Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: roseblood11 on August 04, 2023, 11:43:05 am
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Is is possible to use 500k log pots for volume and tone in a 5e3 build, without changing the sound and response? How would I have to change the cap values?
I`m asking, because I have to squeeze the circuit into a small chassis, where only one hole on the control panel is left. And it`s quite easy to find a 500k log dual concentric pot, but I `ve never seen 1M, at least not at a european retailer.
https://robrobinette.com/images/Guitar/5E3P_Build/5E3_Schematic_Annotated.gif
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I just did a search on Ebay and found two. US sellers, but it might be worth the wait.
Edit... Sorry. Only one. https://www.ebay.com/itm/122547734789?hash=item1c886a0905:g:eacAAOSw8GtZQE-s&amdata=enc%3AAQAIAAAA8OPzcbqewgRZMXGXai6zKPpEYWiwkHKOKTHXQef8WcFJRvPcIODTIp7VGLbRP%2FZZMAaWtk59Z7OO7mpzoAK9mNtOn91S1A0%2FNsiz1LlOWslVCMGRbL3GvVLZsVkrM7ECAp8HcV9hM9IS8V1iYgPdOWsyZF8rxs9gH79Ujyc8EdcJFK7fdcBZt5%2B2jWRlgWuReYMDfEmFnstlmSCkJEG%2B0bFNSrAb%2BpqByX%2FRK%2BgKypmWVeKjQZQfppQSmFAFc88iQf2FCpNuWlZm7bWqAa5%2FiKRis%2F0nBsF6SsGgnSDK51TOwCa5v6YS5VCAit7WqRxbew%3D%3D%7Ctkp%3ABk9SR6jqrJe4Yg
Dave
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https://www.ebay.com/itm/373006274610?hash=item56d8e81032:g:oesAAOSwmfJkSeUC&amdata=enc%3AAQAIAAAA4IZNhMYHl85uvkGs6IVHFA9%2FZ0klbtvy739ZrUJ7B4r87HedHOfsmusfdFjmZVHIO3jOs3XCl2rk35%2FzHa2UCbpJy%2Bu8Pv%2BYW4rHV7biB8n%2B8%2FJ%2BxDWIIORfTY%2FUCJ7eDywAJEY9TbjfhymVhFP3NtUDZxWUwqsWoXMU7K6dTQEshaNzvvaX8%2BiHcB89NkPoDAWFNsruadi33m7UrfgNzTj6PRGADq3GRnbXjT2vLvbH0wQS0AeNTYM3PLv1rc8X9maIg97iBPMDeUc5X3jO2KHlBNp3ehYaIEIjbYeOFdG1%7Ctkp%3ABFBMqOqsl7hi
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He wants Log, not linear?? (So your 2nd link may be better.) (Or is that 2nd link solid-ganged instead of independent like you want for Vol and Tone in the same hole?)
And FWIW, all that crap in an eBay URL after "?hash=" is tracking YOU, we don't need it to find the same item.
https://www.ebay.com/itm/122547734789
https://www.ebay.com/itm/373006274610
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Thx... But the seller doesn`t ship to Europe.
Would it be possible to get away with 500k log?
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Possible, yes. Probable, yes. Will it change the response, yes. Will it matter, that's up to you to decide.
Dave
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I considered 500ka pots as a way to get finer control in low volume situations. With the standard 1M pots there is a big jump between a 1.1 setting and a 1.2 setting. I never tried it. Sorry. I eventually went to a modified 1 stage 6G3 preamp and am happy with that. But recently I saw the DeArmand and Martin circuits using 350ka pots. I wonder how they sound?
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The online version of the old Duncan tone stack calculator has a model of the Princeton 5f2-a.
I can get a very similar frequency response with 1M or 500k pots, but at different levels. Which might be no problem, as I'll have to use a 12ax7 instead of 12ay7 as the first gain stage anyway.
My goal isn't a perfect copy of any of the old Fender circuits.
I'm working on a Vox AC30 clone with three channels. CH1 is the stock top boost channel. But CH2 will be the Fender brownface harmonic tremolo instead of the Vox vib/trem channel - 7 triodes instead of 6. That means, that I need one more tube anyway, and I decided to add a CH3 with the Fender 5e3 preamp topology, instead of the Vox normal channel. So, the 5e3 preamp goes into a LTP phase inverter, the EL84 power amp and a 1*12 + 1*10 combo. Very different from a Tweed Deluxe anyway...
https://www.guitarscience.net/tsc/princeton.htm#RIN=38k&RT=1M&RV=1M&RL=1M&C1=22n&C2=4.7n&C3=500p&RT_pot=LogA&RV_pot=LogA