It looks like I'm going to do some mods to an AC30CC1 to bring some R&C values back near 60's norms. Does anyone have opinions on the technology for the plate resistors? I know it can make a difference.
I have 220Ks in CC, CF and the RN65 style, so I'm looking for Vox correct mojo. I'm not a Vox guy at all.
[after 50+ views] Really? no opinions? I'm not a Vox guy, so I'm just looking for some guidance. If they weren't singe sided boards, I'd experiment more.
AC30 plate resistors -- CC, CF, MF ?
Moderators: pompeiisneaks, Colossal
Re: AC30 plate resistors -- CC, CF, MF ?
I have a Weber AC30TB chassis that I put a Rocket(TB) channel, a Normal channel and an EF86 channel in. (The EF86 channel and the Normal channel are connected to the same side of the PI as the TB channel with a center position on the toggle to disconnect both channels entirely, BTW, to make it identical to the Rocket or the original Vox amp.) The amp was built with all CF resistors, except the plate resistors (220K) which are some Euro made CC resistors (beige in color) from a long time ago. These are over 30 years old and measure within 2% of the stated value, and quiet as well. I'm running a MM Albion clone OT and it sounds great, IMO.
I have worked on/rebuilt 6 real deal AC30TBs (which are all CC) and, whereas I like the original silver and blue speakers very much, the circuits themselves are noisy in what I might call a bit 'fuzzy' way, and the values of the resistors are typically 10-20% higher than the stock markings. Not really a great brand of CC resistor, IMO. In regards to tone, say you listen to a Petty record with a Tele on the bridge pickup, and you hear this pristine crunch with great clarity - the vintage Vox is not this. His recording, American Girl, was done with a tweed Deluxe and a Fender Super Six Reverb I hear, yet it still sounds like a spankin new VoxTB to my ear. Or at least what I want a VOX TB to sound like, ha!
Well, I digress. The Matchless company used 1 watt carbon resistors, beautiful versions that are difficult to find these days. And these amps are minus the noise that is found in the vintage Vox amps. (Eh, and they were around in '94-5 at a few select studios, custom versions Mark built before Matchless got established, just sayin.)
But I digress again. Your current amp is all CF. If it were me, I would maybe try to find some spec on 1 watt CCs for your plate resistors and call it good. [/i]
I have worked on/rebuilt 6 real deal AC30TBs (which are all CC) and, whereas I like the original silver and blue speakers very much, the circuits themselves are noisy in what I might call a bit 'fuzzy' way, and the values of the resistors are typically 10-20% higher than the stock markings. Not really a great brand of CC resistor, IMO. In regards to tone, say you listen to a Petty record with a Tele on the bridge pickup, and you hear this pristine crunch with great clarity - the vintage Vox is not this. His recording, American Girl, was done with a tweed Deluxe and a Fender Super Six Reverb I hear, yet it still sounds like a spankin new VoxTB to my ear. Or at least what I want a VOX TB to sound like, ha!
Well, I digress. The Matchless company used 1 watt carbon resistors, beautiful versions that are difficult to find these days. And these amps are minus the noise that is found in the vintage Vox amps. (Eh, and they were around in '94-5 at a few select studios, custom versions Mark built before Matchless got established, just sayin.)
But I digress again. Your current amp is all CF. If it were me, I would maybe try to find some spec on 1 watt CCs for your plate resistors and call it good. [/i]
Most people stall out when fixing a mistake that they've made. Why?
Re: AC30 plate resistors -- CC, CF, MF ?
+1rooster wrote:I have a Weber AC30TB chassis that I put a Rocket(TB) channel, a Normal channel and an EF86 channel in. (The EF86 channel and the Normal channel are connected to the same side of the PI as the TB channel with a center position on the toggle to disconnect both channels entirely, BTW, to make it identical to the Rocket or the original Vox amp.) The amp was built with all CF resistors, except the plate resistors (220K) which are some Euro made CC resistors (beige in color) from a long time ago. These are over 30 years old and measure within 2% of the stated value, and quiet as well. I'm running a MM Albion clone OT and it sounds great, IMO.
I have worked on/rebuilt 6 real deal AC30TBs (which are all CC) and, whereas I like the original silver and blue speakers very much, the circuits themselves are noisy in what I might call a bit 'fuzzy' way, and the values of the resistors are typically 10-20% higher than the stock markings. Not really a great brand of CC resistor, IMO. In regards to tone, say you listen to a Petty record with a Tele on the bridge pickup, and you hear this pristine crunch with great clarity - the vintage Vox is not this. His recording, American Girl, was done with a tweed Deluxe and a Fender Super Six Reverb I hear, yet it still sounds like a spankin new VoxTB to my ear. Or at least what I want a VOX TB to sound like, ha!
Well, I digress. The Matchless company used 1 watt carbon resistors, beautiful versions that are difficult to find these days. And these amps are minus the noise that is found in the vintage Vox amps. (Eh, and they were around in '94-5 at a few select studios, custom versions Mark built before Matchless got established, just sayin.)
But I digress again. Your current amp is all CF. If it were me, I would maybe try to find some spec on 1 watt CCs for your plate resistors and call it good. [/i]
If you are truly looking for the Vox mojo CC's are the way to go. However, if you are shocked at what a noisy little bastard it is (as many are) the RN65's might not be such a bad idea.
Additionally, I had read that Mike Campbell used an old blonde 6G6 B bassman on a lot of the Heart Breakers tracks, but yeah, sure sounds like a well tuned AC30 to me.
<i> "I've suffered for my music. Now it's your turn."</i>
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chief mushroom cloud
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Re: AC30 plate resistors -- CC, CF, MF ?
step...away...from the kool-aid
Don't overthink it. Just drink it.
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Stevem
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Re: AC30 plate resistors -- CC, CF, MF ?
I do not find that the noise that goes along with the minimum mojo that comes from having CCs in the High voltage section of any amps preamp and or PI is worth it when said amp has more than two stages of gain and or the they are biased for more than a 25 volt signal level boost!
If you feel you must use CC types than use 1 waters where the voltage for a 1/2 watter would work, and 2 watters in the plates of the PI section for less noise.
Yup, they can be a bit of a pain to fit!
If you feel you must use CC types than use 1 waters where the voltage for a 1/2 watter would work, and 2 watters in the plates of the PI section for less noise.
Yup, they can be a bit of a pain to fit!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: AC30 plate resistors -- CC, CF, MF ?
'sup Tracy?chief mushroom cloud wrote:step...away...from the kool-aid
I tacked in the RN65s. The customer likes the compression, so they stay in for now...besides, I only had 1/2W 220Ks in CC.
[edit] fyi sort of thing -- I ended up doing the Caldwell mods and the customer is very happy with the whole thing. He thinks the amp is more flexible too. tia
[update 2015] I put the RN65s in another CC. Happy customer. In think I'm going to recommend it more often.