I used a Classictone Tweed Deluxe OT. I'm using an Emminence Legend 10" 1058 8ohm speaker with the HoSo 56 "the minimalist" which has the 6BM8 tubes.Btw, what OT/primary impedance are you using with the 6BM8s?
With respect, 10thtx
Very Small Special
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Re: Very Small Special
With respect, 10thtx
Re: Very Small Special
I think OT primary on my Gibson GA8T was 10k.
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dorrisant
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1 others liked this
Re: Very Small Special
Got it back in last night... Here's the scoop:
PT = VAC 280-0-280 Secondary w/Primary @ 124 VAC *** loaded = 273-0-273 ***
OT Primary = 7346Ω w/Secondary Loaded @ 8Ω
V1 = 12AX7/ECC830
V2 = 6GW8/ECL86
V3 = 6GW8/ECL86
V4 = 6CA4/EZ81
Dropping String:
47µF -> 1k0 -> 22µF -> 5k6 -> 22µF -> 1k2 -> 22µF
B+1 = 323.6
B+2 = 311.6
B+3 = 286.5
B+4 = 284.2
V1-6 = 189.2
V1-8 = 1.405
V1-1 = 188.9
V1-3 = 1.403
V2-9 = 227.3 Plate *** Triode Section 51k Side ***
V2-1 = 37.04 Cathode
V3-9 = 216.6 Plate *** Triode Section 47k Side ***
V3-1 = 34.22 Cathode
V2-6 = 341.3 Plate
V2-3 = 311.2 Screen
V2-2 = 9.75 Cathode
V3-6 = 319.2 Plate
V3-3 = 311.2 Screen
V3-2 = 9.75 Cathode
Cathode Resistor = 180Ω (177.5Ω actual)
Now, can someone explain why the plate voltage for V2 pentode is higher than what is coming off of the rectifier? This higher voltage stays with the socket if you swap the power tubes. The plates will change by a volt or two but not what you'd expect if the tubes were mismatched. They match almost perfectly on my Hickok.
PT = VAC 280-0-280 Secondary w/Primary @ 124 VAC *** loaded = 273-0-273 ***
OT Primary = 7346Ω w/Secondary Loaded @ 8Ω
V1 = 12AX7/ECC830
V2 = 6GW8/ECL86
V3 = 6GW8/ECL86
V4 = 6CA4/EZ81
Dropping String:
47µF -> 1k0 -> 22µF -> 5k6 -> 22µF -> 1k2 -> 22µF
B+1 = 323.6
B+2 = 311.6
B+3 = 286.5
B+4 = 284.2
V1-6 = 189.2
V1-8 = 1.405
V1-1 = 188.9
V1-3 = 1.403
V2-9 = 227.3 Plate *** Triode Section 51k Side ***
V2-1 = 37.04 Cathode
V3-9 = 216.6 Plate *** Triode Section 47k Side ***
V3-1 = 34.22 Cathode
V2-6 = 341.3 Plate
V2-3 = 311.2 Screen
V2-2 = 9.75 Cathode
V3-6 = 319.2 Plate
V3-3 = 311.2 Screen
V3-2 = 9.75 Cathode
Cathode Resistor = 180Ω (177.5Ω actual)
Now, can someone explain why the plate voltage for V2 pentode is higher than what is coming off of the rectifier? This higher voltage stays with the socket if you swap the power tubes. The plates will change by a volt or two but not what you'd expect if the tubes were mismatched. They match almost perfectly on my Hickok.
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RJ Guitars
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Re: Very Small Special
Another nice creation. Thanks for posting!
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Re: Very Small Special
Oh, yes, I've missed that one... 
It looks like we're using the same shielded wire, but what caps are you using?
It looks like we're using the same shielded wire, but what caps are you using?
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dorrisant
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Re: Very Small Special
"Education is what you're left with after you have forgotten what you have learned" - Enzo
Re: Very Small Special
I surely have missed it as well, but this is super nice and sounds great!
I put 3 different nfb resistors on a switch in my Small Special, along with some other taste related mods.
It does deliver the goods once you reduce the nfb and put it through the right speaker.
As for triode/pentode combos - I have to admit that I don’t like 6bm8s, I find them harsh and tiny and always missing something as opposed to 6gw8. But that’s just me and it is obviously the personal taste
Niki
P.s. nice to see this old layout still gets used
I put 3 different nfb resistors on a switch in my Small Special, along with some other taste related mods.
It does deliver the goods once you reduce the nfb and put it through the right speaker.
As for triode/pentode combos - I have to admit that I don’t like 6bm8s, I find them harsh and tiny and always missing something as opposed to 6gw8. But that’s just me and it is obviously the personal taste
Niki
P.s. nice to see this old layout still gets used