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My new tube amps

R

rebellovw

Super Member
I've finished the build of my Bob Latino M125 Monoblocks. So far they sound absolutely great - I'm still breaking them in and "absorbing" the sound they make - I have some further tweaks that I need to do (replace my noisy preamp tubes.)



At the moment they are sitting on top of my Cornwalls with heavy rubber padding and cloth to help with any vibrations - I know this isn't the ideal setup but the CWs are extremely heavy and so far I'm not hearing any difference in sound from where they were previously placed (too much heat.) I know if I start blasting these puppys then things could get dodgy - but so far at very loud volumes these things sing. When we move into our new place - I'll be able to have a better setup.


Fun for taking pictures of - please excuse these amateur shots - not the greatest camera:



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The kit was very easy to put together and Bob was a great help and extremely responsive if I had any questions.

Thanks!
 

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Very nice. I to had a good experience putting together one of Bob's kits a few years ago and am listening to it right now. His support and service is top notch.

How about a picture of the insides when you can.
 
costerdock said:
I've finished the build of my Bob Latino M125 Monoblocks. So far they sound absolutely great - I'm still breaking them in and "absorbing" the sound they make - I have some further tweaks that I need to do (replace my noisy preamp tubes.)



At the moment they are sitting on top of my Cornwalls with heavy rubber padding and cloth to help with any vibrations - I know this isn't the ideal setup but the CWs are extremely heavy and so far I'm not hearing any difference in sound from where they were previously placed (too much heat.) I know if I start blasting these puppys then things could get dodgy - but so far at very loud volumes these things sing. When we move into our new place - I'll be able to have a better setup.


Fun for taking pictures of - please excuse these amateur shots - not the greatest camera:



attachment.php


attachment.php


attachment.php


attachment.php


The kit was very easy to put together and Bob was a great help and extremely responsive if I had any questions.

Thanks!
Click to expand...

Hmmmmm ... Cornwalls @ 102 dB / watt / meter + 21 dBW of power. Think that will be loud enough? :yikes::stupid:

Congrats on the build man. They must sound fantastic.
 
Whoaaah... I bet that jams. I built a Bob Latino ST-120 and loved it. As soon as I get a steady income again I plan to build another one. I still have the tubes.

How do you like your C220?
 
Very nice! That'll drive you outta the room easily enough. I'd love to hear that combination. I second the underside "nudies" if you can! :thmbsp:
 
Shelly_d mentioned an interesting point > "Hmmmmm ... Cornwalls @ 102 dB / watt / meter + 21 dBW of power. Think that will be loud enough?"

Orchestral peaks sometimes require 10 times (or more) the steady state power levels used when playing music. Driving the 102 dB efficient Cornwall with 125 watts gives a tremendous amount of "headroom" available for peak music levels.

Below - a better look at the top of an M-125 and a photo of the interior wiring.

Bob Latino

M-125Front_1024.jpg


M-125internalwiring.jpg
 
Beautiful! Thanks Bob! Is the SS rectifier the only option or can glass be used too?
 
ruffian said:
How about a picture of the insides when you can.
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Thanks very much ruffian - I'll snap some shots of the internals.

shelly_d said:
Hmmmmm ... Cornwalls @ 102 dB / watt / meter + 21 dBW of power. Think that will be loud enough? :yikes::stupid:

Congrats on the build man. They must sound fantastic.
Click to expand...

Thanks very much Shelly - way too much power - but the cool thing with these is that I can remove two output tubes and run 60 watts - or I can switch to triode mode - and go 60/30 watts - so there is lots of flexibility. Gooo Alameda!


beans said:
Whoaaah... I bet that jams. I built a Bob Latino ST-120 and loved it. As soon as I get a steady income again I plan to build another one. I still have the tubes.

How do you like your C220?
Click to expand...

Thanks beans - this being my first tube amp and first preamp (I've had receivers prior to this -ex Pioneer sx780 and lots of BPC and home theater Onkyo AVRs) I have nothing to compare it against - however I've always wanted McIntosh - I'm very happy with it - very cool looking - the glowing green leds on the tubes are pretty cool - I'll have to take the cover off. The sound is very clean. I'm still trying to understand the subtle differences all of these pieces make.


