Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jamaio on January 18, 2017, 06:47:37 pm
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I am in the planning stage for my second Hoffman build. I have a Fender Sidekick Reverb 35 1x12 combo, it's a solid state amp made in Taiwan. I think it will make a great starting point for a new build. I want to build an amp with tube reverb and I think the Stout fits my plan.
http://el34world.com/projects/18WattStoutReverbNoSwitch_1.htm (http://el34world.com/projects/18WattStoutReverbNoSwitch_1.htm)
It appears that the Stout Reverb has changed some from the original build. The build in the link above uses a 40x20x20x20 cap can but the parts list and layout show 6 22uf/500v FT with 2 wired in series. I do not see a board to mount the 22uf/500v unless the board changed.
http://el34world.com/Hoffman/files/Hoffman_StoutReverb.pdf (http://el34world.com/Hoffman/files/Hoffman_StoutReverb.pdf)
The parts list does not have a PT or OT listed, I suppose the PT and OT used in the Stout TMB will work. Heyboer 18 watt Output transformer and Heyboer 18 watt Power transformer.
Also, the cabinet is only 15 inches wide so the reverb tank in the parts list will not fit, I could strap it to the back of the amp but I will probably find a smaller tank that will fit inside the cabinet. How much will a smaller tank change the reverb?
Here is a link that shows the Fender Sidekick being converted to a tube amp. This will show the cabinet and chassis I am using and possible layout for everything.
https://youtu.be/gmh40eZmG5U (https://youtu.be/gmh40eZmG5U)
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Meh, I like Terry and love his sense of humor but alas in my opinion he's made several "rookie" mistakes like I've seen from many other's that fancy themselves as "cutting edge" designers and builders like Carl from Carl's Custom Amps. Yes, I'm calling them out and don't know if they have a membership here or not? What I find is that they can copy an amp and/or a circuit fine (because they can merely copy how something was done before them) but don't really know anything about the nuances of doing things correctly and properly in a number of ways (layout, lead dress, component placement, grounding scheme, etc) which translates to superior performance including the lowest floor noise possible without oscillations, etc.
I will name one obvious one that all should learn and know immediately from that video that both people I've named are guilty of with each: You do not line up the transformer laminations while having them even remotely near each other. Notice when he first turns the amp on and it's audibly buzzing in the background? Then on subsequent parts while he's talking that the volume knob is down all the way? I'd love, no I dare him to turn the amp up full and put the camera anywhere near that amp the way it sits in that video (and without the input being shorted out or the speaker being disconnected).
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I'll have to update that Stout Reverb Parts list
That was so long ago that I did not even stock The Heyboer transformers and so they are not on the parts list
Just use a the 18 watt Heyboer tranny set on my transformer page here.
http://hoffmanamps.com/MyStore/catalog/Transformers.htm (http://hoffmanamps.com/MyStore/catalog/Transformers.htm)
I also did not stock the 40x20x20x20 caps way back then.
You can use any filter cap arrangement you like
I may update the layout also since the multi cap can is more convenient to use than single caps
There is one more stage on the Stout Reverb, and so you would have to use one single cap + the multi cap
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I added the 18 watt tranny set to the Stout Reverb parts list
That's what I used in that build
Had to go look at my build pics to see what I used
By the way, I still have that purple stout reverb amp
It used to be a silver faced Princeton reverb
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Meh, I like Terry and love his sense of humor but alas in my opinion he's made several "rookie" mistakes like I've seen from many other's that fancy themselves as "cutting edge" designers
Haha!! I have no intention of doing anything he is doing in the video, it was posted just to serve as a reference for the cabinet, chassis and speaker that I am starting with.
I'll have to update that Stout Reverb Parts list
I added the 18 watt tranny set to the Stout Reverb parts list
That's what I used in that build
Had to go look at my build pics to see what I used
By the way, I still have that purple stout reverb amp
It used to be a silver faced Princeton reverb
Thanks Doug!! The chassis and cabinet I am starting with is just a little smaller than the one you used. I have 3 short reverb tanks here so I will try one of those first because they will fit in my cab. I will probably place my order tonight, I have to get a list together of some other things I need as well.
I will consider the cap can option to save space, I was considering this layout for my caps:
(http://el34world.com/Hoffman/images/Dscn0295.jpg)
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My original plan was to convert my solid state amp to a Hoffman Stout Reverb. After receiving all the parts for the Stout Reverb I started planning my layout. I soon realized that the Stout Reverb was not a good choice for the chassis I was using, it would require punching holes for 7 tubes and space was limited. So I decided to convert it to a Hoffman 5F1 Champ.
