First Dumble build

[67plexi]

I have most of the parts to build a #124 build. I would like input if this is a good starting point.
For the power supply I have Sprague powerlytic. 36dx 320uf 350vdc x2 made in USA.
Nos. 6ps. Sprague, atom Sprague, Phillips. I will need Transformers. IM open but I
Like the Heyboer iron if possible. I build one to two amps per year for myself and find the Dumble amp’s interesting. Thanks to Brandon for all the contribution you and others in this forum have provided.

Best regards, Steve.

[talbany]

What type output tubes?

[67plexi]

Output tubes. I have 6l6gb black plates, 6l6wgb gray plates all USA.
KT66 GEC, KT77 GEC,EL34 RFT.

I hope this helps, Thank you,talbany
Regards, Steve.

[67plexi]

some singles, of Quads.

[talbany]

Steve

Transformers from different manufactures around here is a pretty subjective topic...Most here will agree that for the money the off the shelf Heyboer Twin/Showman replacements for 6L' types are the way to go....

For EL 34 types in the same catagory are the Marshall replacements from CE Distrubution... There Marshall power transformers are also very quiet but will put between 465-475 on the plates...Same deal for the money good Iron..

Mercury Mag also makes some good pieces... You can go with there Twin replacements... Although many people here say they cannot hear the difference between the higher priced mags over the lower Heyboer's...Subjective

Other Mercury Mags people have used with good results are..Dynaco A-470
clone..
MM High powered Tweed Twin...

Hammond makes good stuff although sounds to me like they use M6 so they can be a little Hi Fi sounding... There 1650 series are nice

Since the Dumble design doesn't require a large amount of output tube distortion like a plexi... it does however need to carry some beef to help keep it throaty at higher volumes so you don't have to spend a ton of money to get something that sounds Dumbley IMHO...
I think Webber and Mojo carries the Heyboer Twin replacements or maybe someone here will sell you one of there spec.. Transformers...

I assume if you plan on using those tubes your going to install seperate bias supply's?..
Is that a Mullard KT-66 .... Dang!! I just built an Express with a pair of GEC's thats pretty rockin... Good Luck with the build...

Tony VVT

[67plexi]

Tony, Can the A- 470 output transformer take the wattage ?
I have two rocket builds with A-470 iron and love it.
If not should I start with a 40 Watt amp I have a Fender blues deluxe 1983
I hate the sound of the chassis is 22"x7.25"x2.5". It would be cool to
have a wolf in sheeps clothes. I have a 100 watt chassis on order.
I don't think a 40 watt amp will have the headroom but the small clubs
I play in most of the time 40 watts should be ok. I play clean.
I will have all the boards done next week.
The rig I use now 1-express detuned, 1- rocket, 1 superlead plexi 1959 1968. pre 1200 series hendrix tone stack.
I did rebuild a 1965 bandmaster for a friend used mallory caps and did the
power supply filter like #124 and a MM power transformer it was one of the best fender amps I have ever played, All that has played this amp want's it.

Thanks, Steve.

[David Root]

I just started the same build. Plan to try four used RCA blackplates, with backup of four new Russian Tungsol 6L6GC-STR if they don't work out. The STRs look a lot like the short tube blackplate, I'm sure that's no coincidence.

Would like to hear how the blackplates compare with yours. Are yours NOS? That is sure a niiiice stash of tubes you have there!

For iron I am using regular Twin iron by Magnetic Components, have used M-C in other amps and they are good, and VERY good price. I have a backup OT the Marshall 100W by M-C, in case the smaller lighter Twin OT doesn't do it for me. I cannot believe that Marshall OT, eight pounds avoirdupois for only $54, made in USA.

[talbany]

Tony, Can the A- 470 output transformer take the wattage ?
I have two rocket builds with A-470 iron and love it.
If not should I start with a 40 Watt amp I have a Fender blues deluxe 1983
I hate the sound of the chassis is 22"x7.25"x2.5". It would be cool to
have a wolf in sheeps clothes. I have a 100 watt chassis on order.
I don't think a 40 watt amp will have the headroom but the small clubs
I play in most of the time 40 watts should be ok. I play clean.
I will have all the boards done next week.
The rig I use now 1-express detuned, 1- rocket, 1 superlead plexi 1959 1968. pre 1200 series hendrix tone stack.
I did rebuild a 1965 bandmaster for a friend used mallory caps and did the
power supply filter like #124 and a MM power transformer it was one of the best fender amps I have ever played, All that has played this amp want's it.

Thanks, Steve.