Fran604g said:
Very nice! That'll drive you outta the room easily enough. I'd love to hear that combination. I second the underside "nudies" if you can! :thmbsp:
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Thanks Fran - nudies on their way. It seems to sound better the louder it gets - which is going to get me in trouble.


gearhound said:
Sorry, but my eye-sight isn't the greatest.
What are the driver tubes?

Thanks!
Steve
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Thanks Steve. I'm running Electro Harmonix 12BH7 driver tubes and Sovtek KT88 output tubes. I was running Weber Solid State Rectifiers - but I've switched to Sovtek Tube Rectifiers - GZ34s - I think the Webers may be quieter - again - I'm still getting familiar with all of this.
 
Bob01605 said:
M-125internalwiring.jpg
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Thanks Bob - that person did a pretty nice job on the wiring adding their own personal touches to it (using their own colored wire) - mine is going to look different since I used very short distances on the wire vs adding length so that the wire can be grouped/routed differently. Beauty of this is that I can go back in the future and clean this up myself/tweak vs. sending out to someone. Thanks for your help - these kits were a blast to build!
 
To Gearhound > You can use either 12BH7 or12AU7 driver tubes with this amp. You can also use a combination of the two tubes. If you use a combination of 12BH7 and 12AU7's, I recommend a 12AU7 in the front (voltage amplifier) position and a 12BH7 in the rear (phase splitter/inverter) tube. That is the way they are set up on my own M-125 amp in the photo below - a Mullard CV4003 (12AU7 equivalent tube) in the front voltage amplifier and a GE 12BH7A in the rear position.

Driverboardcloseup.jpg


To Fran6004g > You can use a GZ34 or a GZ33 tube rectifier in these amps. If you do, however, the GZ34 will be run at just about their limit for current flow (250 milliamps). A GZ33 can flow 300 milliamps (with a choke input) and works even better. Unfortunately GZ33's are expensive. A Weber WZ68 solid state rectifier can flow 450 milliamps (as can the custom made power transformer) and works much better when using the amp at higher volume levels or when driving difficult loads.

As costerdock mentioned, you can also use just TWO output tubes in these amps if you want. One left side and one right side output tube for 65 watts in ultralinear mode and 35 watts in triode mode. If you do this, all you have to do is rebias the amp. Photo below of the M-125 running just two (in this case Tung-Sol KT120) output tubes.

RunningTWOoutputtubes_1024.jpg


Bob Latino
 
A note on the Cornwalls' limits and the amount of power you have on tap. The specs on the Klipsch site mentioned that the maximum acoustic output of these speakers is 119 dB. Since they produce 102 dB on 1 watt, the difference of 17 dB is what would need to come from the amp to drive the speakers to their maximum output. This translates to 17 dB more then 1 watt, or about 50 watts or so. At 125 watts output on the amps you have a 4 dB headroom between maximum speaker output and amp clipping.

This is a good thing. More speakers are damaged by underpowered amps then over powered ones. And Bob is absolutely correct about the dynamics that music contains. Good rule of thumb is to consider that the loudest passages in music are 10 dB louder then the average. When we set the volume control we tend to do it by the average that we perceive, not the peaks, so the headroom is both a good thing and a necessary thing.

Proving once again that you can never have too much power in a stereo system:D.
 
Bob01605 said:
To Fran6004g > You can use a GZ34 or a GZ33 tube rectifier in these amps. If you do, however, the GZ34 will be run at just about their limit for current flow (250 milliamps). A GZ33 can flow 300 milliamps (with a choke input) and works even better. Unfortunately GZ33's are expensive. A Weber WZ68 solid state rectifier can flow 450 milliamps (as can the custom made power transformer) and works much better when using the amp at higher volume levels or when driving difficult loads.

