NAD: VH f-ing 4 content!!! Tube help plz!!

I got her about a week ago off of someone on Reverb. As you can see from the pic she is not a case queen so I may get the headshell re-tolexed. But dear lord, this amp is all I imagined and more. Haven’t touched ch4 yet. I’m surprised how much I love ch2. It’s like what I always wanted out of a JCM 800. Ch3…. Words don’t do it justice.


I believe she’s a 2009 since the handwritten serial # starts with 09. Came with Tung Sol 6550s and the tube switch is labeled 6550/EL34. I’m planning on getting a new set of power tubes and would greatly appreciate your advice. I was thinking of staying with 6550s since I’ve never had an amp with them, but I am concerned they might be damaging in the long run and perhaps I should go the KT77 route. Thoughts?

Lastly, the poor chassis has a bit of dust/oxidation on the top. Do you all have any recommendations for cleaning it up?

Thanks to all and Peter in particular for this wonderful gift of tone 😁
D283FFC3-CC27-4FD7-840B-D76688FC166C.jpeg
 
Congrats!

I like to use a Horizon Devices Precision drive on channel 2. Takes it to a whole other dimension
 
I love channel 4 for smooth silky leads that flow . It’s never mentioned but wow it’s maybe the best channel for solos ever
 
If you want to go with current 6550 I've always liked the sovtek 6550WE in the VH4
Tung Sol's are a bit too hifi sounding IMO 6550's are ok if biased a bit cold.

Lots of other tube choices, nothing sounds bad in a VH4 just different/

Favorites of mine are
JJ 6L6
GL KT77 ( much better than the JJ IMHO )
TAD EL34 BSTR

For cleaning up the oxidization , try a damp cloth then dry it, if its still not clean use a dab of oil ( wd40, Deoxit ) on a rag and wipe it off afterwards.

Congrads on one of the best amps ever designed!
 
Last edited:
If you want to go with current 6550 I've always liked the sovtek 6550WE in the VH4
Tung Sol's are a bit too hifi sounding IMO 6550's are ok if biased a bit cold.

Lots of other tube choices, nothing sounds bad in a VH4 just different/

Favorites of mine are
JJ 6L6
GL KT77 ( much better than the JJ IMHO )
TAD EL34 BSTR

For cleaning up the oxidization , try a damp cloth then dry it, if its still not clean use a dab of oil ( wd40, Deoxit ) on a rag and wipe it off afterwards.

Congrads on one of the best amps ever designed!
Thanks for the recommendations!
 
I like my Ch 4 with the gain about 11 o'clock and the channel Volume cranked up high about 3-4 o'clock. I find it a bit too compressed and saturated if the gain knob is too high, for my ear.

@rickenbacker198 : How would you describe the 6550's against the 6L6's and KT77's?
I have one VH4 with 6L6 (MSTR) and another with KT77's (GL) so I can relate between them.
 
Hard to describe!!

I’ve tried 3 kinds of 6550 ,
Overall they’re more dynamic and full range then any KT77, EL34 , 6L6.
The 6550’s can be sound a little bloated if your used to EL34’s. I like 6L6 the best overall in my particular VH4.

I found Tung Sols Hifi , harder with more highs/ lows and less mid.

The Sovtek 6550we are full sounding ,have good bass and a slightly rolled off treble, maybe the smoothest of them all. Nice tube for guitar frequencies.

The Wing C was the most dynamic, almost explosive! while still being full / warm sounding.
These were standard for a while in Diezel amps. If you ever have the chance to get a set $$, you’ll see why.
 
Sweet, thanks!

I was used to the KT77's as my standard but I really love how the 6L6's sound now I've heard them in there. I guess my ear prefers their inherent sound after so long with just EL34/KT77's. I've always been interested in the 6550's but I'm hesitant due to Peter's reluctance to their use. I guess if they are biased colder the extra heat shouldn't be as much a factor? I usually like my tubes biased colder anyway, I prefer the higher headroom and less squish that it brings. Hotter bias sounds way too compressed and squishy, esp at cranked volumes. To me.
 
Sweet, thanks!

I was used to the KT77's as my standard but I really love how the 6L6's sound now I've heard them in there. I guess my ear prefers their inherent sound after so long with just EL34/KT77's. I've always been interested in the 6550's but I'm hesitant due to Peter's reluctance to their use. I guess if they are biased colder the extra heat shouldn't be as much a factor? I usually like my tubes biased colder anyway, I prefer the higher headroom and less squish that it brings. Hotter bias sounds way too compressed and squishy, esp at cranked volumes. To me.
My ear prefers the same a colder bias , usually 28ma with 6L6. I can’t remember what Peter said exactly , he did give a bias maximum for 6550 somewhere here on the forum.
I’m guessing if you keep the 6550s under ~40ma / tube you’ll be ok.
 
Hey guys, I have some Jj Kt77s on the way. My VH4 has. 6550/ EL34 switch, so I’m guessing I need to switch to EL34 mode when I drop those in and bias. However, if I ever wanted to try 6L6s or 5881s which way should the switch go?

Thanks!!
 
Hey guys, I have some Jj Kt77s on the way. My VH4 has. 6550/ EL34 switch, so I’m guessing I need to switch to EL34 mode when I drop those in and bias. However, if I ever wanted to try 6L6s or 5881s which way should the switch go?

Thanks!!
I absolutely love 6l6s in all my Diezel amps . It just comes alive for me even more so after that . I honestly do not like the jt77s at all. Almost bland compared to 6l6 in a Diezel. IMO
 
Do you know what are the optimal volume, pres., deep etc. positions during biasing of a VH4?
I`ve read here in the forum, the presence has also an effect on the threshold of biasing... is it true?
 
Do you know what are the optimal volume, pres., deep etc. positions during biasing of a VH4?
I`ve read here in the forum, the presence has also an effect on the threshold of biasing... is it true?
Master at zero, presence and depth to half, no jack connected, but for the speaker!
 
Last edited:
Back
Top