POLL--Thread Idea: (Ginormous Tube Amps)

[Lance Bunyon]

Google Images

 

[walterw]

Yes, that is by design.

My goal was to start a thread where we discuss primarily amps that are somewhat absurd and rare.

gotcha

i like that idea but it should be more explicit in the title, something like “giant tube unicorns”

 

[Lance Bunyon]

Obviously this is a giant tube amp for a giant church organ in a giant church.
1000 watts!?

 

[Lance Bunyon]

Another strange behemoth. Also 1000 watts...
http://www.chambonino.com/construct/const9.html

 

[James Hart]

Hey this page still exists. The black one was mine

Link Removed

View attachment 5223088

and mine was the tweed

Nice! The link is a great resource: Schematics, Owners Manual, Gut Shots, Etc.

I downloaded most of them...just in case .

Good deal! I owned Link Removed for a while but let it go when I got rid of my amp... I built it as a sub domain of my hosting account so that link posted above will work for as long as I am hosing my websites/emails somewhere.


8x KT88 was amazing!!!! but way overkill for my needs / styles. I am very happy with my current 4x KT88 200 watt Ashdown

 

[metron]

Please review, comment, make suggestions.

Proposed list of qualifying amps (350 tube Watts or more clean):

Ashdown Small Block 427
Ashdown BTA 400 *
Fender 400PS
Hiwatt DR405
Marshall VBA 400
Mesa Strategy Eight:88
Peavey Classic 400
Reeves 400
Siegmund Big Boy 330
Trace Elliot VA350*
Trace Elliot VA400*
Trace Elliot HexaValve*
Trace Elliot V6
Trace Elliot V8

* = Reverse hybrid with solid state preamp. Let me know if you agree or disagree with these amps being primary subjects.

We can certainly discuss the Mesa 400 and 400+ and how they compare, but neither is 350W RMS or more clean, so I hadn't planned to list them as primary subjects.

I also did not plan to list stand alone tube power amps as primary subjects.

Dont forget the Aguilar DB728.

I thought the Trace V6 was 300w?

 

[tombowlus]

Dont forget the Aguilar DB728.

He's specifically not including stand alone tube power amps.

 

[Passinwind]

Please review, comment, make suggestions.

Proposed list of qualifying amps (350 tube Watts or more clean):

Ashdown Small Block 427
Ashdown BTA 400 *
Fender 400PS
Hiwatt DR405
Marshall VBA 400
Mesa Strategy Eight:88
Peavey Classic 400
Reeves 400
Siegmund Big Boy 330
Trace Elliot VA350*
Trace Elliot VA400*
Trace Elliot HexaValve*
Trace Elliot V6
Trace Elliot V8

* = Reverse hybrid with solid state preamp. Let me know if you agree or disagree with these amps being primary subjects.

We can certainly discuss the Mesa 400 and 400+ and how they compare, but neither is 350W RMS or more clean, so I hadn't planned to list them as primary subjects.

I also did not plan to list stand alone tube power amps as primary subjects.

Ken Gilbert Big Ass Guitar Amp: ken-gilbert.com » The Big Ass Guitar Amplifier

Insanity Amplification Brownout 1000: 2 X 500 watt DIY Tube Bass Amp

 

[tombowlus]

Please review, comment, make suggestions.

Proposed list of qualifying amps (350 tube Watts or more clean):

Ashdown Small Block 427
Ashdown BTA 400 *
Fender 400PS
Hiwatt DR405
Marshall VBA 400
Mesa Strategy Eight:88
Peavey Classic 400
Reeves 400
Siegmund Big Boy 330
Trace Elliot VA350*
Trace Elliot VA400*
Trace Elliot HexaValve*
Trace Elliot V6
Trace Elliot V8

* = Reverse hybrid with solid state preamp. Let me know if you agree or disagree with these amps being primary subjects.

We can certainly discuss the Mesa 400 and 400+ and how they compare, but neither is 350W RMS or more clean, so I hadn't planned to list them as primary subjects.

I also did not plan to list stand alone tube power amps as primary subjects.

Seems like a good list. I currently own four of those on the list (and previously owned a HexaValve).

 

[agedhorse]

That's interesting. I have found several reports of about 270W (clean) for the 400+ . Also lot's of people who say SVTs are louder...and from what I have seen SVTs frequently don't meet their 300W clean power spec.

I don't have any means of accurately measuring power, but I may have to do a couple of grudge matches pitting my 69 and 87 SVT against my 400+. I do know the 400+ kicks like mule, but I have not felt the need to do a head-to-head...until now .

