Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: sstudley on September 19, 2019, 10:03:55 am
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Hello Folks,
Well, I lugged my 5F6A combo to band practice this past Tuesday and I have to say, it sounded just fine! One thing I did that seemed to make a nice difference was elevated it. I put it in an amp stand slightly angled back, that and having it in a large room seemed to really help. There's no doubt the NFB is working now. I noticed the overall gain was not nearly as hot as previously. Getting the NFB and the getting the correct OT tap made a "Hhuuge" difference!
I'm picking up a $20.00 reverb tank off craigslist today at noon. I'm thinking that adding the reverb tank, shouldn't be too terribly challenging, yes? I took a look at some schematics that incorporate string reverb on Rob Robinettes website. Any words of caution and or advice?
Kind regards,
Steve
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http://el34world.com/Forum/index.php?topic=483.0
might be worth a read, I didn't, but then I don't use reverb :icon_biggrin:
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Thanks Shooter! Kinda wish the picture links were still good. I think there's a circuit similar to what Tore is describing at Rob's website. To be honest, that circuit sounds more invasive than I was hoping. Not sure if that's something I want to do right now. I would like to use the amp for a while, just to see how things go.
Nevertheless, always good to hear other ideas.
Steve
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> I'm picking up a $20.00 reverb tank off craigslist today at noon.
Tanks come in MANY impedances. Makes a real difference in how you drive them.
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https://seattle.craigslist.org/sno/msg/d/bothell-accutronics-spring-reverb-tank/6978841860.html (https://seattle.craigslist.org/sno/msg/d/bothell-accutronics-spring-reverb-tank/6978841860.html)
Hopefully this link will work for you. That is the tank I am buying. There appears to be some writing on the underside that indicates the impedance, 3.9 and 192 ohms. Is that something the 5F6A can work with?
Steve
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There's a LOT more to reverb than just the tank. Adding a reverb circuit to that tweed style chassis will be a huge challenge. Much more than what you experienced just building that kit. Modifying the schematic is easy enough. But, you don't have room on the chassis for two more tubes, a pot, three RCA phono jacks, a reverb transformer, and the extra circuit components. Not gonna say it's impossible, but it's close enough to impossible that I would not attempt this and I usually love a challenge that involves "shoe-horning" a lot of circuit in a small place. I think the complexity of this idea is way over your experience level.
Try some pedals to see if you even like reverb with this amp. If so, may I suggest building the king of Fender reverb, the 6G15 standalone reverb unit. Or step it up a notch and build the Revibe unit. Hoffman has plans and parts for these. No chassis though. Pre-punched chassis and cabs are easily available from other sources.
I would not buy a reverb tank until thinking this idea over more thoroughly. $20 for a used tank of unknown quality is not a good deal.
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And, if you do decide to do reverb...
Reverb tanks are not much more than $20 to buy new.
There is nothing special about one that someone "thinks" is out of a Fender amp.
$20 for a used tank of unknown quality is not a good deal.
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ok, this is exactly why I posted to the forum! I will buy the tank, for a future project or whatever. For some reason, I thought that integrating a spring reverb into the Bassman was gonna be within my ability to do. Funny, now that I begin to see the complexity, I would like learn more about reverb circuits. I will definitely look into the kits you suggested!
I am working on a reverb effects pedal kit, well actually I'm working on a fuzz pedal at the moment. The digital reverb will be after I have this one complete. I bought the kits from Guitar Pedal Parts dot com. I am not impressed with the quality of parts or instructions (there isn't any)! The aluminum chassis are pretty nice though!
As always, thank you for your help!
Steve
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Here you go..5F6A with 6G15 reverb and 15 inch speaker....Sounds pretty good.
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The reverb stuff is a lot like another small amplifier, say a basic Champ. You need a small power tube, and usually a tube to drive that. You need a recovery tube. So where a Champ is triode pot triode pentode transformer, a reverb is triode pentode transformer triode pot. And unless you have lots of excess gain already, probably another stage to recover mixing loss.
Fender made some real changes from 5F6 to the Siverface Reverb series to get the stages in a more holistic structure, but then it isn't a 5F6.
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There is Tubenits one tube reverb.. but I still don't think if would fit inside a tweed 5F6A chassis.. could maybe do it outside of the chassis..