Here are pictures of the chassis before I removed the old parts.
(http://johnmaiorana.com/img/s6/v144/p2197857113-2.jpg) (http://johnmaiorana.com/p955804498/e8300a359)
(http://johnmaiorana.com/img/s12/v171/p2197857146-2.jpg) (http://johnmaiorana.com/p955804498/e8300a37a)
(http://johnmaiorana.com/img/s10/v114/p2197857534-2.jpg) (http://johnmaiorana.com/p955804498/e8300a4fe)
The bare chassis.
(http://johnmaiorana.com/img/s2/v70/p2197857178-2.jpg) (http://johnmaiorana.com/p955804498/e8300a39a)
(http://johnmaiorana.com/img/s11/v36/p2197857574-2.jpg) (http://johnmaiorana.com/p955804498/e8300a526)
This is the first layout with parts for the Stout Reverb, space is limited.
(http://johnmaiorana.com/img/s6/v144/p2197857312-2.jpg) (http://johnmaiorana.com/p955804498/e8300a420)
The layout with parts for the 5f1 Champ, I moved the OT closer to the PT for the final layout.
(http://johnmaiorana.com/img/s9/v89/p2197857349-2.jpg) (http://johnmaiorana.com/p955804498/e8300a445)
Holes punched for the tubes.
(http://johnmaiorana.com/img/s2/v70/p2197857604-2.jpg) (http://johnmaiorana.com/p955804498/e8300a544)
(http://johnmaiorana.com/img/s4/v10/p2197857357-2.jpg) (http://johnmaiorana.com/p955804498/e8300a44d)
This is how I wired the input jacks, I soldered them together then added the resistors and wiring.
(http://johnmaiorana.com/img/s10/v107/p2197857633-2.jpg) (http://johnmaiorana.com/p955804498/e8300a561)
The input jacks installed.
(http://johnmaiorana.com/img/s11/v28/p2197857435-2.jpg) (http://johnmaiorana.com/p955804498/e8300a49b)
The final position of the OT, PT and tubes.
(http://johnmaiorana.com/img/s11/v37/p2197857627-2.jpg) (http://johnmaiorana.com/p955804498/e8300a55b)
All the components installed on the board and wiring complete.
(http://johnmaiorana.com/img/s9/v92/p2197857423-2.jpg) (http://johnmaiorana.com/p955804498/e8300a48f)
The completed amp ready to play. I left the faceplate all original, the input jacks are the only new parts on the front. The front switch only powers the LED. The pots are not connected to anything... yet!!
(http://johnmaiorana.com/img/s9/v93/p2197857060-2.jpg) (http://johnmaiorana.com/p955804498/e8300a324)
The rear panel, I added the Fender Style Lamp, Fuse holder and On/Off/Volume pot.
(http://johnmaiorana.com/img/s2/v53/p2197857053-2.jpg) (http://johnmaiorana.com/p955804498/e8300a31d)
(http://johnmaiorana.com/img/s10/v106/p2197857061-2.jpg) (http://johnmaiorana.com/p955804498/e8300a325)
The build went well, I only had a few minor problems, the first was a lose wire at the output jack. The second problem was a high pitched squeal when the amp was powered on. A quick search of the forum solved my second problem, I switched the wires on the OT and the noise is gone. The amp plays nice and has that classic Fender tone. I ordered a replacement speaker that will be delivered Wednesday.
For my next build I ordered a Princeton Reverb chassis and cabinet from Mojotone for the Hoffman Stout Reverb parts, the cab and chassis will be delivered Wednesday. I will start a new build thread for my 3rd Hoffman build.
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looks good
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looks good
Thanks!!
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Nice work Jamaio!
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Nice work Jamaio!
Thanks!!
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I like these conversion projects. Nice job.
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I like these conversion projects. Nice job.
Thanks!!
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This has become my go to amp when I just want to plug in and play. Keep in mind I only have 2 amps now and I am in the process of building my 3rd.
When I started this build my expectations were low, I did not expect much from a 5 watt amp, boy was I wrong. This amp has a classic Fender sound that is idiot proof, there is only a volume pot so I can not mess up the tone. I can easily get at least 4 distinct sounds by adjusting the volume and choosing the Hi or Low input. The amp can go from very clean to Jimi style distortion. It has the perfect volume for playing without disturbing the neighbors.
I swapped the original Fender speaker with a Celestion Rocket 50 12" 60W 8 ohm speaker that I found online for $40.00 with shipping. The speaker sounds great in this amp and was a good investment for the price.
I can only hope that all my amp builds turn out as good as this one. :icon_biggrin: