Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Stereomour => Topic started by: Pkay on March 18, 2025, 07:47:03 PM

Title: Tube biasing for the older Stereomour
Post by: Pkay on March 18, 2025, 07:47:03 PM

Apologies for the very basis question but I recently received an old version without any instructions or manual.

I was wondering how do I bias the tubes? How loudly do I set the volume initially to turn the dial for the individual tubes?

Is there any must know information before I start?

Thanks for answering my basic questions.

Title: Re: Tube biasing for the older Stereomour
Post by: Paul Joppa on March 19, 2025, 03:39:18 AM

The older Stereomour uses fixed bias - the only adjustments are the two hum balance controls. Center them approximately to start, then adjust each channel for minimum hum.

Manuals are available, which include instructions for voltage checks  to confirm correct operation. If you post a few photos, we can identify the version more precisely so you get the right manual. Since many customers make modifications, we can also identify whether changes have been made, at least in most cases.

Title: Re: Tube biasing for the older Stereomour
Post by: Pkay on March 19, 2025, 08:02:44 PM

I had the pleasure of setting the amp up today and even with speakers which are a mis-match is sounded great.  I was using some Kudos Cardea C20 which are as follows;

pecifications:
Type: 2-way, bass reflex

Recommended amplifier power: 25-200W

Sensitivity: 88dB

Impedance: 8ohm

Frequency response: 30Hz – 30kHz AIRR (average in-room response)

Tweeter: SEAS (Kudos Crescendo K2 spec) 29mm fabric dome

Midbass: Kudos 180mm unit with cast chassis, coated paper cone and 26mm voice coil

Title: Re: Tube biasing for the older Stereomour
Post by: Pkay on March 22, 2025, 09:48:53 PM

Any suggestions for tubes would also be appreciated.

Title: Re: Tube biasing for the older Stereomour
Post by: Paul Birkeland on March 23, 2025, 05:31:31 AM

https://www.aliexpress.us/item/3256808416810940.html?spm=a2g0o.productlist.main.13.33587afdZEBydd&algo_pvid=467b3318-7a09-44ec-824a-55396c8a316b&algo_exp_id=467b3318-7a09-44ec-824a-55396c8a316b-6&pdp_ext_f=%7B%22order%22%3A%22-1%22%2C%22eval%22%3A%221%22%7D&pdp_npi=4%40dis%21USD%2195.98%2171.98%21%21%21692.00%21519.00%21%402101ef5e17427438541158525ec6b4%2112000045912706774%21sea%21US%211982106386%21X&curPageLogUid=T7LOj3d4BRJQ&utparam-url=scene%3Asearch%7Cquery_from%3A (https://www.aliexpress.us/item/3256808416810940.html?spm=a2g0o.productlist.main.13.33587afdZEBydd&algo_pvid=467b3318-7a09-44ec-824a-55396c8a316b&algo_exp_id=467b3318-7a09-44ec-824a-55396c8a316b-6&pdp_ext_f=%7B%22order%22%3A%22-1%22%2C%22eval%22%3A%221%22%7D&pdp_npi=4%40dis%21USD%2195.98%2171.98%21%21%21692.00%21519.00%21%402101ef5e17427438541158525ec6b4%2112000045912706774%21sea%21US%211982106386%21X&curPageLogUid=T7LOj3d4BRJQ&utparam-url=scene%3Asearch%7Cquery_from%3A)

The 300B version of that tube performed really well in a shootout I had a few years ago. 

Title: Re: Tube biasing for the older Stereomour
Post by: Pkay on March 25, 2025, 07:02:01 PM

Thanks for your reply Paul.