This and the other comments raising fear are all thread craps in my book and completely off topic. This thread was started by someone building an amp and happy about building an amp and the choice they made - your criticisms (and others) are off topic - trolling at best. Sure the Rectifier might be too small for the job if the amp is pushed to extremes (use the SS one for this application as per the instructions!!) - but I doubt anyone here is doing that - or getting close to doing that.
Just Pulled the trigger on Bob Latino's VTA-120 tube power amp.
- Thread starter Drummerboy2
- Start date
This and the other comments raising fear are all thread craps in my book and completely off topic. This thread was started by someone building an amp and happy about building an amp and the choice they made - your criticisms (and others) are off topic - trolling at best. Sure the Rectifier might be too small for the job if the amp is pushed to extremes (use the SS one for this application as per the instructions!!) - but I doubt anyone here is doing that - or getting close to doing that.
Drummerboy2
Well-Known Member
The JJ GZ34 is the best sound rectifier so far in my amp but Flashed.
Where did you buy your JJ tubes from if you don't mind me asking? They are very inexpensive. I use the JJ's in my Bass amps.
Drummerboy2
Well-Known Member
It was me who started this thread and I'm very grateful for all the help and information I received from some of the fellow members here that helped me tremendously in certain areas of tube amps that I didn't know before.
At first I was wondering if I had made the right choice after seeing some negative comments posted here but I know there are two sides to a story and from my experience in dealing with customers in a service department, I know they leave a lot of details out when they have a problem and are blaming the product that we service. Most of the time it is something the customer did that wasn't recommended or modified something. Then they would say it was the product and it was a bad design.
Tube amplifiers are a different beast from solid state amps. So once I had my little issue with my VTA 120 and with the help of Bob I corrected all the things that may have caused it, everything has been rock steady and problem free. Everything Bob has told me has been right on the money and there is no need for me to doubt his word on his amps. Yes, the rectifier is a weak link IF pushed to the extreme but under NORMAL listening conditions should be trouble free unless something was changed from the instructions or design outside of higher than normal AC levels coming into the amp that causes problems , then it's your design and not Bob's
I agree with you on some of the comments here, there are a few that will always post negative comments and not contribute to help the thread. I'm not talking about the rectifier warning either, those were just trying to give me a heads up on a weakness and that's cool. I just wish comments like that came from people who actually have the VTA 120 and would give a little background on what happen with their VTA120. Like you, From what I have read during my long research into this amp before buying it, I seen nothing that suggested there was any issues with this amp and its design. I just saw post after post of people that bought and built this kit how happy they were with the sound and reliability of this amp, this was on different forums too.
Like I have posted here, I have really pushed this amp and it has not flinched and just keeps on going. But, I didn't push it to its extreme or abuse it but I don' t baby it either.
Now with the rectifier warnings out of the way, hopefully the thread can resume and help each other and others thinking of buying this kit.
Tom Bombadil
AK Member
Secrets of Home Theater and High Fidelity just gave a very positive review to the VTA ST-120. The reviewer ended up buying the review unit.
http://hometheaterhifi.com/reviews/...ube-audio-st-120-tube-power-amplifier-review/
http://hometheaterhifi.com/reviews/...ube-audio-st-120-tube-power-amplifier-review/
nj pheonix
Lunatic Member
Honestly I think all the posts regarding the rectifier were given with good intentions .
I built and owned one (a VTA ST 120) about 5 years ago . It was my daily driver for probably 4 years, in which time a lot of stuff came and went. I thought it sounded excellent.
Also , I don't know of anybody who supports their product as well as Bob . I have no beef with the amp or Bob. I think you made a good choice. Arguably one of the best deals in the current audio market. I do hope you enjoy your amp. My comments regarding the rectifier (I can only speak for me), were well intentioned . For sake of not being on the hook for 100$ Mullard rectifiers I ran a weber in mine. Enjoy your new amp.
I built and owned one (a VTA ST 120) about 5 years ago . It was my daily driver for probably 4 years, in which time a lot of stuff came and went. I thought it sounded excellent.
Also , I don't know of anybody who supports their product as well as Bob . I have no beef with the amp or Bob. I think you made a good choice. Arguably one of the best deals in the current audio market. I do hope you enjoy your amp. My comments regarding the rectifier (I can only speak for me), were well intentioned . For sake of not being on the hook for 100$ Mullard rectifiers I ran a weber in mine. Enjoy your new amp.
nj pheonix
Lunatic Member
Perhaps bad ground connection.
Bad interconnect.
Possibly a ground loop.
Are both the amp, preamp plugged into same outlet?
You can try running a jumper from chassis of preamp to chassis of amp.
Do you know,for a fact the preamp is healthy in the first place? Have you tried it with a different amp and had no hum?
If you've proved the hum isn't the amplifier, perhaps you should open a new thread descibing the issue in detail.
Bad interconnect.
Possibly a ground loop.
Are both the amp, preamp plugged into same outlet?
You can try running a jumper from chassis of preamp to chassis of amp.
Do you know,for a fact the preamp is healthy in the first place? Have you tried it with a different amp and had no hum?
If you've proved the hum isn't the amplifier, perhaps you should open a new thread descibing the issue in detail.
Drummerboy2
Well-Known Member
Is this a brand new built VTA-120? If so, did you change anything from the original VTA design? Has this amp ever worked properly?
sKiZo
Hates received: 92644 43.20°N 85.50°W
If it's a new build, I'd suspect cold solder. Repoint all the tube sockets and keep your fingers crossed.
Ditto for the can cap. You also want to make sure the cap is well grounded to the case. Lot of hum issues can be tracked to that not being properly secured.
Ditto for the can cap. You also want to make sure the cap is well grounded to the case. Lot of hum issues can be tracked to that not being properly secured.
Drummerboy2
Well-Known Member
Update: Tonight I'm nearing in on 100hrs break in and I noticed my amp started to getting a little dull (not a lot but noticeable) on the upper end the other day until now but the bass has gotten more fuller and soundstage seems to have gotten wider. I think there is one more change in sound in the break in process coming. Hopefully this will be the one that will really be amazing. I know the Jensen Copper Foil takes longer to fully break in along with the K40's. I don't know how long it takes for the Iron to fully break in.
So far I really like what I have heard and people that heard this amp really are just blown away at the sound. I have a hard turning off the amp because I just want to keep on listening to music. So that says a lot.
I need to get back to making a new 2 way or 3 way horn speakers to go with this amp.
So far I really like what I have heard and people that heard this amp really are just blown away at the sound. I have a hard turning off the amp because I just want to keep on listening to music. So that says a lot.
I need to get back to making a new 2 way or 3 way horn speakers to go with this amp.
jvinhj240
Member
Sorry guys, I didnt have a chance to report back I had ankle surgery. Yes , it is a brand new built . THe problem was with the preamp. I am so happy with this amp especially the tubes I got follow sKizo recommend. Can't help it but playing everyday. I am also getting new preamp from Don sach, same kit from Roy @ tubes4hifi.
ccdowenye
Active Member
Thank you for starting this post. As a guy just getting interested in tubes, that wants a “modern” tube amp (VTA 120) that has a proven track record, this whole post has been invaluable helping me decide which way I’d like to go. I just need to pull the trigger
Thanks!
I have Bob's VTA ST-120 I am just starting. I have the delay board just in case. But what is the newest best SS rectifier to get now? It seems to have changed over the years. I plan on using the tube rectifier that Bob sent with the kit. But I wanted a spare, so I thought of the SS kind as the spare. Any suggestions? I just sent out the enclosure and trans covers to get powder coated.
Lavane
Lunatic Member
If he sent a GZ34/5AR4 rectifier, its going to be worked very hard. I've lost one ready in my ST-70, and the 5AR4 is marginal in the ST-70. I would use SS and keep the 5AR4 as a spare. He still has the WZ68 SS rectifier listed as what to use. The difference between it and the one Webber suggests is the WZ68 has a thermistor. That will add another second or more delay at startup. The delay board is probably a good idea also.
There is another tube rectifier that can be used, but they are all old stock and expensive.
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nj pheonix
Lunatic Member
I had exactly that amp as a daily driver for 6(7?) Years.
I added delay after.
In honesty, Bob told me I really didn't need and tried to talk me out of it ( clearly he wasn't pushing to sell me one).
I ran a copper top ss rectifier for the most part. I did try gz34s just , well because.
I couldn't hear any sonic difference and the copper top lasted its entire stay .
There needs to be a slight bias adjust between tube and ss.
For the record I ran relatively efficient speakers at pretty low volume levels so mine at least weren't taxed too much.
If you like it loud or drive difficult loads I'd suggest going ss.
It probably makes little difference which one.
Delay it probably a good idea if you run ss.
Good luck with your new amp.
I added delay after.
In honesty, Bob told me I really didn't need and tried to talk me out of it ( clearly he wasn't pushing to sell me one).
I ran a copper top ss rectifier for the most part. I did try gz34s just , well because.
I couldn't hear any sonic difference and the copper top lasted its entire stay .
There needs to be a slight bias adjust between tube and ss.
For the record I ran relatively efficient speakers at pretty low volume levels so mine at least weren't taxed too much.
If you like it loud or drive difficult loads I'd suggest going ss.
It probably makes little difference which one.
Delay it probably a good idea if you run ss.
Good luck with your new amp.
Pio1980
AK Member
I just acquired a fresh one-off VTA ST-70 clone to compare to the OEM Dyna ST-70, both are solid state rectification by preference with the first designed as such by the builder.
A Mullard GZ-34 is capable of supporting only one channel of a stock Dyna 70 at full output without folding. Otherwise B+ is bouncing with the stress of two channels being pushed.
A Mullard GZ-34 is capable of supporting only one channel of a stock Dyna 70 at full output without folding. Otherwise B+ is bouncing with the stress of two channels being pushed.
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nj pheonix
Lunatic Member
I'd be curious if you have the gear how the 2 compare, testing.
Then, sonically, your perception.
The 120 was a slightly different animal so I don’t know that it sounded just like the vta 70.
That said , something I originally liked and later found irritating, changing driver tubes changed the sonic presentation of the amp.
IMO, that shouldn't be the case.
YMMV.
Then, sonically, your perception.
The 120 was a slightly different animal so I don’t know that it sounded just like the vta 70.
That said , something I originally liked and later found irritating, changing driver tubes changed the sonic presentation of the amp.
IMO, that shouldn't be the case.
YMMV.
Pio1980
AK Member
Unfortunately, I'm not set up to proper bench testing.
What I've found so far is both are competent, agreeable, and pleasing. The OEM Dyna seems to prefer 6CA7, the VTA clone build seems fine with either 6CA7s or EL34.
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