[typericey]

Been wanting to have a tube amp for the longest time to bring that tube sound in the car. Initially wanted a Butler, until someone here wrote that they're one big scam (amp continued to run even with the tubes unplugged, blue LEDS behind the tubes to give it a glow).

Now I'm considering US Amps. Someone at SSA Forums said that it uses 12AX7 tubes, which is a good thing because 12AX7's are an audio staple. Can anybody here validate this?

My old man, who is a crazy tube freak, is even willing to help me do some tweaking, should I get the amp. He can help me source out some low noise Mullard, Amperex or Telefunken NOS tubes to replace the amp's stock tubes which I assume are of the cheap China/Russian variety.

Anybody care to share 1st hand experiences with US Amps tube amps?

 

[Mooble]

Nothing you will likely buy is a true tube amp. They all use fake LED lighting and they are all hybrid tube amps with SS output stages. The only true tube amps cost $2k+ (Tru, Milbert, HSS, and maybe Phass and a few others)

Amps like Mark Antony, Butler (Phaze Audio), Hustler, US Amps, DLS, Cal Cell, Sutherland, etc., are all hybrids. There's nothing wrong with them. Some are very nice amps, but they are not true tube amps.

It's pretty easy to modify the Butlers to take any tube you want as there is plenty of room inside the chassis.

 

[tard]

they do use the 12AX7, they are a hybrid tube.

if you go swapping out the tubes for mullards you will have to adjust the bias and dc offset because of the differences between the tubes.

if you want a TU 600, i have one i will sell. it started sounding real bad so i got some expensive NOS mullards for it, to replace the $15 sovtek's they use. took care of most of the bad sound, but i have never got around to readjust the dc offset or bias to clean it up the rest of the way. it's been sitting in my closet for the last year.

 

[typericey]

@ Mooble - input much appreciated. I'm pretty much ok with the hybrid amps. all i need is the "tube sound" introduced somewhere (line level in this case)

they do use the 12AX7, they are a hybrid tube.

if you go swapping out the tubes for mullards you will have to adjust the bias and dc offset because of the differences between the tubes.

if you want a TU 600, i have one i will sell. it started sounding real bad so i got some expensive NOS mullards for it, to replace the $15 sovtek's they use. took care of most of the bad sound, but i have never got around to readjust the dc offset or bias to clean it up the rest of the way. it's been sitting in my closet for the last year.

thanks for the TU600 offer, I am however looking at their 4 channel model. So they use sovtek's eh? Do these amps have bias adjustment pots in 'em? How would you describe the amp's sonic signature*? Does it have a tube sound to it?

(*once again very controversial these days)

 

[tard]

yes, they have small pots on the board.

years back i replaced a decent american made class AB amp with the TU 600, was on a dyn 240 comp set. i noticed only a little diff in warmth through the mid range, but the biggest diff i noticed was more sparkle and accuracy in the tweeters.

here's an old pic, this amp is from the made in florida era, right before the buyout and move to cali. look for the rectangle, blue pieces at the top portion of the amp. there's 2, one right above the other, about 1/4 of the way from each end of the pic.

 

[typericey]

tard, thanks again for the pic and info i couldn't get anywhere else.

"real" tubes and bias pots sounds like a legit hybrid tube amp...

consulted my old man on Sovteks. He says they're decent tubes. They were on his Audio Research gear back in the '90's. I assume you only replaced the Sovteks with Mullards because the Sovs were dying? Any sonic improvement/difference with the replacement?

 

[tard]

i do believe the sovteks were dying to be the bad sound. started coming on slowly and slowly after the amp was a few years old, over the period of a month or two. i pulled the amp out and put in a different 4 ch and ran active. the amp sat for a few months before i ordered up the mullards (@ about $160 each!).

when they came in i just dropped them in place and tried the amp. most of the bad sound was gone, but there is still some there. there is a gain diff between the sov's and the mull's, and i have yet to take the time to pull the amp out of the closet and tweek dc offset and bias's.

i read a post by another guy who used JJ tesla's in place of the sovteks and he liked the sound diff.

off the top of my head, with what little i played the amp after just dropping in the tubes, i want to say the sound was more "laid back" and the tweeters didn't have the birghtness they had before. but then again, i did not take the time to do the needed adjustments to make it right. i want to say there was a difference in the vocals too, but i can't remember that well or think of how to describe it. it's been about 6 months or so and i only played it for 5 minutes just to hear the drop in results. then i took it out and set it in the closet for a day i have time tune it.

but in the triage scheme..... there seems to be always more pressing projects i have ahead of it.

 

[T-BEAR]

may be you should try a hustler hybrid friend,its a good amp and reasonable usamps good too,whats wrong with butler?

tard, thanks again for the pic and info i couldn't get anywhere else.

