Hi Colin,
I've used Rockingham Display a couple of times. £200 for open baffles and 2 bass cabs in birch ply. Their turnaround can be quite slow as you have to wait for a quiet time. Other companies cost about double.
http://www.rockinghamdisplay.com/
You would need to call Andy Lynch directly.
Cheers,
Clive
Colin's gm70 Boat Anchor monoblocs
#77
Clive,
thanks for the details I have made a note in my diary for future reference.
Well at last I managed a listen to the amps in full stereo last night after installing the replacement Tentlabs unit for the 300b heater.
As the wait to fire up these beasts has been a long and frustrating wait I sat down straight away as soon as the tubes had warmed up, say 5-mins.
Initial impression was the soundstage appeared more constrained and a little thin sounding than I remember in Nick's breadboard version but began to open out more after a couple of LP's and CD's. In fact after the first 3-hours the sound had gained body with fuller deeper bass and more precise positioning of individual instruments and all started to open up and I started to have a big silly grin when I was reminded by my wife the late hour and had to retire to bed.
The breadboard version used a stepped attenuator so was direct into the amp not through a pre. I am wondering perhaps my WAD PREII is perhaps strangling the amps full potential but I will give this the benefit of more time and re-assess things after several more days music though the amps.
Anyone live near me with a different pre to try that is able to drive 6m long leads?
Colin
thanks for the details I have made a note in my diary for future reference.
Well at last I managed a listen to the amps in full stereo last night after installing the replacement Tentlabs unit for the 300b heater.
As the wait to fire up these beasts has been a long and frustrating wait I sat down straight away as soon as the tubes had warmed up, say 5-mins.
Initial impression was the soundstage appeared more constrained and a little thin sounding than I remember in Nick's breadboard version but began to open out more after a couple of LP's and CD's. In fact after the first 3-hours the sound had gained body with fuller deeper bass and more precise positioning of individual instruments and all started to open up and I started to have a big silly grin when I was reminded by my wife the late hour and had to retire to bed.
The breadboard version used a stepped attenuator so was direct into the amp not through a pre. I am wondering perhaps my WAD PREII is perhaps strangling the amps full potential but I will give this the benefit of more time and re-assess things after several more days music though the amps.
Anyone live near me with a different pre to try that is able to drive 6m long leads?
Colin
#78
Managed another 4-hours on the amps last night.
Things are definitely improving leaps and bounds with the sound opening up more, being fuller and richer sounding.
I had a big smug smile on my face listening to Annie Lennox CD Bare towards the end of the evening. It was like she was present in the room with the whole room filled with sound. Most enjoyable. And things can only get better.
As I have a volume control on the output my tubed CD player I did try this direct into the amps. With the volume set at minimum it was still quite loud but did emphasise to me the PREII is adding some colouration to the sound, but I suppose this could be said for any preamp?
A mate at work has loaned me his Croft pre so I will compare this tonight to the PREII.
To the question was it all worth the effort and would I do it again, the answer is a very big resounding YES.
I'm a very happy bunny.
Things are definitely improving leaps and bounds with the sound opening up more, being fuller and richer sounding.
I had a big smug smile on my face listening to Annie Lennox CD Bare towards the end of the evening. It was like she was present in the room with the whole room filled with sound. Most enjoyable. And things can only get better.
As I have a volume control on the output my tubed CD player I did try this direct into the amps. With the volume set at minimum it was still quite loud but did emphasise to me the PREII is adding some colouration to the sound, but I suppose this could be said for any preamp?
A mate at work has loaned me his Croft pre so I will compare this tonight to the PREII.
To the question was it all worth the effort and would I do it again, the answer is a very big resounding YES.
I'm a very happy bunny.
#79
Hi Colin,
6m lines. I would knock yourself up an Aikido pre, or use a low Rp valve 5687, 12BZ4 (can't recall the number exactly, its the one Steve likes in pre's). But I really think an Aikido would be the way forward, 6N6P on output valve duty.
Hmmm....Do you need gain? I'm wondering if Aikido would work the same without the input pair, so just the line driver pair. What do the panel think?
cheers,
-- Andrew
6m lines. I would knock yourself up an Aikido pre, or use a low Rp valve 5687, 12BZ4 (can't recall the number exactly, its the one Steve likes in pre's). But I really think an Aikido would be the way forward, 6N6P on output valve duty.
Hmmm....Do you need gain? I'm wondering if Aikido would work the same without the input pair, so just the line driver pair. What do the panel think?
cheers,
-- Andrew
#80
You would still need the voltage step, so it would introduce another cap, thats the only downside I can think of.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
#81
Yes, absolutely, I realized that just after posting, but an input TX might be a good way of doing that.
So, having noted the downside of the idea, I'd be back to suggesting a decent valve suited to cathode follower operation and loaded with a constant current sink, might be more elegant.
Unless you want to use the Pre3 type concept.
cheers,
-- Andrew
So, having noted the downside of the idea, I'd be back to suggesting a decent valve suited to cathode follower operation and loaded with a constant current sink, might be more elegant.
Unless you want to use the Pre3 type concept.
cheers,
-- Andrew
-
Cressy Snr
- Amstrad Tower of Power
- Posts: 10582
- Joined: Wed May 30, 2007 12:25 am
- Location: South Yorks.