As costerdock mentioned, you can also use just TWO output tubes in these amps if you want. One left side and one right side output tube for 65 watts in ultralinear mode and 35 watts in triode mode. If you do this, all you have to do is rebias the amp. Photo below of the M-125 running just two (in this case Tung-Sol KT120) output tubes.

Bob Latino
Click to expand...

Neat design ideas. Very nice!
 
shelly_d said:
A note on the Cornwalls' limits and the amount of power you have on tap. The specs on the Klipsch site mentioned that the maximum acoustic output of these speakers is 119 dB. Since they produce 102 dB on 1 watt, the difference of 17 dB is what would need to come from the amp to drive the speakers to their maximum output. This translates to 17 dB more then 1 watt, or about 50 watts or so. At 125 watts output on the amps you have a 4 dB headroom between maximum speaker output and amp clipping.

This is a good thing. More speakers are damaged by underpowered amps then over powered ones. And Bob is absolutely correct about the dynamics that music contains. Good rule of thumb is to consider that the loudest passages in music are 10 dB louder then the average. When we set the volume control we tend to do it by the average that we perceive, not the peaks, so the headroom is both a good thing and a necessary thing.

Proving once again that you can never have too much power in a stereo system:D.
Click to expand...

119 dB inside a house? Ouch... Those amps look mighty fine. It's makin my solder iron drool (me too).

My neighbors might take exception to the power rule tho. :smoke: Ah well, they don't talk to me anymore anyways.

Hopefully their 125' tree wont blow onto my house with the help of Irene tomorrow night durring our HC party.


I'm still not really understanding why you would put those amps on a speaker no matter the isolation. Tubes get hot, they are designed to do so, but not so much for vibrations.
I'd put them on the floor and risk kicking them before putting them on speakers. The original pic with them mounted in the rack looked pretty good to me, actually GREAT looking. I would be worried about vibrations and those KT88s ...

VERY nice amps.

Cheers,

Bob
 
shelly_d said:
Is that from the power on tap or the use the volume control is put to?:stupid:
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Well my speakers sound sooo crystal clear that the sound travels .... you know, hey. Sounds better than a gas powered leaf blower at 7am, actually A LOT better (to me anyway, someone whom has a mega garden and no grass).

"Hey that leaf blower is messin with the karma of my veggies; doood wasssup?"

Cheers,

Bob
 
tube-a-lou said:
Hi,
Nice amps!!

Tube
Click to expand...

Thanks very much Tube.

guiller said:
Wonderful gear and system! Thanks for sharing the pics....
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Thanks guiller for the nice words. Sick hobby - you always hope you chose the right pieces - mine are going together pretty well.


bobrown14 said:
119 dB inside a house? Ouch... Those amps look mighty fine. It's makin my solder iron drool (me too).

My neighbors might take exception to the power rule tho. :smoke: Ah well, they don't talk to me anymore anyways.

Hopefully their 125' tree wont blow onto my house with the help of Irene tomorrow night durring our HC party.


I'm still not really understanding why you would put those amps on a speaker no matter the isolation. Tubes get hot, they are designed to do so, but not so much for vibrations.
I'd put them on the floor and risk kicking them before putting them on speakers. The original pic with them mounted in the rack looked pretty good to me, actually GREAT looking. I would be worried about vibrations and those KT88s ...

VERY nice amps.

Cheers,

Bob
Click to expand...

Thanks very much Bob. I decided to move the home theater back - I previously kicked it out - so now my room is really cramped with separate two channel and 5.1 channel. I moved the tube amps to the speakers because I felt they would look much better there than an old AVR and old CD Player. The speakers are so heavy that they do not vibrate too much if at all - I've played them loud in this config and so far so good. Eventually I'll get a new rack where I can have either both on the same shelf or separate selves.

Thanks again for all the nice comments folks - these were quite fun to build and worked the first time I powered them up - no glitches.


Here is a nudie folks have asked for:
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Here is the cramped room shot with both 5.1 and 2.1 - excuse the biga_s TV:

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Note the City of Lost Children print with the tubes helmet - I'm a huge fan of that movie - I didn't even know about tube amps when I got that print years ago - spooky - haha.

Thanks again,

Chris
 

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