpressPCB... I've attached a zip file with the necessary .pcb and .sch files and using those and ExpressPCB software (free) you could get yourself 3 boards for $51 + shipping from ExpressPCB.com using their 'miniboard' deal... with that as motivation you could build 3 100W BM amps!

The board will hold four 16-pin dip format relays (Omron, NEC, NTE, etc.), can be broken apart (in theory), has double-connections to each power & switch connection, on-board clamp diode, dropping resistor if needed, all connections along one edge for flexibility, important markings etched in, etc. The 4-40 mounting holes will be 2" apart. Hopefully this might be useful to someone.

Provided for your convenience and amusement only... All the standard disclaimers apply... I am not guaranteeing anything!

[mdroberts1243]

EDIT: Look for a more recent schematic later in the thread... this one removed as tube pin numbers, etc. changed.

Here is version 7 of the schematic, and now I've really got to start working on a layout... Funk must be getting close with the chassis'!

In this version I went back to the tried and true Dumble-ish plate/cathode values, but kept the strange (for Dumble) ones as bold text notes on the side.

The big innovation in this version is to wire up the rock/jazz switch independant of the relay contacts and to go to a much cleaner/simpler PAB switching that intuitively just makes sense! This simple switching is enabled by the standard Fender tone-stack topology.

Various little changes and tweeks throughout, including transient capacitors across the diodes, 1% resistors where Dumble was known to use them, etc. Also added proposed wiring for the four relays to a 5-pin XLR jack, although I think Funk's chassis is setup for a DIN style connector.

As always, I encourage a dialogue! I hate to think I'm talking to myself!

[heisthl]

swap the ????RK values in the OD section.
Are you sure you want a relay for the FX loop? It really increases the length of the wire runs (whether its a relay or a switch) and I think these amps sound better with the loop on all the time anyway. On my next build with an internal loop I'm going to wire the Send/Return jacks to disable the loop level pots and allow passthrough at a little above unity (roughly 50K at 200K above ground). When you plug in a patch cord the corresponding pot for that jack becomes active. If you want more or less loop gain with that arrangement you could just plug in a short jumper cable. This solves 2 problems 1. no worries about rear panel loop control settings when you're not using anything external and 2. no need for the extra signal runs to front panel switch.
We as builders would know if an amp was too loud or soft because of improper loop settings, but the average guitar player gets frustrated if he's at the mercy of a setting on the back panel he forgot to check.

[mdroberts1243]

swap the ????RK values in the OD section. .

Hi Heisthl,
I'm not sure what you are asking above... the ??? values are consistent with the "Blues Master Mod" column in AmpDoc1's spreadsheet. If you swap the Rk values in the OD section you would get the "SunnyLand" values from one version of the spreadsheet that I just found out about. Is the "SunnyLand" more credible?

Are you sure you want a relay for the FX loop? It really increases the length of the wire runs (whether its a relay or a switch) and I think these amps sound better with the loop on all the time anyway. On my next build with an internal loop I'm going to wire the Send/Return jacks to disable the loop level pots and allow passthrough at a little above unity (roughly 50K at 200K above ground). When you plug in a patch cord the corresponding pot for that jack becomes active. If you want more or less loop gain with that arrangement you could just plug in a short jumper cable. This solves 2 problems 1. no worries about rear panel loop control settings when you're not using anything external and 2. no need for the extra signal runs to front panel switch.
We as builders would know if an amp was too loud or soft because of improper loop settings, but the average guitar player gets frustrated if he's at the mercy of a setting on the back panel he forgot to check.

I like your ideas above, since one of the benefits touted by a dumblator is the additional harmonics I'm not adverse to having it live all the time. I think an FX relay can still be useful, and co-located with the jacks if necessary... it could become a true bypass for the external loop for instance, or an easy way to add another kind of 'boost' for lead, etc. Of course, I'm still struggling with how to fit it all in there!