"real" tubes and bias pots sounds like a legit hybrid tube amp...

consulted my old man on Sovteks. He says they're decent tubes. They were on his Audio Research gear back in the '90's. I assume you only replaced the Sovteks with Mullards because the Sovs were dying? Any sonic improvement/difference with the replacement?

 

[typericey]

whats wrong with butler?

i dug up an old forum thread here in DIYMA and someone said that Butler amps continue to run with the tubes taken off. Also, blue LEDs are too hype-y for me. I'm beginning to question if Butlers are really legit tube amps.

US Amps on the other hand is a better proposition:
1. 12AX7 tubes - this tube type is an audio staple, used in countless of audiophile home audio gear
2. No fancy-schmancy tube display behind a glass window. It sends me a message that they're zero-hype and all business.
3. Made in California. It matters to me.

 

[T-BEAR]

yea i feel u are right ,if not mistaken the tubes are acting as diode replacement,if you replace the tube with diode it will operate.i feel that is just butler's idea.but its a smart idea..a friend told me he can make any oter ss amp work like the butler tube driver and add tube

i dug up an old forum thread here in DIYMA and someone said that Butler amps continue to run with the tubes taken off. Also, blue LEDs are too hype-y for me. I'm beginning to question if Butlers are really legit tube amps.

US Amps on the other hand is a better proposition:
1. 12AX7 tubes - this tube type is an audio staple, used in countless of audiophile home audio gear
2. No fancy-schmancy tube display behind a glass window. It sends me a message that they're zero-hype and all business.
3. Made in California. It matters to me.

 

[tard]

in the us amps TU, i believe the tube section is the input section and is used to drive the solid state output section. on the whole, it's "supposed" to be a little different concept than what others were doing. but i don't remember all the details and comparisons off the top of my head.

on another note, the new Cali based us amps stuff is all essentially made in korea with some assembly of the AX line in CA. the IS line was made in china, don't remember if the xterminator is china or korea. just some trivial info since the topic was brought up a few posts ago.

 

[typericey]

here's the manual of the U.S. Amps AX series. According to the manual, the tubes are indeed used as a line driver. It's supposed to have a "Class A" tube line stage, according to the manual.

www.chpw.de/customer/web/Produkte/usa/AX.manual.pdf

 

[Elektra]

yes, they have small pots on the board.

years back i replaced a decent american made class AB amp with the TU 600, was on a dyn 240 comp set. i noticed only a little diff in warmth through the mid range, but the biggest diff i noticed was more sparkle and accuracy in the tweeters.

here's an old pic, this amp is from the made in florida era, right before the buyout and move to cali. look for the rectangle, blue pieces at the top portion of the amp. there's 2, one right above the other, about 1/4 of the way from each end of the pic.

Hi There

I know this thread is very old... But you guys seem to know your US AMPs.. I have some BNIB amps - 4360c , 300c, 600c (chrome amps) how can I tell if they are the US built versions or the Chinese built versions?

What essentially was the difference between the 2? Can the Chinese built versions be modded to match the US built versions?

What were the good upgrades people did on these amps? - I spoke to someone at US amps and they said that the tubes used in that amp were the best you can get as they tested 30 different makes of tubes and the ones they used were the best sounding

He wasn't sure were these amps came from as it was before his time - the guy who I bought it from was adamant that they were the last ones made in the US before production started in China

Thanks

Massimo

 

[Dubstep]

Hi There

I know this thread is very old... But you guys seem to know your US AMPs.. I have some BNIB amps - 4360c , 300c, 600c (chrome amps) how can I tell if they are the US built versions or the Chinese built versions?

What essentially was the difference between the 2? Can the Chinese built versions be modded to match the US built versions?

What were the good upgrades people did on these amps? - I spoke to someone at US amps and they said that the tubes used in that amp were the best you can get as they tested 30 different makes of tubes and the ones they used were the best sounding

He wasn't sure were these amps came from as it was before his time - the guy who I bought it from was adamant that they were the last ones made in the US before production started in China

Thanks

Massimo

None of the US amps are made in china. They were made in Florida and California. They might have there lowest end line made over seas, but there not what were talking about anyways.. Run the amps, and youll notice how clean US amps really are!

 

[Elektra]

None of the US amps are made in china. They were made in Florida and California. They might have there lowest end line made over seas, but there not what were talking about anyways.. Run the amps, and youll notice how clean US amps really are!

Thanks for the response...

The last few or all of the AX TU amps were made in China - they stopped production due to the boards not being made to US Amps specifications as the company cut too many corners in the production run of these amps - that's why so few are around! That's according to US Amps themselves... (I have an email from them stating this)

They did say they will be releasing a new tube amp next year...

Massimo