IMHO.. If your really looking to nail the D-Tone you pretty much have to go with the 100 watt.. I'ts not about volume it's about tone.. The extra 2 tubes deliver those low mids that gives it that slow growl Dumbles are known for..The 50's just don't seem to do that for me.. some people will argue this point... For me it's cut and dry...Since your going through all the trouble and time of building it do the 100 w/50 switch...
There may be a little learning curve controlling the 100 at first in small rooms but you'll get the hang of it find the guitars that work and never look back.. For you for the money I would use the Heybeor Twin Showman power ... If you like the MM vibe better as I do their Blackface Twin Clone is wonderful... If money is an issue the Heyboer off the shelf will do nicely.. If it's 34's myself and a few others have seen good results with the CE Marshall style...
Word of advice.. There is a Layout I did on 124 in the files/sticky section you want to follow Dumbles grounding scheme note for note..Hope this helps..

Tony VVT

[67plexi]

Tony, Thank you for the heads up on the 100 watt.
I think you saved me from shooting my self in the foot as per 40watt.
I have marshall iron in stock but I want to lean towards the twin/showman
6l6 as per #124. for starters. then a HRM. As far as black plate tubes
I have a set of RCA 6v6 I use for amps that I repair for testing that kill.
Next speakers used, I know EV's are used but I have a 2 x 12 vox cab
with JBL's but you need a man and a boy to move this cab.
Oh! no! a subjective topic, speakers.

Thanks, Steve.

[talbany]

Tony, Thank you for the heads up on the 100 watt.
I think you saved me from shooting my self in the foot as per 40watt.
I have marshall iron in stock but I want to lean towards the twin/showman
6l6 as per #124. for starters. then a HRM. As far as black plate tubes
I have a set of RCA 6v6 I use for amps that I repair for testing that kill.
Next speakers used, I know EV's are used but I have a 2 x 12 vox cab
with JBL's but you need a man and a boy to move this cab.
Oh! no! a subjective topic, speakers.

Thanks, Steve.

The 6V's don't really do the Dumble thing very well IMO...Although a quad in an amp like 124 is pretty cool.. Just becomes a different animal.. Watch the plate voltages on those old 6V's... 450v is too high for NOS.. I recommend the JJ's as they can take those plate voltages...Personally I like the Marshall Iron in a HRM or Bluesmaster.. That's just me..There is plenty of info on here if you do a search about different opinions on certian types of speakers to give you some perspective there..Good Luck with the build...

Tony VVT

[67plexi]

Tony, After Tag's Clip of #183 I will use a quad of el34 RFT dimple top's.
I have a Marstran 1202-55 power transformer, 350v-350v 450volts on the plates. C1998 output transformer 1.75k.C1999 3H choke. on hand.
Thank you for the help. If you want I have a case of sprague powerlytic
36dx 320uf @ 350v made in USA NOS. I will send you a pair if you want
PM me with shipping info.

Regards, Steve.

[BobW]

Tony, Can the A- 470 output transformer take the wattage ?
I have two rocket builds with A-470 iron and love it.
If not should I start with a 40 Watt amp I have a Fender blues deluxe 1983
I hate the sound of the chassis is 22"x7.25"x2.5". It would be cool to
have a wolf in sheeps clothes. I have a 100 watt chassis on order.
I don't think a 40 watt amp will have the headroom but the small clubs
I play in most of the time 40 watts should be ok. I play clean.
I will have all the boards done next week.
The rig I use now 1-express detuned, 1- rocket, 1 superlead plexi 1959 1968. pre 1200 series hendrix tone stack.
I did rebuild a 1965 bandmaster for a friend used mallory caps and did the
power supply filter like #124 and a MM power transformer it was one of the best fender amps I have ever played, All that has played this amp want's it.

Thanks, Steve.

IMHO.. If your really looking to nail the D-Tone you pretty much have to go with the 100 watt.. I'ts not about volume it's about tone.. The extra 2 tubes deliver those low mids that gives it that slow growl Dumbles are known for..The 50's just don't seem to do that for me.. some people will argue this point... For me it's cut and dry...Since your going through all the trouble and time of building it do the 100 w/50 switch...
There may be a little learning curve controlling the 100 at first in small rooms but you'll get the hang of it find the guitars that work and never look back.. For you for the money I would use the Heybeor Twin Showman power ... If you like the MM vibe better as I do their Blackface Twin Clone is wonderful... If money is an issue the Heyboer off the shelf will do nicely.. If it's 34's myself and a few others have seen good results with the CE Marshall style...
Word of advice.. There is a Layout I did on 124 in the files/sticky section you want to follow Dumbles grounding scheme note for note..Hope this helps..

Tony VVT

I certainly agree with Tony, 100W is the way to go!