#82
That would be the 12B4A Andrew.Andrew wrote:Hi Colin,
6m lines. I would knock yourself up an Aikido pre, or use a low Rp valve 5687, 12BZ4 (can't recall the number exactly, its the one Steve likes in pre's)
Additionally, paralleled 5687s are supposed to be very good indeed. Half the plate resistance and masses of current drive. I would have done this with the 6AS7 amp but don't need the gain of 11 in this instance.
Steve.
#83
Ummmm, food for thought gents,
I think I'll wait on Nick coming over for a listen with my present setup and also feeding the sourse direct through a stepped attenuator he will be bringing over.
I would value Nick's impartial and highly critical pair of ears (plus the rest of his body, mind you!) to give me a subjective opinion before I commit down another DIY build. After all this is his baby really.
I've only just got over the last marathon build.
I think I'll wait on Nick coming over for a listen with my present setup and also feeding the sourse direct through a stepped attenuator he will be bringing over.
I would value Nick's impartial and highly critical pair of ears (plus the rest of his body, mind you!) to give me a subjective opinion before I commit down another DIY build. After all this is his baby really.
I've only just got over the last marathon build.#85
Well I've got to blame someone if it all goes tit's up!
I was listening to a Decca test LP last night and one test is to check the balance for high frequency, midrange and bass by using a midrange test tone that is played for around 5-secs closely followed by a high frequency tone and similarly with a very low bass tone. The idea being to adjust ones treble and bass controls so the two tones are equal in loudness. Not that I have these controls mind you, nor need them.
Well, guess what? I could not hear the high frequency generated tone at all, but I was assured by my son it was there and equal in loudness to the generated midrange tone. So I do need a younger pair of ears for subjective listening tests as my son has no interest in hifi only his iPod.
And yes I admit I'm a coward.
I was listening to a Decca test LP last night and one test is to check the balance for high frequency, midrange and bass by using a midrange test tone that is played for around 5-secs closely followed by a high frequency tone and similarly with a very low bass tone. The idea being to adjust ones treble and bass controls so the two tones are equal in loudness. Not that I have these controls mind you, nor need them.
Well, guess what? I could not hear the high frequency generated tone at all, but I was assured by my son it was there and equal in loudness to the generated midrange tone. So I do need a younger pair of ears for subjective listening tests as my son has no interest in hifi only his iPod.
And yes I admit I'm a coward.
#86
Was listening to amp again last night and what is very impressive this amp is just how good it sounds at low listening levels.
To get the same sort of dynamics and bass from my Yarland 845SE and WAD6550 amps I have to have the volume considerably louder.
Since changing the rather microphonic c3g tubes for a new pair, hum is now almost non existant and is only detectable a few inches away the speaker panels. All the TX's are running relatively cool to the touch, even after 4-hours continous running. So I think Nick you have done a splendid job with the specs and design. It's all bedding in rather nicely.
Good on ya mate.
To get the same sort of dynamics and bass from my Yarland 845SE and WAD6550 amps I have to have the volume considerably louder.
Since changing the rather microphonic c3g tubes for a new pair, hum is now almost non existant and is only detectable a few inches away the speaker panels. All the TX's are running relatively cool to the touch, even after 4-hours continous running. So I think Nick you have done a splendid job with the specs and design. It's all bedding in rather nicely.
Good on ya mate.
-
pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#87
Hi Colin-can i just ask if you have tried the monoblocks with your newer full range speakers (the ones with the ferret hole ) and if so how did you find them sounding ? (if you could get the volume low enough )
) and if so how did you find them sounding ? (if you could get the volume low enough )The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#88
Hi Philip,
Yes I did try them with the MLTLs but to be honest they are a bit of a miss match in my room. The amps are directly behind my speakers and hum was an issue that I could not live with to listen to them. Also they produced a lot more cone movement for my peace of mind.
If you recall this amp was specifically designed for my statics that are probably no better than 86db efficiency and these speakers are found to be hard to drive.
If your thinking building a gm70 amp then perhaps Nick would be best placed to advise there suitability for high efficiency speaker use.
I'll be bringing the monoblocs the Owston so you are quite welcome to hook them up to your speakers. I'm also quite willing to demo the amps with the Northern Ferret holes.
However, I note from elsewhere you have acquired a pair of 845 tubes. Now these do sound good with the MLTLs even through my Yarland amp.
Yes I did try them with the MLTLs but to be honest they are a bit of a miss match in my room. The amps are directly behind my speakers and hum was an issue that I could not live with to listen to them. Also they produced a lot more cone movement for my peace of mind.
If you recall this amp was specifically designed for my statics that are probably no better than 86db efficiency and these speakers are found to be hard to drive.
If your thinking building a gm70 amp then perhaps Nick would be best placed to advise there suitability for high efficiency speaker use.
I'll be bringing the monoblocs the Owston so you are quite welcome to hook them up to your speakers. I'm also quite willing to demo the amps with the Northern Ferret holes.
However, I note from elsewhere you have acquired a pair of 845 tubes. Now these do sound good with the MLTLs even through my Yarland amp.
-
pre65
- Amstrad Tower of Power
- Posts: 21400
- Joined: Wed Aug 22, 2007 11:13 pm
- Location: North Essex/Suffolk border.
#89
Hi Colin-thanks for your impressions.
When i posted the question i was 90% sure about 845s-i'm 100% sure now !
When i posted the question i was 90% sure about 845s-i'm 100% sure now !
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)