There is this post where you state 390W RMS for the 400+ and explain the 500W burst rating: Ampeg SVT really 960 watts?

And there is this post from a few years earlier where you said, "...the 400+ does about 300 watts RMS continuous, but with the circuit design could do burst testing to as much as 500 watts RMS. " Do you think there would be a market for a reissue 400/400+?

It’s a typo, should have been ~400 watts not 300 watts.

With good GC tubes, a little over 60 watts rms per pair is achievable.

 

[Wasnex]

Dont forget the Aguilar DB728.

I thought the Trace V6 was 300w?

The DB728 is a power amp, rather than a head.

The V6 was rated 400W. It's probably a bit optimistic. From the back panel:

 

[Wasnex]

It’s a typo, should have been ~400 watts not 300 watts.

Well that's good news, that in this instance carries somewhat of a mixed blessing. My thread concept was based on the premise that 350W+ tube amps are rare. But the 400+ is a fairly common amp, which pretty much shows my assumption as false, and greatly reduces the natural focus and validity of the proposed thread.

I don't want to artificially exclude a qualifying amp, but at the same time, including the 400+ in the thread would be like driving a heard of wild mustangs into a corral designed for unicorn viewing--People would struggle to get a good view of the unicorn.

To achieve my intended vision would require a thread title something like this: "Tube Unicorns Over 350W." But this feels a bit contrived. So I think my thread idea is pretty much dead in the water.

Thanks to all who participated, and feel free to continue in this thread as long as you want.

Maybe I will see some of you in an SVT or 400+ thread down the road .

 

[CryingBass]

I am not worthy, but fortunate...

EDIT: And it goes 3 ways...

 

[CryingBass]

and mine was the tweed
View attachment 5223503



Good deal! I owned Link Removed for a while but let it go when I got rid of my amp... I built it as a sub domain of my hosting account so that link posted above will work for as long as I am hosing my websites/emails somewhere.


8x KT88 was amazing!!!! but way overkill for my needs / styles. I am very happy with my current 4x KT88 200 watt Ashdown

Great cab too! Great matchup ( or, should I say mashup )

 

[groovaholic]

I loved my Peavey Classic 400 enough to carry it...and to underwrite my chiropractor by hoisting it on top of a vertical pair of 4x10.
Yes, a head that weighted 97# and is the size of a 2x10 cab.

Shoot, the output transformer is 55# all by itself...

The upside was instant recognition/respect from sound techs.
The first time I brought it out, the tech plugged into the DI out, then paused, looked at the amp, and said "I'll be right back..."
He reappeared a moment later with an EV RE20 on a mic stand.

During sound check, I played a few notes for him and he said "Dude! That sounds killer"

When I retubed it, I discussed with Bobby Baldwin (bass amp designer for Peavey at that time) and he recommended JJ KT88s as the best match for the impedance of the output transformer.

Since I knew that plenty of dirt pedals create distortion by making the wave form asymmetrical, I went the opposite direction and replaced the phase-inverter tube with a low-noise, high-headroom 12AX7A and paid a few bucks extra for one where both of the triodes were gain matched and had balanced output.

When I finished re-tubing and re-biasing the amp, I connected it to my dummy load and fed it a 40Hz test signal.
I watched the waveform on my oscilloscope and pulled the volume back once I started to see clipping.

The peaks were 40v into that 4 ohm load; a clean 400 watts at 40 hz (the fundamental frequency of a bass' E string).

I don't know if I've ever played an amp that was bigger and bolder down low.

 

[Lance Bunyon]

I loved my Peavey Classic 400 enough to carry it...and to underwrite my chiropractor by hoisting it on top of a vertical pair of 4x10.
Yes, a head that weighted 97# and is the size of a 2x10 cab.

Shoot, the output transformer is 55# all by itself...

The upside was instant recognition/respect from sound techs.
The first time I brought it out, the tech plugged into the DI out, then paused, looked at the amp, and said "I'll be right back..."
He reappeared a moment later with an EV RE20 on a mic stand.

During sound check, I played a few notes for him and he said "Dude! That sounds killer"

When I retubed it, I discussed with Bobby Baldwin (bass amp designer for Peavey at that time) and he recommended JJ KT88s as the best match for the impedance of the output transformer.

Since I knew that plenty of dirt pedals create distortion by making the wave form asymmetrical, I went the opposite direction and replaced the phase-inverter tube with a low-noise, high-headroom 12AX7A and paid a few bucks extra for one where both of the triodes were gain matched and had balanced output.

When I finished re-tubing and re-biasing the amp, I connected it to my dummy load and fed it a 40Hz test signal.
I watched the waveform on my oscilloscope and pulled the volume back once I started to see clipping.

The peaks were 40v into that 4 ohm load; a clean 400 watts at 40 hz (the fundamental frequency of a bass' E string).

I don't know if I've ever played an amp that was bigger and bolder down low.

Great post!
If it wasn't for the weight I'd pursue one. I fear I'd be hospitalized after wrestling it up to the Mancave.

 

[Wasnex]

Grudge Match Tag Team Results

IMHO the winner is 400+!

Seat of my pants testing suggest the 400+ is slightly louder and also fuller down low.

69 SVT came in second by a very small margin. It sounds slightly louder and larger than the 87.

Output Tubes Etc:
The 400+ is running Apex-Matched Sovtek 5881. These came with the amp and look relatively new. If I understand @agedhorse 's comments, the amp does not realize it's full power potential with these tubes.

The 69 SVT is running a Matched set of Jan Philips ECG 6146W. These were installed shortly after I bought the amp and they have relatively low hours on them. This amp has a slightly overwound screen windings in the power transformer. Schematic says 220V for the screen supply. I believe real-world readings are typically within a few volts of 230V and this amps runs 237V. Otherwise, it's pretty much stock.

The 87 SVT is running a Matched set of Philips ECG 6550. I believe these are the original tubes, but the amp appears to have been a closet queen that was not even turned on regularly.

For the test I turned each amp up to the point where thumping on the open E-string introduced audible distortion, then backed the volume off slightly. After that I played two rounds to confirm my impressions. Not a scientific test by any means.

Other observations:
1. The 400+ has a much wider window between clean and output drive. The transition into output drive is more gentle/gradual. In contrast the SVTs transition more abruptly into distortion and produce sort of a farty or splatty quality...I guess Michael Anthony was right. So given a requirement for nice smooth output drive, I would choose the 400+. I think the 400+ could be pushed harder into drive and produce a nice tone that would be suitable for many genres.
2. All of the amps played louder than I typically require, so which is louder is largely irrelevant to me--the ringing in my ears has increased since the grudge match .
3. When pushed near the limit, they seem to loose some of their individuality, and sound more alike. Not sure if this is due to the amps, cabs, or my ears.

Additional info:
1. The bass I used was a Yamaha TRB6P with dead rounds.
2. Connection between bass and amps was an X-Wire 905 series digital wireless.
3. Cabs were a pair of Genz Benz 1288T Uber Quads.
4. Speaker wire included a Hosa 1/4" to speakON adapter and about 40' of 13 gauge speakON

 

[agedhorse]

I loved my Peavey Classic 400 enough to carry it...and to underwrite my chiropractor by hoisting it on top of a vertical pair of 4x10.
Yes, a head that weighted 97# and is the size of a 2x10 cab.

Shoot, the output transformer is 55# all by itself...

The upside was instant recognition/respect from sound techs.
The first time I brought it out, the tech plugged into the DI out, then paused, looked at the amp, and said "I'll be right back..."
He reappeared a moment later with an EV RE20 on a mic stand.

During sound check, I played a few notes for him and he said "Dude! That sounds killer"

When I retubed it, I discussed with Bobby Baldwin (bass amp designer for Peavey at that time) and he recommended JJ KT88s as the best match for the impedance of the output transformer.

Since I knew that plenty of dirt pedals create distortion by making the wave form asymmetrical, I went the opposite direction and replaced the phase-inverter tube with a low-noise, high-headroom 12AX7A and paid a few bucks extra for one where both of the triodes were gain matched and had balanced output.

When I finished re-tubing and re-biasing the amp, I connected it to my dummy load and fed it a 40Hz test signal.
I watched the waveform on my oscilloscope and pulled the volume back once I started to see clipping.

The peaks were 40v into that 4 ohm load; a clean 400 watts at 40 hz (the fundamental frequency of a bass' E string).

I don't know if I've ever played an amp that was bigger and bolder down low.

If the peak voltage is 40V, that’s 200 watts RMS.

 

[groovaholic]

If the peak voltage is 40V, that’s 200 watts RMS.

Good point!
IIRC (this was over 10 years ago) peaks were +40v, troughs were -40v.
The actual peak-to-peak swing was 80v

 

[James Hart]

Great cab too! Great matchup ( or, should I say mashup )

Sounded great at home, but the amp blew it first time out with a full band (audition no less)... I'm happily back to Bag End with a pair of 2x12" cabs and downsized to a 200 watt tube head (only had the one 2x12 with the C400)